Implementation and effectiveness of a care process to prioritize weight management in primary care: a stepped-wedge...

Scalable, pragmatic approaches to obesity implemented in primary care have the potential to curtail population weight gain. In a stepped-wedge cluster-randomized pragmatic trial in the state of Colorado, USA, 56 primary care clinics were randomly assigned to three clusters with staggered start dates for a one-way crossover from usual care to the intervention phase. The intervention (PATHWEIGH) included three components: (1) health system primary care leadership endorsement; (2) an electronic health record-driven care process designed to prioritize, facilitate and expedite weight management; and (3) implementation strategies to support use of the care process and educate clinicians on obesity treatment. The coprimary outcomes were average patient weight loss at 6 months and weight loss maintenance from 6 months to 18 months. In total, 274,182 adults with a body mass index ≥25 kg m² had at least 2 measured weights in one of the clinics between March 2020 and March 2024. A counterfactual analysis comparing differences in weight between the intervention and usual care suggests that PATHWEIGH decreased average weight by 0.29 kg (95% confidence interval (CI): 0.27 kg, 0.32 kg) from the first weight to 6 months later (P < 0.001) and 0.28 kg (95% CI: 0.26 kg, 0.31 kg) from 6 months to 18 months (P < 0.001) for a total difference of 0.58 kg (95% CI: 0.54 kg, 0.61 kg; P < 0.001). PATHWEIGH increased the likelihood of receiving weight-related care during the intervention (OR = 1.23; 95% CI 1.16, 1.31; P < 0.001). The intervention was associated with greater weight loss for those receiving weight-related care (adjusted difference of 2.36 kg over 18 months; 95% CI: 2.31 kg, 2.42 kg, P < 0.001), and weight gain was mitigated in the intervention even when patients did not receive weight-related care (adjusted difference of 0.32 kg over 18 months, 95% CI: 0.30 kg, 0.35 kg; P < 0.001). Thus, PATHWEIGH is a pragmatic, scalable approach showing favorable impact on population weight. ClinicalTrials.gov registration: NCT04678752 .