1. ¹Medical Service, Department of Veterans Affairs, Northern California Health Care System, Martinez, California, USA
2. ²Center for Health Services Research in Primary Care and Department of Medicine, University of California, Davis, California, USA
3. ³Pharmacy Service, Department of Veterans Affairs, Northern California Health Care System, Martinez, California, USA
4. ⁴School of Pharmacy, University of California, San Francisco, California, USA
5. ⁵School of Pharmacy, University of the Pacific, Stockton, California, USA

Correspondence: Dr. David Siegel, Chief, Medical Service, Department of Veterans Affairs NCHCS, 150 Muir Road, Martinez, CA 94553, e-mail: Siegel.David@Martinez.VA.gov

^*The views expressed in the article do not necessarily represent the views of the Department of Veterans Affairs or of the United States Government.

Received 4 May 1998; Revised  0000; Accepted 16 June 1998.

Abstract

Patterns of antihypertensive drug use, the cost of this care and potential savings with changes of treatment patterns, were studied for all hypertensives treated at US Veterans Affairs (VA) medical facilities for fiscal years 1995 and 1996. Data was aggregated by individual medication as well as by antihypertensive drug class. Cost estimates were based on median cost and number of units for each dosage form of each medication dispensed at all facilities. Potential savings were estimated by substituting -blockers or diuretics for calcium antagonists. In a subset of patients the prevalence of hypertension, and among hypertensives the prevalence of coronary artery disease, congestive heart failure, and diabetes mellitus, was determined. For these patients, patterns of treatment by antihypertensive drug class was examined.

For all VA facilities, of the 10 most frequently prescribed antihypertensives in 1995, four were calcium antagonists, two angiotensin converting enzyme (ACE) inhibitors, two -blockers, and two diuretics. In 1996, this was changed by the addition of an ACE inhibitor and the subtraction of a diuretic combination. Calcium antagonists accounted for 37% of treatment days in 1995 and 35% in 1996, ACE inhibitor use went from 34% to 36%, -blockers from 17% to 18%, and diuretic use remained at 12%. In 1996, approximately 86.6 million dollars were spent on calcium antagonists, 51.8 million on ACE inhibitors, 7.9 million on -blockers, and 3.6 million on diuretics. The estimated annual cost savings for each 1% conversion of calcium antagonists to -blockers would be $713,000 and to diuretics $758,000. In a subset of 7526 hypertensive patients with known comorbid conditions, calcium antagonists and ACE inhibitors were also the most commonly used drug classes for all categories of patients, including those without coronary artery disease, congestive heart failure, and diabetes mellitus.

Calcium antagonists and ACE inhibitors were the most commonly dispensed antihypertensives at VA facilities for both 1995 and 1996, with a small decrease in calcium antagonist use from 1995 to 1996. The cost implications of these practice patterns as compared with the primary use of diuretics and -blockers are enormous.