Failure of evidence-based medicine in the treatment of hypertension in older patients

Abstract

Objective: Throughout the 1990s, the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure recommended initial antihypertensive therapy with a thiazide diuretic or a beta-blocker based on evidence from randomized, controlled trials, unless an indication existed for another drug class. The committee also recommended beta-blockers in hypertensive patients with a history of myocardial infarction (MI), and angiotensin-converting enzyme (ACE) inhibitors in patients with congestive heart failure (CHF). Our objective was to determine whether prescribing practices for older hypertensive patients are consistent with evidence-based guidelines.

Methods: We examined prescription patterns from January 1, 1991 through December 31, 1995 for 23,748 patients 65 years or older with a new diagnosis of hypertension from the New Jersey Medicaid program and that state's Pharmacy Assistance for the Aged and Disabled program (PAAD). We linked drug use data with information on demographic variables and comorbid medical conditions.

Results: During the study period, calcium channel blockers were the most commonly prescribed initial therapy for hypertension (41%), followed by ACE inhibitors (24%), thiazide diuretics (17%), and beta-blockers (10%). Eliminating patients with diabetes mellitus, CHF, angina, or history of MI did not substantially affect these results. Overall, initial use of a thiazide declined from 22% in 1991 to 10% in 1995, while initial use of a calcium channel blocker increased from 28% to 43%, despite publication during these years of studies demonstrating a benefit of thiazides in older patients. Only 15% of older hypertensive patients with a history of MI received beta-blockers.

Conclusions: Prescribing practices for older hypertensive patients are not consistent with evidence-based guidelines. Interventions are needed to encourage evidence-driven prescribing practices for the treatment of hypertension.

FIGURE 1

Initial antihypertensive therapy in patients without congestive heart failure, angina, diabetes mellitus, or a history of myocardial infarction. The y-axis is percent of patients receiving the specified medication. The P value represents the trend in prescribing over time relative to thiazide therapy (the referent group). CCB indicates calcium channel blocker; ACE I, angiotensin-converting enzyme inhibitor.

FIGURE 2

Initial drug choice in hypertensive patients with specific comorbid illnesses. The y-axis is percent of patients with the specified comorbidity. The top line represents the percent of patients with congestive heart failure (CHF) who received angiotensin-converting enzyme inhibitor (ACEI) therapy. The second line is the proportion of diabetics (DM) who received ACEI therapy. The third line is the proportion of patients with a history of myocardial infarction (hx MI) who received β-blocker therapy. For each comorbid illness, there was a statistically significant increase in indicated medication use over time (P < .001).