Diabetic retinopathy as a potential marker of Parkinson’s disease: a register-based cohort study

Abstract

Neurodegeneration is an early event in the pathogenesis of diabetic retinopathy, and an association between diabetic retinopathy and Parkinson’s disease has been proposed. In this nationwide register-based cohort study, we investigated the prevalence and incidence of Parkinson’s disease among patients screened for diabetic retinopathy in a Danish population-based cohort. Cases (n = 173 568) above 50 years of age with diabetes included in the Danish Registry of Diabetic Retinopathy between 2013 and 2018 were matched 1:5 by gender and birth year with a control population without diabetes (n = 843 781). At index date, the prevalence of Parkinson’s disease was compared between cases and controls. To assess the longitudinal relationship between diabetic retinopathy and Parkinson’s disease, a multivariable Cox proportional hazard model was estimated. The prevalence of Parkinson’s disease was 0.28% and 0.44% among cases and controls, respectively. While diabetic retinopathy was not associated with present (adjusted odds ratio 0.93, 95% confidence interval 0.72–1.21) or incident Parkinson’s disease (adjusted hazard ratio 0.77, 95% confidence interval 0.56–1.05), cases with diabetes were in general less likely to have or to develop Parkinson’s disease compared to controls without diabetes (adjusted odds ratio 0.79, 95% confidence interval 0.71–0.87 and adjusted hazard ratio 0.88, 95% confidence interval 0.78–1.00). In a national cohort of more than 1 million persons, patients with diabetes were 21% and 12% were less likely to have prevalent and develop incident Parkinson’s disease, respectively, compared to an age- and gender-matched control population without diabetes. We found no indication for diabetic retinopathy as an independent risk factor for incident Parkinson’s disease.

Associations Between Diabetic Retinopathy and Parkinson's Disease: Results From the Catalonian Primary Care Cohort Study

“…Knowing the fact that subjects with prediabetes are at an increased risk of developing T2DM ( 29 ), that the diagnosis of T2DM is usually delayed by between 4 and 7 years ( 30 ), and that both prediabetes and T2DM increase with age ( 31 ), could explain findings in our model that subjects with longer T2DM duration had a higher risk for PD. Similar results were also reported in a recently published case-control study from Denmark, in which the authors did not find an association between DR and PD; further, it should be pointed out that in this study subjects with Parkinson's disease had a longer duration of diabetes ( 32 ). In our sensitivity analysis, when we stratified for diabetes duration, the HRs remained in the same direction; however, there was no association of DR with the development of PD.…”

Diabetic retinopathy is a predictor of chronic respiratory failure: A nationwide register-based cohort study

“…In this study, data from NPR are used from 1995 and forward. CPR was established in 1968, from which we retrieved information on birth-year, sex and marital status [ 26 , 28 ]. DNPR was established in 1995 and contains information on all prescribed medications redeemed at community pharmacies in Denmark, date and information about discharge, drug information etc.…”

“…This study was part of the Ocular And Systemic complications In DR Study (OASIS) initiated by the Danish Excellence Centre in Ophthalmic Epidemiology (DECODE-EYE) [ 33 ], and the study design may be comparable to other studies included in OASIS [ 22 , 28 , 34 ]. Permissions were obtained from the Region of Southern Denmark's record of data processing activities (Journal nr.…”

Attendance in a national screening program for diabetic retinopathy: a population-based study of 205,970 patients

“…This includes information on the Anatomical Therapeutic Chemical (ATC) classification of the medication as well as detailed information on all prescriptions. The Danish National Patient Register and The Danish National Prescription Registry were utilized for categorizing diabetes type (type 1, type 2 or unknown) [ 15 ] as well as to categorize patients' comorbidities according to the Charlson Comorbidity Index score (CCI, 1 = low, 2 = moderate low, 3 = moderate high or 4 = high) [ 16 ]. Furthermore, socioeconomic data were acquired from Statistics Denmark [ 17 ]; we extracted information on equivalent household income (low, moderate low, moderate high and high), highest achieved level of education (lower secondary, upper secondary and post-secondary) in accordance with the International Standard Classification of Education (ISCED) [ 18 ], affiliation to the labor market (employed, student, unemployed, early retirement or retirement) [ 19 ] and ethnicity (Danish or other).…”