Mortality in patients with childhood-onset type 1 diabetes in Finland, Estonia, and Lithuania: follow-up of nationwide cohorts.

OBJECTIVE: To assess mortality of population-based cohorts of childhood-onset type 1 diabetic patients from the Eastern European countries of Estonia and Lithuania and compare this information with recent data from Finland. RESEARCH DESIGN AND METHODS: Estonian (n = 518) and Finnish (n = 5,156) type 1 diabetic cohorts were diagnosed between 1980 and 1994, and the Lithuanian (n = 698) cohort was diagnosed between 1983 and 1994. The mortality of these cohorts was determined in 1995. Life-table analysis, Cox survival analysis with covariates, and standardized mortality ratios (SMRs) were used. Causes of death were analyzed. RESULTS: Survival after 10 years duration of type 1 diabetes was similar in Estonia (94.3%) and Lithuania (94.0%), but much higher in Finland (99.1%). In the Cox survival analysis with covariates, the country of origin and age at diagnosis were found to be significant predictors of mortality. The SMR for the Estonian cohort was 4.35 (95% CI 2.25-7.61), the highest for the Lithuanian cohort was 7.55 (4.89-11.15), and the lowest for the Finnish cohort was 1.62 (1.10-2.28). The most common cause of death in Estonia and Lithuania was diabetic ketoacidosis (DKA), and in Finland, it was violent causes. No deaths from late complications of diabetes have been documented so far in any of the three countries. CONCLUSIONS: Our results demonstrate a high rate of short-term deaths due to DKA and inferior survival of childhood-onset type 1 diabetic patients in Estonia and Lithuania compared with Finland. In Finland, the survival of childhood-onset type 1 diabetic patients has improved and is only slightly inferior to that of the background population.