Association Between Additional Primary Care Services and Healthcare Expenditures

Research Objectives: To estimate the impact of additional primary care services on healthcare expenditures.

Study Design: Data were obtained from the Ingenix Impact Research and Development database. The database includes enrollment, medical, and pharmacy claims data for 53 million members. Patients were selected into the study if they were continuously enrolled and had one or more of the following chronic conditions from January 1, 2005-September 30, 2008: diabetes, coronary artery disease, congestive hearth failure, chronic obstructive pulmonary disease, asthma, depression, or chronic renal failure. Patients were also required to be between the ages of 18 and 64 and have claims data that were linkable to zip code information about socioeconomic factors. The Symmetry Suite of groupers was used to find patients with the conditions of interest and to estimate their health status via the episode risk group (ERG) score. The ERG score predicts a patient's future need for health care services and associated costs. Primary care services were measured as the ratio of claims from primary care doctors to all provider outpatient claims in a year. Multivariate analyses were conducted to estimate the association of impact of primary care services (both in the current and previous years) with healthcare expenditures, while controlling for patient demographics (age, gender, location, inferred income and race) and health status (obesity and ERG score).

Population Studied: After applying the above criteria, 409,717 patients were selected into the study.

Principle Findings: Average annual healthcare expenditures per person were $7,032. The average ratio of primary care to total outpatient provider claims in a year was 41%. The ratio of primary care to total outpatient provider claims in the current year had a significant negative impact on expenditures. A 10% increase in this ratio (e.g., from 41% to 51%) was associated with an average decrease in annual expenditures of about 5% ($318.50). Prior year primary care service use only marginally impacted expenditures.

Conclusions: Current year primary care service use was associated with significantly lower average annual healthcare expenditures. Implications for Policy: Policy-makers are again interest in the theory that better coordination of care can be obtained through increased utilization of primary care providers, which may lead to reduced costs. This study supports part of that theory.