Frailty Attenuates the Impact of Metformin on Reducing Mortality in Older Adults with Type 2 Diabetes - Abstract
Objective: To determine whether the protective effect of metformin against death is modified by frailty status in older adults with type 2 diabetes.
Research Design and Methods: We conducted a cohort study during October 1, 1999 September 30, 2006 among veterans aged 65-89 years old with type 2 diabetes but without history of liver, renal diseases, or cancers, who had sulfonylureas or metformin as the sole antidiabetic drug for ?180 days. The Cox proportional hazard model was used to compare hazard rates of all-cause mortality between the metformin and sulfonylurea users adjusting for the propensity score of metformin use and covariates: age, race/ethnicity, diabetes duration, Charlson comorbidity score, statin use, smoking status, BMI, LDL, and HbA1c.
Results: In this cohort of 2,415 veterans, 307 (12.7%) were metformin users, 2,108 (87.3%) were sulfonylurea users, the mean age was 73.7±5.2 years, the mean study period was 5.6±2.3 years, the mean HbA1c at baseline was 6.7±1.0%, 23% had diabetes for ?10 years, and 43.6% (N=1,048) died during the study period. For patients with and without frailty, the adjusted hazard ratio (HR) of death for metformin vs. sulfonylurea use were 0.92 (95% CI=0.90-1.31, p-value=0.19) and 0.69 (95% CI = 0.60-0.79, p-value<0.001), respectively. Logistic regression analyses showed that metformin (vs. sulfonylurea) was significantly associated with a decreased odds of frailty (OR: 0.66, 95% CI: 0.61-0.71, p-value <.0001)
Conclusion: Our study suggests that metformin could potentially promote longevity via preventing frailty in older adults with type 2 diabetes.