Clinical effects of metformin in patients with nonobese type 2 diabetes

Metformin is indicated for obese insulin-resistant type 2 diabetic patients but also acts clinically in nonobese patients. We retrospectively studied 275 patients-172 men and 103 women undrergoing 1-year metformin monotherapy as outpatient at Saiseikai Central Hospital, Tokyo. Based on BMI, we divided them into Group 1 with a BMI of 22 or less, Group 2 with 22.1-24.9, and Group 3 with 25 and over. By group, baseline age was 60.1±9.8 years old for 1, 59.8±8.6 for 2, and 55.8±11.9 for 3. Diabetes duration was 13.0±7.2 years for Group 1, 11.1±7.3 for Group 2, and 8.7 ±6.3 for Group 3. Group 1 baseline HbA1c was 8.07±0.71%, 8.15±0.96% for Group 2, and 8.16±1.28% for Group 3. Six months after metformin monotreatment alone, HbA1c had decreased by -0.79±0.88% in Group 1, -0.81±1.0% in Group 2, and -0.73±1.06 % in Group 3, with no significant difference. Patient age Group 3 overall was somewhat younger and diabetes duration shorter, but the HbA1c reduction from baseline to six months was similar in all groups. In summary, the metformin effect in nonobese patients was equally effective as in obese patients.