Association Between Insulin Resistance and Development of Microalbuminuria in Type 2 Diabetes

OBJECTIVE An association between insulin resistance and microalbuminuria in type 2 diabetes has often been found in cross-sectional studies. We aimed to reassess this relationship in a prospective Taiwanese cohort of type 2 diabetic subjects. RESEARCH DESIGN AND METHODS We enrolled 738 normoalbuminuric type 2 diabetic subjects, aged 56.6 ± 9.0 years, between 2003 and 2005 and followed them through the end of 2009. Average follow-up time was 5.2 ± 0.8 years. We used urine albumin-to-creatinine ratio to define microalbuminuria and the homeostasis model assessment of insulin resistance (HOMA-IR) to assess insulin resistance. The incidence rate ratio and Cox proportional hazards model were used to evaluate the association between HOMA-IR and development of microalbuminuria. RESULTS We found incidences of microalbuminuria of 64.8, 83.5, 93.3, and 99.0 per 1,000 person-years for the lowest to highest quartiles of HOMA-IR. Compared with those in the lowest quartile of HOMA-IR, the incidence rate ratios for those in the 2nd, 3rd, and highest quartiles were 1.28 (95% CI 0.88-1.87), 1.44 (0.99-2.08), and 1.52 (1.06-2.20), respectively (trend test: P < 0.001). By comparison with those in the lowest quartile, the adjusted hazard ratios were 1.37 (0.93-2.02), 1.66 (1.12-2.47), and 1.76 (1.20-2.59) for those in the 2nd, 3rd, and highest HOMA-IR quartiles, respectively. CONCLUSIONS According to the dose-response effects of HOMA-IR shown in this prospective study, we conclude that insulin resistance could significantly predict development of microalbuminuria in type 2 diabetic patients.