Background Granulomatosis with polyangiitis (GPA) is a granulomatous necrotizing vasculitis with high morbidity and mortality. Anti-neutrophil cytoplasmic antibody (ANCA) is a rvaluable diagnostic marker, however its titer lacks predictive value for the severity of organ involvement. Platelet to lymphocyte ratio (PLR) and mean platelet volume has been regarded as a potential marker in assessing systemic inflammation.
Objectives We aimed to investigate PLR and MPV as inflammatory marker in patients with GPA.
Methods GPA patients and age-sex matched healthy controls were included. Demographic, clinical and laboratory information were extracted from medical records. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), white blood cell (WBC), platelets (PLT), lymphocyte and neutrophils counts and glomerular filtration rate (GFR) were recorded. PLR was calculated. Disease activity was assessed with Birmingham Vasculitis Activity Score for WG vasculitis (BVAS/WG).
Results 56 patients with GPA and 53 healty controls were included. Clinical characteristics and laboratory findings of the study population are shown in Table 1. ESR, CRP, MPV and PLR were significantly higher in patients with GPA than controls. PLR positively correlated with ESR and CRP (r:0.389, p:0.005 and r:0.512 p<0.001, respectively). In contrast, MPV negatively correlated with ESR and CRP (r:-0.308, p:0.028 and r:-0.337 p:0.014, respectively). There were no significant correlation between PLR, MPV and BVAS/WG. Patients with renal involvement had statistically significantly higher PLR than patients without renal involvement (303.01±287.33 vs177.98 + 75.43, p: 0.020 respectively). Moreover PLR negatively correlated with glomerlar filtration rate (r:-0.266 and p:0.009). Receiver operating characteristic curve of PLR, ESR and CRP for differentiating renal involvement is presented in Figure 1. Area Under Curves (AUCs) for PLR, CRP and ESR were 0.703 (95% confidence interval [CI], 0.558–0.849, p=0.016), 0.577 (95% CI: 0.416–0.738, p=0.362), 0.508 (95% CI: 0.337–0.678, p=0.929), respectively. The cutoff level of PLR was 204 (sensitive 65.6%, specifity 62.5%, positive predictive value 70%, negative predictive value 57.7%). Patients with alveolar hemorrhage tended to have higher PLR but this difference did not reach statistically significance (266.60 + 182.90 vs 240.61 + 252.43 p=0.382, respectively).
Conclusions Results suggest that PLR exhibit favorable diagnostic performance in predicting renal involvement in patients with GPA.
Disclosure of Interest None declared