Aims/hypothesis: Comorbidities are frequent among type 1 diabetes patients on renal replacement therapy, yet the effect of comorbidities on survival is unknown. Our aim was to estimate this effect.
Methods: An incident cohort of all patients with type 1 diabetes entering chronic renal replacement therapy (n = 656) in Finland between 2000 and 2008 was followed until death or the end of follow-up on 31 December 2008. All data were obtained from the Finnish Registry for Kidney Diseases, which collects information on comorbidities at the start of renal replacement therapy. The main outcome measure was relative risk of death according to comorbidities.
Results: At start of renal replacement therapy, 22% of the patients with type 1 diabetes had coronary artery disease, 19% peripheral vascular disease, 11% cerebrovascular disease, 33% left ventricular hypertrophy and 7% heart failure. All these comorbidities were significant predictors of death in univariate analyses (RR 1.6-4.9). The 5 year survival probability of patients without comorbidities was 74%, while it was 56% and 37%, respectively, for those with one or more than one comorbidity. When the comorbidities were studied in a multivariate model, adjusting for age and sex, peripheral vascular disease (RR 1.9), left ventricular hypertrophy (RR 1.7) and heart failure (RR 2.5) remained independent risk factors for death. Calculations indicated that one-third of deaths in the study population could be attributed to comorbidities.
Conclusions/interpretation: Among patients with type 1 diabetes entering renal replacement therapy, comorbidities are common and strong predictors of death. Therefore, it is essential to identify and adequately treat comorbidities.