Incidence of and mortality from type I diabetes in Taiwan from 1999 through 2010: A nationwide cohort study

Objective: To evaluate the secular trend in incidence of and mortality from Type 1 diabetes mellitus (T1DM) in Taiwan, 1999-2010. Methods: All 7,225 incident cases of T1DM were retrospectively retrieved from Taiwan's National Health Insurance Research Database from 1999 to 2010. Trend of bi-annual age- and sex-specific incidence rates of T1DM was calculated and tested with Poisson regression model. Standardized mortality ratios (SMRs) were calculated, using age-, sex-, and calendar years-specific mortality rates of the general population as the reference, to estimate the relative mortality risk of T1DM. Results: The number of male and female T1DM was 3,471 (48%) and 3,754 (52%), respectively. The annual number of incident T1DM increased from 543 in 1999 to 737 in 2010. The overall bi-annual incidence rate rose from 1999-00 to 2003-04 and mildly declined thereafter rose to 2009-10, with an insignificant trend (P = 0.489) over the study period. Regardless of gender, the higher age-specific incidence rate was noted in the younger groups (<30 years) and highest at <15 years. The incidence rates in younger groups were constantly higher in female population than in male one. The SMR from all causes was significantly increased at 3.00 (95% Confidence Interval (CI) 2.83-3.16) in patients with T1DM. The sex-specific SMR was 2.66 (95% CI 2.46-2.85) and 3.58 (95% CI 3.28-3.87) for male and female patients, respectively. For both sexes, the age-specific SMR peaked at 15-29 years. Conclusions: Among T1DM patients in Taiwan, there were significant increasing trends in males and female aged <15 years. We also noted a significantly increased overall and sex-specific SMR from all causes in patients with TIDM which suggests a need for improvements in treatment and care of patients with T1DM.