Perceptions of Benefits and Harms Affect Patient Adherence to Medication Therapies

Adherence to evidence-based guidelines for the prevention or management of particular diseases can be influenced by quality-assurance and pay-for-performance initiatives, but patient preference may be at odds with guideline-directed therapy. Guidelines for primary disease prevention are based on the goal of reduced risk of disease-specific outcomes, such as myocardial infarction (MI) or stroke, according to researchers, who added that “implicit in these guidelines is the judgment that these benefits outweigh any potential harms of intervention, a view shared by many clinicians.” However, patients’ views of benefits and harms do not always mirror those of healthcare providers. Adverse medication effects are often seen by patients as unacceptable outcomes, affecting the adherence rate for prescribed therapies. The researchers recently conducted a study to determine older persons’ willingness to take medication for primary cardiovascular disease prevention based on perceptions of benefits and harms. They reported study results in Archives of Internal Medicine [2011;171(10):923-928]. The researchers performed in-person interviews with 356 older persons living in the community. Topics covered in the interviews included participants’ willingness to take medication of primary prevention of MI in the context of varying scenarios. For example, in the first scenario, participants were asked about their willingness to take medication if their risk for MI over the next 5 years was 20 in 100 (baseline risk) if taking the medication would reduce the risk to 14 in 100 (a relative risk reduction of 30%). In subsequent scenarios, the researchers changed the risk with and without the medication to vary the absolute reduction in cardiovascular risk: (1) risk without medication, 20 in 100; with medication, 10 in 100 (risk reduction of 50%); (2) baseline risk and relative risk reduction both increased (risk without medication, 50 in 100; risk with medication, 25 in 100); and (3) baseline risk decreased (risk without medication, 10 in 100; risk with medication, 7 in 100). The next questions returned to the benefit as presented in the first scenario, but the medication was described as having varying adverse effects: (1) mild daily fatigue and dizziness not severe enough to interfere with activities of daily living (ADLs); (2) fatigue and dizziness severe enough to interfere with ADLs; (3) mild nausea not severe enough to interfere with ADLs; (4) nausea severe enough to interfere with ADLs; (5) fuzzy or slowed thinking not severe enough to interfere with ADLs; and (6) fuzzy or slowed thinking severe enough to interfere with ADLs. Responding to the first scenario, medication without adverse effects offering a 30% risk reduction, 88% of the participants said they would take the medication. As the absolute benefit increased, so did the proportion willing to take the medication. Of participants who would not take the medication if the absolute benefit was 6 fewer persons with MI out of 100, 17% said they would take the medication if the absolute benefit was increased to 10 fewer persons with MI. When adverse effects were added to the scenarios, 48% to 69% of the participants said they would be unwilling or uncertain about taking medication with average benefit causing mild fatigue, nausea, or fuzzy thinking. Only 3% indicated they would take medication with adverse effects severe enough to affect functioning. In conclusion, the researchers commented, “older persons’ willingness to take medication for primary cardiovascular disease prevention is relatively insensitive to its benefit but highly sensitive to its adverse effects. These results suggest that clinical guidelines and decisions about prescribing these medications to older persons need to place emphasis on both benefits and harms.”