Eighteen articles reporting 19 trials were included in the review. Treatment effects were estimable for 15 trials (n=1,539 patients), with follow-up ranging from eight days to one year. Of the 19 trials, three met eight of the 10 internal validity criteria, one met seven criteria, five met six criteria, and 10 met five or fewer criteria.
Twelve studies had no sample size calculation to show that they had sufficient statistical power to detect differences between treatments. Five randomised studies failed to report between-group comparisons.
Most studies showed some benefit of crenobalneotherapy or its components, but treatment effects varied widely between studies. Treatment effect was not correlated with sample size, follow-up duration or publication date.