A pragmatic, scalable approach to obesity implemented in primary care has the potential to curtail population weight gain, according to findings from the PATHWEIGH trial. The study found that a multi-component care process successfully mitigated the weight gain observed with usual care and increased the likelihood of patients receiving weight-related treatment.¹
The PATHWEIGH intervention consisted of three components: endorsement from health system primary care leadership; an electronic health record (EHR)-driven care process designed to prioritise and facilitate weight management; and implementation strategies to support the care process and educate clinicians on obesity treatment.
The PATHWEIGH trial (NCT04678752) was a stepped-wedge, cluster-randomised pragmatic trial conducted in 56 primary care clinics in Colorado, USA.² The trial included 274,182 adults with a body mass index (BMI) of ≥25 kg/m² who had at least two measured weights between March 2020 and March 2024. Clinics were randomly assigned to one of three clusters, with staggered start dates for a one-way crossover from usual care to the intervention phase.
The co-primary outcomes were the average patient weight loss at 6 months and weight loss maintenance from 6 to 18 months.
Compared with usual care, the PATHWEIGH intervention was associated with a decrease in average weight of 0.29 kg at 6 months (95% CI: 0.27–0.32 kg; p<0.001) and a further 0.28 kg from 6 to 18 months (95% CI: 0.26–0.31 kg; p<0.001). This resulted in a total difference of 0.58 kg over 18 months (95% CI: 0.54–0.61 kg; p<0.001), effectively mitigating the population weight gain seen in the usual care arm.
The intervention also increased the likelihood of a patient receiving weight-related care by 23% (OR=1.23; 95% CI: 1.16–1.31; p<0.001). For patients who received such care, the intervention was associated with significantly greater weight loss, showing an adjusted difference of 2.36 kg over 18 months (95% CI: 2.31–2.42 kg; p<0.001). Even among patients who did not receive specific weight-related care, the intervention mitigated weight gain, with an adjusted difference of 0.32 kg over 18 months (95% CI: 0.30–0.35 kg; p<0.001).
No adverse safety signals were observed.
These findings demonstrate that implementing a structured, EHR-supported process within primary care can positively influence population weight trajectories. The study authors concluded, “PATHWEIGH is a pragmatic, scalable approach showing favorable impact on population weight.”¹ The results suggest that optimising existing workflows and resources can improve patient outcomes at scale, both by increasing the delivery of direct obesity care and by creating an environment that helps mitigate background weight gain.
References
1. Perreault L, Pan Q, Rodriguez C, et al. Implementation and effectiveness of a care process to prioritize weight management in primary care: a stepped-wedge cluster-randomized trial. Nat Med 2025. https://doi.org/10.1038/s41591-025-04051-5
2. Suresh K, Perreault L, Gritz RM, et al. PATHWEIGH, pragmatic weight management in adult patients in primary care in Colorado, USA: study protocol for a stepped wedge cluster randomized trial. Trials 2022;23:26. https://doi.org/10.1186/s13063-021-05954-7
This study was funded by the National Institutes of Health.
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