Diuretic of Choice in ABFM Hypertension Self-Assessment Module Simulations

Background: Evidence suggests that chlorthalidone has therapeutic advantages over hydrochlorothiazide, perhaps because of a longer antihypertensive effect. Although guidelines such as the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure treat diuretics as a class, some experts believe chlorthalidone is the diuretic of choice in hypertension management. We evaluated diplomates' use of chlorthalidone and hydrochlorothiazide as first-choice diuretics in virtual patient simulations of hypertension in the American Board of Family Medicine Maintenance of Certification for Family Physicians self-assessment modules. Methods: We examined action logs for hypertension simulations completed between 2004 and 2011 and identified initial antihypertensive choices made by diplomates. We tabulated uses of any diuretic as initial treatment, distinguishing between chlorthalidone, hydrochlorothiazide, and other diuretic choices. We examined trends in the use of diuretics and chlorthalidone in simulations using linear models. Results: Chlorthalidone use increased 0.7 percentage points per year (test for beta > 0, P < .0013), from approximately 1.3% of simulation prescriptions in 2004 to about 4.8% in 2010 and 2011, whereas hydrochlorothiazide prescriptions fell 2 percentage points per year (P = .035), from nearly 57% to 47%. As a fraction of all diuretic use, chlorthalidone increased 1.4 percentage points per year (P = .0006), from 2% to 9%. Conclusions: Small but growing numbers of diplomates are heeding recommendations in the growing literature to start with chlorthalidone rather than hydrochlorothiazide, at least in the virtual patient environment. Observed choices in virtual patient management strongly imply that this is a valid topic for additional attention in the hypertension self-assessment module. (J Am Board Fam Med 2012;25:805-809.)