1 SUBMITTED 4 JAN 22 1 REVISION REQ. 16 FEB 22; REVISIONS RECD. 17 MAR 22 2 ACCEPTED 29 MAR 22 3 ONLINE-FIRST: APRIL 2022 4 DOI: https://doi.org/10.18295/squmj.4.2022.032 5 6 Epidemiology of Common Ocular Manifestations among Patients on 7 Haemodialysis in West Bank, Palestine 8 A cross-sectional study 9 Yousef Shanti1, Hamza Hamayel2, Anas Yasin1, Abdul-Raheem Abu Shanab1, 10 Osama Hroub2, Zakaria Hamdan3, *Mujahed Shraim4 11 12 Departments of 1Opthalmology and 3Nephrology, An-Najah National University Hospital, Nablus, Palestine; 2College of Medicine and Health Sciences, Department of Medicine, An- Najah National University, Nablus, Palestine; 4Department of Public Health, College of Health Sciences, Qatar University, QU Health, Doha, Qatar. *Correspondence Author’s e-mail: mshraim@qu.edu.qa 13 14 Abstract 15 Objectives: To assess the prevalence of ocular manifestations and associated factors in patients 16 on haemodialysis. Methods: A cross-sectional study of 191 patients on haemodialysis from a 17 haemodialysis unit in Nablus, Palestine. Medical examination for ocular manifestations 18 (intraocular pressure, cataract, retinal changes, and optic neuropathy) was performed using Tono-19 Pen, portable slit-lamp, and indirect ophthalmoscope. Predictor variables were age, gender, 20 smoking, medical comorbidities (diabetes, hypertension, ischemic heart disease (IHD), and 21 peripheral arterial disease (PAD)), and use of antiplatelet or anti-coagulation medications. 22 Results: The prevalence of any ocular manifestation in at least one eye was 68%. The most 23 common ocular manifestations were retinal changes (58%) and cataract (41%). The prevalence 24 of non-proliferative diabetic retinopathy (NPDR), preoperative diabetic retinopathy (PDR), and 25 either NPDR or PDR was 51%,16%, and 65%, respectively. Increase in age by one year was 26 mailto:mshraim@qu.edu.qa 2 associated with increase in the odds of having cataract by 1.10 (95% confidence interval (CI), 27 1.06, 1.14). Patients with diabetes had higher odds of having cataract (odds ratio (OR) 7.43; 95% 28 CI, 3.26, 16.95) and any retinal changes (OR 109.48, 95% CI, 33.85, 354.05) than patients 29 without diabetes. Patients with diabetes and IHD or PAD had higher odds of having NPDR than 30 patients with diabetes and free from IHD or PAD (OR 7.62; 95% CI, 2.07, 28.03). Conclusion: 31 Retinal changes and cataract are very common ocular manifestations among patients on 32 haemodialysis. The findings emphasize the importance of periodic screening for ocular problems 33 this vulnerable population, especially older patients and those with diabetes, to prevent visual 34 impartment and associated disability. 35 Keywords: Kidney Failure, Chronic; Renal Dialysis; Eye Diseases; Eye Manifestations; Cross-36 Sectional Studies. 37 38 Advances in knowledge 39  The prevalence and factors associated with ocular manifestations among patients on 40 haemodialysis in West Bank, Palestine, is unknown. 41  The present study showed that 68% of patients on haemodialysis in West Bank have at least one 42 ocular manifestation in at least one eye. The most common ocular manifestations were retinal 43 changes, cataract, and non-proliferative and proliferative diabetic retinopathy. 44  Age and diabetes were associated with presence of cataract, and diabetes was associated with 45 retinal changes especially among patients with ischemic heart disease and peripheral arterial 46 disease. 47 Application to patient care 48  Ocular problems are highly prevalent among patients on haemodialysis. 49  Periodic screening and early detection and management of ocular manifestations among 50 haemodialysis patients, especially older patients and those with diabetes, will help in prevention 51 of visual impartment and associated disability in this vulnerable population. 52 53 Introduction 54 Visual impairment and blindness represent a significant cause of disability. Worldwide, about 55 2.2 billion people suffer from visual impairment, and 50% of these visual impairments are 56 3 preventable and treatable.1 Chronic kidney disease (CKD) is very common, with a global 57 prevalence of 11% to 13%.2 CKD is often gradual and may lead to irreversible loss of kidney 58 function known as end-stage renal disease (ESRD). Dialysis, either haemodialysis or peritoneal 59 dialysis, and kidney transplantation are the only treatment options for patients with ESRD.3, 4 60 Patients with ESRD are at increased risk of ocular problems due to uraemia, effects of 61 haemodialysis, and other co-morbid conditions, such as diabetes, hypertension, and 62 cardiovascular disease.5 Common ocular problems among patients on haemodialysis include 63 cataract, retinal changes (retinopathy, retinal haemorrhage, vitreous haemorrhage, and retinal 64 detachment), and other conjunctival and corneal changes.5, 6 65 66 The prevalence of ESRD in Palestine reached 240.3 per million population in 2010,7 which is 67 relatively lower than that in other countries in the Middle East and other regions in the world.8 68 However, the total number of patients with ESRD on haemodialysis has increased from 666 69 cases in 2011 to 1014 cases in 2015.8, 9 Therefore, early detection of ocular problems through 70 screening of patients with ESRD may help in prevention of visual impairment and associated 71 disability in this population. Research on epidemiology of ocular manifestations and associated 72 factors among ESRD patients in Palestine has been given little attention until now. The aim of 73 this study was to estimate the prevalence of ocular manifestations and associated factors in 74 sample of Palestinian patients on haemodialysis. 75 76 Methods 77 Study design, population, and setting 78 This was a cross-sectional study of patients with ESRD on haemodialysis from the 79 haemodialysis unit of An-Najah National University Hospital, Nablus, West Bank, Palestine. All 80 patients were on four-hours haemodialysis three times per week. The number of haemodialysis 81 patients in this unit represents about 20% of all haemodialysis patients’ population in West 82 Bank.9 During the study period (August and December 2016), there were 214 patients receiving 83 haemodialysis in the unit. All patients who agreed to participate in the study were included (n= 84 191). The study was approved by the Institutional Review Board of An-Najah National 85 University (ethical approval archive number 03/AUG/2016). Full verbal and written consent 86 have been obtained from all participants. 87 4 88 Data collection 89 Demographic and clinical information, previously associated with ESRD and ocular problems10 90 were extracted from medical records (age, gender, duration on haemodialysis in years, diabetic 91 status (yes, no), hypertension status (yes, no), use of anti-platelet or anticoagulation medication 92 (yes, no), and diagnosis of ischemic heart disease (IHD) or peripheral arterial disease (PAD) 93 (yes, no). Patients were asked about their smoking history (yes, no). All patients underwent the 94 clinical ophthalmic examination in the haemodialysis unit after completing their dialysis sessions 95 by two registered ophthalmologists from An-Najah National University Hospital. For each 96 patient, the clinical ophthalmic examination started with intraocular pressure (IOP) measurement 97 using a Tono-Pen XL Tonometer11 after applying local anaesthetic drops (lidocaine 4%) in both 98 eyes. Generally, normal IOP ranges between 10 and 21 mmHg.12 IOP more than 21 mmHg was 99 classified as raised IOP. Two IOP measurements were taken on each eye and then were 100 averaged. After that, both pupils were dilated with Tropicamide 1% (one drop per eye every 10 101 minutes for half an hour). Presence of cataract was evaluated using a portable slit-lamp,13 and 102 presence of any vitreous or retinal changes was evaluated using indirect ophthalmoscope.14 Any 103 vitreous or retinal changes in non-diabetic patients such as arteriovenous nipping or tortuous and 104 vitreous haemorrhage were classified as retinal changes. We used the International Clinical 105 Diabetic Retinopathy Disease Severity Scale to classify diabetic retinopathy among diabetic 106 patients into non-proliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy 107 (PDR).15 According to this classification, any microaneurysm or intraretinal macrovascular 108 abnormalities were classified as NPDR, and neovascularization or vitreous/preretinal 109 haemorrhage were classified as PDR. Presence of optic disc pallor or cupping were used as a 110 relative measure of optic neuropathy.16, 17 111 112 Data analysis 113 Descriptive statistics were used to summarize the data. Categorical variables were summarized 114 with numbers and percentages. Continuous variables were summarized with mean and standard 115 deviation (SD). We performed multivariable logistic regression analyses to obtain adjusted 116 associations between predictor variables (demographic and medical characteristics of patients) 117 and presence of ocular manifestations of interest (raised IOP, cataract, retinal changes, optic 118 5 neuropathy) for all patients, and NPDR, PDR, or either NPDR or PDR for patients with diabetes. 119 In analysis, all ocular manifestations were categorized as binary variables (yes, no). Associations 120 between the predictor variables and the ocular manifestations were summarised using odds ratios 121 (OR) with 95% confidence intervals (CI). Any association with a p-value of < 0.05 was 122 considered statistically significant. Data analysis was performed using Statistical Package for 123 Social Sciences (SPSS) version 27.0. 124 125 Results 126 Table 1 presents the characteristics of participants. The mean age was 57.5 years, and 46.6% 127 were females. The mean duration on haemodialysis was 3.3 years. About 80.6% and 57.1% of 128 participants had hypertension and diabetes, respectively. Around 19.4% had IHD or PAD, and 129 52.4% were on antiplatelet or anticoagulant medications. The prevalence of smoking among 130 participants was 24.6%. 131 132 Table 2 presents the prevalence of ocular manifestations in at least one eye among participants. 133 The overall prevalence of any ocular problem was 68.0%. About 40.8% of patients had cataract 134 in at least one eye, and 21.5% of patients had a history of cataract surgery. The prevalence of 135 retinal changes in at least one eye was 58.1%. About 9.9% of patients had optic neuropathy at 136 least in one eye. Only 3 patients (1.6%) had raised IOP at least in one eye. 137 138 Around 51.4% and 15.6% of patients with diabetes had NPDR and PDR in at least one eye, 139 respectively. The prevalence of either NPDR or DRP was 65.1% (Table 2). 140 141 As shown in table 3, age and diabetes status were the only two variables associated with 142 presence of cataract. Increase in age by one year was associated with higher odds of having 143 cataract in at least one eye by 1.10 (95% CI 1.06, 1.14). Similarly, patients with diabetes had 144 higher odds of having cataract in at least one eye by 7.43 times (95% CI, 3.26, 16.95) than 145 patients without diabetes. 146 147 6 Diabetes was the only variable associated with any retinal changes among participants (Table 4). 148 Patients with diabetes had significantly higher odds of having any retinal changes by 109.48 149 times (95% CI, 33.85, 354.05) as compared to patients without diabetes. 150 As shown in Table 5, no statistically significant associations were found between characteristics 151 of participants and optic neuropathy including age (OR 1.02, 95% CI 0.98, 1.05), gender (OR 152 2.04, 95% CI 0.71, 5.86), duration on haemodialysis (OR 1.04, 95% CI 0.87, 1.23), diabetes (OR 153 0.83, 95% CI 0.28, 2.49), hypertension (OR 0.98, 95% CI 0.17, 5.21), IHD or PAD (OR 0.63, 154 95% CI 0.16, 2.50), anti-platelet or anticoagulation therapy (OR 1.98, 95% CI 0.70, 5.63), and 155 smoking (OR 0.41, 95% CI 0.10, 1.63). 156 157 Among patients with diabetes, there were no statistically significant associations between the 158 characteristics of participants and diabetic retinopathy (either NPDR or PDR); see Table 6. 159 Patients with diabetes and IHD or PAD had higher odds of having NPDR than patients with 160 diabetes and without IHD or PAD, but this was not statistically significant (OR 2.09, 95% CI 161 0.78, 5.61) 162 163 Discussion 164 The aim of current study was to estimate the prevalence of ocular manifestations among a 165 sample of Palestinian patients on haemodialysis and identify associated factors. The study 166 showed that common ocular manifestations are highly prevalent among patients on 167 haemodialysis. About two thirds of patients had at least one ocular manifestation in at least one 168 eye. Retinal changes and cataract were the most common ocular manifestations. About two 169 thirds of patients with diabetes had either NPDR or PDR in at least on eye. About 10% of 170 patients had optic neuropathy at least in one eye. Age was positively associated with cataract, 171 and diabetes was associated with presence of cataract and any retinal changes. Among patients 172 with diabetes, the presence of IHD or PAD was associated with NPDR. 173 174 The study showed that 40.8% haemodialysis have cataract, and 21.5% of patients had cataract 175 surgery. This finding is consistent with prior studies that cataract is common among patients on 176 haemodialysis.18-20 For example, one study found that 61% of patients on haemodialysis have 177 cataract.20 In the current study, the prevalence of NPDR (51%) and PDR (16%) are very similar 178 7 to those found in a previous study, which reported a prevalence of 57% and 14% for NPDR and 179 PDR among patients on haemodialysis, respectively.20 Similarly, the prevalence of optic 180 neuropathy (10%) in our study is consistent with the prevalence of optic neuropathy (7%) 181 reported in a previous study.21 This finding also agrees with previous reports on occurrence of 182 optic neuropathy among patients on haemodialysis.22 In the current study, the prevalence of 183 raised IOP was very low (2%), which is identical to the findings of a prior study.20 Our finding of 184 an independent positive associations between age and diabetes with cataract is consistent with 185 the findings of a 12-year prospective cohort study of patients on haemodialysis.23 We found that 186 diabetic patients had significantly higher odds of having any retinal changes, which is also 187 consistent with the literature.5, 6, 24 Among patients with diabetes, we found no association 188 between any of the included patients’ characteristics and the prevalence of diabetic retinopathy. 189 This finding underscores the important independent associations between diabetes and retinal 190 changes, including NPDR and PDR. Diabetic retinopathy is the most common microvascular 191 complication of diabetes due to hyperglycaemia and related macro and microvascular 192 abnormalities.25-27 The independent association between IHD or PAD and NPDR observed in the 193 current study also agrees with the literature. Prior studies have shown associations between 194 retinal microvascular abnormalities and coronary heart disease among patients with diabetes.28 195 The mechanisms underlying ocular manifestations and observed associations are likely explained 196 by multifactorial pathogenesis associated with aging, ESRD and comorbid conditions (diabetes 197 and hypertension), uraemia and haemodialysis, chronic anaemia, and “polypharmacy”.10 The 198 main hypothesized multifactorial pathogenesis includes atherosclerosis, endothelial dysfunction, 199 oxidative stress, chronic inflammation, renin–angiotensin system dysfunction, genetic 200 polymorphisms, Klotho, hypocalcaemia, the accumulation of toxic metabolites, and repeated 201 osmotic shift during dialysis.5, 6, 10, 23, 29 202 203 Strengths and limitations 204 The main strength of this study is that patients in the haemodialysis unit in An-Najah National 205 University Hospital represent roughly 20% of patients on haemodialysis in West Bank. 206 Additionally, this study included the majority (89%) of patients undergoing haemodialysis in the 207 unit and covered a wide range of age groups. It is unlikely that the sociodemographic and clinical 208 characteristics of patients in An-Najah National University Hospital to differ from those in other 209 8 units in West Bank because haemodialysis service and related costs is free and completely 210 covered by the Palestinian Ministry of Health. Additionally, ophthalmic examination of the 211 participants was performed independently by two resident ophthalmologists. Very few 212 disagreements in classification of ocular manifestations were present. These were resolved by 213 discussion or by seeking the opinion of a third resident ophthalmologist. Therefore, the potential 214 for diagnostic errors or misclassification of ocular manifestations is unlikely to have affected our 215 findings significantly. Additionally, our findings were consistent with those of previous studies 216 on ocular manifestations among patients on haemodialysis. Therefore, the findings from this 217 study are highly likely to be generalizable to other patients on haemodialysis in West Bank. 218 219 The study has some limitations. This was a cross-sectional study design, and therefore, temporal 220 associations remain unclear. Another limitation is that this study did not examine for other ocular 221 manifestations among patients on haemodialysis, such as dry eyes and corneal abnormalities. 222 However, our study covered most prevalent ocular manifestations among this population (e.g. 223 cataract, retinal changes, and optic neuropathy) which are associated with visual impairment and 224 disability globally.30 Also, medical records had no clinical information on previous history of 225 ocular problems among patients, and many elderly patients said that they have a history of 226 ophthalmic problems but did not know what they were. So, we were not able to establish whether 227 the observed ophthalmic manifestations were new or old in majority of patients. However, our 228 aim was to estimate the prevalence of ocular manifestations rather than incidence of ophthalmic 229 manifestations which requires a different study design with long follow-up period. Additionally, 230 although Goldman applanation tonometer is considered the gold standard instrument for 231 measuring IOP, we measured IOP using a Tono-Pen instrument. Prior research suggests that 232 Tono-Pen underestimates IOP in persons with elevated IOP.31 However, one study found no 233 statistically significant differences in IOP values between Goldman applanation tonometer and 234 Tono-Pen in non-glaucoma patients with systemic illness.32, 33 Another limitation is that retinal 235 changes were examined using indirect ophthalmoscope. It would be more ideal to take fundus 236 photographs for evaluation by retina specialists. However, this was not feasible in the present 237 study. 238 9 239 Conclusion 240 Ocular problems are highly prevalent among patients on haemodialysis. Most common ocular 241 manifestations were retinal changes and cataract. Without early detection and treatment, such 242 conditions may lead to significant visual impairment and disability. The findings underscore the 243 importance of regular ophthalmic screening for patients on haemodialysis, especially older 244 patients and those with diabetes, to prevent visual impartment and associated disability in this 245 population. 246 247 Authors’ Contribution 248 YS and MS led study conception and design, supervision, data collection, statistical analysis, 249 interpreting data, and drafting of manuscript. OY, AAS, ZH, OH, and HH were involved in study 250 concept and design and data collection. All authors reviewed the manuscript critically for 251 important intellectual content. All authors read and approved the final version of the manuscript. 252 253 Acknowledgement 254 We thank the participants and An-Najah National University Hospital for granting us the 255 privilege to conduct this study. 256 257 Conflict of Interest 258 The authors declare no conflicts of interest. 259 260 Funding 261 No funding was received for this study. 262 263 References 264 1. World Health Organization. Blindness and vision impairment. WHO; 2021 [30 December 265 2021]. Available from: https://www.who.int/en/news-room/fact-sheets/detail/blindness-and-266 visual-impairment. 267 10 2. Hill NR, Fatoba ST, Oke JL, Hirst JA, O'Callaghan CA, Lasserson DS, et al. Global 268 Prevalence of Chronic Kidney Disease - A Systematic Review and Meta-Analysis. PLoS 269 One. 2016;11(7):e0158765. 270 3. Kidney disease international global outcomes. KDIGO 2012 Clinical Practice Guideline for 271 the Evaluation and Management of Chronic Kidney Disease. 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Comparison of three methods 337 of tonometry in normal subjects: Goldmann applanation tonometer, non-contact airpuff 338 tonometer, and Tono-Pen XL. Clin Ophthalmol. 2014;8:1069-74. 339 340 Table 1 Characteristics of participants 341 Variable Mean (SD) or number (%) Age (years) 57.5 (13.8) Gender Female Male 89 (46.6) 102 (53.4) Duration on Haemodialysis (years) 3.3 (2.9) Diabetes Mellitus No Yes 82 (42.9) 109 (57.1) Hypertension No Yes 37 (19.4) 154 (80.6) IHD or PAD No Yes 154 (80.6) 37 (19.4) Anti-platelet or anticoagulation No Yes 91(47.6) 100 (52.4) Smoking No Yes 144 (75.4) 74 (24.6) SD, standard deviation; IHD, Ischemic Heart Disease; PDA, Peripheral Arterial Disease 342 13 Table 2 Prevalence of ocular manifestations in at least one eye among participants 343 Ocular manifestation Number (%) Cataract No Yes Previous cataract surgery 87 (45.5) 78 (40.8) 41 (21.5) Retinal changes No Yes 80 (41.9) 111 (58.1) Optic neuropathy No Yes 172 (90.1) 19 (9.9) Intraocular pressure Normal Raised 188 (98.4) 3 (1.6) NPDR No Yes 53 (48.6) 56 (51.4) PDR No Yes 92 (84.4) 17 (15.6) NPDR or PDR No Yes 38 (34.9) 71 (65.1) NPDR, Non-proliferative diabetic retinopathy; PDR, Proliferative diabetic retinopathy 344 14 Table 3 Association between characteristics of participants and cataract 345 Variable Patient has no cataract (n=87) Patient has cataract (N=104) Adjusted OR (95 % CI) P- value Age (years) 50.1 (14.7) 63.6 (9.4) 1.10 (1.06, 1.14) <0.001 Gender Female Male 41 (47.1) 46 (52.9) 48 (46.2) 56 (53.8) Ref 0.80 (0.36, 1.81) 0.597 Duration on Haemodialysis (years) 3.4 (3.3) 3.2 (2.5) 1.13 (0.98, 1.30) 0.102 Diabetes Mellitus No yes 59 (67.8) 28 (32.2) 23 (22.1) 81 (77.9) Ref 7.43 (3.26, 16.95) <0.001 Hypertension No Yes 22 (25.3) 65 (74.7) 15 (14.4) 89 (85.6) Ref 0.65 (0.23, 1.85) 0.413 IHD or PAD No Yes 74 (85.1) 13 (14.9) 80 (76.9) 24 (23.1) Ref 0.52 (0.20, 1.32) 0.165 Anti-platelet or anticoagulation No Yes 50 (57.5) 37 (42.5) 41 (39.4) 63 (60.6) Ref 1.72 (0.78, 3.78) 0.178 Smoking No yes 66 (75.9) 21 (24.1) 78 (75.0) 26 (25.0) Ref 1.05 (0.39, 2.77) 0.930 IHD, Ischemic heart disease; PAD, Peripheral arterial disease; OR, Odds ratio; CI, Confidence 346 interval. Note: percentages may not add up to 100 due to rounding 347 15 Table 4 Association between characteristics of participants and retinal changes 348 Variable Patient has no retinal changes (n=80) Patient has retinal changes (n=111) Adjusted OR (95 % CI) P- value Age (years) 52.2 (16.4) 61.2 (10.1) 1.01 (0.97, 1.06) 0.561 Gender Female Male 39 (48.8) 41 (51.2) 50 (45.0) 61 (55.0) Ref 0.84 (0.25, 2.81) 0.771 Duration on Haemodialysis (years) 3.8 (3.5) 2.9 (2.2) 1.06 (0.88, 1.27) 0.558 Diabetes Mellitus No yes 73 (91.3) 7 (8.8) 9 (8.1) 102 (91.9) Ref 109.48 (33.85, 354.05) <0.001 Hypertension No Yes 27 (33.8) 53 (66.3) 10 (9.0) 101 (91.0) Ref 1.98 (0.51, 7.78) 0.326 IHD or PAD No Yes 75 (93.8) 5 (6.3) 79 (71.2) 32 (28.8) Ref 2.44 (0.46, 13.02) 0.298 Anti-platelet or anticoagulation No Yes 47 (58.8) 33 (41.3) 44 (39.6) 67 (60.4) Ref 1.33 (0.44, 4.03) 0.616 Smoking No yes 61 (76.3) 19 (23.8) 83 (74.8) 28 (25.2) Ref 0.42 (0.10, 1.74) 0.231 IHD, Ischemic heart disease; PAD, Peripheral arterial disease; OR Odds ratio; CI, Confidence 349 interval. Note: percentages may not add up to 100 due to rounding 350 16 Table 5 Association between characteristics of participants and optic disc pallor/cupping 351 Variable Patient has no optic disc pallor (n=172) Patient has optic disc pallor (n=19) Adjusted OR (95 % CI) P- value Age (years) 57.2 (14.0) 59.4 (12.3) 1.02 (0.98, 1.05) 0.411 Gender Female Male 82 (47.7) 90 (52.3) 7 (36.8) 12 (63.2) Ref 2.04 (0.71, 5.86) 0.188 Duration on Haemodialysis (years) 3.3 (2.8) 3.6 (3.6) 1.04 (0.87, 1.23) 0.678 Diabetes Mellitus No yes 73 (42.4) 99 (57.6) 9 (47.4) 10 (52.6) Ref 0.83 (0.28, 2.49) 0.740 Hypertension No Yes 33 (18.6) 140 (81.4) 5 (26.3) 14 (73.7) Ref 0.98 (0.17, 5.21) 0.984 IHD or PAD No Yes 138 (80.2) 34 (19.8) 16 (84.2) 3 (15.8) Ref 0.63 (0.16, 2.50) 0.512 Anti-platelet or anticoagulation No Yes 84 (48.8) 88 (51.2) 7 (36.8) 12 (63.2) Ref 1.98 (0.70, 5.63) 0.201 Smoking No yes 128 (74.4) 44 (25.6) 16 (84.2) 3 (15.8) Ref 0.41 (0.10, 1.63) 0.204 IHD, Ischemic heart disease; PAD, Peripheral arterial disease; OR Odds ratio; CI, Confidence 352 interval. Note: percentages may not add up to 100 due to rounding 353 17 Table 6 Association between characteristics of participants and diabetic retinopathy 354 Variable Patient has no NPDR or PDR (n=38) Patient has NPDR or PDR (n=71) Adjusted OR (95 % CI) P- value Age (years) 62.1 (7.2) 61.3 (10.7) 0.99 (0.95, 1.04) 0.710 Gender Female Male 14 (36.8) 24 (63.2) 33 (46.5) 38 (53.5) Ref 0.99 (0.39, 2.50) 0.981 Duration on Haemodialysis (years) 2.4 (2.4) 2.9 (2.0) 1.09 (0.89, 1.34) 0.423 Hypertension No Yes 4 (10.5) 34 (89.5) 5 (7.0) 66 (93.0) Ref 1.88 (0.43, 8.24) 0.405 IHD or PAD No Yes 30 (78.9) 8 (21.1) 47 (66.2) 24 (33.8) Ref 2.09 (0.78, 5.61) 0.142 Anti-platelet or anticoagulation No Yes 14 (36.8) 24 (63.2) 29 (40.8) 42 (59.2) Ref 0.82 (0.32, 2.10) 0.667 Smoking No yes 23 (60.5) 15 (39.5) 56 (78.9) 15 (21.1) Ref 0.42 (0.15, 1.15) 0.091 NPDR, Non-proliferative diabetic retinopathy; PDR, Proliferative diabetic retinopathy; IHD, 355 Ischemic heart disease; PAD, Peripheral arterial disease; OR Odds ratio; CI, Confidence interval. 356 Note: percentages may not add up to 100 due to rounding 357