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The risk of proliferative retinopathy in siblings with Type 1 diabetes
Author(s) -
Hietala K.,
Forsblom C.,
Summanen P.,
Groop P.H.
Publication year - 2012
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.2012.03768.x
Subject(s) - medicine , interquartile range , retinopathy , diabetes mellitus , diabetic retinopathy , hazard ratio , cumulative incidence , population , type 2 diabetes , cohort , type 1 diabetes , incidence (geometry) , cohort study , nephropathy , pediatrics , endocrinology , confidence interval , physics , environmental health , optics
Diabet. Med. 29, 1567–1573 (2012) Abstract Aims The siblings first affected by Type 1 diabetes (probands) within a sibship have been shown to have a lower age at onset of Type 1 diabetes compared with their later‐affected siblings. The aim of the present study was to investigate whether this difference affects the long‐term risk of proliferative diabetic retinopathy. Methods A cohort of 396 siblings with Type 1 diabetes in 188 sibships was drawn from a larger Finnish Diabetic Nephropathy Study population (4800 patients). Ophthalmic records were obtained for 369/396 (93%) patients. Retinopathy was graded based on fundus photographs and/or repeated ophthalmoscopies. Results The median age at onset of Type 1 diabetes was 8.4 (interquartile range 4.2–13.3) years in probands and 16.9 (interquartile range 10.2–27.8) years in later‐affected siblings ( P < 0.001). Proliferative retinopathy was diagnosed in 115/369 (31%) patients. The cumulative incidence estimates for proliferative retinopathy, accounting for the competing risk of death, were 21% (95% CI 15–27) in probands and 26% (95% CI 19–35) in later‐affected siblings at 20 years of diabetes duration, and the respective 30 years’ incidences were 37% (95% CI 29–45) and 53% (95% CI 40–64), ( P = 0.05, Gray’s test). The risk of proliferative retinopathy, adjusted for conventional risk factors, age at onset and sibship size, was higher in later‐affected siblings [hazard ratio 1.75 (95% CI 1.13–2.75), P = 0.01] compared with their probands. Conclusion The siblings first affected by Type 1 diabetes had a better long‐term prognosis with regards to development of proliferative retinopathy compared with their later‐affected siblings.