Objective: To study patterns of referral between primary and specialty care providers among Medicare beneficiaries and to identify correlates of the probability of referral.
Data sources: The 1992 and 1993 Medicare Current Beneficiary Survey (MCBS), including associated claims data. MCBS data are linked to the Area Resource File (ARF) and the Physician Identification Master Record (PIMR).
Study design: This is a retrospective design using cross-sectional descriptive and multivariate correlational analysis. Estimates are made for two years. Key variables include two alternative definitions of referrals, patient socio-demographic and health status, physician characteristics, and county-level descriptors.
Data collection: The MCBS is a panel survey of a stratified random sample of Medicare beneficiaries begun in 1991. The data are linked to Medicare claims records for survey respondents. The ARF is a health resources data set that contains more than 7,000 variables at the county level, including information on health facilities, health professions, services resources and utilization, and socioeconomic and environmental characteristics. The PIMR is a record of all physicians in the United States and describes their professional characteristics.
Principal findings: The overall rate of physician referrals in the MCBS, approximately 10 percent, is higher than that found in prior research, as is the level of self-referral to specialists at about 70 percent. Depending on the dependent variable definition, between 60 and 85 percent of all Medicare beneficiaries had at least one referral, and the average number of referrals per person per year was greater than two. Referrals show a multi-directional pattern rather than a simple pattern of primary to specialty care, with referrals between primary care physicians, referrals between specialists, and referrals from specialty to primary care being not uncommon. Strong predictors of referral include patient health and patient insurance coverage and income. Physician factors do not contribute much to explaining referrals.
Conclusions: Medicare referral patterns are similar to those found in other studies. Patient factors appear to be a more important factor in explaining referrals than was estimated from prior research. Additional research is needed to explain the more complex dynamics of referral patterns.