High-Risk Medication Use, Frailty and Hospitalization among Older Assisted Living Residents
MetadataShow full item record
Background: With substantial comorbidity, high levels of medication use and age-related physiological changes, older adults are at an increased risk of drug-related errors and adverse events. Of particular concern are (i) antipsychotic medications, which are often prescribed off-label to individuals with dementia; and (ii) high-risk (HR) drugs (anticoagulants, oral antiplatelet agents, insulins, and oral hypoglycemic agents), which have been shown to be responsible for the majority of drug-related hospital admissions. Given the risk associated with these medications, medication management and monitoring are particularly important for older individuals at risk of adverse drug events. However, assisted living (AL) facilities, increasingly popular residential options for older adults requiring supportive care, are often characterized by lower levels of staffing and professional service, raising concerns about the care and oversight of vulnerable older adults in these settings. The concept of frailty offers a promising avenue for identifying vulnerable older adults who may require increased monitoring when using high-risk medications; however, frailty has been relatively unexplored in this context or setting. Objectives: The present research addresses knowledge gaps with respect to frailty and medication use by: (i) estimating the baseline prevalence of HR (anticoagulants, oral antiplatelet agents, insulins, and oral hypoglycemic agents) /antipsychotic medication use and frailty among AL residents using the frailty index (FI), cardiovascular health study (CHS) criteria, and health instability (CHESS) scale (ii) examining the associations of high-risk / antipsychotic medication use and selected frailty measures with risk of inpatient hospitalization over 1 year; and, (iii) examine the role of these 3 frailty measures in modifying the association between high-risk/antipsychotic medication exposure and hospitalization risk over 1 year. Methods: 1,089 residents of 59 Assisted Living (AL) facilities from the Alberta Continuing Care Epidemiological Studies (ACCES) were included as participants (mean age 84.9±7.3; 77% female). Baseline (2006-08) and 1-year follow-up assessments of resident clinical and drug use data were carried out by research nurses using the interRAI-AL. Facility-level data was captured through administrator interviews. Hospitalization events were captured through linkage with provincial health service utilization data from the Alberta Inpatient Discharge Abstract Database. Multivariable Cox proportional hazards models were used to estimate risk of hospitalization associated with frailty, medication exposure, and medication -frailty interaction terms. Results: Among AL residents, the prevalence of pre-frail/frail residents was 38.9%/27.5% for the FI; 55.0%/19.2% for the CHS; and, 29.4%/24.4% for the CHESS scale. The cumulative annual incidence of hospitalization was 38.9% (35.9-41.9%). All 3 frailty measures were significantly associated with hospitalization after adjusting for age, sex and comorbidity, with the highest risk observed for frail (vs. non-frail) residents defined by the CHS criteria (adj. HR=2.11, 95% CI 1.53-2.92). Overall, use of antipsychotics (26.4% [94.0% atypical agents]), and use of any of the specified HR medication classes (63.5% using at least 1 HR medication class) showed no association with hospitalization. However, the FI, and occasionally CHS, acted as effect modifiers of drug-outcome associations for certain medication classes. Relative to non-frail resident using the medication class of interest, pre-frail/frail individuals had an increased risk of hospitalization when using antipsychotic agents (adj. HR=2.30, 95%CI 1.43-3.70 and adj. HR=2.20, 95% CI 1.3-3.74, with frailty defined using FI and CHS, respectively), anticoagulants (adj. HR=1.64, 95% CI 1.06-2.53, with frailty defined using FI) and antiplatelet agents (adj. HR=1.66, 95% CI 1.15-2.38, with frailty defined using FI). The CHESS measure was a weaker effect modifier. Pre-frail/frail residents using antipsychotic agents were also significantly more likely than non-frail antipsychotic users to reside in facilities with no licensed practical and/or registered nurse on site (25.5% vs. 13.6%) and with no pharmacist involvement in the past month (34.4% vs. 19.7%). Conclusions: These findings suggest that frailty (particularly when measured using FI) may be a means of identifying older individuals vulnerable to drug-related adverse events. Clinical and policy-level interventions in AL settings may enhance quality of care and reduce hospitalizations among residents.