Table 1.

Features of the studies included in the review

Study; Thermal center, Country Study design Source of funding Osteoarthritis localization	Sample size and population main features	Balneotherapy treatment	Control/other groups procedure	Results and original concluding remarks of authors	Drugs used during treatments	Quality control using CLEAR NTP checklist
Szucs et al. [25]; Puspokladany, Hungary Double blinded, controlled clinical trial Not reported Knee	62 (number of procedures and controls not reported); 40–70 years old	20 min of bathing in thermal water for 3 consecutive weeks except Sundays	20 min of bathing in drinking water having the same temperature of thermal water for 3 consecutive weeks except Sundays	Significant reduction of motion pain and pressure sensibility or articular tenderness in subjects having bath in thermal water by the end of the treatment period compared to controls	Standard doses of pain-killer or non-steroid type anti-inflammatory drugs	4 yes, 6 not reported High bias risk
Nguyen et al. [26]; Vichy, France Randomized controlled clinical trial Private Lumbar spine, knee and hip	188 (91 procedures and 97 controls); 71 F (procedures); 82 F (controls); average age: 64 ± 7 (procedures); 63 ± 6 (controls)	20 min of bathing in thermal water for 3 consecutive weeks	Routine outpatient care at home for 3 consecutive weeks	Significant reduction of pain and significant improvement of functional ability and quality of life at 4 and 24 weeks after treatment respect to before balneotherapy treatment compared to the control group	Analgesic or non-steroidal anti-infiammatory drugs	3 yes, 3 no, 4 not reported High bias risk
Ekmekcioglu et al. [27]; Kurzentrum Baden bei Wien, Austria Randomized, single blinded for investigators, controlled clinical trial Not reported Not reported	38 (19 procedures and 19 controls); 11 F (procedures); 13 F (controls); average age: 52 ± 3 (procedures); 47 ± 4 (controls)	20 min of bathing in thermal water for 3 consecutive weeks + spa therapies	The same spa therapies without balneotherapy for 3 consecutive weeks	Significant reduction of the superoxide dismutase enzyme activity by the end of balneotherapy and compared to before the start of treatment	Not reported	4 yes, 2 no, 4 not reported High bias risk
Kovács and Bender [28]; Cserkeszölö, Hungary Randomized, double blinded, controlled clinical trial Not reported Knee	58 (31 procedures and 27 controls); other features not reported	30 min/day for 15 consecutive days of knee bathing in thermal water	30 min/day for 15 consecutive days of knee bathing in “placebo” drinking water (mixed with thermal water) having the same temperature of thermal water	Significant reduction of pain and palpation sensibility, significant improvement of mobility, deambulation, ability to climb stairs, outcomes of medical objective assessment and subjective assessment of patients right after the treatment and after 3 months in patients receiving balneotherapy compared to before the start of treatment	No drug therapy allowed	5 yes, 1 no, 4 not reported Medium bias risk
Odabaşi et al. [29]; Sandikli, Turkey Single blinded for investigators, controlled clinical trial Not reported Knee	49 (25 procedures and 24 procedures + mud therapy); 18 F (procedures); 17 F (procedures + mud therapy); average age: 60,4 ± 6,1 (procedures); 60,3 ± 6,2 (procedures + mud therapy)	20 min twice a day of bathing in thermal water for 8 consecutive days	20 min, once a day for 8 consecutive days of bathing in thermal water + mud therapy with thermal mud	Even if therapy combining thermal bath and mud applications seems to have greater improvement than the thermal bath alone, this difference may be not relevant from a clinical point of view. Both therapy regiments determine significant reduction of pain and significant improvement of disability and functional ability (according to physical exercises) at the end of treatments compared to before the start	No drug therapy allowed	3 yes, 2 no, 2 not reported 2 no for double blind, but similar concomitant treatments Medium bias risk
Yurtkuran et al. [30]; thermal center not reported, Turkey Randomized, double blinded, controlled clinical trial Not reported Knee	52 (27 procedures and 25 controls); 25 F (procedures); 24 F (controls); average age: 52.9 ± 6.8 (procedures); 55.5 ± 6.2 (controls)	20 min, once a day, 5 days/ week for a total of 2 weeks bathing in thermal water	20 min, once a day, 5 days/week for 2 consecutive weeks of bathing in drinking having the same temperature of thermal water	Significant reduction of pain and significant improvement of functional ability and quality of life at 2 and 12 weeks compared to before the start of treatment and significant reduction of pain and articular tenderness at 2 and 12 weeks since balneotherapy compared to control group	No drug therapy allowed	4 yes, 1 no, 5 not reported High bias risk
Alp et al. [31]; thermal center not reported, Turkey Randomized, double blinded, controlled clinical trial Not reported Knee	47 (23 procedures and 24 controls); 1 F (procedures); 1 F (controls); average age: 54.34 ± 6.4 (procedures) 56 ± 4.32 (controls)	20 min, 1 time per day, 5 days per week for 2 weeks of dive in thermal water	20 min, 1 time per day, 5 days per week for 2 consecutive weeks of bathing in drinking water having the same temperature of thermal water	Significant reduction of pain and serum levels of interleukin-2 receptors at 2 and 12 weeks compared to before the start of balneotherapy. Significant reduction of pain during motion at 2 weeks and serum levels of interleukin-2 receptors at 2 and 12 weeks since balneotherapy compared to control group	No drug therapy allowed	7 yes, 3 not reported Medium bias risk
Bálint et al. [32]; Nagybaracska, Hungary Randomized, double blinded, controlled clinical trial Not reported Both of knees	52 (27 procedures and 25 controls); 17 F (procedures); 16 F (controls); age ranging from 50 to 75	30 min, once a day, 5 days/ week for 4 weeks of bathing in thermal water	30 min, once a day, 5 days/ week for 4 weeks of bathing in drinking water having the same temperature of thermal water	Significant reduction of pain due to balneotherapy compared to the control group lasting for 3 months after the end of treatment with thermal water	No drug therapy allowed	5 yes, 1 no, 3 not reported, 1 no for single blind for therapists, but similar concomitant treatments and withdrawal and loss rate at follow-up Medium bias risk
Evcik et al. [33]; thermal center not reported, Turkey Controlled clinical trial Not reported Knee	80 (25 procedures, 29 controls and 26 other controls); 23 F (procedures) 22 F (controls) 24 F (other controls); average age: 55 ± 8.7 (procedures), 57.4 ± 9 (controls) 59.6 ± 9.2 (other controls)	20 min, once a day, 5 days/ week for 2 weeks of bathing in thermal water	Local application of mud therapy and hot packs, at 42 °C per 20 min, once a day, 5 days/week for 2 consecutive weeks	Significant reduction of pain and significant improvement of functional ability and quality of life at 2 and 3 months compared to before the start and to the control group	If needed patients were allowed to take paracetamol in a maximum dose of 1500 mg per day	2 yes, 2 no, 6 not reported High bias risk
Kiliçoğlu et al. [17]; Balikesir, Turkey Non controlled clinical trial Not reported Knee	30; 15 F; age ranging from 49 to 77	20 min, twice a day, for 2 consecutive weeks except Sundays of bathing in thermal water	Not performed	Significant improvement of function (checked by physical exercises), pain and quality of life, concomitant disability reduction at 2 weeks of since balneotherapy compared to before treatment start	Not reported	Good scientific value of the journal, feasible included sample size and methods. High bias risk due to lack of a control group
Fioravanti et al. [34]; Siena, Italy Randomized, single blinded, controlled clinical trial Not reported Knee	60 (30 procedures, 30 controls); 12 F (procedures), 18 F (controls); average age: 69.33 ± 7.63 (procedures), 72.45 ± 7.14 (controls)	20 min, once a day, 6 days/ week for 2 consecutive weeks of bathing in thermal water	Routine outpatient care at home	Significant reduction of pain and significant improvement of functional ability and quality of life at 2 weeks and 3 months compared to before the start of balneotherapy and to control group	Patients were advised to continue their established pharmacological treatments, with the exception of analgesic drugs (acetaminophen) and NSAIDs (Diclofenac, Piroxicam, Naproxen, Aceclofenac), which were to be noted daily in a diary. No corticosteroid, hyaluronic acid infiltrations or chondroprotective agents allowed	6 yes, 2 no, but similar concomitant treatments and withdrawal and loss rate at follow-up, 2 not reported Low bias risk
Horváth et al. [35]; Gunaras, Hungary Randomized, single blinded, controlled clinical trial No funding Hands	63 (21 procedures at 36 °C, 21 procedures at 38 °C, 21 controls); 17 F (procedures at 36 °C), 16 F (procedures at 38 °C), 18 F (controls); average age: 63.5 ± 4.7 procedures at 36 °C; 62.3 ± 4.8 procedures at 36 °C; 63.8 ± 4.4 controls	20 min, 5 days/week for 3 consecutive weeks of bathing in thermal mineral water at 36 °C + 20 min of magnetotherapy, 5 days/week for 3 consecutive weeks of bathing in thermal mineral water at 38 °C + magnetotherapy	Only magnetotherapy	Significant reduction of pain and significant improvement of functional ability during the follow-up due to balneotherapy compared to control group. No differences reported with different water temperatures	No drug therapy allowed	6 yes, 2 no, 2 not reported Medium bias risk
Kovács et al. [36]; Mezőkövesd, Hungary Randomized, double blinded, controlled clinical trial Not reported Hands	45 (24 procedures; 21 controls); 23 F (procedures), 19 F (controls); age ranging from 47 to 73 (47–71 procedures; 50–73 controls)	20 min, 5 days/week for 3 consecutive weeks of bathing in thermal water	20 min, 5 days/ week for 3 consecutive weeks of bathing in drinking water having the same temperature of thermal water	Significant reduction of pain and disability, significant quality of life improvement right after balneotherapy compared to before and to control group. Significant reduction of pain and disability at 6 months after treatment compared to before. Significant reduction of pain and disability at 3 months compared to the control group	No non-steroid drugs allowed. They were allowed to take paracetamol or metamisole if necessary	5 yes, 1 no, 4 not reported Medium bias risk
Kulisch et al. [37]; Lago di Hévíz, Hungary Randomized, single blinded, controlled clinical trial Not reported Knee	77 (38 procedures, 39 controls); 30 F (procedures), 30 F (controls); average age: 65.6 ± 6.4 (procedures), 65.7 ± 7.7 (controls)	20 min, 5 days/ week for 3 consecutive weeks of bathing in thermal water	20 min, 5 days/week for 3 consecutive weeks of bathing in drinking water having the same temperature of thermal water	Significant reduction of pain and significant improvement of functional ability and quality of life at 3 and 15 weeks compared to before the start and to control group	Nonsteroidal anti-inflammatory and chondroprotective therapy	8 yes, 2 no, but similar concomitant treatments and withdrawal and loss rate at follow-up, 2 not reported Low bias risk
Şahin-Onat et al. [38]; thermal center not reported, Turkey Controlled clinical trial No funding Knee	46 (19 procedures, 27 controls); 13 F (procedures), 23 F (controls); average age: 71.0 ± 8.2 (procedures), 70.6 ± 7.3 (controls)	20 min, 5 days/week for 3 consecutive weeks of bathing in thermal water at 38 °C + physiotherapy	Only physiotherapy	Significant reduction of pain and disability and significant improvement of walking speed right after balneotherapy compared to before and to control group	No drug therapy allowed	1 yes, 3 no, 6 not reported High bias risk
Kovács et al. [39]; Mezőkövesd, Hungary Randomized, single blinded, controlled clinical trial Not reported Hip	41 (21 procedures and 20 controls); average age: 59.14 ± 7.55 procedures and 60.66 ± 7.6 controls	20 min, 5 days/week for 3 consecutive weeks of bathing in thermal water + physical exercises at home	Only physical exercises at home	Significant reduction of stiffness by the end of balneotherapy compared to the control group. Significant reduction of pain and stiffness, improvement of functional ability and quality of life after 12 weeks of balneotherapy compared to control group	Not reported	7 yes, 1 no, 2 not reported Medium bias risk
Hanzel et al. [40]; Szigetvár, Hungary Randomized, double blinded, controlled clinical trial Not reported Knee and/or Hip	50 (26 procedures and 24 controls); 17 F (procedures) and 16 F (controls); average age: 66.22 ± 4.68 procedures and 67.43 ± 4.95 controls	30 min, 5 days/week for 3 consecutive weeks of bathing in a jacuzzi filled with thermal water	30 min, 5 days/week for 3 consecutive weeks of bathing in a jacuzzi filled with tap water	Significant reduction of pain and improvement of function and quality of life right after the balneotherapy treatment and at 3 months compared to before the start and to control group	Not reported	6 yes, 1 no, 3 not reported Medium bias risk