Type 1 and type 2 diabetes mellitus: clinical outcomes due to COVID-19. A systematic review of the literature and meta-analysis of observational studies

Abstract

ABSTRACT: Introduction: Most studies do not differentiate between patients with type 1 and type 2 diabetes in COVID-19. Objective: To identify whether there are differences in clinical outcomes between COVID-19 patients with diabetes (type 1 and type 2) and with COVID-19 patients without diabetes. Methods: MEDLINE, EMBASE, LILACS, OVID, WHO COVID-19 Research Database and Scopus were searched from December 01, 2019, to August 15, 2022. We included observational studies without restriction of geographic region, language, sex, or age, whose outcome was mortality, intensive care unit (ICU) admission, and hospitalization. Two authors independently performed the selection, data extraction and quality assessment (National Institutes of Health tool). A third reviewer resolved discrepancies. Data were synthesized according to sociodemographic and clinical characteristics of the patients. Meta-analysis was performed using the random effects method reporting Odds Ratio (OR) with 95% Confidence Intervals (CI). Results: 94 primary studies were included for this systematic review and 47 for the meta-analysis. When assessing the risk of bias, it was found that 46%, 40% and 14% of the articles presented good, fair, and poor quality, respectively. The OR for mortality, ICU admission and hospitalization for patients with diabetes was 2.62 (95% CI 2.10 to 3.28; I2 100%), 2.63 (95% CI 1.55 to 4.47; I2 95%) and 3.70 (95% CI 1.90 to 7.21; I2 98%) respectively. Patients with type 1 diabetes also had a higher odds of hospitalization (OR 2.43 95% CI 1.98 to 2.98; I2 0%) and patients with type 2 diabetes higher odds of death (OR 2.54 95% CI 1.84 to 3.51; I2 93%). The study population and sample size were identified as potential sources of heterogeneity in the subgroup analysis. Conclusion: Regardless of the type of diabetes, there is a greater possibility of unfavorable clinical outcomes due to COVID-19. Therefore, clinical, and public health measures should be aimed at guaranteeing comprehensive management and care for patients with diabetes.