Socioeconomic disparities in asthma health care utilization, exacerbations, and mortality: A systematic review and meta-analysis

Background: Prior studies investigating the effect of socioeconomic status (SES) on asthma health care outcomes have been heterogeneous in the populations studied and methodologies used. Objective: We sought to systematically synthesize evidence investigating the impact of SES on asthma health care utilization, exacerbations, and mortality. Methods: We searched Embase, Medline, and Web of Science for studies reporting differences in primary care attendance, exacerbations, emergency department attendance, hospitalization, ventilation/intubation, readmission, and asthma mortality by SES. Study quality was assessed using the Newcastle Ottawa Scale, and meta-analyses were conducted using random-effects models. We conducted several prespecified subgroup analyses, including by health care system (insurance based vs universal government funded) and time period (before vs after 2010). Results: A total of 61 studies, comprising 1,145,704 patients, were included. Lower SES was consistently associated with increased secondary health care utilization including emergency department attendance (odds ratio [OR], 1.61; 95% confidence interval [CI], 1.40-1.84), hospitalization (OR, 1.63; 95% CI, 1.34-1.99), and readmission (OR, 1.31; 95% CI, 1.19-1.44). Substantial associations were also found between SES and ventilation/intubation (OR, 1.76; 95% CI, 1.13-2.73), although there was no association with primary care attendances (OR, 0.79; 95% CI, 0.51-1.24). We found evidence of borderline significance for increased exacerbations (OR, 1.18; 95% CI, 0.98-1.42) and mortality (OR, 1.12; 95% CI, 0.92-1.37) among more deprived groups. There was no convincing evidence that disparities were associated with country-level health care funding models or that disparities have narrowed over time. Conclusions: Patients with a lower SES have substantially increased secondary care health care utilization. We found evidence suggestive of increased exacerbations and mortality risk, although CIs were wide. These disparities have been consistently reported worldwide, including within countries offering universally funded health care systems. Systematic review registration: CRD42020173544.