Impact of Prognostic Nutrition Index on the Waitlist Mortality of Lung Transplantation

Abstract

<h3>Purpose</h3> Preoperative nutritional status affects surgical complications and prognoses postoperatively. The prognostic nutrition index (PNI) is a nutritional and inflammatory index recently regarded as a new preoperative prognostic score in the field of lung transplantation (LTx). However, no studies have reported the correlation between PNI and waitlist mortality for LTx. Thus, this study aimed to investigate the impact of PNI as a prognostic parameter of mortality on the waiting list for LTx. <h3>Methods</h3> A retrospective review was conducted on the data of 132 patients who were registered for LTx in our department between January 2013 and June 2020. Patients who registered for re-transplantation and those with insufficient data at the time of registration were excluded. Patients who finally received LTx were analyzed as censored data. The overall survival was evaluated using the Kaplan-Meier method for preoperative factors including PNI. Discriminative abilities of continuous variable factors were evaluated using a receiver operating characteristic (ROC) curve for overall mortality. <h3>Results</h3> The median follow-up period and age of patients on the waiting list were 16.3 months and 46 (range, 19-60) years, respectively. Sixty-six (52%) patients were male, and 52 (41%) had a smoking history. The largest number of indications for LTx was idiopathic interstitial pneumonias (n = 44, 35%). The cut-off value, calculated by the ROC curve, of the PNI for the waitlist mortality was 45.8. The low PNI group had a significantly worse prognosis (<i>p</i> = 0.0005). Multivariate analysis demonstrated that idiopathic interstitial pneumonia as an indication for LTx (<i>p</i> = 0.00002), PNI (<i>p</i> = 0.0005), lung allocation score (LAS) (<i>p</i> = 0.0009), and age (<i>p</i> = 0.012) were independent prognostic factors for waitlist mortality. In addition, PNI was significantly correlated with LAS (r = -0.22, <i>p</i> = 0.014). <h3>Conclusion</h3> PNI can be an independent prognostic parameter in registered candidates for LTx.