The National Ambulatory Medical Care Survey: A resource for understanding the outpatient dermatology treatment

Background: The National Ambulatory Care Survey (NAMCS) collects information on outpatient medical care in the United States. Key characteristics of the NAMCS methodology are not well recognized. We describe the NAMCS survey design and patient visits to dermatologists and to present information on the validity of the NAMCS data by comparing key features of the dermatologist sample to other surveys of dermatologists. Methods: NAMCS data on dermatologists and skin-related visits from 1993 to 2010 were analyzed and compared to the Dermatology Physician Profile Survey (DPPS), a survey by the American Academy of Dermatology. Results: A total of 29 554 patient visits to dermatologists were sampled from 1993 to 2010. On average, 118 dermatologists were sampled annually to participate in the NAMCS, and response rates ranged from 47 to 77%. The NAMCS and the DPPS found similar dermatologist demographics, practice settings and reimbursement sources. Conclusion: Overall, the NAMCS achieves high-response rates and provides a generalizable sample that has been used in scores of studies of dermatology outpatient treatment. In a time of changing health care delivery systems, NAMCS is valuable for understanding how physicians care for patients with skin disease.