Efficacy of a natural mineral complex in North American adults with osteoarthritis of the knee: a randomized double-blind placebo-controlled study

PURPOSE: This study evaluated the efficacy of a hydrothermal mineral complex (HMC) supplement in participants with knee osteoarthritis. PATIENTS AND METHODS: This was a double-blind, placebo-controlled, 12-week crossover study with 150 participants receiving either placebo or HMC for 4 weeks, with a 4-week washout period. The primary endpoint was WOMAC™ pain, and secondary endpoints were WOMAC™ physical function and stiffness, the 36-Item Short Form Health Survey (SF-36), high-sensitivity C-reactive protein, tumor necrosis factor α, interleukin 6, and safety. RESULTS: There were no significant differences in WOMAC™ pain, stiffness, or physical function scores between groups. Within groups, subjects on both HMC and placebo reported improvements (P<0.001) in all WOMAC™ domains. HMC performed significantly better in total SF-36 scores (P=0.05) and physical function (P=0.02), and had improved total physical activity (P=0.06) and social functioning (P=0.09) scores compared with placebo. Within groups, physical function (P=0.01), limitations due to mental health/emotional well-being (P=0.02), bodily pain (P=0.001), and total physical (P=0.003) and mental health scores (P=0.02) improved in participants on HMC, whereas improvements in bodily pain (P=0.001), general health (P=0.01), and total physical activity (P=0.04) were reported in placebo. Subjects on HMC with body mass index (BMI) <25 kg/m(2) showed a trend toward decreased pain scores (P=0.10), while pain increased in those administered placebo. Minimal clinically important improvement (MCII) in WOMAC™ pain scores increased from 28% of HMC-administered participants at week 2 to 41% at week 4, and decreased to 37% after 2 weeks of washout. In comparison, 41% of placebo-administered subjects achieved MCII by week 2 and week 4. A 10.4% greater increase in tumor necrosis factor α levels was seen in participants receiving placebo than those receiving HMC (P=0.07). There were no differences between groups in adverse events. CONCLUSION: HMC significantly improved physical function and total physical activity, improving the quality of life of participants. HMC was most effective in normal-weight subjects. Increased dosage may be required for North American subjects with BMI >25 kg/m(2).