Relationship between Annualized Case Volume and Mortality in Sepsis: A Dose-Response Meta-analysis.
BACKGROUND
The relationship between annualized case volume and mortality in patients with sepsis is not fully understood. The authors performed a dose-response meta-analysis to assess the effect of annualized case volume on mortality among patients with sepsis in the intensive care unit, emergency department, or hospital, hypothesizing that higher annualized case volume may lead to lower mortality.


METHODS
The authors searched PubMed and Embase through July 2015 to identify observational studies that examined the relationship between annualized case volume and mortality in sepsis. The predefined outcome was mortality. Odds ratios with 95% CIs were pooled using a random-effects model.


RESULTS
Ten studies involving 3,495,921 participants and 834,009 deaths were included. The pooled estimate suggested that annualized case volume was inversely associated with mortality (odds ratio, 0.76; 95% CI, 0.65 to 0.89; P = 0.001), with high heterogeneity (I = 96.6%). The relationship was consistent in most subgroup analyses and robust in sensitivity analysis. Dose-response analysis identified a nonlinear relationship between annualized case volume and mortality (P for nonlinearity less than 0.001).


CONCLUSIONS
This meta-analysis confirmed the study hypothesis and provided strong evidence for an inverse and a nonlinear dose-response relationship between annualized case volume and mortality in patients with sepsis. Variations in cutoff values of category for annualized case volume across studies may mainly result in the overall heterogeneity. Future studies should uncover the mechanism of volume-mortality relationship and standardize the cutoff values of category for annualized case volume in patients with sepsis.
From the Department of Anesthesiology, Drum Tower Hospital, Medical College of Nanjing University, Nanjing, China (W.-J.G., J.Z., Z.-L.M., X.-P.G.); Department of Orthopaedic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China (X.-D.W.); Department of Science and Education, First People's Hospital of Changde City, Changde, China (Q.Z.); and Department of Anesthesiology, General Hospital of Jinan Military Command, Jinan, China (F.W.).
Wan-Jie
WJ
Gu
Xiang-Dong
XD
Wu
Quan
Q
Zhou
Juan
J
Zhang
Fei
F
Wang
Zheng-Liang
ZL
Ma
Xiao-Ping
XP
Gu
D003422:Critical Care / Q000706:statistics & numerical data; D004632:Emergency Medical Services / Q000706:statistics & numerical data; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D018805:Sepsis / Q000453:epidemiology / Q000401:mortality* / Q000628:therapy