Crenobalneotherapy (spa therapy) in patients with knee and generalized osteoarthritis: a post-hoc subgroup analysis of a large multicentre randomized trial.

OBJECTIVE: To determine whether the addition of spa therapy to home exercises provides any benefit over exercises and the usual treatment alone in the management of generalised osteoarthritis associated with knee osteoarthritis. METHODS: This study was a post-hoc subgroup analysis of our randomised multicentre trial (www.clinicaltrial.gov: NCT00348777). Participants who met the inclusion criteria of generalized osteoarthritis (Kellgren, American College of Rheumatology, or Dougados criteria) were extracted from the original randomised controlled trial. They had been randomised using Zelen randomisation. The treatment group received 18days of spa treatment in addition to a home exercise programme. Main outcome was number of patients achieving minimal clinically important improvement at six months (MCII) (≥-19.9mm on the VAS pain scale and/or ≥-9.1 points in a WOMAC function subscale), and no knee surgery. Secondary outcomes included the "patient acceptable symptom state" (PASS) defined as VAS pain ≤32.3mm and/or WOMAC function subscale ≤31 points. RESULTS: From the original 462 participants, 214 patients could be categorized as having generalised osteoarthritis. At sixth month, 182 (88 in control and 94 in SA group) patients, were analysed for the main criteria. MCII was observed more often in the spa group (n=52/94 vs. 38/88, P=0.010). There was no difference for the PASS (n=19/88 vs. 26/94, P=0.343). CONCLUSIONS: This study indicates that spa therapy with home exercises may be superior to home exercise alone in the management of patients with GOA associated with knee OA.