Workflow Redesign Improved Weight Care in Primary Care Trial

Key Takeaways

• PATHWEIGH was associated with a modest population-level change in weight trajectory during routine primary care.
• The intervention phase was linked to more discernable weight-related care and larger weight reductions among patients who received such care.
• No health metric worsened by 1% or more, and most clinics showed at least moderate implementation engagement.

The intervention also coincided with more discernable, documented weight-related care across the network in the Nature Medicine trial. Investigators said the difference should be viewed as a population-level shift rather than a clinically meaningful change for an individual patient.

Researchers used an effectiveness-implementation hybrid type 1 stepped-wedge design, with clinic-level randomization and one-way crossover from usual care to intervention in one Colorado health system. The primary analysis included 274,182 adults aged 18 years or older with BMI 25 kg/m2 or higher and at least two measured weights. PATHWEIGH combined primary care leadership endorsement, an EHR-driven care process, and implementation strategies to support workflow use and clinician education on obesity treatment. The workflow centered on a weight-prioritized visit, a portal questionnaire sent 72 hours before the encounter, and note-embedded tools and order sets, with coprimary endpoints of weight change at 6 months and weight-loss maintenance from 6 to 18 months. Usual care ran from March 2020 to March 2021, followed by staggered crossover in 2021, 2022, and 2023, so outcomes reflected usual-care and intervention phases.

Estimated average weight was 0.29 kg lower from the first weight to 6 months and 0.28 kg lower from 6 to 18 months, together accounting for the 18-month difference. PATHWEIGH also increased the likelihood of receiving discernable weight-related care, with an odds ratio of 1.23 and a 95% confidence interval of 1.16 to 1.31. Trackable care included referrals, bariatric procedures, and patient acknowledgement of active anti-obesity medication use, and about one quarter of eligible patients received such care at least once. In associative analyses, the adjusted 18-month difference reached 2.37 kg between intervention-phase patients who did versus did not receive discernable care, while mitigated weight gain was 0.32 kg among those never receiving care. The intervention phase was also associated with elimination of the population weight gain seen during usual care.

Across eight implementation activities, 64% of clinics showed moderate engagement, 21% showed greater engagement, and 14% showed lesser engagement. The most common activities were the virtual introductory meeting and in-person all-clinic training. No health metric changed by 1% or more in an unfavorable direction, and investigators said the higher intervention-phase death rate likely reflected an older intervention-phase patient mix; COVID-related deaths became less common later in the trial. Anti-obesity medication use mediated 4% of observed weight loss. Limitations included sporadic real-world weights requiring trajectory modeling, generalizability restricted to patients with two measurements, possible COVID or medication trend effects, and associative care analyses in the PATHWEIGH study.