Abstract
Purpose::
It is known that type 1 diabetic patients live shorter than non-diabetic patients. The aim of this study was to examine the survival of a previously defined population based cohort of type 1 diabetic patients and to investigate the influence of baseline parameters on survival 25 years later.
Methods::
All insulin-treated diabetic patients from the Danish County of Fyn with an onset before the age of 30 as of July 1st 1973 (n=728) have previously been identified. In 1981-1982 91.9% (577 of 628) of those still alive and living in Denmark participated in a clinical follow-up investigation focusing mainly on diabetic eye complications.In November 2006 we examined survival status by means of the Danish Central Office of Civil Registration.
Results::
Of the original cohort initially consisting of 414 men and 314 women, 320 were still alive (44.0%). 379 had died (52.1%) and the remainder 29 (4.0%) had either emigrated or were unaccounted for. At baseline in 1973 there was no significant difference (p=0.79) between mean age of men (31.6 years) and women (32.5 years). In 2006 225 (54.4%) men had died compared to 154 (49.0%) women. Extended mean survival time was 61.8 and 66.4 years for men and women respectively indicating a longer survival among women (p=0.02).A Cox regression model based on the results of the follow-up investigation in 1981-1982 and adjusted for age and gender, showed a significantly increased hazard ratio (HR) of death for patients with proliferative retinopathy (HR 2.48, p<0.001) and diabetic maculopathy (HR 1.59, p=0.001) compared to those without. Hazard ratio was not significantly elevated for patients with higher diastolic (CI 0.88-1.63) or systolic blood pressure (CI 0.88-1.67), nor did it depend on the quartile of HbA1c (CI 0.94-1.20) as measured once.
Conclusions::
Life expectancy of type 1 diabetic patients is shorter among men compared with women. Development of proliferative diabetic retinopathy or maculopathy leads to an increased hazard ratio for death. Blood pressure and glycemic regulation 25 years ago did not affect hazard ratio for survival.
Keywords: diabetes • diabetic retinopathy • clinical (human) or epidemiologic studies: risk factor assessment