ORIGINAL ARTICLE
Medication Adherence Among Community-Dwelling Patients With Heart Failure

https://doi.org/10.4065/mcp.2010.0732Get rights and content

OBJECTIVE

To determine medication use and adherence among community-dwelling patients with heart failure (HF).

PATIENTS AND METHODS

Residents of Olmsted County, Minnesota, with HF were recruited from October 10, 2007, through February 25, 2009. Pharmacy records were obtained for the 6 months after enrollment. Medication adherence was measured by the proportion of days covered (PDC). A PDC of less than 80% was classified as poor adherence. Factors associated with medication adherence were investigated.

RESULTS

Among the 209 study patients with HF, 123 (59%) were male, and the mean ± SD age was 73.7±13.5 years. The median (interquartile range) number of unique medications filled during the 6-month study period was 11 (8-17). Patients with a documented medication allergy were excluded from eligibility for medication use within that medication class. Most patients received conventional HF therapy: 70% (147/209) were treated with β-blockers and 75% (149/200) with angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. Most patients (62%; 127/205) also took statins. After exclusion of patients with missing dosage information, the proportion of those with poor adherence was 19% (27/140), 19% (28/144), and 13% (16/121) for β-blockers, angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, and statins, respectively. Self-reported data indicated that those with poor adherence experienced more cost-related medication issues. For example, those who adhered poorly to statin therapy more frequently reported stopping a prescription because of cost than those with good adherence (46% vs 6%; P<.001), skipping doses to save money (23% vs 3%; P=.03), and not filling a new prescription because of cost (46% vs 6%; P<.001).

CONCLUSION

Community-dwelling patients with HF take a large number of medications. Medication adherence was suboptimal in many patients, often because of cost.

Section snippets

PATIENTS AND METHODS

This is a population-based study conducted in Olmsted County, Minnesota, the estimated 2008 population of which was 141,360. Most residents are white (89%), and approximately 50% are female.13 This type of study is possible in this county because of the small number of medical providers, including Mayo Clinic, Olmsted Medical Center, and a few private practitioners. The records from each institution are indexed through the Rochester Epidemiology Project, a centralized data system that allows

RESULTS

Between October 10, 2007, and February 25, 2009, 402 patients with HF were approached for enrollment, and 245 (61%) consented to the pharmacy portion of the study. We could not obtain all pharmacy records for 25 patients, 8 were nursing home residents, and 3 did not speak English, resulting in a final study population of 209. The population was older, with a mean ± SD age of 73.7±13.5 years; 123 (59%) were male, 93 (48%) had a preserved EF, and comorbid conditions such as hypertension and

DISCUSSION

Community-dwelling patients with HF are commonly required to take a large number of prescription medications, and over half take at least 1 medication 3 times daily. Overall, 13% to 20% of patients with HF exhibit poor adherence to conventional HF medications. Cost is a notable barrier to adherence.

CONCLUSION

Community-dwelling patients with HF take a substantial number of medications, often several times a day. Use of β-blockers, ACEIs or ARBs, loop diuretics, and statins was common among patients with both preserved and reduced EF. Medication adherence was suboptimal in many patients, and those with poor adherence were more likely to report cost-related medication issues. Further work is needed to determine the effect of interventions to improve medication adherence among patients with HF. Efforts

Acknowledgments

We thank Kay Traverse, RN, Annette McNallan, RN, and Amy Wagie, BS, for their study support.

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    This study was supported by grants from the National Institutes of Health (RO1HL72435, T32 HL07111-31A1) and was made possible by the Rochester Epidemiology Project (AG034676, National Institute on Aging).

    An earlier version of this article appeared Online First.

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