Relationship between Pain and Functional Status in Patients with Amyotrophic Lateral Sclerosis: A Multicenter Cross-Sectional Study

Background: Pain is a widely neglected symptom in patients with amyotrophic lateral sclerosis (ALS), even though it may be common and have a significant impact on the quality of life. Objective: The aim of this study was to determine the frequency and characteristics of pain and its treatment in ALS patients. Design: A multicenter cross-sectional study. Setting/Subjects: Eighty patients with ALS from eight hospitals. Measurements: Data on demographics, functional status, and pharmacological treatment were collected. The Barthel Index (BI) was used to assess functional status. Pain was measured using the 0-5-point Wong-Baker FACES Pain Rating Scale. Results: Pain was reported by 53.8% of ALS patients, and 36.3% reported receiving pain medication. Opioids were the drugs most commonly used to treat pain. The differences in pain frequency according to functional status were not statistically significant (p=0.38). The pain intensity in patients whose functional status was total dependence (BI 0-20, 2.51.2) was significantly worse than that in those with better functional status (BI 21-60, 1.4 +/- 0.7; BI 61-99, 1.4 +/- 0.5; p<0.01). Conclusions: Our study indicates that all patients with ALS have the potential to suffer from pain, the intensity of which increases with decreased functional status.