Does the predominance of central sensitization alter the effect of balneotherapy combined with conventional physical therapy in patients with chronic low back and knee pain?

Various methods, including balneotherapy, are employed in the management of patients with chronic pain. This research investigated the effect of the predominance of central sensitization on responses to balneotherapy applied together with conventional physical therapy in patients with chronic low back and knee pain. This prospective study included 75 patients with chronic low back or knee pain, classified as having predominant central sensitization (n = 35) or not (n = 40). All participants received a three-week course of whole-body balneotherapy combined with conventional physical therapy, including transcutaneous electrical nerve stimulation, hot pack, and therapeutic ultrasound. Pain intensity, as the primary outcome, was assessed using the visual analogue scale (VAS), while quality of life and emotional status were evaluated using the Short Form-12 (SF-12) and the Hospital Anxiety and Depression Scale (HADS), respectively. Disability associated with chronic pain was evaluated using the Roland Morris Disability Questionnaire in patients with low back pain and the Knee Injury and Osteoarthritis Outcome Score (KOOS) in those with knee pain. Changes in outcomes over time and between groups were analyzed using linear mixed-effects models. Improvement in the VAS, SF-12 Physical and Mental Component, HADS-Depression, and HADS-Anxiety scores was observed in both groups post-treatment (between p < 0.01 and p = 0.015). Also, post-treatment improvement in disability scores was observed in both groups (between p < 0.01 and 0.021). Group × time interaction was observed only for the SF-12 mental component score, in favor of the predominant central sensitization group (ΔΔ = 5.95, 95% CI 1.31 to 10.59, p = 0.013). No significant group × time interaction was observed for other outcomes (range: 0.10-0.97). Applied together with physical therapy agents with balneotherapy can reduces pain severity and disability levels, and increases their quality of life in patients with chronic pain with and without predominant central sensitization. Improvements in mental health-related quality of life were more pronounced in patients with predominant central sensitization.