Excess mortality examined in older patients with diabetes
Excess mortality associated with diabetes was highest in patients younger than age 75 who had had diabetes for a longer time period, with the relative hazard highest in women, a study found.
Older patients with diabetes have significant excess mortality that is not explained by comorbid conditions or polypharmacy, according to a recent study.
Researchers used data from the Health Innovation Network database to perform a 10-year cohort study that compared mortality in diabetic patients and nondiabetic patients ages 70 years and older. The goal of the study was to determine the effect of comorbidity, polypharmacy, and diabetes duration on risk for death. The study results were published online May 28 by Diabetic Medicine.
Overall, 35,717 patients (mean age, 78.1±5.8 years) were included in the diabetic cohort, and 307,918 patients (mean age, 79.0±6.3 years) were included in the nondiabetic cohort. The nondiabetic cohort had more women (60.7% vs. 52.3%), while the diabetic cohort was more overweight (64.6% vs. 37.5%) and included more former smokers (35.9% vs. 22.2%). Thirty percent of the diabetic cohort had had diabetes for more than 10 years (mean diabetes duration, 8.2±8.1 years).
Patients in the diabetic cohort had more comorbid conditions and more prescriptions than patients in the nondiabetic cohort, as well as lower 5-year and 10-year survival rates (64% and 39% vs. 72% and 50%). Excess mortality in the diabetic cohort was highest in patients younger than age 75 who had had diabetes for a longer time period, with the relative hazard highest in women. Hazard ratios for more than 4 comorbid conditions and 7 or more prescribed medications were 1.29 (95% CI, 1.19 to 1.41) and 1.34 (95% CI, 1.25 to 1.43) in the diabetic cohort and 1.63 (95% CI, 1.57 to 1.70) and 1.48 (95% CI, 1.40 to 1.56) in the nondiabetic cohort.
The authors noted that the higher hazard ratios for comorbid conditions and polypharmacy in the nondiabetic group may be due to the protective effect of therapies commonly prescribed for diabetes (e.g., hypertensive agents and lipid-lowering drugs). This was a limitation of their study, they wrote, because they considered only the number of medications prescribed rather than the type. Other potential limitations included varying accuracy of the data and changes in classification of chronic kidney disease that took place during the study period. However, the authors concluded that excess mortality in older adults with diabetes is not completely explained by comorbidity and polypharmacy and could be due to effect of the disease or to treatment-related risks. “More research is demanded to help identify appropriate tools to inform risk stratification and therapeutic decision making for older people with diabetes,” the authors wrote.