Predictors of uncontrolled hypertension in ambulatory patients

Abstract

Hypertension remains poorly controlled in the United States. Improvement of its management will require an understanding of the patient characteristics and treatment factors associated with uncontrolled hypertension. We studied antihypertensive medication use, comorbidity, and blood pressure measurements for 525 hypertensive patients in 3 different healthcare systems over a 1-year period. We concomitantly conducted comprehensive patient interviews covering demographic factors, knowledge of hypertension and its treatment, and medication side effects. Ordinal logistic regression was used to identify factors associated with poor blood pressure control. Mean age of the patients was 65±11 years. Mean systolic blood pressure (SBP) was 143±15 mm Hg; and mean diastolic blood pressure (DBP), 80±9 mm Hg. Only 39% (203/525) of patients had mean blood pressure <140/90 mm Hg during the study period; about half (257/525) had stage 1 hypertension (mean SBP 140 to 159 mm Hg and/or mean DBP 90 to 99 mm Hg), and 12% (65/525) had stage 2 or greater hypertension (SBP >160 mm Hgand/or DBP >100 mm Hg). Multivariate analysis revealed several independent predictors of poor control: older age, multi-drug regimens, lack of knowledge by the patient of their target SBP, and a report of antihypertensive drug side effects. Patients with angina had a higher likelihood of adequate blood pressure control. Fewer than 40% of the treated patients studied had a mean blood pressure ≤140/90 mm Hg, and specific patient-related factors appear to predict poor control. Some of these may be amenable to modification. Further identification of patients at risk of poor control can lead to targeted interventions to improve management.