Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Center for Drug Safety and Effectiveness, Johns Hopkins University, Baltimore, Maryland, USA.
J Am Geriatr Soc. 2024 Jan;72(1):91-101. doi: 10.1111/jgs.18665. Epub 2023 Nov 7.
The growth of oral muscle relaxant prescriptions among older adults in the United States is concerning due to the drugs' adverse sedative effects. Baclofen is a gamma-aminobutyric acid agonist muscle relaxant that is associated with encephalopathy. We characterized the risk of fall and fracture associated with oral baclofen against other muscle relaxants (tizanidine or cyclobenzaprine) in older adults.
We designed a new-user, active-comparator study using tertiary health system data from Geisinger Health, Pennsylvania (January 2005 through December 2018). Older adults (aged ≥65 years) newly treated with baclofen, tizanidine, or cyclobenzaprine were included. Propensity score-based inverse probability of treatment weighting (IPTW) was used to balance the treatment groups on 58 baseline characteristics. Fine-Gray competing risk regression was used to estimate the risk of fall and fracture.
The study cohort comprised of 2205 new baclofen users, 1103 new tizanidine users, and 9708 new cyclobenzaprine users. During a median follow-up of 100 days, baclofen was associated with a higher risk of fall compared to tizanidine (IPTW incidence rate, 108.4 vs. 61.9 per 1000 person-years; subdistribution hazard ratio [SHR], 1.68 [95% CI, 1.20-2.36]). The risk of fall associated with baclofen was comparable to cyclobenzaprine (SHR, 1.17 [95% CI, 0.93-1.47]) with a median follow-up of 106 days. The risk of fracture was similar among patients treated with baclofen versus tizanidine (SHR, 0.85 [95% CI, 0.63-1.14]) or cyclobenzaprine (SHR, 0.85 [95% CI, 0.67-1.07]).
The risk of fall associated with baclofen was greater than tizanidine, but not compared to cyclobenzaprine in older adults. The risk of fracture was comparable among the older users of baclofen, tizanidine, and cyclobenzaprine. Our findings may inform risk-benefit considerations in the increasingly common clinical encounters where oral muscle relaxants are prescribed.
美国老年人口中口腔肌肉松弛剂处方的增长令人担忧，因为这些药物有不良镇静作用。巴氯芬是一种γ-氨基丁酸激动剂肌肉松弛剂，与脑病有关。我们描述了与其他肌肉松弛剂（替扎尼定或环苯扎林）相比，口服巴氯芬在老年人中与跌倒和骨折相关的风险。
我们使用宾夕法尼亚州盖辛格健康系统的三级医疗系统数据（2005 年 1 月至 2018 年 12 月）设计了一项新用户、活性对照研究。纳入新接受巴氯芬、替扎尼定或环苯扎林治疗的年龄≥65 岁的老年人。采用倾向评分逆概率治疗加权（IPTW）法对 58 项基线特征进行治疗组平衡。精细灰色竞争风险回归用于估计跌倒和骨折的风险。
研究队列包括 2205 名新的巴氯芬使用者、1103 名新的替扎尼定使用者和 9708 名新的环苯扎林使用者。在中位随访 100 天期间，与替扎尼定相比，巴氯芬与跌倒风险增加相关（IPTW 发生率，108.4 与 61.9 每 1000 人年；亚分布风险比 [SHR]，1.68 [95%CI，1.20-2.36]）。与环苯扎林相比，巴氯芬的跌倒风险相当（SHR，1.17 [95%CI，0.93-1.47]），中位随访时间为 106 天。巴氯芬与替扎尼定（SHR，0.85 [95%CI，0.63-1.14]）或环苯扎林（SHR，0.85 [95%CI，0.67-1.07]）使用者的骨折风险相似。
与替扎尼定相比，巴氯芬与跌倒相关的风险更高，但与环苯扎林相比并非如此。巴氯芬、替扎尼定和环苯扎林在老年使用者中的骨折风险相当。我们的发现可能为日益常见的临床情况下使用口服肌肉松弛剂提供风险效益考虑。
