Importance of Therapy Intensification and Medication Nonadherence for Blood Pressure Control in Patients With Coronary Disease
Arch Intern Med. 2008;168(3):271-276. P. Michael Ho, MD, PhD; David J. Magid, MD, MPH; Susan M. Shetterly, MS; Kari L. Olson, PharmD, BCPS; Pamela N. Peterson, MD, MPH; Frederick A. Masoudi, MD, MPH; John S. Rumsfeld, MD, PhD
Background: Despite the importance of blood pressure (BP) control in secondary prevention, a significant proportion of patients with coronary disease have uncontrolled BP.
Methods: This retrospective cohort study of patients with coronary disease (N = 10 447) evaluated the impact of medication nonadherence and therapy intensification on reaching target BP goals. Medication adherence was calculated as the proportion of days covered for filled prescriptions of antihypertensive medications. Therapy intensification included dosage increase or increase in number of antihypertensive medications. The primary outcome was uncontrolled systolic BP (SBP) over time, using a latent class model that incorporated longitudinal SBP data and assigned patients to SBP trajectory groups. Multivariable regression evaluated the association between medication nonadherence (ie, proportion of days covered, <0.80) and therapy intensification with SBP control over time, with adjustment for demographics and clinical characteristics.
Results: Three SBP trajectory groups were identified: (1) patients with BP that remained controlled (ie, SBP, ≤140 mm Hg) over time (n = 9114 [87.2%]); (2) patients with high BP that became controlled (n = 779 [7.5%]); and (3) patients with BP that remained high over time (n = 554 [5.3%]). In multivariable analyses, therapy intensification (odds ratio, 1.31; 95% confidence interval, 1.01-1.70) and medication nonadherence (odds ratio, 1.73; 95% confidence interval, 1.34-2.24) were associated with uncontrolled BP compared with high SBP that became controlled over time.
Conclusions: These findings suggest that medication nonadherence can help explain why BP levels remained elevated despite intensification of antihypertensive medications. Successful BP control is seen with a combination of intensification and adherence, suggesting that therapy intensification must be coupled with interventions to enhance medication adherence.