ObjectiveTo examine the different combinations of health insurance and types of payments, and their influence on physicians' prescribing of antihypertensive drug therapy.DesignThe study was based on information collected in physicians' practices, obtained from medical records and physician visits. The analysis uses simple logistic and ordinal logistic regressions in order to test the influence of different combinations of insurance profiles and types of payments on antihypertensive drug prescribing. Special attention was given to Medicare patients due to the lack of coverage for prescription drugs in this program.Patients and ParticipantsA sample of 1844 individuals diagnosed with hypertension was extracted from the 1996 US National Ambulatory Care Survey, a national probability sample survey conducted among physicians.ResultsThere was a significant reduction in the likelihood of access to drug therapy for patients insured with Medicare only compared to those patients with other types of insurance. Patients with Medicare cover only that were in a Health Maintenance Organization or had a prepaid type of payment were twice as likely to be prescribed antihypertensive drug therapy than patients with Medicare cover only and whom had other forms of payment such as fee for service or payment within a Preferred Prescriber Organization.ConclusionsThe results suggest that the health insurance status of patients does have some influence on physician prescribing decisions for patients with hypertension, especially for patients covered by Medicare alone. This indicates that the lack of additional coverage for prescription drugs in the US health insurance system may limit access to antihypertensive drug therapy.