Serum laminin as a marker of diabetic retinopathy development: A 4-year follow-up study

PURPOSE: The usefulness of laminin as a serum marker of diabetic retinopath y is a topic that generates conflicting views, The aim of the present study was to investigate the effect of diabetic retinopathy on serum laminin-P1, the larger pepsin resistant fragment of laminin, and to elucidate whether serum laminin-P1 could be an indicator of the risk for development of diabe tic retinopathy, METHODS: In a prospective study, 97 consecutive diabetic patients (35 type 1 and 62 type 2) without diabetic retinopathy and a urinary albumin excreti on rate lower than 20 mu g per minute were enrolled in a 4-year follow-up s tudy. Patients who developed microalbuminuria during the study were exclude d in order to avoid the influence of diabetic nephropathy on serum laminin- P1. At the end of follow-up, data from ophthalmologic studies and serum lam inin-P1 were evaluated in the 66 normoalbuminuric diabetic patients who com pleted the study. RESULTS: No statistical differences were observed in baseline laminin-P1 se rum concentrations between patients who developed diabetic retinopathy (n = 15) and patients who remained without it during follow-up (n 51), However, serum laminin-P1 levels obtained at the end of the study were significantl y higher in patients who developed diabetic retinopathy (1.75 +/- 0.33 U/ml versus 1.47 +/- 0.27 U/ml; P = .002), Furthermore, statistical difference was observed when initial and final values of serum laminin-P1 were compare d in patients who developed diabetic retinopathy (1.56 +/- 0.27 U/ml versus 1.75 +/- 0.33 U/ml; P = .001), Remarkably, an increase in serum laminin-P1 concentration was detected in all but two of the patients who developed di abetic retinopathy, The relative risk of development of diabetic retinopath y in patients who showed an increase in serum laminin-P1 during follow-up w as 5.4 (95% confidence interval, 1.32 to 22.13). CONCLUSIONS: Serum laminin-P1 is a marker and a risk indicator of diabetic retinopathy but is not an early predictor of its development. (C) 2000 by E lsevier Science Inc. All rights reserved.