Access to publicly funded weight management services in England using routine data from primary and secondary care (2007–2020): An observational cohort study

Adults living with overweight/obesity are eligible for publicly funded weight management (WM) programmes according to national guidance. People with the most severe and complex obesity are eligible for bariatric surgery. Primary care plays a key role in identifying overweight/obesity and referring to WM interventions. This study aimed to (1) describe the primary care population in England who (a) are referred for WM interventions and (b) undergo bariatric surgery and (2) determine the patient and GP practice characteristics associated with both. An observational cohort study was undertaken using routinely collected primary care data in England from the Clinical Practice Research Datalink linked with Hospital Episode Statistics. During the study period (January 2007 to June 2020), 1,811,587 adults met the inclusion criteria of a recording of overweight/obesity in primary care, of which 54.62% were female and 20.10% aged 45 to 54. Only 56,783 (3.13%) were referred to WM, and 3,701 (1.09% of those with severe and complex obesity) underwent bariatric surgery. Multivariable Poisson regression examined the associations of demographic, clinical, and regional characteristics on the likelihood of WM referral and bariatric surgery. Higher body mass index (BMI) and practice region had the strongest associations with both outcomes. People with BMI [greater than or equal to]40 kg/m.sup.2 were more than 6 times as likely to be referred for WM (10.05% of individuals) than BMI 25.0 to 29.9 kg/m.sup.2 (1.34%) (rate ratio (RR) 6.19, 95% confidence interval (CI) [5.99,6.40], p < 0.001). They were more than 5 times as likely to undergo bariatric surgery (3.98%) than BMI 35.0 to 40.0 kg/m.sup.2 with a comorbidity (0.53%) (RR 5.52, 95% CI [5.07,6.02], p < 0.001). Patients from practices in the West Midlands were the most likely to have a WM referral (5.40%) (RR 2.17, 95% CI [2.10,2.24], p < 0.001, compared with the North West, 2.89%), and practices from the East of England least likely (1.04%) (RR 0.43, 95% CI [0.41,0.46], p < 0.001, compared with North West). Patients from practices in London were the most likely to undergo bariatric surgery (2.15%), and practices in the North West the least likely (0.68%) (RR 3.29, 95% CI [2.88,3.76], p < 0.001, London compared with North West). Longer duration since diagnosis with severe and complex obesity (e.g., 1.67% of individuals diagnosed in 2007 versus 0.34% in 2015, RR 0.20, 95% CI [0.12,0.32], p < 0.001), and increasing comorbiditie