AB0232 THE USEFULNESS OF THE PROGNOSTIC NUTRITIONAL INDEX (PNI) FOR THE DISEASE ACTIVITY IN PATIENTS WITH RHEUMATOID ARTHRITIS

Abstract

BackgroundMany prognostic factors and laboratory biomarkers have been put forward to correlate disease activity in Rheumatoid arthritis (RA). The prognostic nutritional index (PNI) was first established to assess perioperative immunonutritional status and surgical risk in patients undergoing gastrointestinal surgery. The PNI, which reflects albumin concentration and lymphocyte count, is a newly established inflammation-based nutritional score.ObjectivesIn this study, we aimed to determine the relationship between this simple risk index, which was first adapted and analyzed in malnourished patients, and disease activity in RA patients.MethodsThis prospective study included 77 RA patients who fulfilled the 2010 revised criteria of the American College of Rheumatology for RA. The demographic characteristics of the patients, duration of the disease and clinic characteristics of the patients such as the 28-joint Disease Activity Score based on the erythrocyte sedimentation rate (DAS28-ESR), Visual Analogue Scale, Health Assessment Questionnaire-Disability Index were collected. Labotaruvary findings including erythrocyte sedimentation rate, C-reactive protein levels, lymphocyte count, albumin were noted. The PNI was calculated using the following formula: 10 x serum albumin value (g/dL) + 0.005 x total lymphocyte count in the peripheral blood (per mm3). Based on the DAS28-ESR level, the included patients were categorized into two groups, namely, inactive to mild active RA (n=31; DAS28-ESR level <3.2) and moderate to highly active RA (n=46; DAS28-ESR level ≥3.2). These groups were compared with the parameters described above.ResultsSeventy-seven patients (90.9% female) with a mean age of 53.6 (SD:10.2) years were recruited into the study. The age, gender and disease therapy duration of the patients were similar in both groups. Patients who DAS28-ESR ≥3.2 had a significantly lower PNI compared to those who did not [41,57 (SD:3,64) vs. 43,78 (SD:2,30), p=0.017] (Table 1). Multivariate logistic regression analyses revealed that PNI was an independent predictor of moderate to highly active RA (OR: 0.770, 95%CI: 0.635–0.935; p=0.008). A receiver operating characteristic curves analysis yielded that the optimal cut-off value of PNI for moderate to highly active RA was 42.01 with sensitivity 67.7% and specificity 47.9% (AUC: 0.662, 95%CI: 0.541-0.782, p=0.017) (Figure 1).Table 1.Demographic, clinical features and laboratory findings of the patients with rheumatoid arthritis based on disease activity measured by DAS28-ESRDAS28-ESR <3.2 n=(31)DAS28-ESR ≥3.2 n=(46)P valueAge (years; mean SD)55,80 SD 9,3952,13 SD 10,670.124Female, gender, n (%)26(%83,9)44(%95,7)0.111Prognostic Nutritional Index (mean SD)43,78 SD 2,3041,57 SD 3,640,017Disease symptoms duration(month; mean SD)112,2 SD 97,3120,9 SD 79,70.316Disease therapy duration (month; mean SD)93,2 SD 94,2110,0 SD 76,00.126DAS28-ESR (mean SD)2,55 SD 0,474,47 SD 0,85<0.001Visual Analogue Scale (mm, mean SD)7,38 SD 16,5820,17 SD 25,76<0,001Health Assessment Questionnaire-Disability Index (mean SD)0,69 SD 0,620.84 SD 0,600,259ESR (mm/h, mean SD)26,35 SD 18,9831,73 SD 16,950.083CRP (mg/L, mean SD)6,30 SD 4,4912,75 SD 19,540.106Albumin (g/dl, mean SD)4,37 SD 0,234,15 SD 0,360.010Lymphocyte (cells/µL, mean SD)2,01 SD 0,622,07 SD 0,650.570Abbreviations: DAS28-ESR, the 28-joint Disease Activity Score based on the erythrocyte sedimentation rate; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein.Figure 1.ConclusionBased on the study findings, we were able to show that simple and easily obtained PNI could be an independent predictor of disease activity in rheumatoid arthritis patients.