Comparison of culture-negative and culture-positive sepsis or septic shock: a systematic review and meta-analysis

Background Mortality and other clinical outcomes between culture-negative and culture-positive septic patients have been documented inconsistently and are very controversial. A systematic review and meta-analysis was performed to compare the clinical outcomes of culture-negative and culture-positive sepsis or septic shock. Methods We searched the PubMed, Cochrane and Embase databases for studies from inception to the 1st of January 2021. We included studies involving patients with sepsis or septic shock. All authors reported our primary outcome of all-cause mortality and clearly compared culture-negative versus culture-positive patients with clinically relevant secondary outcomes (ICU length of stay, hospital length of stay, mechanical ventilation requirements, mechanical ventilation duration and renal replacement requirements). Results were expressed as odds ratio (OR) and mean difference (MD) with accompanying 95% confidence interval (CI). Results Seven studies including 22,655 patients were included. The primary outcome of this meta-analysis showed that there was no statistically significant difference in the all-cause mortality between two groups (OR = 0.95; 95% CI, 0.88 to 1.01; P = 0.12; Chi-(2) = 30.71; I-2 = 80%). Secondary outcomes demonstrated that there was no statistically significant difference in the ICU length of stay (MD = - 0.19;95% CI, - 0.42 to 0.04; P = 0.10;Chi-(2) = 5.73; I-2 = 48%), mechanical ventilation requirements (OR = 1.02; 95% CI, 0.94 to 1.11; P = 0.61; Chi(2) = 6.32; I-2 = 53%) and renal replacement requirements (OR = 0.82; 95% CI, 0.67 to 1.01; P = 0.06; Chi-(2) = 1.21; I-2 = 0%) between two groups. The hospital length of stay of culture-positive group was longer than that of the culture-negative group (MD = - 3.48;95% CI, - 4.34 to - 2.63; P < 0.00001;Chi-(2) = 1.03; I-2 = 0%). The mechanical ventilation duration of culture-positive group was longer than that of the culture-negative group (MD = - 0.64;95% CI, - 0.88 to - 0.4; P < 0.00001;Chi-(2) = 4.86; I-2 = 38%). Conclusions Culture positivity or negativity was not associated with mortality of sepsis or septic shock patients. Furthermore, culture-positive septic patients had similar ICU length of stay, mechanical ventilation requirements and renal replacement requirements as those culture-negative patients. The hospital length of stay and mechanical ventilation duration of culture-positive septic patients were both longer than that of the culture-negative patients. Further large-scale studies are still required to confirm these results.