Clinical Significance of Ascitic Fluid Polymorphonuclear Leukocyte (PMN) Percentage in Cirrhosis Patients without Spontaneous Bacterial Peritonitis (SBP)

Abstract

Background & Aims: Absolute PMN count (PMN-C) ≥250cells/mm3 in ascites is the diagnostic hallmark of spontaneous bacterial peritonitis (SBP) and is associated with high morbidity and mortality. However, the clinical significance of ascitic PMN percentage (PMN-%) as well as PMN-C in the absence of SBP as additional biomarkers for mortality and future incidence of SBP has not been determined. Methods: This retrospective cohort included adults with cirrhosis undergoing first-recorded paracentesis with initial PMN-C<250cells/mm3 at two tertiary medical centers between 2015-2020. Patients with prior SBP were excluded. Outcomes were death and SBP development. Cox regression estimated hazard ratios(HR) for risk of death and SBP development and Akaike information criterion(AIC) to compare model fit. Results: 384 adults (73% male, median age 58, 67% with alcohol-associated cirrhosis, median PMN-C 14cells/mm3[IQR 5-34], and median PMN-% 10%[IQR 4-20]) were included in this study. Univariate risk of death increased 10% per 25-unit increase in PMN-C (95%CI 1.01-1.21, p=0.03) and 19% per 10-unit increase in PMN-% (95%CI 1.06-1.33, p=0.003) with PMN-% demonstrating better model fit in assessing mortality risk (AIC:1044 vs. 1048, respectively). In models adjusted for age, HCV, and MELD-Na, PMN-% was associated with risk of death (PMN-% 10-29% HR 1.17, p=0.50; PMN-% ≥30% group HR 1.94, p=0.03; vs. PMN-% <10%) and SBP development (PMN-% 10-29% HR 1.68, p=0.07; PMN-% ≥30% HR 3.48, p<0.001; vs. PMN-% <10%). Conclusion: Our results suggest PMN-% at first paracentesis represents a better biomarker compared to PMN-C for assessing risk of death and future SBP development in patients with PMN-C<250cells/mm3.