Abstract
Objective: To determine the association of systemic immune inflammation index with DAS 28ESR (disease activity score) for rheumatoid arthritis and its value as an emerging biochemical marker for rheumatoid arthritis disease activity.
Methodology: This retrospective cross-sectional study was performed at the rheumatology unit of Federal Government Polyclinic Hospital, Islamabad from December 2020 to June 2021. A total of 290 rheumatoid arthritis patients’ data was analyzed. DAS 28 ESR was computed using the DAS 28 ESR calculator and the systemic immune inflammation index (SII) was obtained by the equation platelet count x neutrophil count/lymphocyte count. Data were analyzed using several parametric and nonparametric tests on the SPSS version 23.
Results: Out of 238 patients, 186(82.1%) were females and 52 (17.9%) males. Mean age was 45.2±12 years. DAS28 ESR score showed disease activity as 8.9% in remission, while 10% had low disease activity, 55.9 % had moderate activity, and 25.2% had high disease activity. Mean SII with DAS 28 ESR ≤3.2 was 673.85±433.74 while patients showing moderate to high disease activity (DAS 28 ESR ≥3.2) exhibited an SII of 1005.46±607.6. Advanced statistical tests showed this to be a significant finding [spearman’s correlation analysis (p=0.000)].
Conclusion: SII was found to be a reliable, cheap, and easily available index for measuring status of disease in patients with rheumatoid arthritis.
Key Words: Rheumatoid Arthritis, systemic immune inflammation index (SII

Key words: Rheumatoid Arthritis, systemic immune inflammation index (SII), Disease Activity score ESR (DAS 28).