Dr. Mann is assistant professor of medicine, Mount Sinai School of Medicine, New York, New York.

Disclosure: The author states that he has nothing to disclose.

Abstract

Mann DM. Resistant disease or resistant patient: problems with adherence to cardiovascular medications in the elderly. Geriatrics. 2009;64(9):10-15.

Key words: medication adherence, cardiovascular medications, elderly

Drugs discussed: angiotensin-converting enzyme (ACE) inhibitor, atorvastatin, clopidogrel, lisinopril, rosuvastatin, simvastatin

Clinical scenario: A very pleasant, 70-year-old woman with diabetes has been under your care for the past 18 months with erratic follow-up, and during a chart review, you notice that her periodic lipid assessments show fluctuating low-density lipoprotein (LDL) levels, with measures ranging from 90 mg/dL to 150 mg/dL. When you started caring for her, her LDL was 145, and you initiated simvastatin 20 mg. Two months later her LDL was 120 mg/dL. Over the next 6 months, you titrated up her simvastatin and eventually changed her over to atorvastatin 20 mg to achieve a LDL of 80 mg/dL, with normal liver enzymes and no reports of adverse effects. Her latest LDL is 110 mg/dL, and you are considering changing her to rosuvastatin. Is this a resistant form of hyperlipidemia, or is the patient resistant to taking her statin as prescribed?

Scope of the problem

The case above is a common clinical scenario that depicts an obstinate problem endemic in the care of older adults: poor adherence to medication. Many factors beyond adherence, ranging from pharmacokinetics to changes in diet, can affect LDL levels or other cardiovascular risk factor measures such as blood pressure and hemoglobin A_1c (HbA_1c ). However, the ability to detect and manage how poor adherence affects cardiovascular risk factor control is limited by our poor understanding of what drives adherence and the dearth of effective tools for diagnosing it. The goal of this article is to briefly review the current evidence describing the etiology, diagnosis, and treatment of poor adherence to cardiovascular medications among the elderly.

According to the World Health Organization, medication adherence is "the extent to which a person's behavior in taking medication corresponds with agreed recommendations from a health care provider."¹ The breakdown between what clinicians prescribe and what patients actually take creates an enormous toll on the health care system, with estimated costs as high as $100 billion annually and contributing to 10% of all hospital admissions.² This is partly because of high rates of poor adherence to cardiovascular medications. For example, in a study of 34,501 insurance enrollees more than 65 years old, only 1 in 4 were still adherent to their statin medication after 5 years.³ Poor adherence is not just an abstract statistic. In an analysis of 6,486 patients with diabetes in a managed care organization who were prescribed a statin, patients with poor adherence had double the mortality rate.⁴ Similar findings of high rates of poor adherence and concomitant elevated risks for morbidity and mortality among the elderly have been reported with antihypertensive, antiplatelet, and antidiabetic medications.^5-7 In a study of 21,011 patents with hypertension, rates of adherence were 75% at 6 months and 55% at 3 years, and in another study of 8,406 managed care enrollees, only 1 in 3 patients were still adherent to both their antihypertensive and lipid-lowering therapy over a 6-month period.^8,9 The dangerous outcomes of suboptimal adherence may be best illustrated in the high rates of poor clopidogrel adherence after drug-eluting stent placement (13.6% at 30 days) and the 9-fold increased risk of death in those who had prematurely discontinued clopidogrel.¹⁰