Prognostic value of the prognostic nutritional index in sepsis, pneumonia, and tuberculosis: a systematic review and meta-analysis

The study evaluated the prognostic value of the Prognostic Nutritional Index (PNI) in patients with infectious diseases, specifically sepsis, pneumonia, and tuberculosis. The analysis included 10 studies with a total of 28,757 patients from five medical databases. PNI was calculated using the formula: serum albumin (g/L) + 5 × lymphocyte count (×10⁹/L). Results showed that elevated PNI in sepsis was associated with significantly lower mortality risk (HR: 0.63), similarly in pneumonia (HR: 0.47). In tuberculosis, however, the association between PNI and mortality was not statistically significant. Overall, higher PNI represented a significant protective factor against mortality (HR: 0.52, p < 0.0001). The authors concluded that current evidence is too heterogeneous to support universal use of PNI in infectious diseases.