Presence of Acanthosis Nigricans Indicates Nephropathy in People with Type 2 Diabetes

Background Acanthosis nigricans (AN) has been proposed as a vascular risk indicator, but evidence linking it to specific diabetes-related complications is minimal and weak. This study evaluated the utility of AN as a novel clinical predictor and an unexplored marker of vascular complications in type 2 diabetes (T2D). Materials and Methods In this prospective, observational, cross-sectional comparative study, 300 adults with T2D were enrolled: 150 with moderate-to-severe AN and 150 age-matched individuals without non-AN (NAN). Microvascular (nephropathy, retinopathy, neuropathy) and macrovascular complications were systematically assessed using standardized protocols. Multivariable logistic regression models were adjusted for age, sex, diabetes duration, body mass index (BMI), and lifestyle factors. Results Nephropathy was nearly three times more prevalent in participants with AN than without (50.0% vs. 17.3%). After comprehensive adjustment for potential confounders, AN independently predicted nephropathy (adjusted OR, 4.21, 95% CI 2.35–7.53; p <0.001). On further analysis, prevalence of AN was 75.0% among those with nephropathy versus 37.5% among those without nephropathy ( p <0.001), yielding an odds ratio for AN in the nephropathy group of 4.93 (95% CI 2.78–8.74). No significant associations were observed between AN and retinopathy, neuropathy, or macrovascular disease. Individuals with AN exhibited higher BMI, greater abdominal adiposity, elevated triglycerides, reduced HDL cholesterol, and significantly increased microalbuminuria, despite comparable glycemic control. Conclusions AN is an easily identifiable novel clinical marker independently associated with diabetic nephropathy in Asian Indians. To our knowledge, this is the first study offering a cost-free bedside tool and providing a new viewpoint to stratify nephropathy risk in diabetes care and needs to be validated in other populations