How effective is weight loss in reducing cardiometabolic risk? An observational analysis of two randomised controlled trials of community weight loss programmes

Abstract

Abstract Background: Guidelines recommend clinicians identify individuals at high cardiometabolic risk and support weight loss in those with overweight or obesity. However, individual level data quantifying the benefits of weight change for individuals, to guide these discussions in primary care, is lacking. Aim: Examine how weight change affects cardiometabolic risk factors, to facilitate shared decision-making between patients and clinicians regarding weight loss. Design and setting: Observational analysis using data from two trials of referral of individuals with overweight or obesity in primary care to community weight loss groups. Method: Linear mixed effects regression modelling, examining the association between weight change and change in systolic and diastolic blood pressure (SBP,DBP), fasting glucose, HbA1c, and lipid profile across multiple timepoints (baseline to 24 months). Subgroup analyses examined changes in individuals with hypertension, diabetes and hyperlipidaemia. Results: 2041 participants had a mean(±SD) age of 50 ±13.5 years, baseline weight 90.6 ±14.8kg and Body Mass Index 32.7 ±4.1kg/m2. Mean(±SD) weight change was -4.3 ±6.0kg. All outcome measures showed statistically significant improvements. Each 1kg weight loss was associated with 0.4mmHg reduction in SBP and 0.3mmHg reduction in DBP, or 0.5mmHg and 0.4mmHg/kg respectively in people with hypertension. Each 1kg weight loss was associated with 0.2mol/mol reduction in HbA1c, or 0.6mmol/mol in people with diabetes. Effects on plasma lipids were negligible. Conclusion: Weight loss achieved through referral to community weight loss programmes, which are commonly accessible in primary care, can lead to clinically relevant reductions in blood pressure and glucose regulation, especially in those at highest risk.