Archives of Academic Emergency Medicine. 2021; 9(1): e37 https://doi.org/10.22037/aaem.v9i1.1187 OR I G I N A L RE S E A RC H Comparing the Accuracy of Ohmann and Alvarado Scor- ing Systems in Detection of Acute Appendicitis; a Cross- Sectional Study Seyed Jalal Eshagh Hoseini1, Mostafa Vahedian2, Alireza Sharifi3∗ 1. Department of Surgery, School of Medicine, Shahid Beheshti Hospital, Qom University of Medical Sciences, Qom, Iran. 2. Research Center for Environmental Pollutants, Qom University of Medical Sciences, Qom, Iran. 3. Student research committee, Qom University of Medical Sciences, Qom, Iran. Received: February 2021; Accepted: April 2021; Published online: 5 May 2021 Abstract: Introduction: Alvarado Scoring System (ASS) and Ohmann Scoring System (OSS) are two scoring systems for di- agnosing acute appendicitis (AA). This study was designed to compare the diagnostic accuracy of the two men- tioned scores in detection of acute abdominal cases at risk for AA. Methods: In this prospective cross-sectional study, patients admitted to the emergency departments of two academic hospitals in Qom, Iran, with right lower quadrant (RLQ) abdominal pain suspected to AA were evaluated. All cases were scored using ASS and OSS, and screening performance characteristics of the two scores were calculated and reported considering the patho- logic findings as a gold standard. Results: 174 patients with a preliminary AA diagnosis and the mean age of 38.1 ± 10.63 years (11- 73) were included in this study (62.07% male). At the optimal cutoff point of ≥7 for the ASS, the sensitivity and the specificity were 46.43% (95% CI: 37.97%-55.07%), 97.05% (95% CI: 84.67%-92.93%), respectively. At the optimal cutoff point of ≥11 for the OSS, the sensitivity and the specificity were 74.29% (95% CI: 66.22%-81.29%), and 55.88% (95% CI: 37.89% - 72.82%), respectively. Conclusion: Based on the finding of this study, the ASS ≥ 7 was more accurate than the OSS ≥ 11 for detection of AA. But it should be considered that the overall accuracy of Alvarado and Ohmann scores in this regard were fair (0.83) and poor (0.67), respectively. Keywords: Appendicitis; Decision Support Systems, Clinical; Data Accuracy; Comparative Study Cite this article as: Eshagh Hoseini S J, Vahedian M, Sharifi A. Comparing the Accuracy of Ohmann and Alvarado Scoring Systems in Detec- tion of Acute Appendicitis; a Cross-Sectional Study. Arch Acad Emerg Med. 2021; 9(1): e37. 1. Introduction The most common cause of acute abdominal pain is Acute Appendicitis (AA) with a lifetime risk of 7–8% (1, 2). It has dangerous complications such as perforation and peritoni- tis, which can be associated with morbidity and mortality (1). The incidence of AA is stable in most Western countries, but recent studies show that AA is rapidly rising in newly indus- trialized countries (3). Ghasemian M. et al. study, performed in 2019, reported that the annual incidence of AA in Birjand (Iran) was 12.74 per 10000 population (4). AA most often hap- pens in individuals with the age of 10-30 years and it occurs in males and females with a ratio of approximately 1.4:1(5). ∗Corresponding Author: Alireza Sharifi; Student Research Committee, Qom University of Medical Sciences, Qom, Iran. Email: habiball.al.sh@gmail.com, Phone: +989106180377, ORCID: https://orcid.org/0000-0002-6905-4539. Although AA has a high incidence, its diagnosis can often be a challenge for physicians as the classic presentations of AA, such as periumbilical pain followed by vomiting, nausea and Rovsing’s sign, happen in only 50-60% of cases (6). There is no single symptom, sign, or diagnostic tool to ac- curately confirm the diagnosis (7); therefore, the diagnosis of AA is based on a combination of history, physical exam- ination, and laboratory findings, supplemented by selective focus imaging (8). Imaging modalities such as radiography, ultrasound, CT scan, and MRI are used to diagnose AA (9, 10) but there is major controversy over their diagnostic role (8). In an attempt to improve the accuracy of AA diagno- sis, several scoring systems such as Alvarado Scoring System (ASS) and Ohmann Scoring System (OSS) have been devel- oped to systematically combine laboratory values, physical exam findings, symptoms and patient characteristics (6). ASS was first introduced in 1986. It is the most reported scor- ing system for evaluating the AA (6). Another common scor- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem S J. Eshagh Hoseini and et al. 2 ing system is OSS that includes seven clinical parameters and a White Blood Cell (WBC) count (11). Different studies report different diagnostic accuracies for these scoring systems, for example, Yilmaz et al. study in 2017 (12) reported that ASS and OSS can be useful for predicting AA, but Arzu Sencan et al. study in 2014 (13) stated that their specificity and sen- sitivity were not sufficient for diagnosing AA. Although ASS and OSS are inexpensive, easy to use and reproducible with high success rates, they still have not become the main part of routine practice (14). So, this study was designed to com- pare the diagnostic accuracy of Alvarado and Ohmann scores in detection of acute abdominal cases in favor of AA. 2. Methods 2.1. Study design and setting In this prospective cross-sectional study, patients who were admitted to the emergency department of Nekuee and Shahid Beheshti Hospitals, Qom, Iran, with right lower quad- rant (RLQ) abdominal pain suspected to AA, during one year, were evaluated. This study was approved by the ethics com- mittee of Qom University of Medical Sciences (Ethics code: D/24/350). All subjects consented to participate in the study, and the data were recorded by emergency department (ED) physicians. 2.2. Participants All patients above 11 years old with RLQ abdominal pain sus- pected to AA and candidate for appendectomy, who were referred to ED during the study period, were included us- ing non-probability sampling method. The exclusion criteria were as follows: (a) being under 11 years of age, (b) elective appendectomy, (c) pregnancy, (d) phlegmon formation, (e) existence of abdominopelvic malignancy. 2.3. Data gathering The following data were recorded for all subjects: Complaints at the time of admission, physical examination, and labora- tory findings. The obtained data were used to calculate Al- varado and Ohmann scores by a surgeon before appendec- tomy. The parameters of ASS and OSS are demonstrated in appendix 1. All patients underwent appendectomy and were categorized into two groups according to histopathologic di- agnosis: positive appendectomy (PA) and negative appen- dectomy (NA). ASS evaluates 8 parameters, which include symptoms, clini- cal findings, and leukocyte count. The highest possible score is 10, and our optimal cutoff point for appendectomy was ≥ 7. OSS is also composed of 8 parameters (Tenderness in right lower quadrant, rebound tenderness, presence of urinary system complaint, character of pain, re-localization of pain to the right lower quadrant, age, leukocyte count, and ab- dominal rigidity). The highest possible score is 16, and we recommended appendectomy for scores ≥ 11. 2.4. Statistical analysis The data were analyzed using SPSS version 22.0. Descriptive statistics for categorical data were expressed as numbers and percentages and median (minimum-maximum) were used to express continuous data based on normal distribution. Student’s t-test was used for variables with normal distribu- tion. The screening performance characteristics of the scor- ing systems were measured. A greater area under the re- ceiver operating characteristic (ROC) curve (AUC) indicates better diagnostic value. p<0.05 was considered statistically significant. Sensitivity, specificity, positive predictive value (PPV ), negative predictive value (NPV ), positive likelihood ration (PLR) and negative likelihood ration (NLR), and accu- racy with 95% confidence interval were calculated and com- pare between two scoring systems. In the present study, area under the curve of 90 to 100 was considered as excellent ac- curacy, 80 to 90 as good, 70 to 80 as fair, 60 to 70 as poor, and 50 to 60 as fail. 3. Results 3.1. Baseline characteristics of studied cases Appendectomy was performed for 181 patients with sus- picion to AA but after histopathology consideration, 7 pa- tients were excluded because they had tumoral appendici- tis. Therefore, 174 patients with a preliminary AA diagno- sis and the mean age of 38.1 ± 10.63 years (11- 73) were in- cluded in this study (62.07% male). Table 1 shows the base- line characteristics of studied cases. The diagnosis of AA was histopathologically confirmed in 136 cases (78.16%) and 38 (21.84%) patients had negative appendectomy. 3.2. Comparing the scores The median ASS and OSS scores were 7 (2 - 10) and 14 (3 - 16), respectively. Screening performance characteristics of the studied systems in determining the cases with AA are pre- sented in table 2 and figure 1. Sensitivity and specificity of OSS in the cut-off value of ≥11 were 74.29% (95% CI: 66.22 - 81.29), and 55.88% (95% CI: 37.89 - 72.82), respectively. For ASS, these measures were 46.43% (95% CI: 37.97 - 55.07) and 97.05% (95% CI: 84.67 - 92.93), respectively. Area under the ROC curves of ASS and OSS in detection of AA cases were 0.83 (95% CI: 0.77- 0.88) and 0.67 (95% CI: 0.598 to 0.742), respec- tively (p = 0.001). This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 3 Archives of Academic Emergency Medicine. 2021; 9(1): e37 4. Discussion In our study, OSS’s (cut off point ≥11) sensitivity, specificity, and PPV and NPV were 74.29%, 55.88%, 87.4%, and 34.5%, re- spectively. Also, ASS’s (cut off point ≥7) sensitivity, specificity, and PPV and NPV were 46.43%, 97.6%, 98.5%, and 30.6%, re- spectively. Based on the results of the current study, OSS has higher sensitivity and NPV than Alvarado scoring system in diagnosis of AA, but Alvarado score has higher specificity and PPV than Ohmann score. AA is the most common reason for abdominal pain in cases seen in surgery clinics and emergency services but its defini- tive diagnosis can be difficult. Delayed diagnosis and inter- vention in patients with AA can lead to high-risk complica- tions such as perforation, sepsis, and morbidity and mor- tality (12). Appendectomy is performed in 12 to 23% of all people during their lifetime (15). On the other hand, the rate of unnecessary negative appendectomy based on the intraoperative and histopathological results is high (about 12% -40%). However, there are now many diagnostic scor- ing systems such as ASS and OSS, as well as advanced imag- ing methods to decrease the rate of negative appendectomies (12). In Chong CF et al. study, ASS has been reported to be less spe- cific in Asian populations compared to American/European populations (7). The present study was designed to compare the ability of ASS and OSS in predicting AA. ASS is thought to have high sensitivity and specificity (12). Many studies have been done affirming validity for predict- ing AA. For example, In Schneider et al. study (16), Alvarado score ≥7 had sensitivity and specificity of 72% and 82%, re- spectively. In another study conducted by Hamid Kariman et al. (17), Alvarado score greater than 7 yielded 37% sensitivity and 95.65% specificity. The sensitivity and specificity of ASS in our study were higher than those reported in Kariman and Schneider studies. OSS is an easy and useful system employed in diagnosis of AA (18). Hassan Erdem et al. study (19) reported sensitivity, specificity, PPV and NPV of OSS (cutoff point = 12) as 96%, 42%, 78% and 83%, respectively. In another study by Sanjay N Koppad et al. (11) the sensitivity, specificity, PPV, and NPV of OSS (cutoff point = 12) were 96%, 66.7%, 82.8, and 90.9%, respectively. The reported PPV in our study was higher than these studies. Some studies have compared ASS and OSS in diagnosis of AA. In Korkut et al. study in 2020 (14), 74 Patients were cat- egorized into two groups according to their histopatholog- ical results: positive and negative appendectomy. The ac- curacy of different scoring systems in diagnosis of the AA was investigated. Sensitivity, specificity, PPV and NPV were 71.9%, 89.9%, 97.92%, 30.77%, respectively, for OSS; versus 60.9%, 89.9%, 97.56% and 24.24%, respectively, for ASS. Their study reported a higher accuracy rate for OSS. In another study done by Yilmaz et al.(12), a total of 105 patients diag- nosed with AA were enrolled, then OSS and ASS scores were calculated, separately. They concluded that ASS can predict AA better than OSS, while OSS was more useful for provid- ing guidance in diagnosing AA when conditions are more ob- scured and uncertain. In a review study conducted by Daniel LH et al. in 2017, the classical picture of shifting pain associated with nau- sea, vomiting, and anorexia happens in less than half of pre- sentations (20), while in our study, shifting pain, vomiting, and loss of appetite percentile is reported in 73.61% (n=106), 59.19% (n=103) and 70.68% (n=123) of cases, respectively. Abdominal pain has been introduced as the most common manifestation (21), which is in line within our study result (89.65% (n=156)). Based on our study results, the most com- mon symptoms and signs were RLQ pain (n=156), RLQ ten- derness (n=151), and loss of appetite (n=123), respectively. There is not any specific bloods test for AA. However, if there is an increased WBC, C reactive protein (CRP), proportion of polymorphonuclear (PMN) cells, or granulocyte count, then AA is more likely (21); while leukocytosis is reported in 71.26%(n=124) of the cases in our study. Considering the fair and poor accuracy of studied scoring systems, it seems that ASS and OSS need further modifica- tions to be more accurate than what they are now to be ap- plicable in routine practice. 5. Limitations The small sample size and intrinsic shortcomings of cross- sectional studies were among the most important limitations of the present study. 6. Conclusion Based on the finding of this study, ASS ≥ 7 was more accurate than the OSS ≥ 11 for detection of AA. But it should be con- sidered that the overall accuracy of Alvarado and Ohmann scores in detection of AA were fair and poor, respectively. 7. Declarations 7.1. Author contribution Study concept and design and analysis and interpretation of data: S.J.E.H.; drafting of the manuscript: A.SH.; statistical analysis and interpretation of data M.V.; critical revision of the manuscript for important intellectual content: A.SH. 7.2. Ethical approval Ethics committee approval was received for this study from Qom University of Medical Sciences. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem S J. Eshagh Hoseini and et al. 4 7.3. Funding/Support We did not receive any funding and support for this study. 7.4. Conflict of interest There is no conflict of interest for authors. References 1. Addiss DG, Shaffer N, Fowler BS, Tauxe RV. The epidemiology of appendicitis and appendectomy in the United States. American journal of epidemiology. 1990;132(5):910-25. 2. Sartelli M, Baiocchi GL, Di Saverio S, Ferrara F, Labric- ciosa FM, Ansaloni L, et al. Prospective observational study on acute appendicitis worldwide (POSAW ). World Journal of Emergency Surgery. 2018;13(1):1-10. 3. Ferris M, Quan S, Kaplan BS, Molodecky N, Ball CG, Cher- noff GW, et al. 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Acute appendicitis-new di- agnostic algorithm using RIPASA score and non-contrast Computeed Tomography Scan. JPMA J Pak Med Assoc. 2019;69(1ŝ1). 16. Schneider C, Kharbanda A, Bachur R. Evaluating appen- dicitis scoring systems using a prospective pediatric co- hort. Annals of emergency medicine. 2007;49(6):778-84. e1. 17. Kariman H, Shojaee M, Sabzghabaei A, Khatamian R, Derakhshanfar H, Hatamabadi H. Evaluation of the Al- varado score in acute abdominal pain. Ulus Travma Acil Cerrahi Derg. 2014;20(2):86-90. 18. Kiyak G, Korukluoğlu B, Ozgün Y, Devay AO, Kuşdemir A. Evaluation of Ohmann and Eskelinen scores, leuko- cyte count and ultrasonography findings for diagnosis of appendicitis. Ulusal travma ve acil cerrahi dergisi= Turkish journal of trauma & emergency surgery: TJTES. 2009;15(1):77-81. 19. Erdem H, Çetinkünar S, Daş K, Reyhan E, Değer C, Aziret M, et al. Alvarado, Eskelinen, Ohhmann and Raja Isteri Pengiran Anak Saleha appendicitis scores for diagnosis of acute appendicitis. World Journal of Gastroenterology: WJG. 2013;19(47):9057. 20. Baird DL, Simillis C, Kontovounisios C, Rasheed S, Tekkis PP. Acute appendicitis. Bmj. 2017;357. 21. Humes D, Simpson J. Acute appendicitis. Bmj. 2006;333(7567):530-4. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 5 Archives of Academic Emergency Medicine. 2021; 9(1): e37 Figure 1: The area under the receiver operating characteristic (ROC) curves of Alvarado and Ohmann scoring systems (p = 0.001). Appendix 1: Parameters of Alvarado and Ohmann scoring systems Alvarado parameters Score Ohmann parameters Score Migration RLQ pain 1 Tenderness in RLQ 4.5 Anorexia 1 Rebound tenderness 2.5 Nausea and vomiting 1 Absence of urinary complications 2 RLQ tenderness 2 Steady pain 2 Rebound tenderness 1 White blood cell count >10000/cm3 1.5 Fever (>37.3) 1 Age <50 years 1.5 Leukocytosis 2 Migration RLQ pain 1 Shift to the left of neutrophils 1 Rigidity 1 Total 10 Total 16 RLQ: right lower quadrant. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem S J. Eshagh Hoseini and et al. 6 Table 1: Baseline characteristics of studied patients Variables Values (n= 174) Age (years) Mean ± SD 38.1 ± 10.63 Gender Male 108 (62.07) Female 66 (37.93) Appendectomy findings Positive 136 (78.16) Negative 38 (21.84) Scoring systems parameters RLQ tenderness 156 (89.66) Migrating RLQ pain 10 (60.92) Anorexia 12 (70.69) Nausea and vomiting 103 (59.2) Shift to the left of neutrophils 85 (48.85) Rebound tenderness 11 (64.37) Rigidity 54 (31.03) Fever (>37.3) 62 (35.63) Leukocytosis 124 (71.26) Negative urine complications 142 (81.61) Steady pain 120 (68.97) Age< 50 year 151 (86.78) Data are presented as mean ± standard deviation (SD) or frequency (%). RLQ: right lower quadrant. Table 2: Screening performance characteristics of Alvarado and Ohmann scoring systems in prediction of acute appendicitis in emergency department Character Alvarado (≥ 7) Ohmann (≥ 11) True positive 65 104 False positive 1 15 True negative 33 19 False negative 75 36 Sensitivity 46.43 (37.97 - 55.07) 74.29 (66.22 - 81.29) Specificity 97.05 (84.67 - 92.93) 55.88 (37.89 - 72.82) Positive predictive value 98.5 (90.34 - 99.78) 87.4 (82.43 - 91.11) Negative predictive value 30.6 (27.17 - 34.16) 34.5 (25.93-44.31) Positive likelihood ratio 15.77 (2.27-109.76) 1.68 (1.14 - 2.50) Negetive likelihood ratio 0.55 (0.47 - 0.65) 0.46 (0.31 - 0.69) This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem Introduction Methods Results Discussion Limitations Conclusion Declarations References