Weight changes in type 2 diabetes and the impact of gender

Many studies suggest that weight gain occurs during treatment of type 2 diabetes, irrespective of the treatment type. The aim of this study was to address the questions (i) whether weight gain is inevitable in patients treated for type 2 diabetes, and (ii) whether treatment escalation is prompted by a rise in glycaemic control [haemoglobin A 1c (HbA 1c)] or weight gain.

A diabetes database was used to identify all patients with type 2 diabetes attending our clinic between 1 January 1990 and 31 December 2000. To facilitate further analysis, independent anonymized database resources were established. Data collected included height, weight, gender, HbA(1c), age and diabetes treatment at each visit.

One thousand and eighty-four patients were included; after 6 months of treatment, patients' average weight had reduced by 1.0 kg (s.d. 4.6) (p < 0.001). Sixty per cent of the patients had either a decrease or no change in weight, while 40% demonstrated a weight gain. Women demonstrated more weight loss than men. After a mean follow-up of 50 months (s.d. 25.7), 439 patients (40%) who received treatment with diet alone, diet followed by metformin or metformin alone demonstrated a maintained weight reduction in addition to improved glycaemic control. A rise in HbA(1c) rather than weight gain prompted treatment change.

This study provides evidence that weight gain is not a necessary consequence of the treatment of type 2 diabetes. Women were more successful than men in losing weight, and diet, with or without the addition of metformin, was the treatment type most usually associated with weight loss.