Abstract
Purpose: :
To examine the 25-year cumulative incidence of PDR, its relation to various risk factors and whether the prevalence of PDR was lower in more recently diagnosed cohorts.
Methods: :
Persons with T1DM were examined at baseline (1980-82) and in at least 1 of the 4 follow-up examinations (4-year, 10-year, 14-year, and 25-year). The 25-year cumulative incidence of PDR was detected by masked grading stereoscopic color fundus photographs using the modified Airlie House classification and the Early Treatment Diabetic Retinopathy Study retinopathy severity scheme.
Results: :
The 25-year cumulative incidence of PDR (accounting for competing risk of death) was 42%. Multivariate models showed increased risk of PDR (Hazard Ratio, 95% Confidence interval and p-value) with more severe baseline retinopathy (1.81, 1.49-2.22, P<.0001), higher glycosylated hemoglobin (1.34 per %, 1.27-1.42, P<.0001), presence of gross proteinuria (1.43, 1.01-2.0, P=.05) and greater body mass index (BMI) (per 1.0 kg/m2, 1.03, 1.00-1.07, P=.04) but not systolic or diastolic blood pressure (BP) or smoking status. Further analyses using multivariable models with time-dependent covariates showed PDR was associated with diastolic BP (1.25 per SD, 1.07-1.47, P=.006). PDR prevalence was significantly (P<.0001) lower in persons with similar durations of type 1 diabetes diagnosed more recently (1975-1980) than those diagnosed in earlier periods (1922-1974). For example, the prevalence of PDR in those with 20-24 years of diabetes varied from 50% in those diagnosed in 1922-1959 to 26% in those diagnosed in 1975-1980.
Conclusions: :
These data suggest relatively high 25-year cumulative incidence of PDR and show that persons diagnosed most recently had lower risk of prevalent PDR independent of duration of diabetes, possibly reflecting improvement in care over the period of the study.
Keywords: clinical (human) or epidemiologic studies: prevalence/incidence • diabetic retinopathy • clinical (human) or epidemiologic studies: risk factor assessment