Physician underutilization of effective medications for resistant hypertension at office visits in the United States: NAMCS 2006-2010.

BACKGROUND

The American Heart Association (AHA) published guidelines for treatment of resistant hypertension in 2008 recommending use of thiazide diuretics (particularly chlorthalidone), aldosterone antagonists, and fixed-dose combination medications, but it is unclear the extent to which these guidelines are being followed.

OBJECTIVE

To describe trends in physician use of recommended medications for resistant hypertension and assess variations in medication use based on geography, physician specialty and patient characteristics.

DESIGN

Cross-sectional analysis using the National Ambulatory Medical Care Survey from 2006 to 2010.

STUDY SAMPLE

We analyzed visits of hypertension patients to family physicians, general internists, and cardiologists. Resistant hypertension was defined as concurrent use of ≥ 4 classes of blood pressure (BP) medications or elevated BP despite the use of ≥ 3 medications. Pregnant patients and visits with diagnosed heart failure or end-stage renal disease were excluded.

MAIN OUTCOME

Use of AHA-recommended medications for management of resistant hypertension.

RESULTS

Of 19,500 patient visits with hypertension, 1,567 or 7.1 % CI (6.6-7.7 %) met criteria for resistant hypertension. Thiazide diuretic use was reported in 58.9 % of visits pre-guidelines vs. 54.8 % post-guidelines (p = 0.37). Use of aldosterone antagonists was low and also did not change significantly after guideline publication (3.1 % vs. 4.5 %, p = 0.27). Fixed-dose combinations use was 42.0 % before and 37 % after guideline publication (p = 0.29). Each 10-year increase in patient age was associated with lower thiazide use (OR 0.87, CI 0.77-0.97), as was presence of comorbid ischemic heart disease (OR 0.62, CI 0.41-0.94). Medication use did not vary by geography or physician specialty.

CONCLUSION

Use of AHA-recommended medications for resistant hypertension remains low after publication of guidelines. Healthcare systems should encourage more frequent prescribing of these medications to improve care in this high-risk population.