Clinical background of Japanese patients with type 1 diabetes mellitus who have received insulin therapy for 50 years or longer

Aims: We clarified the clinical background of Japanese patients with type 1 diabetes mellitus (T1DM) who have received insulin therapy for 50 years or longer.

Methods: Of 1,412 patients diagnosed with T1DM at an age younger than 30 years old between 1962 and 2000, 29 had a 50-year or longer history of diabetes. We investigated the mean values of HbA1c and systolic blood pressure (SBP) during follow-up, as well as diabetic retinopathy, diabetic nephropathy, and macroangiopathy.

Results: The mean age of the subjects at the time of diagnosis was 10 years and that at the completion of this survey was 66 years. The mean follow-up period was 43 years. The mean HbA1c value and SBP during the follow-up period were 8.2% and 130 mmHg, respectively. Seventeen percent of patients did not have diabetic retinopathy, 59% had proliferative retinopathy, and 66% had undergone photocoagulation. Fifty-four percent of patients did not have microalbuminuria and 11% had end-stage renal disease. Macroangiopathy was observed in 46%, cardiovascular disease (CVD) in 25%, and ischemic stroke in 18%.

Conclusions: It became possible for patients with T1DM to live more than 50 years in Japan.