Effectiveness of herbal medicine on patients with amyotrophic lateral sclerosis: Analysis of the PRO-ACT data using propensity score matching

Abstract

Background: Patients with amyotrophic lateral sclerosis (ALS) have restricted pharmacotherapy options and thus resort to herbal medicines (HMs), despite limited and conflicting evidence. Therefore, use of HMs needs to be assessed in patients with ALS.

Purpose: This study aimed to evaluate the benefits of HMs in ALS and to describe the characteristics of HM users.

Study design: The correlation between HMs and prognosis was determined based on data obtained from the largest ALS database with high-quality clinical trials. Propensity score (PS) matching was used to address confounding and selection bias.

Methods: In total, 321 and 231 HM users with at least a 4-week HM prescription were identified and PS-matched with non-HM users at a 1:1 ratio based on predefined confounders. Time-to-event models with censoring at 12 or 18 months were established for survival analyses. For evaluating activity limitation and respiratory function, 320 and 376 HM users were included, respectively, and analyzed using multivariate analysis of variance (MANOVA).

Results: The profiles of 321 HM users indicated a better condition compared with that of non-HM users before PS-matching, including higher weight (median [IQR], 77.90 [21.8] kg vs. 74.00 [21.2] kg, p < 0.01), higher body mass index (26.00 [5.4] vs. 25.20 [5.8], p < 0.01), more percentage of limb onset (261 [81.3%] vs. 2366 [67.2%], p < 0.01), and slower progression (0.47 [0.5] vs. 0.51 [0.5], p = 0.03). HM did not significantly affect survival at 12 months (adjusted hazard ratio [HR] 0.71, 95% confidence interval [CI] 0.49-1.03; log-rank p = 0.069), but it significantly prolonged survival at 18 months (adjusted HR 0.74, 95% CI 0.56-0.98; log-rank p = 0.038). After imputation of missing data, MANOVA revealed significant effectiveness of HMs in improving activity limitation (Pillai trace, 0.0195; p = 0.03).

Conclusion: PS-based methods eliminated baseline differences between HM and non-HM users. Overall, the use of HM to treat patients with ALS is favored based on their association with prolonged overall survival within 18 months and improved activity limitation.

Keywords: Database; Medicinal plant; Motor neuron disease; Phytomedicine; Propensity score; Survival.