A Systematic Review and Meta-Analysis Evaluating Geographical Variation in Outcomes of Cancer Patients Treated in ICUs

OBJECTIVES: The reported mortality rates of cancer patients admitted to ICUs vary widely. In addition, there are no studies that examined the outcomes of critically ill cancer patients based on the geographical regions. Therefore, we aimed to evaluate the mortality rates among critically ill cancer patients and provide a comparison based on geography. DATA SOURCES: PubMed, EMBASE, and Web of Science. STUDY SELECTION: We included observational studies evaluating adult patients with cancer treated in ICUs. We excluded non-English studies, those with greater than 30% hematopoietic stem cell transplant or postsurgical patients, and those that evaluated a specific type of critical illness, stage of malignancy, or age group. DATA EXTRACTION: Two reviewers independently applied eligibility criteria, assessed quality, and extracted data. Studies were classified based on the continent in which they were conducted. Primary outcomes were ICU and hospital mortality. We pooled effect sizes by geographical region. DATA SYNTHESIS: Forty-six studies were included (n = 110,366). The overall quality of studies was moderate. Most of the published literature was from Europe (n = 22), followed by North America (n = 9), Asia (n = 8), South America (n = 5), and Oceania (n = 2). Pooled ICU mortality rate was 38% (95% CI, 33-43%); the lowest mortality rate was in Oceania (26%; 95% CI, 22-30%) and highest in Asia (51%; 95% CI, 44-57%). Pooled hospital mortality rate was 45% (95% CI, 41-49%), with the lowest in North America (37%; 95% CI, 31-43%) and highest in Asia (54%; 95% CI, 37-71%). CONCLUSIONS: More than half of cancer patients admitted to ICUs survived hospitalization. However, there was wide variability in the mortality rates, as well as the number of available studies among geographical regions. This variability suggests an opportunity to improve outcomes worldwide, through optimizing practice and research.