A comparison between antihypertensive medication adherence and treatment intensification as potential clinical performance measures

Circulation: Cardiovascular Quality and Outcomes, 05/17/2012

Patient adherence to antihypertensive medications is not associated with blood pressure (BP) control at the clinic level and may not be suitable as a performance measure. TI is associated with BP control, but its use as a performance measure may be constrained by challenges in measuring it and by concerns about unintended consequences of aggressive hypertension treatment in some subgroups of patients.

Methods

  • Authors included 162 879 patients among 89 clinics in the Cardiovascular Research Network Hypertension Registry with incident hypertension who were started on antihypertensive medications.
  • Adherence was measured by the proportion of days covered (PDC).
  • TI was defined by the standard based method with scores ranging between –1 to 1 and categorized as: –1 indicated no TI occurred when BP was elevated; 0 indicated TI occurred when BP was elevated; and 1 indicated that TI was made at all visits, even when BP was not elevated.
  • Logistic regression models assessed the association between adherence and TI with blood pressure control (BP ≤140/90 at the clinic visit closest to 12 months after study entry) at the patient and clinic levels.
  • Mean adherence was 0.77±0.28 (PDC±SD) at the patient level and 0.78±0.05 at the clinic level.
  • Mean TI was 0.026±0.23 at the patient level and 0.01±0.04 at the clinic level.

Results

  • At the patient level, for each 0.25 increase in adherence and TI, the odds (OR) of achieving blood pressure control increased by 28% and 55%, respectively [OR for adherence, 1.28 (1.26–1.29), and for TI, 1.55 (1.53–1.57)].
  • At the clinic level, each 0.04 increment increase in treatment intensification was associated with a 25% increased odds of achieving blood pressure control (OR, 1.24; 95% CI, 1.21–1.27).
  • In contrast, there was an inverse association between increasing adherence and BP control (OR, 0.93; 95% confidence interval, 0.90–0.95).

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