The Association between a Recorded Diagnosis of Obesity and Clinically Significant Weight Loss in the Primary Care Setting: A Nationwide Registry.

Introduction: Overweight and obesity (OW/OB) are underdiagnosed. The primary aim was to assess whether a diagnosis of OW/OB recorded by a primary care physician (PCP) is associated with clinically significant weight loss, compared to a missed diagnosis. The secondary aim was to investigate the association between OW/OB diagnosis and patient attendance at dietary consultations.

Methods: This retrospective, observational cohort study was conducted using a nationwide healthcare database. The study included a random sample of 200,000 adults with BMI ≥25 kg/m2, recorded on a primary care visit, between 2014 and 2020. Patients with prior diagnosis of OW/OB or obesity-related complications were excluded. The independent variable was OW/OB diagnosis recorded by the PCP immediately after BMI measurement. The outcome variable was ≥5% weight loss at a second weight measurement within 9-15 months. Multivariate regression analysis was applied.

Results: Of the 200,000 people with OW/OB, 36,033 (18.0%) had a diagnosis of OW/OB, and 37,368 (18.7%) had a second body weight measurement, of which 7,635 (20.4%) lost ≥5% of their baseline body weight. The prescription rate of anti-obesity medication was 1.2% and did not differ between patients who achieved weight loss and those who did not. Those with a recorded diagnosis were 2.6 times more likely to visit a dietitian (odds ratio [OR] 2.57, 95% confidence interval [CI]: 2.56-2.64) and 2.5 times more likely to achieve weight loss (OR 2.53, 95% CI: 2.46-2.60). After adjusting for multiple confounders, including attendance at dietary consultation, people who received OW/OB diagnosis were 32% more likely to achieve weight loss (OR 1.32, 95% CI: 1.28-1.36, p < 0.001) compared to people with missed diagnosis.

Conclusions: Recording a diagnosis of obesity among relatively healthy people is associated with clinically significant weight loss at 1-year follow-up, independent of attendance at dietary consultation. Early obesity diagnosis is a significant opportunity to promote weight loss in the primary care setting and may affect weight trajectory.