Pain in amyotrophic lateral sclerosis: a population-based controlled study

Background and purpose: To assess the prevalence and characteristics of pain in an epidemiological series of patients with amyotrophic lateral sclerosis (ALS) compared to population-based controls.

Methods: Of the 183 patients with ALS resident in the province of Torino, Italy, 160 accepted to be interviewed. Controls were randomly selected from the lists of general practitioners. Pain was assessed using the Brief Pain Inventory.

Results: Patients with ALS reported pain more frequently than controls [91 (56.9%) vs. 53 (33.1%); P = 0.001]. Pain frequency and intensity were correlated with a worse functional score and a longer disease duration. In patients with ALS, pain was more frequently located at the extremities (P = 0.006). Pain interfered with all areas of daily function, but patients reported a greater interference than controls in the domains of enjoyment of life and relation with other people. Sixty-four patients (70.3% of those with pain) and 24 controls (45.3% of those with pain) (P = 0.003) were treated for pain, most frequently with non-steroidal anti-inflammatory drugs. ALS cases were also more frequently prescribed non-opioid analgesics and opioids than controls.

Conclusions: Our study indicates that pain is frequent in all stages of ALS, but that it often goes underrecognized and undertreated. It is significantly more frequent in patients with ALS than in population-based controls. Future studies need to clarify the mechanisms of pain in ALS and determine the most effective treatment strategy.