Objective: We performed a cross-sectional observation study to investigate the influence of long-term treatment with biguanide on the reduction of vitamin B12 (Vit B12) levels and prospectively evaluated the clinical benefits of Vit B12 supplementation. Methods: We examined 28 patients with type 2 diabetes mellitus (T2DM) who had taken biguanide over a five-year period; all of the patients had been taking metformin at the time of registration. We also examined 20 T2DM patients who had not been taking biguanide. First their serum Vit B12 concentrations were measured and the patients' tendon reflexes and vibratory sensations were examined. Nine Vit B12 deficient (≤298 pg/mL) patients were prospectively investigated after the administration of mecobalamin (1,500 μg/day) for a six-month period. Results: The average dose of metformin was 950 mg per day (250-1500 mg). The Vit B12 levels did not decrease in the patients who received 250-750 mg of metformin per day. However, they significantly decreased in those taking 1.5 g of metformin per day. Mecobalamin supplementation improved the neurological findings in the six patients out of nine with decreased Vit B12 levels. Conclusions: It is clinically useful to screen the serum Vit B12 levels in Japanese T2DM patients who take metformin at doses of ≥1.5 g per day as it will allow for the timely diagnosis of the onset of neuropathy.

Data on treatment aspects, especially psychological and social aspects, for 508 people with diabetes, 120 patients' family members living with people with diabetes, and 283 healthcare professional from Japan gathered by the second Diabetes Attitudes, Wishes and Needs study (DAWN2™) were compared with the global data for 8,596 patients, 2,057 family members living with people with diabetes, and 4,785 healthcare professional from 17 countries (including Japan). The results showed that overall, diabetes mellitus placed a large burden on the patients and their families in daily life and also caused them to experience great anxiety about hypoglycemia. The patients' treatment and psychological status varied by country. Patients and healthcare professional showed different levels of awareness on the use or non-use of actually performed interventions. Although Japanese patients were well informed on the utility of long-term glycemic control indices as a diabetes control tool, they were less aware of the need for an examination of the feet, diet control practices, or medical interventions, reflecting the patients' lives and psychological status. Japanese healthcare professionals hoped for varied programs educating patients on diabetes care and were little involved in but strongly motivated to participate in future programs addressing the psychological aspects, fostering behavior modification, and providing sufficient self-care support.

We herein report the case was of a 90-year-old Japanese man. One year and 5 months prior to presenting to our hospital, he had shown a fasting plasma glucose level of 121 mg/dL. Four months later, he was diagnosed with diabetes, based on a fasting plasma glucose level of 169 mg/dL, and an HbA1c value of 7.2 %. He was diagnosed with type 2 diabetes due to the absence glutamic acid decarboxylase (GAD) antibodies and because treatment with oral hypoglycemic agents was effective. His glucose control gradually deteriorated, and he was admitted to our hospital. On admission, his HbA1c level was as high as 11.0 %, and his fasting serum and urinary C-peptide levels were decreased to 0.6 ng/mL, and 22.9 μg/day, respectively. Based on these results, multiple insulin injections were administered. The patient was positive for insulinoma-associated antigen-2 (IA-2) antibodies (7.8 U/mL, reference range, <0.4 U/mL) and the patient's HLA genotype, which included DRB1*04: 05-DQB1*04: 01, indicated susceptibility to type 1 diabetes. These findings indicated a possible diagnosis of slowly progressive type 1 diabetes mellitus (SPIDDM). After the patient was discharged, zinc transporter 8 (ZnT8) antibody positivity was also detected. We herein report a rare case of an elderly man with possible SPIDDM who was IA-2 antibody-positive and GAD antibody-negative.

The principal causes of death among 45,708 patients with diabetes (29,801 men and 15,907 women) who died in 241 hospitals throughout Japan during 2001-2010 were determined based on a survey of the hospital records. Autopsy had been conducted in 978 of the 45,708 cases. 1. The most frequent cause of death was malignancy (38.3 %), followed, in order of descending frequency, by infections (17.0 %) and then vascular diseases (14.9 %), including renal failure (3.5 %), ischemic heart diseases (4.8 %) and cerebrovascular diseases (6.6 %). Diabetic coma associated with hyperglycemia with or without ketoacidosis accounted for only 0.6 % of the deaths. 2. With regard to the relationship between the age and cause of death in patients with diabetes, the incidence of death due to vascular diseases was higher in patients over the age of 30 or 40 years, and 97.0 % of the total deaths due to vascular diseases were observed in patients over 50 years of age. The incidence of death due to infections, especially pneumonia, increased in an age-dependent fashion, and 80.7 % of the total deaths due to pneumonia were observed in patients over 70 years of age. 3. "Poorer" glycemic control was associated with a reduced lifespan among patients with diabetes, especially those with nephropathy. The average age at death in the survey population was 72.6 years. The lifespan was 1.6 years shorter in patients with "poorer" glycemic control than in those with "better" glycemic control. 4. In patients with diabetes of less than 10 years' duration, the incidence of death due to macroangiopathy was higher than that due to nephropathy. 5. Of the 45,708 patients with diabetes, 33.9 % were on oral medication, 41.9 % received insulin therapy, and 18.8 % were treated by diet alone. Among the patients in whom the cause of death was diabetic nephropathy, a high percentage was on insulin therapy (53.7 %). 6. The average age at death of the 45,708 patients with diabetes was 71.4 years in men and 75.1 years in women. However, the report of the Ministry of Health and Welfare of Japan in 2010 set the average lifespan of the Japanese at 79.6 years for men and 86.3 years for women. Thus, the average lifespan of patients with diabetes in Japan still appears to be markedly shorter than that of the general Japanese population. However, the differences in the lifespan between patients with diabetes and the general population were less than those in previous surveys.