Long-term benefits of radon spa therapy in rheumatic diseases: results of the randomised, multi-centre IMuRa trial

In chronic rheumatic diseases, recent treatment regimens comprise multimodal concepts including pharmacologic, physical/exercise, occupational and psychological therapies. Rehabilitation programmes are used for long-term management of disease. Spa therapy is often integrated in various middle and south European and Asian countries. Here, we investigated radon spa therapy as applied in health resorts compared to a control intervention in rheumatic out-patients. Randomised, blinded trial enroling 681 patients [mean age 58.3 (standard deviation 11.1); female 59.7 %] in 7 health resorts in Germany and Austria with chronic back pain (n (1) = 437), osteoarthritis (OA) (n (2) = 230), rheumatoid arthritis (n (3) = 98), and/or ankylosing spondylitis (n (4) = 39); multiple nominations in 146 cases). Outcomes were pain (primary), quality of life, functional capacity, and medication measured before start, after end of treatment, and 3 times thereafter in 3 monthly intervals. Adverse events were documented. To analyse between-group differences, repeated-measures analysis of covariance was performed in metric endpoints and Fisher's exact test in rates. Two-sided significance level of 5 % was chosen. Until end of follow-up, superiority of radon therapy was found regarding pain relief (p = 0.032) and analgesic drug consumption (p = 0.007), but not regarding quality of life. Functional capacity was assessed specific to the underlying indication. Significant benefits were found in radon-treated OA patients until 6-month follow-up (p = 0.05), but not until end of study (p = 0.096). Neither the back pain sub-population nor the two smaller patient populations with inflammatory indications benefited significantly in functional capacity. Results suggest beneficial analgesic effects of radon spa therapy in rheumatic diseases until 9 months post-intervention.