To assess whether the neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) can predict those who subsequently require escalation of disease modifying therapy because of continued disease activity in rheumatoid arthritis (RA).
Patients with newly diagnosed RA were recruited from the Early Arthritis Clinic at the Royal Adelaide Hospital. All patients commenced "triple-therapy" with a standardised protocol of methotrexate, sulfasalazine and hydroxychloroquine, and were reviewed every three to six weeks. DMARD therapy was adjusted according to a pre-defined algorithm if not in low disease activity. The NLR, PLR and other markers of disease activity including ESR, CRP and DAS28 were collected, as well as current therapy. The primary outcome measure was failure of triple-therapy to maintain low-disease activity (DAS28<3.2) at 12 months.
Two-hundred and twenty-two patients met inclusion criteria. The mean age was 54.2 ± 15.4 years, with a mean disease duration of 22.3 ± 25.0 weeks. Forty-five (20%) patients had failed triple therapy by one year. The mean baseline NLR was significantly higher in those who failed triple therapy compared with those who did not (3.7 ± 2.8 vs. 2.9 ± 1.5; p = 0.02), however, the PLR was not significantly different. A baseline NLR>2.7 was an independent predictor of treatment failure (OR 2.65, CI 1.23-5.72, p = 0.01) whilst the PLR, ESR, CRP and DAS-28ESR were not.
The NLR is significantly increased in those who subsequently fail triple-therapy for RA, and it outperformed conventional markers of disease activity. The NLR may offer an inexpensive, objective and reproducible prognostic marker in RA. Further studies are justified to confirm its potential role in guiding the management of RA.