Mortality and incidence of renal replacement therapy in people with type 1 diabetes mellitus--a three decade long prospective observational study in the Lainz T1DM cohort

Abstract

Context and objective: We investigated long term mortality, requirement for renal replacement therapy (RRT), and incidence of other late diabetic complications in an observational cohort study of 641 people with type 1 diabetes (T1DM).

Design: Prospective observational cohort study.

Setting: The study was conducted at a Tertiary Diabetes Centre in Vienna, Austria.

Patients: A cohort with all people with T1DM (n = 641, 47% females, 30 ± 11 years) attending their annual diabetes review was created in 1983-1984. Biomedical data were collected.

Main outcome measures: In 2013 we investigated mortality rates and incidence rates of RRT by record linkage with national registries and incidence of other major diabetes complications by questionnaire.

Results: 156 (24%) patients died [mortality rate: 922 (95%CI: 778-1066) per 100 000 person years]. Fifty-five (8.6%) received RRT [incidence rate: 335 (95%CI: 246-423) per 100 000 person years]. The 380 questionnaires (78% return rate) recorded cardiac events, strokes, limb amputations, and/or blindness, affecting 21.8% of survivors. Mortality and incidence of RRT increased in each quartile of baseline HbA1c, with the lowest rates in the quartile with HbA1c ≤ 6.5% (48 mmol/mol) (P < .05).

Conclusions: In people with established type 1 diabetes who were observed for almost three decades, the overall mortality was 24% and the incidence of renal replacement therapy was 8.6%, with a 21.8% combined incidence rate of the other hard endpoints in the surviving people. A clear linear relationship between early glycemic control and the later development of end stage renal disease and mortality has been found.