SAT0734-HPR Correlates of pain and predictors of pain relief in a controlled ra study in indian patients
Authors: T. Kianifard, M. Saluja, S. Samukaddam, A. Chopra
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Potassium (K) enriched vegetarian diet (PEVT) significantly reduced pain (primary hypothesis and efficacy) compared to ad libitum diet in RA patients on standard drugs. We had earlier validated Indian version of RA Pain Scale/RAPS.<sup>EULAR 2014</sup> <h3>Objectives</h3> To determine correlates of pain (VAS) and RAPS and predictors of 'pain relief' in RA in a dietary intervention study <h3>Methods</h3> In the primary study, 172 consenting symptomatic patients (≥4 cms pain VAS) were randomised into a 3 arm 16 week study [2 active PEVT arms, I control routine diet] with ongoing background medication [72% methotrexate, 60% prednisolone]; 155 patients completed study. Evaluation included ACR core set and other measures (plus dietary) and RAPS (4 domains- physiological, affective, sensory discriminative, cognitive; 24 questions, score 0–144). The study (80% power, α &lt;0.05) sample size was based on improvement in pain VAS (0–10 cms, with no pain at 0). Reduction in pain VAS of least 1 cm on VAS was considered 'responder'. A Pearson correlation matrix was computed. A linear logistic regression model was used (good fit after 5 iterations). The dependent variable was number of 'respondents' (pain). 28 independent variables included clinical (+patient functional), laboratory (+steroid assay), drug use and dietary analytics (+micronutrients) at baseline. From the latter, 13 qualified variables (a -priori significance) were run in a forward stepwise model. <h3>Results</h3> Data below shows significant correlation of pain measures (p&lt;0.05). Other measures with significant correlation ≥0.3 were: patient global assess-DAS 28, C-reactive protein (CRP)-Erythrocyte Sed rate (ESR), Haemoglobin-ESR, health assessment questionnaire score (HAQ)-medical outcome short form 36 physical (SF 36-phy), DAS 28-painful tender joint count, HAQ-general health on 100 mm VAS (GH). Significant (p&lt;0.05) predictors in the first regression run were allocation to K intervention, female gender, and disease duration (less than 5 years). In the subsequent run, the significant predictors [Odd's Ratio, 95% confidence interval] were: K allocation arm(1.13, 5.27), disease duration less 5 years (1.98, 9.67), female gender (p=0.01), serum K (1.44, 6.29), body mass index (0.99, 4.76) Correlates of RAPS:Swollen joint count (0.16), general health assessment 100 mm VAS (−0.18), morning stiffness (0.16), SF 36 phy (−0.35), SF36-mental (−0.21), serum potassium/K (0.16), C-reactive protein (0.25) Correlates of PAIN VAS:Painful joint count (0.16), general health assessment 100 mm VAS (−0.43), C-reactive protein (0.2), dietary K (−0.22) <h3>Conclusions</h3> Despite a complex questionnaire, RAPS shared significant correlates with the popular and seemingly simplistic pain VAS. The association between dietary K and pain VAS was inverse and modest (p&lt;0.01) and consistent with the primary study hypothesis. The predictors of pain response included patient 'allocation to the PEVD' in support of the efficacy result in the primary study. <h3>References</h3> [1] Kainifard T, et al. (Oral Potassium Reduces Pain in RA) Arthritis Rheumatol2015;67(suppl 10) [2] Anderson LD (RAPS). Arthritis Care Res2001;45:317–323. <h3>Acknowledgements</h3> Arthritis Research Care Foundation Centre for Rheumatic Diseases Pune (India) for education reserch grant and all the patient participants and colleagues <h3>Disclosure of Interest</h3> None declared