Association of the Functional Medicine Model of Care With Patient-Reported Health-Related Quality-of-Life Outcomes

IMPORTANCE: The incidence of chronic disease is increasing along with health care–related costs. The functional medicine model of care provides a unique operating system to reverse illness, promote health, and optimize function. The association between this model of care and patient’s health-related quality of life (HRQoL) is unknown. OBJECTIVE: To assess the association between functional medicine and patient-reported HRQoL using Patient-Reported Outcome Measurement Information System (PROMIS) global health measures. DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort study was performed to compare 7252 patients aged 18 years or older treated in a functional medicine setting with propensity score (PS)–matched patients in a primary care setting. Sensitivity analyses assessed improvement limited to patients seen at both 6 and 12 months. The study included patients who visited the Cleveland Clinic Center for Functional Medicine or a Cleveland Clinic family health center between April 1, 2015, and March 1, 2017. MAIN OUTCOMES AND MEASURES: The primary outcome was change in PROMIS Global Physical Health (GPH) at 6 months. Secondary outcomes included PROMIS Global Mental Health (GMH) at 6 months and PROMIS GPH and GMH at 12 months. The PROMIS GPH and GMH scores were transformed to a T-score from 0 to 100 with a mean of 50. Higher scores indicate a better health-related quality of life. RESULTS: Of the 7252 patients (functional medicine center: 1595; family health center: 5657), 4780 (65.9%) were women; mean (SD) age was 54.1 (16.0) years. At 6 months, functional medicine patients exhibited significantly larger improvements in PROMIS GPH T-score points than were seen in patients treated at a family health center (mean [SD] change, functional medicine center: 1.59 [6.29] vs family health center: 0.33 [6.09], P = .004 in 398 PS-matched pairs). At 12 months, functional medicine patients showed improvement similar to that observed at 6 months; however, comparisons with patients seen at the family health center were not significant. Patients in the functional medicine center with data at both 6 and 12 months demonstrated improvements in PROMIS GPH (mean [SD], 2.61 [6.53]) that were significantly larger compared with patients seen at a family health center (mean [SD], 0.25 [6.54]) (P = .02 in 91 PS-matched pairs). CONCLUSIONS AND RELEVANCE: In this study, the functional medicine model of care demonstrated beneficial and sustainable associations with patient-reported HRQoL. Prospective studies are warranted to confirm these findings.