Melissa Andreia de Moraes Silva, Luis Cu Nakano, Lígia L Cisneros, Fausto Miranda

Chronic venous insufficiency (CVI) is a progressive and common disease that affects the superficial and deep venous systems of the lower limbs. CVI is characterised by valvular incompetence, reflux, venous obstruction or a combination of these symptoms, with consequent distal venous hypertension. Clinical manifestations of CVI include oedema, pain, skin changes, ulcerations and dilated skin veins in the lower limbs. It places a large financial burden on health systems. There is a wide variety of treatment options for CVI, ranging from surgery and medication to compression and physiotherapy. Balneotherapy (treatments involving water) may be a relatively cheap and efficient way to deliver physiotherapy to people with CVI. This is an update of a review first published in 2019. To assess the effectiveness and safety of balneotherapy for the treatment of people with chronic venous insufficiency. We used standard, extensive Cochrane search methods. The latest search date was 28 June 2022. We included randomised and quasi-randomised controlled trials comparing balneotherapy to no treatment or other types of treatment for CVI. We also included studies that used a combination of treatments. We used standard Cochrane methods. Our primary outcomes were 1. disease severity, 2. health-related quality of life (HRQoL) and 3. Our secondary outcomes were 1. pain, 2. oedema, 3. leg ulcer incidence and 4. skin pigmentation changes. We used GRADE to assess the certainty of evidence for each outcome. We included nine randomised controlled trials involving 1126 participants with CVI. Seven studies evaluated balneotherapy versus no treatment, one study evaluated balneotherapy versus a phlebotonic drug (melilotus officinalis), and one study evaluated balneotherapy versus dryland exercises. We downgraded our certainty in the evidence due to a lack of blinding of participants and investigators, participant-reported outcomes and imprecision. Balneotherapy versus no treatment Balneotherapy compared to no treatment probably results in slightly improved disease severity signs and symptoms scores as assessed by the Venous Clinical Severity Score (VCSS; mean difference (MD) -1.75, 95% confidence interval (CI) -3.02 to -0.49; 3 studies, 671 participants; moderate-certainty evidence). Balneotherapy compared to no treatment may improve HRQoL as assessed by the Chronic Venous Insufficiency Quality of Life Questionnaire 2 (CIVIQ2) at three months, but we are very uncertain about the results (MD -10.46, 95% CI -19.21 to -1.71; 2 studies, 153 participants; very low-certainty evidence). The intervention may improve HRQoL at 12 months (MD -4.48, 95% CI -8.61 to -0.36; 2 studies, 417 participants; low-certainty evidence). It is unclear if the intervention has an effect at six months (MD -2.99, 95% CI -6.53 to 0.56; 2 studies, 436 participants; low-certainty evidence) or nine months (MD -6.40, 95% CI -13.84 to 1.04; 1 study, 59 participants; very low-certainty evidence). Balneotherapy compared with no treatment may have little or no effect on the occurrence of adverse effects. The main adverse effects were thromboembolic events (odds radio (OR) 0.35, 95% CI 0.09 to 1.42; 3 studies, 584 participants; low-certainty evidence), erysipelas (OR 2.58, 95% CI 0.65 to 10.22; 2 studies, 519 participants; low-certainty evidence) and palpitations (OR 0.33, 95% CI 0.01 to 8.52; 1 study, 59 participants; low-certainty evidence). No studies reported any serious adverse effects. Balneotherapy compared with no treatment may improve pain scores slightly at three months (MD -1.12, 95% CI -1.35 to -0.88; 2 studies, 354 participants; low-certainty evidence); and six months (MD -1.02, 95% CI -1.25 to -0.78; 2 studies, 352 participants; low-certainty evidence). Balneotherapy compared with no treatment may have little or no effect on oedema (measured by leg circumference) at 24 days to three months, but we are very uncertain about the results (standardised mean difference (SMD) 0.32 cm, 95% CI -0.70 to 1.34; 3 studies, 369 participants; very low-certainty evidence). Balneotherapy compared with no treatment may have little or no effect on the incidence of leg ulcers at 12 months, but we are very uncertain about the results (OR 1.06, 95% CI 0.27 to 4.14; 2 studies, 449 participants; very low-certainty evidence). Balneotherapy compared with no treatment may slightly reduce skin pigmentation changes as measured by the pigmentation index at 12 months (MD -3.60, 95% CI -5.95 to -1.25; 1 study, 59 participants; low-certainty evidence). Balneotherapy versus melilotus officinalis For the comparison balneotherapy versus a phlebotonic drug (melilotus officinalis), there was little or no difference in pain symptoms (OR 0.29, 95% CI 0.03 to 2.87; 1 study, 35 participants; very low-certainty evidence) or oedema (OR 0.21, 95% CI 0.02 to 2.27; 1 study, 35 participants; very low-certainty evidence), but we are very uncertain about the results. The study reported no other outcomes of interest. Balneotherapy versus dryland exercise For the comparison balneotherapy versus dryland exercise, evidence from one study showed that balneotherapy may improve HRQoL as assessed by the Varicose Vein Symptom Questionnaire (VVSymQ), but we are very uncertain about the results (MD -3.00, 95% CI -3.80 to -2.20; 34 participants, very low-certainty evidence). Balneotherapy compared with dryland exercises may reduce oedema (leg volume) after five sessions of treatment (right leg: MD -840.70, 95% CI -1053.26 to -628.14; left leg: MD -767.50, 95% CI -910.07 to -624.93; 1 study, 34 participants, low-certainty evidence). The study reported no other outcomes of interest. For the comparison balneotherapy versus no treatment, we identified moderate-certainty evidence that the intervention improves disease severity signs and symptoms scores slightly, low-certainty evidence that it improves pain and skin pigmentation changes, and very low-certainty evidence that it improves HRQoL. Balneotherapy compared with no treatment made little or no difference to adverse effects, oedema or incidence of leg ulcers. Evidence comparing balneotherapy with other interventions was very limited. To ensure adequate comparison between trials, future trials should standardise measurements of outcomes (e.g. disease severity signs and symptoms score, HRQoL, pain and oedema) and follow-up time points.