The usefulness of the prognostic inflammatory and nutritional index (PINI) in a haemodialysis population

Abstract

Background and aim Protein–Energy Wasting and inflammation are the principal risk factors of haemodialysis complications. We evaluated the reliability of a simple and non expensive test, the Prognostic Inflammatory and Nutritional Index (PINI), for regular screening of maintenance haemodialysis (MHD) patients in order to detect early onset of inflammation and malnutrition. Methods and results 121 adult patients on maintenance dialysis were followed up for 32 months and screened every 6 months for PINI, calculated as alpha1-Acid Glycoprotein (α1-AG) × C-Reactive Protein (CRP)/Albumin × Transthyretin. PINI score ≤1 was considered normal. Patients were stratified according to their PINI score: 86 patients (71.66%) had a normal score, whereas 35 (28.33%) had PINI ≥ 1. The latter also had higher CRP levels, despite no clinical evidence of inflammation at the time of enrolment. Survival in patients with normal PINI was similar to patients with normal CRP, while in patients with abnormal PINI it was significantly lower than in patients with low serum albumin ( p < 0.05) or elevated CRP ( p < 0.05). After follow-up, all surviving MHD patients with PINI ≥ 1 had at least one cardiovascular event vs 2.5% of patients with PINI ≥ 1. Conclusion The assessment of PINI can reliably identify MHD patients at higher risk of mortality and morbidity even in the absence of overt Malnutrition-Inflammation Complex Syndrome (MICS). This simple test appears to be more sensitive and specific of the single components, and not expensive, so that it could be routinely used to identify patients with sub-clinical inflammation and/or malnutrition.