Adjunct role of potassium-rich vegetarian diet and a novel potassium food supplement to improve pain in chronic rheumatoid arthritis on supervised standard care: a randomised controlled study.

Introduction: An earlier food survey showed dietary potassium deficiency in rheumatoid arthritis (RA).

Objective: To evaluate an adjunct role of oral potassium to reduce joint pain in RA.

Methods: 172 consenting eligible symptomatic patients (median duration 6.5 years) on standard care were randomised into an assessor blind, parallel efficacy, controlled, prospective, multiarm single-centre study (80% power, drug trial design) of 16 weeks duration-arm A (potassium-rich vegetarian diet), arm B (arm A plus novel potassium food supplement) and arm C (control, regular diet). Standard efficacy (American College of Rheumatology recommendation) and safety and diet intake (3-day recall) were assessed at monthly intervals (protocol). Standard soft-ware package (SPSS V.20) was used for statistical analysis; analysis of variance), Mann-Whitney statistic and χ test.; significant p<0.05, two sided). Study arms were found matched at baseline. Background RA medication remained stable. Preset target for increased potassium intake (India standards) were mostly achieved and participants remained normokalemic.

Results: 155 patients (90.1%) completed the study and several showed improvement (maximum improved measures in arm B). Potassium intervention was safe and well tolerated. Adverse events were mild; none caused patient withdrawal. On comparison, the mean change in pain visual analogue scale (-2.23, 95% CI -2.99 to -1.48) at week 16 (primary efficacy) from baseline was significantly superior in arm B (per protocol analysis). A high daily potassium intake (5-7.5 g, arm B) was significantly associated with low pain (study completion); OR 2.5 (univariate analysis), likelihood ratio 2.9 (logistic regression). Compliance (intervention), diet record and analysis, RA medication and absence of placebo were potential confounders.

Conclusion: High oral potassium intake, based on a suitable vegetarian diet and food supplement, reduced joint pain and improved RA. It was a safe adjunct to standard care, Further validation studies are required.

Trial Registration: CTRI/2022/03/040726; Clinical Trial Registry of India.