Prognostic Role of Lymphocyte-to-C-Reactive Protein Ratio in Patients with Pulmonary Arterial Hypertension

<b>Background:</b> Inflammation plays a critical role in the prognosis of patients with pulmonary arterial hypertension (PAH). The lymphocyte-to-C-reactive protein ratio (LCR), as a novel inflammatory marker, has not been studied in patients with PAH. The objective of this study was to investigate the prognostic value of the LCR in patients with PAH. <b>Methods:</b> A retrospective cohort study was conducted on 116 patients with PAH diagnosed in Renji Hospital, School of Medicine, Shanghai Jiao Tong University, from January 2014 to December 2018. The primary outcome was a composite endpoint that included lung transplantation, rehospitalization for PAH, and all-cause death. The LCR is the ratio of the blood lymphocyte count to the C-reactive protein concentration. <b>Results:</b> A total of 116 patients with PAH were included in this study, with an average age of 41.53 years; 92.2% were female, and the event rate was 57.8%. Restricted cubic spline analysis confirmed a linear association between the LCR and the risk of clinical worsening events. Multivariate Cox proportional hazards analysis showed that the LCR was significantly negatively associated with clinical worsening events, with hazard ratios and 95% confidence intervals of 0.772 (0.614-0.970). The Kaplan-Meier curve showed that event-free survival decreased significantly when the LCR was less than 1.477. LASSO regression selected four potential predictors, including the LCR, to construct a nomogram. The nomogram had a high predictive strength, with an area under the ROC curve of 0.805 (0.713-0.896). The calibration curves and decision curve analysis indicated that the nomogram had good predictive performance and the ability to guide clinical management. <b>Conclusions:</b> The LCR is a valuable prognostic marker for predicting long-term clinical events in patients with PAH, and the nomogram incorporating the LCR could effectively stratify risk and guide clinical decision making.