Insulin sensitivity and secretion in older patients differ according to age at diabetes diagnosis.

INTRODUCTION. Little is known on insulin sensitivity and secretion in older patients with type 2 diabetes mellitus (DM2), a heterogeneous group of patients. METHODS. Cross-sectional study of 210 consecutive older (≥75 years) patients followed for DM2 at the outpatient diabetes clinic of an academic hospital. DM2 was classified as habitual-onset diabetes (HODM2) when diagnosed <65 years or elderly-onset diabetes (EODM2) when diagnosed ≥65 years. Insulin sensitivity and β-cell function were assessed by HOMA modeling. Statistical significance (p<0.05) of differences was assessed using Student’s t-test, Welch’s test or Fisher’s Exact test. RESULTS. Patients with EODM2 (n=88; 82.6±5 years), as compared to HODM2 (n=122; 81.2±6 years), had a shorter history of DM2 (10±5vs.26±10 years). Both groups were not different in terms of cardio-vascular risk factors and DM2-related complications, except at the micro-vascular level (EODM2vs.HODM2: 45vs.72%). Concerning metabolic profile, EODM2 significantly differed from HODM2 in 4 anthropometric and metabolic characteristics: lower BMI (26.6vs.28.2 kg/m2), lower prevalence of obesity (18vs.27%), higher insulin sensitivity (66vs.53%) and higher residual β-cell secretion (68vs.52%). Although HbA1c was similar in both groups (7.31vs.7.62%), HbA1c <7% was more frequently observed in EODM2 patients than in HODM2 ones (49vs.37%). EODM2 patients, as compared to HODM2 ones, received significantly less intensive anti-diabetic regimens, specifically oral ones (bi- or tri-therapies: 28%vs.59%) and insulin (32vs.66%, p