Peak expiratory flow rate: relationship to risk variables and mortality: the Wisconsin Epidemiologic Study of diabetic retinopathy.

OBJECTIVE To examine correlates of peak expiratory flow rate in people with type 1 diabetes and to evaluate the relationship of peak expiratory flow rate to mortality. RESEARCH DESIGN AND METHODS A cohort study that was originally designed to determine the prevalence, incidence, and severity of diabetic retinopathy also provided the opportunity to measure peak expiratory flow rate. This was first measured at a 10-year follow-up and was evaluated in regard to risk factors for microvascular complications of diabetes. Mortality during 6 years of follow-up after the measurement was also ascertained. RESULTS In multivariable analysis, peak expiratory flow rate was associated with sex, age, height, BMI, history of cardiovascular disease, pulse rate, duration of diabetes, glycosylated hemoglobin, and end-stage renal disease. Peak expiratory flow rate was significantly associated with survival in categorical analyses. Even after considering age, sex, renal disease, history of cardiovascular disease, respiratory symptoms, duration of diabetes, cigarette smoking, and hypertension, peak expiratory flow rate was still significantly related to survival (hazard ratio 0.61 [95% CI 0.46-0.82]). CONCLUSIONS These data indicate that peak expiratory flow rate is associated with risk factors for other complications of diabetes. In addition, peak expiratory flow rate is a significant predictor of survival over even a relatively short period of time (6 years) in patients with younger-onset diabetes.