Are primary care services a substitute or complement for specialty and inpatient services?

Area of Science:

• Health Services Research
• Health Economics
• Primary Care Medicine

Background:

• Strategies to increase primary care utilization are common in healthcare systems.
• The impact of increased primary care use on other health services and costs is not fully understood.
• Understanding substitution or complementation effects is crucial for cost-effective healthcare delivery.

Purpose of the Study:

• To evaluate whether increased primary care service utilization leads to substitution or complementation of other health services.
• To assess the impact of increased primary care use on overall healthcare costs.
• To determine the cost-effectiveness of strategies promoting primary care access.

Main Methods:

• Utilized a natural experiment design within the Department of Veterans Affairs (VA) from 1995-1999.
• Analyzed encounter and cost data, comparing areas with new Community-Based Outpatient Clinics (CBOCs) to matched control areas.
• Employed Ordinary Least Squares (OLS) regression and instrumental variables analysis to address potential endogeneity bias.

Main Results:

• Increased access to primary care significantly predicted higher primary care visits.
• OLS showed increased primary care use correlated with higher specialty outpatient and inpatient services and costs.
• Instrumental variables analysis indicated increased primary care encounters were associated with decreased specialty medical encounters and no significant increase in physical health admissions or costs.

Conclusions:

• Increased primary care utilization does not necessarily drive up overall physical health costs.
• Health systems can promote primary care use without adverse financial consequences.
• Findings support the integration and expansion of primary care services within healthcare systems.