Differential mortality with COVID-19 and invasive mechanical ventilation between high-income and low-and middle-income countries: a systematic review, meta-analysis, and meta-regression

Abstract

The COVID-19 pandemic has markedly affected the health care of patients in low- and middle-income countries (LMICs), but no systematic study to corroborate this effect has been undertaken. In addition, the survival outcomes of patients with COVID-19 who received invasive mechanical ventilation (IMV) have not been well established. We pooled evidence from all available studies and did a systematic review and meta-analysis to assess and compare mortality outcomes between LMICs and high-income countries (HICs). We searched MEDLINE and the University of Michigan Library according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines from December 1, 2019, to July 15, 2021, for case-control studies, cohort studies, and brief reports that discussed mortality ratios and survival outcomes among patients with SARS-CoV-2 who received IMV. We excluded studies and case reports without comparison groups, narrative reviews, and preprints. A random-effects estimate of the arcsine square root transformation (PAS) of each outcome was generated with the DerSimonian-Laird method. Seven eligible studies, consisting of 243,835 patients with COVID-19, were included. We identified a significantly higher mortality rate (i.e., a larger PAS) among the patients receiving IMV in LMICs (PAS, 0.754; 95% CI, 0.569-0.900; P<.001) compared to patients in HICs (PAS, 0.588; 95% CI, 0.263-0.876; P<.001). Considerable heterogeneity was present within the individual subgroups possibly because of the extent of the included studies, which had data from specific countries and states but not from individual hospitals or health care centers. Moreover, the sample population in each study was diverse. Meta-regression showed that a higher mortality rate among patients with COVID-19 who received IMV in both HICs (P<.001) and LMICs (P=.04) was associated with chronic pulmonary disease. Our study suggests that chronic pulmonary diseases and poor demographics lead to a worse prognosis among patients with COVID-19 who received IMV. Moreover, the survival outcome is worse in LMICs, where health care systems are usually understaffed and poorly financed.

Keywords: COVID-19; invasive mechanical ventilation; invasive respiratory support; meta-analysis; mortality outcome.

Figure 1

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Flowchart of Study Selection. UoM indicates University of Michigan.

Figure 2

Funnel Plot. Symmetry indicates an absence of publication bias. Black circles represent high-income countries; red diamonds, low- and middle-income countries. OR indicates odds ratio.

Figure 3

Results of Meta-analysis. The forest plots represent results of a 1-arm analysis of studies reporting mortality rates among patients with COVID-19 who received invasive mechanical ventilation in high-income countries (A) or in low- and middle-income countries (B). The squares and horizontal lines correspond to the study-specific arcsine square root transformation (PAS) and 95% CIs. The vertical dashed line indicates the overall pooled PAS.

Figure 4

Bubble plot for patients with COVID-19 who received invasive mechanical ventilation in high-income countries. The covariate was chronic pulmonary disease. PAS indicates arcsine square root transformation.

Figure 5

Bubble plot for patients with COVID-19 who received invasive mechanical ventilation in low- and middle-income countries. The covariate was chronic pulmonary disease. PAS indicates arcsine square root transformation.