Background Potassium (K+), predominantly intracellular, has several critical physiological functions. Dietary K+ is considered important in hypertension and stroke but its role in RA though sparsely described remains speculative.
Objectives To estimate intake of dietary K+ in RA patients and correlate with clinical variables and pain in particular.
Methods 139 RA patients (79% women, mean age 46.3 years, median duration illness 4 years) on supervised DMARD (60%methorexate, 22% steroids) and 165 unrelated healthy controls (mean age 36.1 years)were interviewed by TK for a 3 day recall diet survey following oral consent during the period Jun 2012-Feb 2013. Patients were selected in no particular order from the CRD clinic in Pune metropolis (State Maharashtra, West India) during routine follow up. Clinical data was extracted from standard rheumatology case record forms; mean pain VAS (range 0-10 cms) was 4.75 cm (±1.67). National Indian dietary and food composition standards (2007) were referred (NIN, ICMR, Hyderabad) to calculate dietary K+, and other minerals and composition (data not shown); recommended dietary allowance for K+ is 3750 mg for men and 3225 mg for women (1). SPSS stat software used: significant p<0.05 (non parametric); unless stated standard deviation shown in parenthesis.
Results Mean daily dietary K+ was 1238.7 mg (±770.3) in RA and 3334.9 mg (±756.3) in controls (p<0.001); corresponding values were 1651.2 mg (RA) and 3438.8 in men and 1161.3 mg (RA) and 3170.9 in women. Women patients consumed significantly low K+. All patients were normokalemic (mean serum K+ 4.37 mEq/l). 44% RA and 77% controls consumed vegetarian diet; predominantly Hindu ethnic subjects. Weak negative correlations (not significant) were found between dietary K+ and painVAS scores (-0.16), HAQ score (-0.14) and serum cortisol (AM, -0.14); correlation in parenthesis. There was no correlation between dietary K+ and several other clinical variables (including joint counts pain/tenderness and swelling, ESR, CRP and DAS 28). The results were almost similar when patients taking steroids were excluded.
Conclusions The dietary K+ intake in RA patients was significantly low and women consumed lesser K+ compared to men. The overall diet of our RA patients seem to be inadequate and reasons range from community beliefs to psychosocial and economic factors. Other dietary constituents like sodium and essential minerals need to be studied vis-a-vis K+. Though the clinical significance is uncertain, observations favor a likely association of low dietary K+ with higher pain. We are carrying out controlled interventional studies (high K+ diet and K+ supplement) in patients with active painful RA.on supervised standard of care therapy.
http//icmr.nic.in/RDA-2010.pdf (accessed on 27 Jan 2013)
Acknowledgements Patients, Community and Arthritis Research Care Foundation-CRD Pune India
Disclosure of Interest None declared