Comparing mortality between positive and negative blood culture results: an inverse probability of treatment weighting analysis of a multicenter cohort

Aibo Liu,Tzu-Chun Hsu,Chia-Hung Yo,Chien-Chang Lee,Wan-Ting Hsu,Hoi Sin Tong,Lu Nie,Hua Yu,Kuihai Wu

doi:10.1186/s12879-021-05862-w

Abstract

BackgroundThe association between blood culture status and mortality among sepsis patients remains controversial hence we conducted a tri-center retrospective cohort study to compare the early and late mortality of culture-negative versus culture-positive sepsis using the inverse probability of treatment weighting (IPTW) method.MethodsAdult patients with suspected sepsis who completed the blood culture and procalcitonin tests in the emergency department or hospital floor were eligible for inclusion. Early mortality was defined as 30-day mortality, and late mortality was defined as 30- to 90-day mortality. IPTW was calculated from propensity score and was employed to create two equal-sized hypothetical cohorts with similar covariates for outcome comparison.ResultsA total of 1405 patients met the inclusion criteria, of which 216 (15.4%) yielded positive culture results and 46 (21.3%) died before hospital discharge. The propensity score model showed that diabetes mellitus, urinary tract infection, and hepatobiliary infection were independently associated with positive blood culture results. There was no significant difference in early mortality between patients with positive or negative blood culture results. However, culture-positive patients had increased late mortality as compared with culture-negative patients in the full cohort (IPTW-OR, 1.95, 95%CI: 1.14–3.32) and in patients with severe sepsis or septic shock (IPTW-OR, 1.92, 95%CI: 1.10–3.33). After excluding Staphylococcal bacteremia patients, late mortality difference became nonsignificant (IPTW-OR, 1.78, 95%CI: 0.87–3.62).ConclusionsCulture-positive sepsis patients had comparable early mortality but worse late mortality than culture-negative sepsis patients in this cohort. Persistent Staphylococcal bacteremia may have contributed to the increased late mortality.

Highlights

The association between blood culture status and mortality among sepsis patients remains controversial we conducted a tri-center retrospective cohort study to compare the early and late mortality of culture-negative versus culture-positive sepsis using the inverse probability of treatment weighting (IPTW) method
In the United States, severe sepsis and septic shock remain the dominant cause of death in intensive care units (ICUs), with approximately 900,000– 3,000,000 cases yearly [2]
We provided the information on the microbiology of bacteria isolated in Supplementary Table 3

Summary

Introduction

The association between blood culture status and mortality among sepsis patients remains controversial we conducted a tri-center retrospective cohort study to compare the early and late mortality of culture-negative versus culture-positive sepsis using the inverse probability of treatment weighting (IPTW) method. Sepsis is a leading cause of morbidity and mortality among hospitalized patients and results in a significant healthcare burden [1]. In the United States, severe sepsis and septic shock remain the dominant cause of death in intensive care units (ICUs), with approximately 900,000– 3,000,000 cases yearly [2]. Sepsis was ranked in the top four most expensive conditions, costing an aggregate of $20,298,000 yearly in US hospitals [3, 4]. Mortality from severe sepsis and septic shock remains unacceptably high, ranging between 20 and 40% depending on the severity of illness [5]. Blood culture remains an essential test in the care of sepsis patients [6]. In approximately one third to two thirds of sepsis patients, no specific organism can be identified by culture [10]

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