Trends in Physician Referrals in the United States, 1999-2009

Study Questions:

What are the changes in the annual rate of referrals to other physicians from physician office visits in the United States from 1999 to 2009?


The investigators analyzed nationally representative cross-sections of ambulatory patient visits in the United States, using a sample of 845,243 visits from the National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey from 1993 to 2009, focusing on the decade from 1999 to 2009. The main outcome measures were survey-weighted estimates of the total number and percentage of visits resulting in a referral to another physician across several patient and physician characteristics. Authors tested for trends across time using survey-weighted logistic regression by estimating the P value of the coefficient for year as an explanatory variable for the outcome of physician referral disposition across the relevant subgroup.


From 1999 to 2009, the probability that an ambulatory visit to a physician resulted in a referral to another physician increased from 4.8% to 9.3% (p < 0.001), a 94% increase. The absolute number of visits resulting in a physician referral increased 159% nationally during this time, from 41 million to 105 million. This trend was consistent across all subgroups examined, except for slower growth among physicians with ownership stakes in their practice (p = 0.02) or those with the majority of income from managed care contracts (p = 0.007). Changes in referral rates varied according to the principal symptoms accounting for patients’ visits, with significant increases noted for visits to primary care physicians from patients with cardiovascular, gastrointestinal, orthopedic, dermatologic, and ear/nose/throat symptoms.


The authors concluded that the percentage and absolute number of ambulatory visits resulting in a referral in the United States grew substantially from 1999 to 2009.


The study reports a marked increase in referral rates nationally from 1999 to 2009, with the absolute number of ambulatory visits resulting in a referral more than doubling during this period. This evolution in care patterns may be playing a role in the rising trajectory of health care spending in the United States because referrals to specialists may lead to increased use of higher-cost services. As federal and state policymakers consider policies for reforming the health care system, developing methods to measure appropriateness criteria for referrals and using these to promote appropriate referrals may be an important strategy for controlling growth in health care spending. Also, if payments for groups of patients are bundled, then generalists and specialists can organize their services in the most cost-effective way promoting more desirable clinical outcomes, including good communication and coordination between generalists and specialists.

Keywords: Physicians, Nose, Outcome Assessment (Health Care), Managed Care Programs, Physicians' Offices, Referral and Consultation, Physicians, Primary Care, Pharynx, Health Care Surveys, Logistic Models, United States

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