Resistant Hypertension Revisited: A Comparison of Two University-Based Cohorts

Background More than a decade ago, we found that a suboptimal medication regimen was the leading cause of resistant hypertension (RH) among patients referred to a tertiary care clinic. Since then, lower blood pressure (BP) goals have been recommended, suggesting that more patients may have RH. To assess whether the reasons for and treatment of RH have changed, we determined the frequency of various causes of resistance, the proportion of patients achieving goal BP, and the changes made in antihypertensive regimens. Methods The charts of all new patients seen at the RUSH University Hypertension Center between January 1, 1993, and November 1, 2001, were reviewed for strict criteria for RH: 1) physician referral for uncontrolled hypertension; 2) BP ≥140/90 mm Hg despite use of three antihypertensive drugs; and 3) at least one follow-up visit. Patients were followed-up until goal BP was achieved on two consecutive visits or their last visit or until March 2002. Results Of 1281 patients, 141 met criteria for RH. A cause of resistance was found in 94% of cases, including the following: drug-related causes (58%); nonadherence (16%); psychological causes (9%); office resistance (ie, in-clinic BP readings that were higher than goal despite treatment with antihypertensive medications and despite normotensive BP outside of the clinic as demonstrated by 24-h ambulatory BP monitoring) (6%); and secondary hypertension (5%). Overall, 53% of patients had their BP controlled to <140/90 mm Hg, largely from regimen optimization and intensification, proper use of diuretics, and on average 4.1 ± 1 antihypertensive medications (3.7 ± 0.9 on referral). Conclusions These data are strikingly similar to those from our previous study of RH, in which a suboptimal medication regimen was the most common reason for resistance. Goal BP was most commonly achieved after optimizing the diuretic regimen and increasing the number of medications, suggesting that physicians should use these measures to attain the recommended lower BP goals If goal BP is not reached, referral to a clinical hypertension specialist may be appropriate.