Introduction: Variability in the referral patterns of primary care physicians is well established. The objective of this study was to determine which factors have the most impact on a family physician's decision to refer a patient.
Methods: In March 2002, surveys were mailed to 1200 randomly selected members of the American College of Osteopathic Family Physicians (ACOFP) and 1200 randomly selected members of the American Academy of Family Physicians (AAFP). To increase the response rate, there were two follow-up mailings to non-responders at 2 and 4 weeks following the initial mailing. Main outcome measures included: physician and practice characteristics (ie, age, sex, degree, training, practice type, population) and perceived workload. 'High' referral rate was defined as 11% or more of patients seen (the top quartile in the survey). Logistic regression models were used to determine which factors influence physician referral rate. Variables of interest for predicting high referral rates were age group, gender, DO versus. MD, residency training, perceived workload, years in practice, type of practice, and practice site population.
Results: Four hundred and fifty surveys sent to ACOFP members and 419 of those sent to AAFP members were returned (37% overall response rate). The significant differences in referral rates were for DO versus MD (OR = 1.46; 95% CI, 1.07-1.98); residency trained versus not residency trained (OR = 1.40; 95% CI, 1.00-1.97); and population of the practice site: 25,001-100,000 (OR = 1.56; 95% CI, 1.05-2.31) and more than 100,000 (OR = 1.61; 95% CI, 1.12-2.32). After adjustment for potential confounding variables, the only significant finding was population of the practice site, 25,001-100,000 (OR = 1.88; 95% CI 1.22-2.90) and more than 100,000 (OR = 1.71; 95% CI, 1.14-2.57).
Conclusions: The only factor that showed a significant association with having a high referral rate was the population of the practice site. Physicians in larger towns and cities have higher referral rates than physicians in small towns.