Medication use and functional status decline in older adults: a narrative review.

BACKGROUND: Functional status is the cornerstone of geriatric care and serves as an indicator of general well-being. A decline in function can increase health care use, worsen quality of life, threaten independence, and increase the risk of mortality. One of several risk factors for decline in functional status is medication use.
OBJECTIVE: Our aim was to critically review published articles that have examined the relationship between medication use and functional status decline in the elderly.
METHODS: The MEDLINE and EMBASE databases were searched for English-language articles published from January 1986 to June 2011. Search terms included aged, humans, drug utilization, polypharmacy, inappropriate prescribing, anticholinergics, psychotropics, antihypertensives, drug burden index, functional status, function change or decline, activities of daily living, gait, mobility limitation, and disability. A manual search of the reference lists of the identified articles and the authors' article files, book chapters, and recent reviews was conducted to retrieve additional publications. Only articles that used rigorous observational or interventional designs were included. Cross-sectional studies and case series were excluded from this review.
RESULTS: Nineteen studies met the inclusion criteria. Five studies addressed the impact of suboptimal prescribing on function, 3 of which found an increased risk of worse function in community-dwelling subjects receiving polypharmacy. Three of the 4 studies that assessed benzodiazepine use and functional status decline found a statistically significant association. One cohort study identified no relationship between antidepressant use and functional status, whereas a randomized trial found that amitriptyline, but not desipramine or paroxetine, impaired certain measures of gait. Two studies found that increasing anticholinergic burden was associated with worse functional status. In a study of hospitalized rehabilitation patients, users of hypnotics/anxiolytics (eg, phenobarbital, zolpidem) had lower relative Functional Independence Measure motor gains than nonusers. Use of multiple central nervous system (CNS) drugs (using different definitions) was linked to greater declines in self-reported mobility and Short Physical Performance Battery (SPPB) scores in 2 community-based studies. Another study of nursing home patients did not report a significant decrease in SPPB scores in those taking multiple CNS drugs. Finally, 2 studies found mixed effects between antihypertensive use and functional status in the elderly.
CONCLUSIONS: Benzodiazepines and anticholinergics have been consistently associated with impairments in functional status in the elderly. The relationships between suboptimal prescribing, antidepressants, and antihypertensives and functional status decline were mixed. Further research using established measures and methods is needed to better describe the impact of medication use on functional status in older adults.