Impact of Drug–Drug and Drug–Disease Interactions on Gait Speed in Community-Dwelling Older Adults

Abstract

Background Gait speed decline, an early marker of functional impairment, is a sensitive predictor of adverse health outcomes in older adults. The effect of potentially inappropriate prescribing on gait speed decline is not well known. Objective To determine if potentially inappropriate drug interactions impair functional status as measured by gait speed. Methods The sample included 2,402 older adults with medication and gait speed data from the Health, Aging and Body Composition study. The independent variable was the frequency of drug-disease and/or drug-drug interactions at baseline and three additional years. The main outcome was a clinically meaningful gait speed decline ≥ 0.1 m/s the year following drug interaction assessment. Adjusted odds ratios and 95% confidence intervals were calculated using multivariate generalized estimating equations for both the overall sample and a sample stratified by gait speed at time of drug interaction assessment. Results The prevalence of drug-disease and drug-drug interactions ranged from 7.6–9.3% and 10.5–12.3%, respectively, with few participants (3.8–5.7%) having multiple drug interactions. At least 22% of participants had a gait speed decline of ≥ 0.1 m/s annually. Drug interactions were not significantly associated with gait speed decline overall or in the stratified sample of fast walkers. There was some evidence, however, that drug interactions increased the risk of gait speed decline among those participants with slower gait speeds, though p values did not reach statistical significance (adjusted odds ratio 1.22, 95% confidence intervals 0.96–1.56, p=0.11). Moreover, a marginally significant dose-response relationship was seen with multiple drug interactions and gait speed decline (adjusted odds ratio 1.40; 95% confidence intervals 0.95–2.04, p=0.08). Conclusions Drug interactions may increase the likelihood of gait speed decline among older adults with evidence of preexisting debility. Future studies should focus on frail elders with less physiological reserve who may be more susceptible to the harms associated with potentially inappropriate medications.

Polypharmacy and gait speed in individuals with mild cognitive impairment

“…Some previous studies have reported that comorbidity and drug–drug interactions affected gait speed. However, in the present study, we found that the effects of the number of medications on gait speed were independent from the prescription of PIM and from the Charlson Comorbidity Index, and that the number of medications was associated with gait independently from these factors.…”

Drug interactions among older adults followed up in a comprehensive medication management service at Primary Care

“…( 12 , 15 ) Several studies with older patients demonstrated the association of drugs that act on the central nervous system with falls and fractures. ( 16 , 17 ) We, therefore, emphasize the need to comprehensively manage drug therapy in older patients, with a focus on reducing the use of drugs that act on the central nervous system, as well as choosing medications associated with lower risk and lower effective doses when indicated. ( 15 , 16 )…”

“…In our search, we did not identify studies evaluating interactions between two drugs in the presence of specific diseases, or the list of drug interactions proposed by Dumbreck et al ( 13 ) We observed a high prevalence of disease-drug-drug interactions (27.2%), which was higher than the prevalence we found using the Beers criteria (4.9%) and of studies that evaluated disease-drug or drug-drug interactions with other lists of interactions, including in Brazil, ranging from 7.8 to 18.9%. ( 12 , 14 , 17 , 20 , 21 )…”

“…( 12 , 15 ) Inúmeros estudos realizados com idosos têm demostrado a associação entre medicamentos que atuam no sistema nervoso central com quedas e fraturas. ( 16 , 17 ) Desse modo, ressalta-se a necessidade do gerenciamento da terapia medicamentosa em pacientes idosos, com enfoque na diminuição do uso de medicamentos que atuam no sistema nervoso central, bem como escolha de medicamentos associados a um menor risco e a menores doses efetivas quando indicado. ( 15 , 16 )…”

“…Em nossas buscas, não foram identificados estudos que avaliaram interações entre dois medicamentos na presença de doenças específicas ou a lista de interações medicamentosas propostas por Dumbreck et al ( 13 ) Identificamos elevada prevalência das interações doença-medicamento-medicamento (27,2%), que foi superior à prevalência que identificamos nas interações do critério de Beers (4,9%) e de estudos que avaliaram interações doença-medicamento ou medicamento-medicamento com outras listas de interações, inclusive no Brasil, que variaram de 7,8 a 18,9%. ( 12 , 14 , 17 , 20 , 21 )…”