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FACTORS ASSOCIATED WITH NONADHERENCE TO MEDICATION IN COMMUNITY‐DWELLING DISABLED OLDER ADULTS IN JAPAN

2010; Wiley; Volume: 58; Issue: 5 Linguagem: Inglês

10.1111/j.1532-5415.2010.02837.x

1532-5415

Masafumi Kuzuya, Hiromi Enoki, Sachiko Izawa, Jun Hasegawa, Yusuke Suzuki, Akihisa Iguchi,

Schizophrenia research and treatment

To the Editor: Nonadherence to drug therapy is a serious problem for older people, because adherence to medication is essential for obtaining the optimal therapeutic effects of medication.1–4 Although numerous studies have identified the factors related to nonadherence to drug therapy, only limited studies have taken a wider perspective, focusing on adherence in older community-dwelling disabled adults and on factors affecting adherence.5,6 The aim of this study was to identify the factors associated with nonadherence to drug therapy in older community-dwelling disabled adults. The present study used baseline data on participants in the Nagoya Longitudinal Study for Frail Elderly.4,7,8 The study population consisted of 1,722 older community-dwelling disabled adults (611 men, 1,161 women; mean age 80.3±7.6, range 65–104) and 1,502 caregivers (375 men, 1127 women; mean age 64.1±12.6, range 31–93). The baseline data included the recipients' demographic characteristics, activities of daily living (ADLs), depressive symptoms as assessed using the short version of the Geriatric Depression Scale (GDS-15), physician-diagnosed chronic conditions, living arrangement, number of prescribed medications, and self-reported difficulty with self-medication management, which was assessed as previously described.4 The participants or family were also asked whether they were receiving any assistance for taking medication or medication management from others. The participants were divided into two groups: no difficulty with self-medication management, and difficulty with self-medication management. Data were also obtained from caregivers concerning their own personal demographic characteristics, their subjective health status, and burden as assessed according to the Zarit Burden Interview. The adherence rate to the prescribed medication was defined as the total number of pills taken divided by the total number of prescribed pills as assessed by the self-reported average medication adherence during 1 month. It was decided to use self-reporting rather than other forms of adherence measurements because they are prohibitively expensive and cumbersome, and there is little evidence that they are superior to self-report instruments.1,9 Nonadherence was defined as less than 80% of the adherence rate. Univariate and multivariate logistic regression were used to determine which characteristics of the disabled older adult or caregiver predicted nonadherence to prescribed medication. Of 1,772 participants, 223 (12.6%) were categorized as nonadherent. Univariate logistic analysis demonstrated that participants living alone (vs living with someone, odds ratio (OR)=1.43, 95% confidence interval (CI)=1.04–1.96), with depression (GDS-15≥11 vs <5, OR=1.61, 95% CI=1.03–2.53), and with dementia (vs its absence, OR=1.47, 95% CI=1.10–1.96) and participants who had difficulty with self-medication management (vs no difficulty with self-medication, OR=1.69, 95% CI=1.24–2.30) were more likely to be nonadherent. Multivariate analysis (Table 1, Model 1) showed that medication nonadherence was associated with participants living alone, having depression, and having difficulty with self-medication. When participants who had difficulty with self-medication were divided as to the absence or presence of assistance (Model 2), nonadherence was associated with participants living alone, participants with depression, the presence of dementia, participants who had difficulty with self-medication but had no assistance, and participants with assistance. For participants who had difficulty with self-medication and had assistance, none of the variables of care recipients were associated with nonadherence in univariate analysis. Multivariate analysis revealed that a male caregiver and poor subjective health status of the caregiver were likely to result in nonadherence in participants having assistance. In the present study, it was observed that participants who had difficulty with self-medication management had a high risk of nonadherence to medication. In particular, participants needing support but who did not have any, had a OR of nonadherence 3.2 times as high as those who had no difficulty with self-medication management, suggesting that medication management assessment is needed to determine which older people are at risk of medication management problems and to minimize adverse events attributable to poor medication adherence. Participants receiving medication management assistance had an OR of medication nonadherence 1.64 times as high as participants who had no difficulty with self-medication management. These results may imply that families or relatives living with disabled older patients may not always give appropriate assistance for medication management. A male caregiver and subjective poor health status of the caregiver were associated with recipient nonadherence to prescribed medication, suggesting that caregivers with those characteristics may tend to provide inadequate levels of assistance for medication or that neglectful behavior by caregivers may be involved in this association. In conclusion, the results suggest that, in older community-dwelling disabled adults, the lack of medication assistance for those needing medication support was associated with a higher risk of nonadherence, although even those receiving assistance had a higher risk of nonadherence than those with no difficulty with self-medication management. The authors wish to thank all the patients and caregivers and the many nurses participating in the study and the Nagoya City Health Care Service Foundation for Older People for their vigorous cooperation. Conflict of Interest: Kuzuya M has received financial support from a Grant-in-Aid for the Comprehensive Research on Aging and Health from the Ministry of Health, Labor, and Welfare of Japan. This study was supported by a Grant-in-Aid for the Comprehensive Research on Aging and Health from the Ministry of Health, Labor, and Welfare of Japan, and a grant from Mitsui Sumitomo Insurance Welfare Foundation. The authors have no conflicts of interest with the manufacturers of any drug evaluated in this letter. Author Contributions: Masafumi Kuzuya: study concept, design, conduct of study, interpretation of data, study supervision, and preparation of manuscript. Hiromi Enok: and Sachiko Izawa: analysis and interpretation of data. Jun Hasegawa and Yusuke Suzuki: conduct of study and interpretation of data. Akihisa Iguchi: study supervision. Sponsor's Role: The sponsor had no role in the design, methods, subject recruitment, data collection, analysis, or letter preparation.