Changes in the prognosis of Japanese patients who developed type 1 diabetes before the age of 30 years

Mortality in childhood-onset type 1 diabetes mellitus with onset between 1959 and 1996: A population-based study in Hokkaido, Japan

Aim

To examine the mortality rate and causes of death in childhood-onset type 1 diabetes in Japan.

Methods

For a median 36.7 years, we followed 391 patients under the age of 15 years who developed type 1 diabetes between 1959 and 1996. We calculated the mortality rate per 100,000 person-years and the standardised mortality ratio (SMR) according to risk factors.

Results

The mortality rates and SMRs were 823 and 8.8 with onset during 1959-1979, 370 and 5.9 with onset during 1980-1989, and 133 and 3.2 with onset during 1990-1996, respectively. The mortality rates and SMRs were 359 and 8.4 in men, and 235 and 6.0 in women. Mortality rates and SMRs were 452 and 7.3 in patients with diabetes onset before puberty and 514 and 6.3 in patients with onset after puberty. The main causes of death with shorter disease duration were sudden death, accident/suicide, and acute diabetic complications. With a more than 30-year disease duration, the main causes of death were end-stage renal disease and cardiovascular disease.

Conclusions

This cohort study revealed a decrease in the mortality rate between 1959-1979 and 1990-1996 in patients with childhood-onset type 1 diabetes in Japan. Patients with onset after puberty had a higher mortality rate than those with onset before puberty.

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.