Clinical and Hematological Correlation of Nail Changes in Type 2 Diabetes Mellitus: A Retrospective Study.

Background Nail abnormalities are common but often overlooked manifestations of type 2 diabetes mellitus (DM). Their relationship with glycemic control and disease duration remains incompletely understood. This study aimed to evaluate the spectrum of nail abnormalities in patients with type 2 DM and to determine their association with glycemic parameters and duration of DM. Methods A retrospective observational study was conducted among patients with type 2 DM attending a tertiary care hospital between January 2023 and December 2024. Patients were divided into two groups: those with nail abnormalities (Group A) and those without nail abnormalities (Group B). Demographic and clinical data, fasting blood sugar (FBS), postprandial blood sugar (PPBS), random blood sugar (RBS), glycated hemoglobin (HbA1c), and duration of DM were analyzed. Nail abnormalities were evaluated clinically and by onychoscopy. Statistical analysis included the Chi-square test, Student's t-test, correlation analysis, and receiver operating characteristic (ROC) curve analysis. Results The study consisted of 100 patients in each group, with Group A (M: 68, F: 32) and Group B (M;52, F: 48). Longitudinal ridging (64%) was the most frequent nail abnormality, followed by onychomycosis (36%), chronic paronychia (26%), Beau's lines (25%), and nail dystrophy (18%). Patients with nail abnormalities had significantly higher FBS, PPBS, RBS, and HbA1c levels than those without nail abnormalities (all p < 0.001). ROC curve analysis demonstrated that glycemic parameters exhibited superior predictive performance for nail abnormalities compared with the duration of diabetes, with RBS showing the highest sensitivity and HbA1c the highest specificity. Although Beau's lines were associated with longer disease duration, most nail abnormalities did not demonstrate a significant relationship with the duration of diabetes. Total nail change scores showed a positive correlation with worsening glycemic parameters. Conclusions Nail abnormalities in type 2 DM are closely associated with poor glycemic control and may reflect cumulative metabolic injury more closely than the chronological duration of disease. Routine nail examination, supplemented by onychoscopy when indicated, may serve as a simple, non-invasive adjunct for identifying patients who require closer metabolic evaluation. Prospective longitudinal studies are warranted to validate these findings.