Mechanistic pain profiling may help predict response to treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) plus paracetamol for knee osteoarthritis, according to a study published in Pain. These results add to a growing body of evidence suggesting that some patients with osteoarthritis and central pain sensitization may require specific pain management strategies.
The study included 132 participants with knee osteoarthritis receiving ibuprofen (1200 mg/daily), paracetamol (3 g/daily), and pantoprazole (20 mg/daily) for a period of 3 weeks. Cuff pain detection, pain tolerance threshold, and temporal summation of pain were assessed at baseline, and worst pain within the last 24 hours and pain during activity were evaluated at baseline and at the end of the 3-week treatment using a visual analog scale and the Knee Injury and Osteoarthritis Score (KOOS), respectively. KOOS, a 42-item self-administered questionnaire, assesses pain, symptoms, activities of daily living, sports and recreation function, and knee-related quality of life.
Of the 132 participants with complete follow-up data, 52 (39%) achieved 30% pain relief based on the worst pain within the last 24 hours and 32 (25%) achieved 50% pain relief. Participants who reported 30% pain relief based on pain in the past 24 hours vs those who did not, had increases in KOOS symptoms (P =.028), KOOS activities of daily living (P =.007), a trend toward increased KOOS quality of life (P =.056), and a trend toward increased KOOS pain (P =.071) before treatment.
Individuals reporting 30% pain relief based on pain during physical activity indicated increases in KOOS pain (P <.001), KOOS symptoms (P =.005), KOOS activities of daily living (P <.001), and KOOS quality of life (P =.010) before treatment compared with the group that did not obtain 30% pain relief. Individuals with 30% pain relief who responded to the NSAID plus paracetamol treatment also had facilitated temporal summation of pain at baseline compared with those who did not respond to treatment (P <.02).
Using linear regression models, the researchers identified facilitated temporal summation of pain (P <.01) and low clinical pain scores (P <.001) as independent factors that predicted poor response to treatment.
“Future research should aim to link mechanistic pain profiling to pain alleviation using these drugs in patients [with osteoarthritis] who are characterized as centrally pain sensitive to enhance our understanding of the treatment options,” the researchers wrote.
Peterson KK, Olesen AE, Simonsen O, Arendt-Nielsen L. Mechanistic pain profiling as a tool to predict the efficacy of 3-weeks non-steroidal anti-inflammatory drugs (NSAIDs) plus paracetamol in patients with painful knee osteoarthritis. [published online October 26, 2018]. Pain. doi:10.1097/j.pain.0000000000001427