Baseline characteristics of participants
| Characteristics | Control | Spa therapy |
|---|---|---|
| Male, n/N (%) | 119/223 (53.4) | 118/228 (51.8) |
| Age, mean±SD (n) | 64.3±10.4 (223) | 63.0±9.1 (228) |
| History of treatment for the knee | ||
| Medication, n/N (%) | 187/223 (83.9) | 195/228 (85.5) |
| Massage, n/N (%) | 70/223 (31.4) | 73/228 (32.0) |
| Intra-articular injection, n/N (%) | 51/223 (22.9) | 59/228 (25.9) |
| Hyaluronic acid treatment, n/N (%) | 92/223 (41.3) | 95/228 (41.7) |
| Surgery, n/N (%) | 82/223 (36.8) | 81/228 (35.5) |
| Previous spa therapy n/N (%) | 74/218 (33.9) | 61/227 (26.9) |
| Other physical treatment, n/N (%) (brace, traction, manipulation or physiotherapy in past 3 months) | 10/223 (4.5) | 10/228 (4.4) |
| Prognostic factors | ||
| Length of present episode, in months, mean±SD (n) | 63.9±73.3 (223) | 60.5±72.0 (228) |
| Number of acute episodes, mean±SD (n) | 7.8±10.5 (223) | 8.6±16.9 (228) |
| Family history of osteoarthritis, n/N (%) | 116/223 (52.0) | 117/228 (51.3) |
| Body mass index, mean±SD (n) | 29.0±4.6 (223) | 30.7±5.9 (228) |
| Knee examination | ||
| Knee joint swelling, n/N (%) | 94/223 (42.2) | 96/228 (42.1) |
| Knee joint effusion, n/N (%) | 62/223 (27.8) | 58/228 (25.4) |
| Knee joint crepitation on active motion, n/N (%) | 107/223 (48.0) | 107/228 (46.9) |
| Radiological severity (Kellgren and Lawrence), n/N(%) | ||
| Grade 1 | 53/223 (23.8) | 54/228 (23.7) |
| Grade 2 | 70/223 (31.4) | 73/228 (32.0) |
| Grade 3 | 83/223 (37.2) | 82/228 (36.0) |
| Grade 4 | 17/223 (7.6) | 19/228 (8.3) |
| WOMAC pain score, 0–100, mean±SD (n) | 42.0±18.1 (223) | 45.1±17.8 (224) |
| WOMAC function score, 0–100, mean±SD (n) | 38.9±17.1 (218) | 42.6±19.7 (214) |
| VAS pain, 0–100 mm, mean±SD (n) | 45.7±19.0 (223) | 49.9±20.2 (225) |
| PASS, n/N (%) | 36/223 (16.1) | 27/225 (12.0) |
| SF-36 scores | ||
| Physical, mean±SD (n) | 38.6±7.5 (216) | 37.4±7.7 (216) |
| Psychological, mean±SD (n) | 46.6±10.0 (216) | 46.2±11.5 (216) |
| Medication (at the time of inclusion) | ||
| At least one medication, n/N (%) | 110/223 (49.3) | 117/228 (51.3) |
| NSAID, n/N (%) | 33/223 (14.8) | 37/228 (16.2) |
| SYSADOA, n/N (%) | 58/223 (26.0) | 52/228 (22.8) |
| Analgesic, n/N (%) | 49/223 (22.0) | 62/228 (27.2) |
| Hyaluronic acid, n/N (%) | 1/223 (0.4) | 1/228 (0.4) |
PASS is the value beyond which patients can consider themselves well. It is composed of the VAS pain (cutoff ≤32 mm), the WOMAC function scores (cutoff ≤31 mm) and the patient's global self assessment of disease.
NSAID, non-steroidal anti-inflammatory drug; PASS, patient acceptable symptom state; SF36, Short Form 36; SYSADOA, symptomatic slow acting drug in osteoarthritis; VAS, visual analogue scale; WOMAC, Western Ontario and McMaster Universities osteoarthritis index.