Weight change and risk of obesity-related complications: A retrospective population-based cohort study of a UK primary care database

Aims: To examine associations between weight loss/gain and risk of developing 13 obesity-related complications (ORCs), stratified by baseline body mass index (BMI).

Materials and methods: In this retrospective cohort study, we included adults with obesity (>30 kg/m² ) from the UK Clinical Practice Research Datalink GOLD database with weight change (-50% to +50%) between Years 1 and 4 (N = 418 774 [median follow-up: 7 years]). Associations between weight change, baseline BMI and risk of developing ORCs during follow-up were assessed using Cox proportional hazard models.

Results: The impact of weight change on ORCs was generally dependent on baseline BMI. Four clear patterns were seen across the 13 outcomes. Pattern 1 showed greatest weight loss benefit for people with low baseline BMI (type 2 diabetes, sleep apnoea, hypertension and dyslipidaemia); Pattern 2 showed most weight loss benefit at lower baseline BMI but no significant weight loss effect at higher baseline BMI (asthma, hip/knee osteoarthritis and polycystic ovary syndrome); Pattern 3 showed benefit in most cardiovascular diseases with weight loss (chronic kidney disease, heart failure, atrial fibrillation and venous thromboembolism), but no additional benefit with >10% weight loss; Pattern 4 showed no clear relationship between weight change and unstable angina/myocardial infarction and depression. We found similar but opposite patterns for weight gain.

Conclusions: Weight loss benefit is dependent on weight loss magnitude and initial BMI, and weight gain is associated with a similar risk increase. Four patterns of association were identified between degree of weight change, baseline BMI and 13 ORCs.