Prospective Analysis of Mortality, Morbidity, and Risk Factors in Elderly Diabetic Subjects

Abstract

OBJECTIVE—To clarify mortality and morbidity of intensively managed elderly diabetic individuals and to explore factors predicting mortality and diabetes-related end points. RESEARCH DESIGN AND METHODS—A total of 390 elderly (≥65 years of age) outpatients with type 2 diabetes ( 173 men and 217 women, mean age 73.0 years) were analyzed. The mean HbA1c upon entry was 6.8% (332 receiving oral hypoglycemics and/or insulin) and blood pressure upon entry was 136/74 mmHg (219 receiving antihypertensive drugs). The patients have been followed-up for 3 years with HbA1c <7.0% and blood pressure <145/80 mmHg as targets, with mortality and an aggregate of fatal and nonfatal diabetes-related events as end points. Mortality rate and causes of mortality, as well as risk factors for mortality and morbidity, were determined. RESULTS—The mortality rate, 2.9% per year, was comparable to that of the age- and sex-matched general population. Stroke was a leading cause of mortality after malignancy. By the univariate Cox proportional hazards model, only high serum creatinine and prior stroke were highly significant and strong risks for both end points. In those without prior stroke and receiving antihypertensive agents, the incidence of the diabetes-related end point based on their systolic blood pressure (SBP) quartile was U-shaped, with the nadir at the 3rd (SBP, 137–147 mmHg) and the peak at the 1st (SBP ≤ 125 mmHg) quartile. CONCLUSIONS—In well-controlled elderly diabetic subjects, there was no excessive mortality compared to the age- and sex-matched general population. Renal dysfunction and prior stroke were independent risks for mortality and morbidity. In those without prior stroke, a risk of too much lowering of blood pressure was suggested.