The prognostic significance of the prognostic nutritional index in cancer: a systematic review and meta-analysis

Abstract

Purpose: The prognostic nutritional index (PNI) is a simple and effective parameter, initially created to evaluate preoperative nutritional conditions and surgical risk. It has been recently been found to be associated with short- and long-term outcomes of various malignancies. We performed a meta-analysis to determine the predictive significance of PNI in cancer, as a mean to assist in determining the optimal surgery timing and in improving the survival of cancer patients.

Methods: Data were retrieved from PubMed and ISI Web of Science to identify eligible studies. Odds ratios (ORs) and hazard ratios (HRs) were extracted and pooled to explore the relationships of PNI with patient survival and clinicopathological features.

Results: Fourteen studies with a total of 3,414 participants met the inclusion criteria. Low PNI was associated with poor overall survival (pooled OR 1.80, 95 % confidence interval [CI] 1.59-2.04) and the presence of post-operative complications (pooled OR 2.45, 95 % CI 1.31-4.58) in cancer patients, but not with cancer-specific survival (CSS) (pooled HR 1.81, 95 % CI 0.94-3.49). PNI was also found to be associated with invasion depth (pooled OR 5.07, 95 % CI 2.34-10.96) and lymph node metastasis (pooled OR 3.70, 95 % CI 2.32-5.92) in gastric cancer, whereas TNM stage was the only clinicopathological feature associated with PNI in colorectal carcinoma (pooled OR 1.81, 95 % CI 1.24-2.64).

Conclusions: PNI might be an effective predictive indicator for the prognosis of cancer, especially digestive system carcinomas. Further studies are required to verify the significance of PNI in clinical practice.

Fig. 1

Flow diagram of the meta-analysis

Fig. 2

Subgroup analyses of the associations between the prognostic nutritional index and overall survival in cancer according to a the type of carcinoma, b region, c quality score, and d cut-off value. The segments represent the 95 % confidence intervals (CIs) of each study. The diamonds represent the overall effect sizes, and the diamond widths represent the overall 95 % CIs. OR, odds ratio

Fig. 3

Funnel plot of the association between the prognostic nutritional index and overall survival in cancer patients. OR odds ratio

Fig. 4

Meta-analyses of the associations between the prognostic nutritional index and a post-operative complications and b cancer-specific survival in cancer patients. The segments represent the 95 % confidence intervals (CI) of each study. The diamonds represent the overall effect sizes, and the diamond widths represent the overall 95 % CIs. OR odds ratio

Fig. 5

Meta-analyses of the associations between a clinicopathological factors (depth of invasion and lymph node metastasis) and overall survival in gastric cancer and b clinicopathological features (depth of invasion, lymph node metastasis, histological type, post-operative complications, and TNM stage) and overall survival in colorectal carcinoma. The segments represent the 95 % confidence intervals (CI) of each study. The diamonds represent the overall effect sizes, and the diamond widths represent the overall 95 % CIs. OR odds ratio

Fig. 6

Meta-analysis of the associations between clinicopathological features (lymph node metastasis, post-operative complications, histological type, and carcinoembryonic antigen [CEA]) and overall survival in cancer patients. The diamonds represent the overall effect sizes, and the diamond widths represent the overall 95 % CIs. OR odds ratio