









































5 J Global Clinical Engineering Vol.6 Issue 1: 2023

Received May 5, 2023, accepted October 3, 2023, date of publication November 28, 2023

An Analysis of Adverse Event Reports in FDA’s MAUDE 
Database

By Spilios Zisimopoulos, Nicolas Pallikarakis

Institute of Biomedical Technology (INBIT), Greece

ABSTRACT

Background and Objectives: Medical devices (MDs) are pivotal in the modern healthcare environment. Adverse events are 
an expected part of an MD’s lifecycle. Various vigilance systems have been established worldwide to prevent such events' re-
currence. The Manufacturer and User facility Device Experience (MAUDE) database of the US Food and Drug Administration 
(FDA) is a publicly accessible database that contains data on medical device reports (MDRs) submitted to FDA since 1991. This 
study aims to examine the evolution of MD adverse event reports and analyze several characteristic parameters as they evolved 
during the last three decades.
Material and Methods: An analysis of MAUDE data was performed to examine the outcomes and device characteristics of ad-
verse event reports from 1991 up to 11/2022. These outcomes included the event type, remedial action, report source, reporter 
occupation and device evaluation by manufacturer. Specific MD groups were analyzed separately to examine their effect on 
the event outcomes. Segregated files of the database that contain different types of information on adverse event reports were 
combined to investigate the various aspects of these reports.
Results: Event outcomes are presented as annual histograms. An overall of about 15 million reports have been submitted to 
MAUDE during the 30 years examined with more than 2.5 million of them during the first 10 months of 2022. This number is 
growing at an increasing rate. Most of the events (63.5%) have resulted in simple device malfunctions without serious implica-
tions to the patient. Depending on the device type, however, the health risks may be higher (98.4% injuries from specific dental 
implants and 3.2% deaths from implantable defibrillators). About 20% of the reports have led to recalls or corrective actions. 
Most of the reports (96%) are submitted by manufacturers, and over 70% of the devices returned to them are evaluated, follow-
ing the requirements of FDA 21 CFR, 803. Finally, the average device age was found to be 5.4 years, with an increasing tendency 
observed over the years, while 43% of the events that occur are associated with devices during their first year of operation.
Conclusion: A medical device adverse event reporting system is a critical component of safety in the use of medical technology 
in modern healthcare. The information available in MAUDE and its use continues to grow at an accelerated rate and allows criti-
cal improvements of MDs, especially in terms of risk prevention, as it gives perception about their safety issues. FDA has taken 
various steps to encourage and facilitate adverse event reporting and make the data available to the public.

Keywords – MAUDE, FDA, Adverse Events Reports, Medical Devices, Vigilance.

Copyright © 2023. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY): Creative Commons - Attribu-
tion 4.0 International - CC BY 4.0. The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) 
are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is 
permitted which does not comply with these terms.

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Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

J Global Clinical Engineering Vol.6 Issue 1: 2023  6

INTRODUCTION

In today's world, medical devices (MDs) have become 
a fundamental component of modern healthcare systems. 
MDs range from simple face masks and syringes to complex 
implantable devices and medical imaging systems and 
are used to diagnose, treat, and manage various medical 
conditions. However, like any other medical procedure, 
MDs are not without risks. Adverse events can occur due 
to various factors like device malfunction or misuse, re-
sulting in serious patient harm. To prevent and mitigate 
these risks, it is essential to have a robust MD vigilance 
system involving Health Competent Authorities1  and MD 
manufacturers that investigate and eventually perform 
necessary remedial actions following adverse events with 
MDs. In most developed countries MD vigilance systems 
have been implemented for more than 30 years, aiming 
to reduce the likelihood of similar adverse events hap-
pening again in another place and time. The cornerstone 
of the MD vigilance systems is adverse event reporting.

A medical device adverse event reporting system is 
a mechanism that enables healthcare facilities, patients, 
and manufacturers to report incidents associated with 
MDs. These systems provide standardized processes for 
reporting such events and allow the collecting and analysis 
of information related to MD safety. Such a system is of 
the utmost importance, as it is critical in ensuring patient 
safety and improving healthcare quality.

One of the primary benefits of an MD adverse event 
reporting system is that it enables healthcare providers 
and manufacturers to identify and address safety con-
cerns related to medical devices. The report of adverse 
events by healthcare facilities helps manufacturers gain 
insight into the performance and safety of their devices. 
The information provided can then be used to identify 
design flaws, manufacturing defects, software problems, 
or other issues that may contribute to adverse events and 
take appropriate action to address these issues, such as 
modifying the device design or implementing new quality 
control processes. On the other hand, when information 
about the risks associated with specific devices is publically 
available, healthcare providers can investigate whether an 

event they faced has also been manifested in a different 
facility, and, in that case, follow the instructions that the 
manufacturer has proposed.

A medical device adverse event reporting system also 
enables better communication between healthcare pro-
viders, regulatory agencies, and competent authorities. 
When adverse events are reported, the authorities can 
use this information to take appropriate action when 
necessary. For example, if a particular device is associated 
with a high rate of adverse events, regulatory agencies 
may require additional testing or labeling changes from 
the manufacturer to improve safety.

Finally, a medical device adverse event reporting sys-
tem can promote transparency and accountability in the 
healthcare industry.(a) By publicly making information 
about adverse events, the system can help hold manufac-
turers, distributors, and healthcare providers accountable 
for their actions. This can help with the trust-building 
process between patients and healthcare providers and 
ensure that the healthcare industry is held to the highest 
safety and quality standards.

The aim of this study is to examine the evolution of 
medical device adverse event reports, available at the 
Manufacturer and User facility Device Experience (MAUDE) 
database of the US Food and Drug Administration (FDA) 
and analyze several characteristic parameters of these 
reports as they evolved during the last three decades.

Adverse events reporting systems 

There are several MDs adverse event reporting systems 
worldwide, aiming to address safety issues that arise from 
the use of medical devices. The reports can be generally 
made by manufacturers, healthcare professionals and 
volunteers. 

FDA's MAUDE database, designed to collect reports 
of adverse events associated with MDs is the most well 
known, it is available to the public and can be accessed 
online, allowing the analysis of the available data.2 MAUDE 
contains the reports submitted through the Medical Device 
Reporting (MDR) system, which are used by manufacturers, 

a  The Competent Authorities for Medical Devices (CAMD) facilitate implementing and enforcing the Regulations on medical devices and on In Vitro Diagnostic medical 
devices in the EU. https://health.ec.europa.eu/medical-devices-dialogue-between-interested-parties/overview_en#competent-authorities-for-medical-devices---camd

https://health.ec.europa.eu/medical-devices-dialogue-between-interested-parties/overview_en#competent-authorities-for-medical-devices---camd


7 J Global Clinical Engineering Vol.6 Issue 1: 2023

Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

importers and users of MDs. The MDR system is a manda-
tory reporting system, and manufacturers must report 
any adverse event that involves their device.3 

The European Databank on Medical Devices (EU-
DAMED) is maintained by the European Union (EU) and 
is designed to provide a living picture of the lifecycle of 
MDs, including modules related to device registration, 
notified bodied and certificates among others. The data-
base has been established in the 2000s according to the 
MDs Directives: 90/385/EEC for the Active Implantable 
Medical Devices (AIMD), 93/42/EEC (MD) for the Medi-
cal Devices and 98/79/EC for the In Vitro Diagnostics. 
The EU vigilance system is based on the MEDDEV 2.12/1 
rev.8 series of guidelines of 2012(b) on Post-Market sur-
veillance and Vigilance System adopted in 2019.(c) The 
EU's new 2017/745 and 2017/746 MDRs, reshaped the 
structure and use of EUDAMED to improve the safety and 
performance requirements of medical devices bearing a 
CE Mark.4 However, access to EUDAMED is restricted only 
to Competent Authorities and partially to Notified Bod-
ies for devices that are involved, and the information on 
MDs related incident reports is not yet available to other 
parties, despite the explicit reference in the regulations. 

Various other adverse event reporting systems are be-
ing used at the national level. Some well known examples 
are the Australian Therapeutic Goods Administration 
(TGA) Adverse Event Reporting System,5 Health Canada's 
Medical Device Adverse Event Reporting (MDAERS),6 UK’s 
Medicines and Healthcare products Regulatory Agency 
(MHRA)7 and Germany’s Federal Institute for Drugs and 
Medical Devices (BfArM).8 These systems are used to 
report or access adverse events associated with MDs and 
are open to healthcare professionals, patients and manu-
facturers, while they can also be accessed online. Many 
other countries have also similar systems in place, and 
many manufacturers have their own reporting systems 
for post-market surveillance purposes. 

Relevant work using MAUDE

A search was performed in the PubMed database 
on papers published from 2000 to date, with the term 

“MAUDE database” included in the title or abstract of 
the paper (MAUDE database [Title/Abstract]). This was 
done to include only papers whose content was focused 
on the analysis of MAUDE’s data, and the search yielded 
303 results. Next, another query was performed, adding 
the terms “MAUDE” and “FDA” in the title or abstract of 
the journal papers (MAUDE database [Title/Abstract] 
OR (MAUDE[Title/Abstract] AND FDA [Title/Abstract])). 
The latter broader search was performed to find articles 
that may have been eluded from the initial query, while 
keeping their content mainly based on data from MAUDE 
and excluding ones with simple references and various 
irrelevant synonyms. The final search yielded 308 results 
up to 2022 (Figure 1), with 31 additional articles been 
published during the first quarter of 2023. Most of these 
studies analyze adverse events for specific medical device 
groups.9 Recent years examples involve MDs like Injectable 
Fillers, Deep Brain Stimulators, middle ear prostheses, 
ossicular prostheses and catheters.10–14 During the last 
years, a couple of studies analyzed MAUDE data taking 
into consideration the full spectrum of medical device 
groups.15–17 However, they were focused on limited aspects 
of the available data, like reporting source and reporter 
occupation, and they were published before the boom of 
reports submitted to MAUDE after 2019 (Figure 2). 

The number of studies mining the information used 
from MAUDE are constantly increasing during the last 
ten years and provide very valuable insights on safety 

b https://ec.europa.eu/docsroom/documents/32305
c ttps://ec.europa.eu/docsroom/documents/32305

FIGURE 1. PubMed articles with relevant MAUDE terms in 
title/abstract. 

https://ec.europa.eu/docsroom/documents/32305
ttps://ec.europa.eu/docsroom/documents/32305


Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

J Global Clinical Engineering Vol.6 Issue 1: 2023  8

issues concerning MDs. This trend was reported in a study 
by P. Malataras and N. Pallikarakis, regarding the use of 
MAUDE’s data in research between the years 2005 and 
2014,9 where a linear increase of papers published each 
year was showcased. To add into that, a sharp increase 
of publications has been observed in the last couple of 
years, highlighting the developing interest in utilizing 
FDA’s MAUDE data as shown in Figure 2.

MATERIALS & METHODS

The MAUDE database was used for the analysis per-
formed in this study. Of all the afore-mentioned adverse 
event report databases, MAUDE is the best structured 
and most complete, with data ranging from 1991 to date. 
Furthermore, it can be easily accessed and has been used 
in other studies in the past. Data processing and analysis 
was performed using the Jupyter Notebook web applica-
tion, along with the Python Data Analysis (pandas) and 
Numerical Python (NumPy) Libraries.

Data acquisition and pre-processing

All data used in this study are publicly available on FDA’s 
MAUDE page.2 Data available in MAUDE span from 1991 up 
to 2022 (user facility reports since 1991, distributor and 
voluntary reports since 1993 and manufacturer reports 

since 1996). For the remainder of this work, data referring 
to the year 1997 will consist of events reported between 
1991 up to 1997, according to MAUDE’s “foidevthru1997” 
file. Data regarding 2022 contains reports that were 
available on MAUDE until 4/11/2022, due to the time 
of research. For the remainder of the work, data up to 
4/11/2022 will be referred to as data for the year 2022. 
Device information associated with an event was taken 
from the available “foidevxxxx” and “devicexxxx” files, were 
xxxx annotates the year. Information about the adverse 
event was found in the files named “mdrfoithru2021”, which 
contains data from inception up to 2021 and “mdrfoi”, 
which contains data of the present year (i.e., 2022). The 
device and mdrfoi files were joined together using the 
“MDR_REPORT_KEY” field as primary key. 

Data pre-processing

A total mdrfoi dataframe was created by merging the 
“mdrfoithru2021” and “mdrfoi” files. After data cleaning 
by deleting rows with wrong field format, wrong delimiter, 
unreadable characters, duplicate key values etc. 15,387,348 
lines of data remained. The same process was carried out 
for all “devicexxxx” files, and a total device dataframe 
was created containing 15,386,069 lines of data. After 
merging these mdrfoi and device dataframes, using the 
MDR report key value as primary key, a final dataframe 
with 15,343,314 lines of data was created, upon which 
the analysis of adverse event reports was carried out.

Event Outcomes

All adverse event reports available on MAUDE were 
analyzed under the scope of various event outcomes. Using 
the various outcome codes presented below as queries, 
the data are organized and presented as histograms of 
number of reports for each year until 2022. Outcomes 
included whether the device was evaluated by the manu-
facturer, event type, remedial action, problem code, and 
device age (year of report minus year of manufacture). 

Event Type

The Event Type (H1 field on the 3500A form) is used 
to describe the impact of adverse events. It is only consid-
ered relevant by the FDA when the reporter of the event 
is a manufacturer and makes use of the following codes: 

FIGURE 2. Annual MAUDE adverse event reports. Data until 
4/11/2022



9 J Global Clinical Engineering Vol.6 Issue 1: 2023

Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

D = Death, {IN, IL, IJ} = Injury, M = Malfunction, O = Other, 
{Blank}= No answer provided. Only one code may be used 
for each event. A malfunction refers to an adverse event 
where the device demonstrated an unexpected behavior, 
without any further implications to the patient or the 
user. One should keep in mind that the submission of an 
MDR itself is not evidence that the device caused or con-
tributed to the adverse outcome or event. Moreover, the 
Event Type field is not available on the form for voluntary 
reporting of adverse events.

Remedial Actions

A Remedial Action (H7 field on the 3500A form) cor-
responds to any actions outside the scope of routine 
maintenance of a device, when necessary to prevent an 
adverse event from recurring that could pose safety issues. 
The following codes and their interpretations are being 
used by the MAUDE database at this point: RC = Recall, RP 
= Repair, RL = Replace, RB = Relabeling, OT = Other, NO 
= Notification, IN = Inspection, PM = Patient Monitoring, 
MA = Modification/Adjustment, {Blank}= Invalid Data/ 
NaN. According to 21 CFR Part 7, recall means a firm's 
removal or correction of a marketed product that the FDA 
considers to be in violation of the laws it administers and 
against which the agency would initiate legal action, e.g., 
seizure.(d) A recall can be initiated by the manufacturer, the 
FDA, or both, and may be required when a device poses a 
significant risk of harm to patients or users. Replacement, 
on the other hand, is the process of providing a new, cor-
rected or modified device to replace a defective or unsafe 
device that has already been distributed to patients or 
healthcare facilities. A replacement may be initiated by the 
manufacturer as a proactive measure to address a safety 
issue or may be required by the FDA as part of a recall. In 
some cases, the manufacturer may offer a replacement 
device to patients as a voluntary corrective action, even 
if the device has not been recalled by the FDA.

Apart from the removal of the unsafe device from the 
market and the notification, healthcare providers and pa-
tients may be requested to return the device for corrective 

action to address the safety issue. Correction means 
repair, modification, adjustment, relabeling, destruction, 
or inspection (including patient monitoring) of a product 
without its physical removal to some other location. As 
a result, an adverse event report may be associated with 
one or more remedial action codes, for example RC, RP.

Report Source

The Reporting Source refers to the official submitter of 
the report to FDA. The available codes are P= Voluntary 
report, U = User Facility report, D = Distributor report 
and M = Manufacturer report. The initial reporter of the 
event can be any person. For example, an affected patient 
may choose to submit the report himself (using the 3500 
form), which will then be classified as voluntary report, 
or send it to the manufacturer who is obligated to submit 
it (using the 3500A form). In the latter case, the code M 
will be used. Track is also kept of the initial reporter.

Initial Reporter Occupation

Regardless of the formal submitter of an event to FDA 
(i.e., a user or a manufacturer), the occupation of the initial 
reporter is recorded separately (E3 field on the 3500A 
form). The classification codes for the initial reporter 
occupation consist of three digits and can be found on 
the MAUDE database site.(e) The available occupations 
range from physician and patient to biomedical engineer 
or attorney.

Device Evaluated by Manufacturer

According to CFR 21, 803, §50, manufacturers are 
responsible for conducting an investigation of each event 
and evaluating the cause of the event. In case the device 
was returned to them and information in a report is not 
complete, they must provide an explanation on why, as 
well as the steps taken to obtain it. To this end, the “Device 
Evaluated By Manufacturer” (H3 field on the 3500A form) 
is being used. The acceptable values are: Y = Yes, N = No, 
R = Device not returned to manufacturer and {BLANK}= 
No answer provided. These values are mutually exclusive.

d  https://www.ecfr.gov/current/title-21/chapter-I/subchapter-A/part-7
e  https://www.fda.gov/medical-devices/mandatory-reporting-requirements-manufacturers-importers-and-device-user-facilities/
about-manufacturer-and-user-facility-device-experience-maude

https://www.ecfr.gov/current/title-21/chapter-I/subchapter-A/part-7
https://www.fda.gov/medical-devices/mandatory-reporting-requirements-manufacturers-importers-and-device-user-facilities/about-manufacturer-and-user-facility-device-experience-maude
https://www.fda.gov/medical-devices/mandatory-reporting-requirements-manufacturers-importers-and-device-user-facilities/about-manufacturer-and-user-facility-device-experience-maude


Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

J Global Clinical Engineering Vol.6 Issue 1: 2023  10

Device Age

The associated device age for the adverse events was 
calculated by subtracting the year of the device manu-
facture date (H4 field on the 3500A form), as filled in by 
the manufacturer of the device, from the year in which 
the report was submitted to the FDA.

Device Groups

Event outcomes such as Event Type and Remedial Ac-
tion were analyzed separately for various device groups. 
This was done to investigate the differences an adverse 
event may have regarding the involved device. The MD 
groups chosen were ones with a notable percentage of 
each year’s total reports and are presented in Table 1.  

RESULTS

Number of Reports

The histogram of the annual number of submitted re-
ports to FDA from 1997 to 2022 is presented in Figure 1. 
About 15 million reports have been submitted to MAUDE 
until the end of 2022 and over 2.5 million of them occurred 

during the last year. A big increase in the number of reports 
can be observed over the last few years.

Event Types

Table 2 presents the distribution of event types for 6 
different examples of prominent MD groups, as well as 
all the average values for all available FDA Device groups 
that exist in MAUDE. From the grand total of the reports 
in Table 2, we can see that most of the events result in 
simple device malfunction, without further implications 
to the patient (63.5%). About 1% of the total reported 
events is associated with patient death.

TABLE 2. Event Type Distribution for Various MD Groups 

Event type

Malfunction Injury Death Other - n/a

Glucose monitors 
['MDS', 'OYC', 'PQF'] 89.1 10.7 0.2 ≈ 0.0

Glucose test ['CFR', 
'LFR', 'NBW'] 90.2 9.0 ≈ 0.0 0.8

Pump, Infusion 98.3 1.4 ≈ 0.1 ≈ 0.2

Implantable 
Cardioverter 
Defibrillator 
(Non-CRT)

36.3 60.0 3.2 ≈ 0.5

Prosthesis, Hip, Semi-
Constrained (Metal 

Uncemented Acetabular 
Component)

2.7 95.0 0.3 ≈ 0.0

Implant, Endosseous, 
Root-Form 1.6 98.4 ≈ 0.0 ≈ 0.0

Average for all Device 
Groups 63.5 34.3 1.2 1.0

The average numbers derived from all the available 
device types can vary significantly across different device 
groups. As observed in the trend (Figure 3), there is a 
steady decline in the ratio of adverse events that result 
in deaths, from 2.5% up until 1997 to 0.3% in 2022 (R2 = 
0.66). Similarly, events with outcome categorized as “Other” 
or without applicable information (n/a) decreased from 
7.5% in 1997 to almost 0% in 2022 (R2 = 0.85), showing 

TABLE 1. Medical Device Groups with Frequently Presented 
Adverse Events 

FDA Group 
Code Group Name

CFR HEXOKINASE, GLUCOSE

LFR GLUCOSE DEHYDROGENASE, GLUCOSE

NBW SYSTEM, TEST, BLOOD GLUCOSE, OVER THE 
COUNTER

MDS SENSOR, GLUCOSE, INVASIVE

OYC PUMP, INFUSION, INSULIN, TO BE USED WITH 
INVASIVE GLUCOSE SENSOR

PQF SENSOR, GLUCOSE, INVASIVE, NON-ADJUNCTIVE

LWS IMPLANTABLE CARDIOVERTER DEFIBRILLATOR 
(NON-CRT)

DZE IMPLANT, ENDOSSEOUS, ROOT-FORM

FRN PUMP, INFUSION

KWA PROSTHESIS, HIP, SEMI-CONSTRAINED (METAL 
UNCEMENTED ACETABULAR COMPONENT)



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Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

the increased completeness of the information provided 
to the FDA over the years. Subsequently, more incidents 
are manifested as device malfunctions, with 73% reported 
as such in 2022, compared to only 40% up to 1997 (R2 = 
38%). Although injury reports dropped from 49.2% in the 
period 1991 - 1997 to 26.6% in 2022, their fluctuations 
seem to be independent of the time (R2 ≈ 0).

According to Table 2, more than 90% of events related 
to glucose test groups have been about device malfunc-
tions, with the rest (about 10%) being associated with 
injuries. In contrast, about 95% of the reported inci-
dents of Metal Uncemented Acetabular Component hip 
prostheses (KWA) resulted in patient injury. Similarly 
with implantable defibrillators, the majority of dental 
implant event types were categorized as injuries (98.4%). 
Implantable defibrillators adverse events have the high-
est probability of death (3.2%) compared to the rest of 
the examined device groups, due to their crucial role in 
physiological heart function. Finally, most of the reports 
regarding infusion pumps (over 98%) were about simple 
device malfunctions. 

Figure 4 shows that most reports have no remedial 
action connected with them (80%). Nevertheless, for 
the remaining 20%, where information is available, the 
most common action happens to be a recall, which is 
associated with three-quarters of adverse events (Table 
3). Repair of the affected devices was a common action 
during 2011, 2013 and 2014 and may depend on the types 
of affected devices. Actions categorized as “Other” were 
more common until the mid ‘10s, while being the most 
common remedial action during the older years. Recently, 
the “Other” category stopped being used so frequently 
(7% of total reports). 

Remedial Actions

Different MD groups are associated with different 
remedial actions (Table 3). For example, reports involv-
ing continuous glucose monitoring devices and infusion 
pumps resulted in a recall action by the manufacturer or 
FDA 9 out of 10 times. On the other hand, dental implants 
resulted in almost no recalls, and the main action taken 
by the manufacturers was either an inspection (69.7%) 
or replacement of the implant (26.0%). Finally, about 1 
out of 10 reports about glucose test device groups led 
to a recall, as devices like test strips are not so crucial to 
patient safety compared to previously referred devices. 
Replacement (38.0%), Notification (28.6%) and Other 
(23.3%) were the most frequent remedial actions for 
dealing with issues such as incorrect measurements.

FIGURE 3. Adverse Event Types. Number of reports(top) and 
percentage evolution(bottom).



Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

J Global Clinical Engineering Vol.6 Issue 1: 2023  12

Report Source

The majority of the total reports (96%) were filed 
by the device manufacturers, as shown in Figure 5. This 
concerns the stricter requirements about adverse event 
reporting imposed on manufacturers. In the last 4 years 
there has been an increase in distributor reports. During 
these years, dental implants and implantable defibrillators 
were the main types of devices reported.

Initial Reporter Occupation

Figure 6 presents the occupation of the initial adverse 
event reporter. The initial reporter may be different than 
the one that submits the final report to FDA, like in the 
case when a user of a medical device notifies an event to 
its manufacturer, who is then obligated to file an official 
report to the FDA. Physicians and other health care profes-
sionals have a constant rate of reporting adverse events. 
In the years 2012 and 2013, a considerable number of 
events were reported by attorneys. This was the period 
of lawsuits filed against metal-on-metal hip prosthetics 
manufacturers.18,19 

Between 2013 and 2018 about 15% of reports (peaking 
at 21% in 2016) were made by the patients themselves. 
During this period, insulin pumps and glucose sensor 
events were predominant, so it makes sense that home 
users initially made a lot of the reports. An increase in 
the percentage of reports initially submitted by dentists 
can be observed after 2019. Deeper analysis showed FIGURE 4. Adverse event remedial actions.

TABLE 3. Adverse Event Remedial Action Distribution for Various MD Groupss 

Remedial Action (%)

Recall Repair Replace Relabeling Other Notification Inspection
Patient 

Monitoring
Modification/ 
Adjustment

Glucose monitoring 
['MDS', 'OYC', 'PQF'] 93.58 0.01 4.27 0.01 0.12 1.99 0.01 0.01 ≈ 0.0

Glucose test ['CFR', 
'LFR', 'NBW'] 9.55 0.10 38.03 0.02 23.27 28.60 0.02 ≈ 0.0 0.40

Pump, Infusion 89.86 9.53 0.05 ≈ 0.0 0.42 0.10 0.02 ≈ 0.0 0.03

Implant, Endosseous, 
Root-Form 0.36 0.03 26.04 0.02 3.76 0.06 69.66 0.06 0.01

Average for all Device 
Groups 74.0 7.0 5.5 ≈0.1 7.0 3.6 2.1 0.2 0.5



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Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

that many of the events were caused by dental implants 
(peaking at 24% of the total reports in 2021) during the 
last 4 years. Finally, more events have been reported in 
the previous five years, especially in 2022 (35%), by other 
non-healthcare professionals than in the past.

Device Evaluated by Manufacturer

Figure 7 shows the status of reports as far as the de-
vice evaluation by the manufacturer is concerned. More 
than half of the devices reported (52.3%) are sent to the 
manufacturer, and most of them are evaluated (70.8% of 
sent devices). 2022 was an exception, with 55% of the 

devices sent to the manufacturer not being evaluated.

Device Age

The mean age of the devices involved in all adverse 
events of the MAUDE database is 5.4 years. However, 
this result is strongly influenced by the impact of the last 
couple of years’ reports, as shown in Figure 8. Up until 
2019, the average device age was 2.8 years. The seeming 
rise in the device's age might be related to the reported 
devices' types. Most of the events (43%) are associated 
with devices during their first year of operation.

FIGURE 5. Adverse events report source.

FIGURE 6. Adverse event initial reporter occupation.

FIGURE 7. Device evaluation by manufacturers.



Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

J Global Clinical Engineering Vol.6 Issue 1: 2023  14

DISCUSSION

There has been an obvious increase in the number of 
reports over the last years (see Figure 1), which can be 
attributed to several factors. One reason is the increased 
awareness and reporting of adverse events by healthcare 
professionals and patients due to improved access to 

information and reporting systems. Another reason is 
the growing number and complexity of MDs, which in-
creases the likelihood of adverse events. In addition, the 
FDA has expanded the types of adverse events that must 
be reported by manufacturers and healthcare facilities, 
which has led to an increase in the number of reports 
submitted to MAUDE. Other changes included updated 
reporting requirements for specific devices and improved 
clarity on using the FDA Forms 3500/ 3500A for reporting. 
These requirements are outlined in the Code of Federal 
Regulations (CFR) Title 21, Part 803,(f) which establishes 
the mandatory medical device reporting criteria. This Rule 
was published in 2014 and implemented in 2015. Under 
its requirements, manufacturers and importers of MDs 
are required to report to the FDA any serious injuries or 
deaths associated with their devices within 30 calendar 
days of becoming aware of the incident. Additionally, 
manufacturers must report any malfunctions that could 
result in a serious injury or death within 5 workdays of 
becoming aware of the issue. Moreover, healthcare facilities, 
such as hospitals, nursing homes, and outpatient clinics, 
must report certain adverse events related to MDs to the 
FDA within 10 days. These events include incidents that 
result in serious injury or death or require intervention 
to prevent serious injury or death. Finally, in 2014, the 
FDA published a final rule on Electronic Medical Device 
Reporting (eMDR), effective from 2015, that requires 
manufacturers and importers to submit MDRs to the FDA 
in an electronic format that the FDA can process, review, 
and archive(20). Last but not least, in the previous two 
decades, there has been observed an increasing number 
of MDs that have received a 510(k) clearance compared 
to a premarket approval (PMA). Safety issues are raised as 
the clearance provision pathway does not require clinical 
trials and is less rigorous than the PMA process (21,22).

Considering the number of total reports in MAUDE 
and the death event type percentage of these reports 
presented in Table 2, it means that more than 180,000 
adverse events are historically related to patient death. 
However, this number can be used only as an approxima-
tion due to the limitations of the database (i.e., multiple 
reports on the same incident, underreporting, incomplete 

FIGURE 8. Device age distribution. Annual mean age of reported 
devices (top) and Total device age histogram (bottom).

f  https://www.ecfr.gov/current/title-21/chapter-I/subchapter-H/part-803. Medical Device Reporting: Electronic Submission Requirements. A Rule by the Health 
and Human Services Department, and the Food and Drug Administration. Published 2014. Effective after 2015.

https://www.ecfr.gov/current/title-21/chapter-I/subchapter-H/part-803


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Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

information, etc.). Although the decrease in deaths and 
increase in malfunctions reported in Figure 3, although 
possible, does not explicitly indicate an increase in device 
safety, as it could also mean the intensified reporting of 
less severe adverse events compared to the past years.

Some intuition can be gained about the event types 
for each examined device group. Glucose testing devices, 
such as test strips, are associated mainly with a less 
serious malfunction (see Table 2). An example of such a 
malfunction could be wrong glucose test results. Although 
not crucial as an adverse event itself, such a malfunction 
could pose more serious consequences for the patient in 
the long term. This may be why these devices have a very 
high rate of recalls (Table 3). In contrast to glucose testing 
devices, most of the reported incidents of hip prostheses 
(KWA) resulted in serious patient injury, with a probability 
of patients having to undergo revision surgery. Patient 
injury was almost universal (98.4%) for dental implant 
adverse events. A factor that may be of importance is the 
absence of implant dentistry from the recognized dental 
specialties of the American Dental Association.(g) Al-
though the FDA monitors and regulates MDs, it does not 
act toward healthcare practice regulations. The fact that 
implantable defibrillators adverse events showcase the 
highest probability of death (3.2%) compared to the rest 
of the examined device groups is expected, due to their 
crucial role in physiological heart function. Finally, the 
fact that almost all the reports regarding infusion pumps 
were about simple device malfunctions, without further 
serious implications to the patients, may indicate an in-
creased awareness regarding adverse event reporting of 
crucial devices. However, it should be noted that infusion 
pumps malfunctions have a high potential for patient 
injury and must be treated as near-miss adverse events. 
These events are incidents that can potentially cause 
harm to a patient but are caught or mitigated before any 
actual harm occurs. Examples of reported infusion pump 
problems that could lead to such incidents include lack of 
warning when inappropriate data is entered or failure to 
generate audible alarms for critical problems such as an 
occlusion in the tubing.23 and adverse events are often 
avoided due to luck or vigilant healthcare professionals.

Remedial action codes were found to be often omitted 
from the adverse event reports. It is unclear whether this 
is because the event resulted in no action to be taken by 
the manufacturer or the information was not correctly 
updated in the database. As a silver lining, the rate of exist-
ing remedial actions has risen in the last year. Moreover, 
the “Other” category is used less frequently, which may 
indicate that the report form became more user friendly 
and awareness toward adverse event reporting has risen. 

The fact that the device manufacturers have filed 96% 
of the reports, while the trend is continuously rising (Fig-
ure 5), is related to the stricter requirements imposed on 
manufacturers by CFR 21, 803. This is also the reason behind 
the high device evaluation percentage by the manufactur-
ers (Figure 7). Adding to this, many users from facilities 
or homecare prefer to file a report to the manufacturer, 
who then submits it to FDA. This is the reason why the 
initial reporter occupation is analyzed separately. Data 
for 1997 consists of all data available from 1991 to that 
year. According to MAUDE, user facility reports have been 
submitted since 1991, distributor and voluntary reports 
since 1993 and manufacturer reports since 1996. For this 
reason, the report rates by manufacturers are quite low 
until 1996, compared to the next years.

According to CFR 21, 803, §50, manufacturers are re-
sponsible for conducting an investigation on each event 
and evaluating the cause of the event. If the device was 
returned to them and information in a report is incomplete, 
they must explain why and the steps taken to obtain it. This 
is why most devices returned to the manufacturer by the 
user facility or the distributors are evaluated (70.8% on 
average). The last year was an exception, and the reason 
could be further investigated.

Regarding the MAUDE database, several issues were 
discovered. First, there are some instances of unintuitive 
or straight up incorrect information on the use or descrip-
tion of the files. As an example, the “deviceproblemcodes” 
file should contain the MDR report keys with the corre-
sponding device problem code, while the “foidevproblem” 
file should contain a list of device problem codes with 
their matching code description, according to the site’s 

g  https://ncrdscb.ada.org/recognized-dental-specialties

https://ncrdscb.ada.org/recognized-dental-specialties


Zisimopoulos, Pallikarakis: An Analysis of Adverse Event Reports in FDA’s MAUDE Database

J Global Clinical Engineering Vol.6 Issue 1: 2023  16

description. However, the data contained in these files are 
interchanged. Additionally, “mdrfoi” file’s description was 
not updated for the current year, at the time of this work. 
Though it contained data from 2023, it read “MAUDE Base 
records received for 2022”. The mdrfoithruxxxx file also 
contains a vast amount of information of 5 GB, making it 
difficult for casual users to access it. Splitting it as is the 
case with device files would facilitate further database 
usage.

Other shortcomings of MAUDE derive from adverse 
event reporting system issues. A common problem for all 
vigilance systems worldwide is underreporting adverse 
events. Though events seem to be reported more frequently 
during the last years, it is still plausible that more adverse 
events occur than those finally reported to the FDA. The 
rate of medical device adverse events underreporting is 
difficult to determine, as the number of incidents is un-
known accurately. Non-reporting can be attributed to many 
factors, such as fear of blame, lack of time, complexity of 
the reporting system, or even perceived ineffectiveness. 
Adding to this, in cases of human error, underreporting 
is expected to be even more prevalent.24,25 

Other issues may be the symptoms of underutilizing the 
MDR system’s potential. For example, although more than 
one remedial action code can be assigned to an adverse 
event, in practice reports in MAUDE, use a single code. As 
a result, when an event is marked with a corrective action 
(i.e. replacement of the device), the recall code is omitted 
and vice versa. Therefore, it becomes unclear whether 
the corrective action was part of a recall, or a voluntary 
preventive manufacturer action.

Finally, it is important to note that an increase in ad-
verse event reports does not necessarily mean that the 
number of adverse events has increased, but rather that 
reporting systems have become more effective in captur-
ing and documenting these events.

CONCLUSIONS

It is obvious that the FDA encourages reporting adverse 
events and MAUDE plays an essential role in identifying 
potential safety issues and facilitating corrective actions that 
protect public health. It also provides an essential source 
of data for review studies in this area, as demonstrated by 

the increasing number of related publications mentioned 
in the introduction. 

In Europe, despite the explicit reference in the MD 
regulations on the availability of the vigilance data in the 
EUDAMED, this part of the database is still not accessible. 
This fact restricts the utilization of this critical data for 
advancing safety in medical technology in Europe and 
worldwide. 

In conclusion, using an adverse event reporting system 
efficiently facilitates communication between regulatory 
agencies and healthcare providers and promotes trans-
parency and accountability in the healthcare industry. 
Ensuring that MDs are safe and effective will improve 
patient outcomes, with clear benefits for the healthcare 
sector that remains a cornerstone of our society.

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