Association Between Prognostic Nutritional Index and Disease Activity in Patients with Rheumatoid Arthritis: A Retrospective Cohort Study

The prognostic nutritional index (PNI), derived from serum albumin and lymphocyte count, reflects immuno-nutritional status and may be influenced by systemic inflammation. This study examined the association between PNI and disease activity in rheumatoid arthritis (RA). A total of 730 patients fulfilling the 2010 ACR/EULAR criteria were retrospectively analysed. Demographic, clinical, and laboratory data were collected; disease activity and disability were assessed using the DAS28-CRP and Health Assessment Questionnaire (HAQ). Correlation analyses, multivariable linear regression, ROC analyses, subgroup testing, and mediation analyses were performed. The mean age was 56.2±12.5 years and 76.3% were women. Median DAS28-CRP was 3.38, with 11.2% classified as having high disease activity. Mean PNI was 54.0±5.34. PNI was significantly lower in patients with high DAS28-CRP and in severe HAQ categories (p