The use of the Markov process in describing the natural course of diabetic retinopathy.
The natural course of early diabetic retinopathy in young subjects with insulin-dependent diabetes mellitus was evaluated during 693 patient visits for 259 subjects during a mean of 2.4 years. Diabetic retinopathy is considered a progressive disease among people with insulin-dependent diabetes mellitus (type I). Improvement of early retinopathy has not been recognized as a part of the natural course. In our experience, 25% of observations in subjects with early diabetic retinopathy (grades 2 and 3) showed improvement. Thus, 28 of 174 observations of diabetic retinopathy improved from grade 2 to grade 1, and 34 of 79 observations improved from grade 3 to grades 2 or 1. Markov chains indicate that 25% of observations of diabetic retinopathy will change from grade 1 to grade 5 or 6 in 17.0 years and 25% will change from grade 2 to grade 5 or 6 in 16.0 years. Future studies of diabetic retinopathy should consider a matrix of estimated transition probabilities, depending on the population, to judge probabilities of transition between states of retinopathy.
Department of Pediatrics, University of Colorado Health Sciences Center, Denver 80262.
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D000293:Adolescent; D000328:Adult; D003922:Diabetes Mellitus, Type 1 / Q000150:complications; D003930:Diabetic Retinopathy / Q000145:classification / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008390:Markov Chains; D011336:Probability; D011379:Prognosis