The researchers extracted data from the UK General Practice Research Database to determine trends in weight change for each year from 1995 to 2010 for both prevalent and incident cases of diabetes, and also investigated the impact of different glucose-lowering regimens on weight. Results showed a continual increase in mean weight over time, specifically 8.6 kg for men and 6.3 kg for women.
At 6, 12 and 24 months there were significant changes in weight for the majority of glucose-lowering regimens. People who were prescribed metformin monotherapy had a median average reduction in weight of −1.0 kg at 6 months, −1.1 kg at 12 months and−1.5 kg at 24 months. Insulin monotherapy was associated with an average weight gain of 2.1 kg at 6 months, 3.4 kg at 12 months and 4.5 kg at 24 months.
In terms of combination therapy, at 6 months, the largest weight increase (2.6 kg) was seen in people who were prescribed metformin, insulin, sulphonylurea and a thiazolidinedione, and the largest reduction was in those prescribed metformin, insulin and exenatide (−5.0 kg). The largest weight increase at 12 months was in people prescribed insulin and a thiazolidinedione (4.1 kg) and the largest weight decrease was in those who were prescribed metformin and exenatide (−7.0 kg). At 24 months, the largest weight increase was in people treated with metformin, insulin, sulphonylurea and a thiazolidinedione (6.0 kg) and the largest decrease was in those treated with metformin and exenatide (−8.7 kg).
Over the 24-month period, mean HbA1c for people treated with insulin remained at 8.3%. For metformin, this fell from 7.7 to 7.1%; for metformin and sulphonylurea combined, it fell from 8.3 to 7.6%; and for sulphonylurea, it fell from 7.7 to 7.2%.
The authors noted that the progressive increase in weight observed in people with type 2 diabetes could be partly accounted for by the increase in weight in society in general. However, they also found little evidence that any treatment regimen was impacting upon the primary purpose of diabetes-related treatment of glucose control.
Reference
Morgan C et al (2012) Weight change in people with type 2 diabetes: secular trends and the impact of alternative antihyperglycaemic drugs. Diabetes Obes Metab 2012; Advance online publication
