Concerns and beliefs about medicines and inappropriate medications: An Internet-based survey on risk factors for self-reported adverse drug events among older adults.

BACKGROUND: Adverse drug events (ADEs), which can be especially problematic in older adults, often can be prevented by detecting potential risk factors. Sociopsychological factors such as concerns and beliefs about medicines (patients' anxieties about the harmful effects of prescribed medications) may also be risk factors related to self-reported ADEs, even when considering clinical variables such as receiving an inappropriate medication.

OBJECTIVES: This study was designed to quantify the use of inappropriate medications among older adult outpatients and to determine whether an association exists between the use of inappropriate medications, concerns and beliefs about medicines, and self-reported ADEs.

METHODS: This cross-sectional, Internet-based survey of Medicare beneficiaries was conducted in 2007. Harris Interactive, a New York-based marketing research firm, invited participants from their online panel who were >or=65 years of age, residents of the United States, and enrolled in the Medicare health plan to participate in the survey. The updated Beers criteria and a modified version of the Assessing Care of Vulnerable Elders quality indicators were used to determine the appropriateness of medications. Respondents' concerns about their medicines were assessed using items from a validated scale such as "Having to take medicines worries me" and "I sometimes worry about the long-term effects of my medicines." To establish self-reported ADEs, respondents were asked, "Did you see a doctor about any side effects, unwanted reactions, or other problems from medicines you were taking in the past year?"

RESULTS: Of the 1024 panelists who responded to the survey, 874 provided all of the information required for analysis. The respondents who were included in the analyses ranged in age from 65 to 94 years; 56.6% were female, 94.4% were white, and 20.3% self-reported an ADE. The frequency of patients receiving either an inappropriate medication or a medication that failed a quality indicator was 45.8%. Stronger concerns and beliefs about medicines (odds ratio [OR] = 1.57; 95% CI, 1.02-2.39; P = 0.04) and having more symptoms (OR = 2.26; 95% CI, 1.22-4.22; P = 0.01) were significantly related to self-reporting of ADEs, whereas receiving an inappropriate medication (OR = 1.03; 95% CI, 0.65-1.64) and the number of medications received (OR = 1.28; 95% CI, 0.52-3.13) were not.

CONCLUSIONS: Stronger concerns and beliefs about medicines and having more symptoms were significantly related to self-reporting of ADEs. Receiving an inappropriate medication and the number of medicines received were not significantly related.