The Relationship Between the Supply of Primary Care Physicians and Measures of Breast Health Service Use

Background: To investigate whether women are more likely to report receipt of a mammography recommendation from a doctor or mammography use if they reside in primary care service areas (PCSAs) having a greater number of clinically active primary care physicians. Materials and Methods: The analysis used a nationally representative sample of women, aged 40 years and above (n = 10,706 unweighted respondents), extracted from the 2005 National Health Interview Survey. The restricted geocoded addresses of the respondents were linked to PCSA data on physician density at a secure research data center. Multivariable logistic regression was used to determine whether, after adjustment, specific measures of primary care providers (e.g., the number of obstetricians and gynecologists [Ob-GyNs] per 10,000 population) were associated with either recommendation receipt or mammography use. Results: After adjusting for other factors, a one-unit increase in the PCSA number of Ob-GyNs per 10,000 population increased the odds of mammography recommendation receipt by 9% and the odds of mammography use by 9%. The ratio of international medical graduate Ob-GyNs to US-trained Ob-GyNs in a PCSA was negatively associated with mammography use. Conclusion: The results from this nationwide study underscore the importance of using physician density measures estimated from within bounded medical markets, where women reside and actually seek preventive breast health services. Results support the hypothesis that PCSA physician supply is independently associated with both mammography recommendation receipt and mammography utilization.