Primary care quality and cost for privately insured patients in and out of US Health Systems: Evidence from four states

Abstract

Objective: To characterize physician health system membership in four states between 2012 and 2016 and to compare primary care quality and cost between in-system providers and non-system providers for the commercially insured population.

Data sources: Physician membership in health systems was obtained from a unique longitudinal database on health systems and matched at the provider level to 2014 all-payer claims data from Colorado, Massachusetts, Oregon, and Utah.

Study design: Using an observational study design, we compared physicians in health systems to non-system physicians located in the same state and geography on average cost of care (risk-adjusted using the Johns Hopkins' Adjusted Clinical Grouper), five HEDIS quality measures, one measure of developmental screening, and two Prevention Quality Indicator Measures.

Data collection/extraction methods: Patients in commercial health plans were attributed to a primary care physician accounting for the plurality of office visits. A cohort for each quality measure was constructed based on appropriate measure specifications.

Principal findings: The share of physicians in health systems increased steadily from 2012 to 2016 and ranged from 48% in Colorado to 63% in Utah in 2016. Compared to physicians not in a system, system physicians performed similarly on most HEDIS quality metrics compared to non-system physicians. Patients attributed to in-system physicians had about 40% higher rates (P < .05) of Ambulatory Care Sensitive Admissions (measured in admissions per 100 000:921.33 in-system vs 674.61 not-in-system for acute composite; 2540.91 in-system vs 1972.17 for chronic composite In-system providers were associated with $29 (P < .05) higher average per member per month costs (453.37 vs 432.93). Overall, differences in performance by system membership were relatively small compared to differences across states and geography.

Conclusion: A growing share of physicians is part of a health system from 2012 to 2016. Providers in health systems are not delivering primary care more efficiently than non-system providers for the commercially insured.

Keywords: cohort studies; geography; health care cost; ownership; primary care; quality of health care.

FIGURE 1

Share of physicians in health systems. Notes: Data from the Health System and Provider Database. Physicians are assigned to states based on their office location. Data on delivery system organization come from the Health System and Provider Database (HSPD) created by the National Bureau of Economic Research Center of Excellence for research performed under the AHRQ Comparative Health Systems Performance initiative. ¹⁰ Data from more than 20 sources were combined to identify health systems as groups of commonly owned or managed provider organizations and facilities containing at least one general short‐term acute care hospital, ten primary care physicians, and 50 total physicians co‐located within a single Hospital Referral Region (HRR). In the HSPD, physicians are identified by their National Provider Identification (NPI) number and assigned to practices based on billing patterns observed in claims data and reassignment of Medicare payments observed in the CMS Provider Enrollment and Chain Ownership System (PECOS). For this study, physicians were assigned to the practice accounting for the majority of their claims [Color figure can be viewed at wileyonlinelibrary.com]

FIGURE 2

Cross‐state comparison of cost and quality. Note: All quality measures were computed from the APCD claims data for individuals attributed to a primary care provider accounting for the plurality of evaluation and management (E&M) visits in 2014. For HEDIS metrics, higher rates suggest higher quality. For PQI metrics, lower rates are usually interpreted as better primary care quality [Color figure can be viewed at wileyonlinelibrary.com]

FIGURE 3

State and geography adjusted comparisons between in‐system and non‐system providers (* indicates statistically significant differences at the 5% level). Note: Bars show the state and geography adjusted means for in‐system and non‐system providers across all four states, using predicted results from regression results from Equation (2) with the state and geography distribution set at the sample average. AAantibio stands for Adult Avoidance of Antibiotics, ADDinit stands for ADD Initiation Phase, AMMacut stands for AMM Acute Phase, ADOwell stands for Adolescent Well Care, Chalmy stands for Chlamydia Screening, DEVscrn stands for Developmental Screening, PQIacut and PQIchro stand for PQI Acute Composite and PQI Chronic Composite, respectively. PMPM stands for per member per month cost [Color figure can be viewed at wileyonlinelibrary.com]