Association of High-Cost Health Care Utilization With Longitudinal Changes in Patient-Centered Medical Home Implementation.

In 2010, the US Veterans Health Administration (VHA) implemented one of the largest patient-centered medical home (PCMH) models in the United States, the Patient Aligned Care Team initiative. Early evaluations demonstrated promising associations with improved patient outcomes, but limited evidence exists on the longitudinal association of PCMH implementation with changes in health care utilization. To determine whether a change in PCMH implementation is associated with changes in emergency department (ED) visits, hospitalizations for ambulatory care-sensitive conditions (ACSCs), or all-cause hospitalizations. This cohort study used national patient-level data from the VHA and Centers for Medicare & Medicaid Services between October 1, 2012, and September 30, 2015. A total of 1 650 976 patients from 897 included clinics were divided into 2 cohorts: patients younger than 65 years who received primary care at VHA sites affiliated with a VHA ED and patients 65 years or older who were enrolled in both VHA and Medicare services. Clinics were categorized on improvement or decline in PCMH implementation based on their Patient Aligned Care Team implementation progress index (Pi2) score. Change in the number of ED visits, ACSC hospitalizations, and all-cause hospitalizations among patients at each clinic site. The study included a total of 1 650 976 patients, of whom 581 167 (35.20%) were younger than 65 years (mean [SD] age, 49.03 [10.28] years; 495 247 [85.22%] men) and 1 069 809 (64.80%) were 65 years or older (mean [SD] age, 74.64 [7.41] years; 1 050 110 [98.16%] men). Among patients younger than 65 years, there were fewer ED visits among patients seen at clinics that had improved PCMH implementation (110.8 fewer visits per 1000 patients; P < .001) and clinics that had somewhat worse implementation (69.0 fewer visits per 1000 patients; P < .001) compared with clinics that had no change in Pi2 score. There were no associations of change in Pi2 scores with all-cause hospitalizations or ACSC hospitalizations among patients younger than 65 years. In patients 65 years or older, those seen at clinics that had somewhat worse PCMH implementation experienced fewer ED visits (20.1 fewer visits per 1000 patients; P = .002) and all-cause hospitalizations (12.4 fewer hospitalizations per 1000 patients; P = .007) compared with clinics with no change in Pi2 score. There was no association between change in Pi2 score with ACSC hospitalizations among patients 65 years or older. There were no consistent associations of change in Pi2 score with high-cost health care utilization. This finding highlights the key differences in measuring PCMH implementation longitudinally compared with cross-sectional study designs.