Chronic RA Pain Reduced with Dietary Potassium
SAN FRANCISCO, CA—Improved dietary-based potassium intake is a useful adjunct in the management of patients with chronic symptomatic rheumatoid arthritis (RA), research presented at the 2015 ACR/ARHP Annual Meeting has found.
In addition to reduced pain, other possible benefits included reduced disease activity, improved quality of life and function, and "better blood pressure status," reported Toktam Kainifard, PhD fellow, from Pune, India. Her colleague, Arvind Chopra, MD, Director and Consultant Rheumatologist of the Center for Rheumatic Diseases in Pune, presented the study results on her behalf.
Data from the 1988–1994 U.S. National Health and Nutrition Survey III showed that low potassium levels were seen in patients with RA. Potassium is essential in nociceptive processing and other processes such as oxidant tissue damage, T-lymphocyte function, and cortisol secretion. According to standards from India's National Institute of Nutrition (Hyderabad) and controlled diet survey, researchers showed that potassium levels were low (P<0.05) in patients with RA, especially in women.
Kainifard and colleagues conducted a study that randomized 172 patients with chronic RA with active pain (visual analog scale [VAS] >4cm) into an assessor-blind, 3-arm study for 16 weeks at a community rheumatology center. Oral potassium intake for the three arms were as follows: K+ rich vegetarian diet (Arm A; 3.5–4g K+ per day); K+ supplement powder consisting of K+ rich pulses and seeds plus oral rehydration salt 3g (Arm B; 7.5–8g K+ per day); and a control routine diet (Arm C; 2–3g K+ per day).
Study patients continued their pre-trial standard rheumatology treatment including methotrexate (72%) and low-dose steroid (60%), and were permitted use of rescue analgesics; other non-pharmacologic interventions were not advised. Compliance checks included a urinary K+ assay. Standard efficacy and safety measures, along with diet intake, were assessed monthly. The three study arms were well matched for mean DAS 28 values and withdrawals.
Results showed an improvement in pain and several ACR efficacy measures (P<0.05) with K+ intervention. An intent-to-treat analysis demonstrated that the difference was not significant (mean change VAS: -1.3cm, 2cm, and 1.2cm for Arms A, B, and C, respectively; P=0.17). However, a separate completer analysis showed significant change in mean pain VAS in Arm B (P=0.04). Arm B also resulted in the best response (P<0.05) in the proportion of patients with ≥50% reduction and minimal clinical important difference in pain VAS on completion from baseline; the maximum improvement in HAQ and SF 36 physical score was also seen in this study arm.
Potassium augmentation also led to reductions in the mean DAS score by -1.38, -1.22, and -1.05 for Arms A, B, and C, respectively. All arms with potassium intervention showed a reduction in systolic blood pressure.
Study findings from the intervention-control study showed a reduction in pain beyond standard drug therapy when using K+ augmentation. “Overall, this seemed to be a gentle useful adjunct therapy in RA,” concluded Kainifard.