Background/Purpose

Psoriatic arthritis (PsA) is an inflammatory arthritis associated with psoriasis. There are few biomarkers for disease activity in PsA. Traditional acute phase reactants are elevated only in about 50% of patients with active PsA. Neutrophil-Lymphocyte Ratio (NLR) has been recently shown to be a marker of inflammation with prognostic value in inflammatory, cardiovascular and malignant diseases. We therefore evaluated NLR as a marker of disease activity in patients with PsA.

Methods

The study was conducted in a large PsA cohort were patients are seen accordingly to a standard protocol that includes clinical and laboratory assessment. Swollen joint count (SJC) and PASI score were used as  measures of disease activity in PsA at baseline. NLR was calculated from the neutrophil and lymphocyte count obtained from a complete blood count done at the time of clinic assessment. Pearson correlation between NLR and disease activity markers (SJC, PASI) and traditional acute phase reactants [ESR, haemoglobin (Hb), platelet count] were investigated. The association between ESR, Hb, platelet count and NLR with SJC and PASI score was determined using univariate and multivariate linear regression. Since the NLR was not normally distributed, lognormal transformation was done.

Results

1130 (631 males) with a mean age of 45 years, age at onset of psoriasis 29 years and of PsA 38 years were included. At the time of the first assessment these patients had 11 active, 5 swollen and 8 clinically damaged joints and the PASI score was 5.3. The mean ESR was 23 mm/hr, Hb 139 g/dL, platelet count 286,000/microL and NLR 3.2. The NLR significantly correlated with SJC (r=0.12, p<0.0001), PASI (r=0.15, p<0.0001), ESR (r=0.24, p<0.0001), Hb (r= -0.18, p<0.0001) and platelet count (r=0.15, p<0.0001). Multivariate linear regression analysis showed that NLR (β 0.16, p = 0.04) and ESR (β 0.11, p = 0.003) were independently associated with SJC. Similarly, multivariate linear regression analysis showed that NLR (β 0.41, p = <0.0001) and ESR (β 0.11, p = 0.007) were independently associated with PASI score.

Conclusion

NLR has a potential as a marker of disease activity in PsA independent of traditional acute phase reactants. Further evaluation to determine threshold of abnormal values in the context of psoriatic disease, as well as prognostic value in predicting joint damage and cardiovascular disease is required.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/neutrophil-lymphocyte-ratio-as-a-marker-of-disease-activity-in-psoriatic-arthritis/