Changes in antihypertensive prescribing during US outpatient visits for uncomplicated hypertension between 1993 and 2004

Monitoring national patterns of antihypertensive drug therapy is essential to assessing adherence to treatment guidelines and the impact of major scientific publications on physician prescribing. We analyzed data from 2 US National Ambulatory Care Surveys to examine trends between 1993 and 2004 in the prescription of antihypertensive drug classes for uncomplicated hypertension and the association between thiazide and beta-blocker prescribing and physician and patient characteristics. Diuretic prescriptions remained level through 2001 (39%; 95% CI: 34% to 44%) but increased to 53% (48% to 58%) in 2003, largely because of a 72% increase in thiazide prescriptions in the first quarter of 2003 (50%; 95% CI: 40% to 59%). However, these increases did not sustain in 2004. beta-Blocker prescriptions increased modestly from 1993 (24%; 95% CI: 19% to 29%) to 2004 (33%; 95% CI: 28% to 39%). Prescription of calcium channel blockers and angiotensin-converting enzyme inhibitors declined significantly following the sixth Joint National Committee report, but both subsequently rebounded to prereport levels. Prescription of angiotensin II receptor blockers increased continuously from 1% in 1995 to 23% by 2004. Polytherapy prescriptions, particularly those involving >= 3 drug classes, became increasingly prevalent, accounting for 60% of antihypertensive drug visits by 2004. Prescriptions of thiazides and beta-blockers were both more likely in 1998-2004 (versus 1993-1997). Blacks, women, and hospital outpatients were more likely to receive thiazides. Also, cardiologists were more likely to prescribe beta-blockers. Evidence-based guidelines for antihypertensive drug therapy do impact physician prescribing, but the impact seems to be short lived. Future interventions are imperative for promoting long-term adherence to published guidelines.