Low medication adherence and hypertension control among adults with CKD: data from the REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study

Abstract

Background: Low adherence to antihypertensive medication is an important barrier to achieving blood pressure control. Few data are available for medication adherence in adults with chronic kidney disease (CKD).

Study design: Cross-sectional.

Setting & participants: 3,936 and 9,129 participants with and without CKD using antihypertensive medication in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study, respectively. CKD was defined as albuminuria with albumin excretion>or=30 mg/g or estimated glomerular filtration rate<60 mL/min/1.73 m2.

Outcomes: Medication adherence and uncontrolled hypertension.

Measurements: Medication adherence was assessed using a validated 4-item scale. Blood pressure was measured 2 times by trained staff.

Results: In REGARDS participants with and without CKD, 1,426 (36.2%) and 2,421 (26.5%) had uncontrolled hypertension with blood pressure>or=140/90 mm Hg, and 2,656 (67.5%) and 5,627 (61.6%), >or=130/80 mm Hg. Also, 27.7% of those with CKD and 27.9% of those without CKD responded "yes" to ever forgetting to take their medication and 4.4% and 4.2%, respectively, responded yes to being careless about taking their medication. Also, 5.7% and 5.3% responded yes to missing taking medication when they felt better, and 4.2% and 3.6%, to missing it when they felt sick. Overall, 23.3% and 23.7% of participants with and without CKD responded yes to 1 adherence question, whereas 7.7% and 7.2%, respectively, responded yes to 2 or more adherence questions. In those with CKD, the multivariable adjusted ORs for uncontrolled hypertension (blood pressure>or=140/90 mm Hg) for individuals answering yes to 1 and 2 or more versus 0 adherence questions were 1.26 (95% CI, 1.05-1.51) and 1.49 (95% CI, 1.12-1.98), respectively. Analogous ORs for systolic/diastolic blood pressure>or=130/80 mm Hg were 1.06 (95% CI, 0.78-1.45) and 1.20 (95% CI, 0.88-1.64).

Limitations: Pharmacy fill data were not available.

Conclusions: Individuals with CKD had similarly poor medication-taking behaviors as those without CKD.

Copyright (c) 2010 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

Prevalence of uncontrolled hypertension (systolic or diastolic blood pressure ≥ 140/90 mmHg) among REGARDS participants taking antihypertensive medication without chronic kidney disease (top panel) and with chronic kidney disease (bottom panel) by level of medication adherence. * p

Figure 2

Multivariable adjusted odds ratios for uncontrolled hypertension (systolic or diastolic blood pressure ≥ 140/90 mmHg) associated with responses to the 4-item medication adherence screener among REGARDS participants without chronic kidney disease (left panel) and with chronic kidney disease (right panel) taking antihypertensive medication. Rectangles represent odds ratio, bar represents the 95% confidence interval. Odds ratios are adjusted for age, sex, race, education, income, current smoking, alcohol consumption, marital status, region of residency (stroke belt, stroke buckle, or other)[ND4], symptoms of depression, cognitive impairment, diabetes, history of cardiovascular disease, and number of antihypertensive medications taken.