Patients with type 2 diabetes mellitus (T2D) who faced heightened health risks throughout and since the Covid-19 pandemic, were more than three times likelier to die from Covid than those without the condition.
Their comprehensive analysis, led by the National Research Tomsk State University in Russia, sought to evaluate and quantify the specific impact of T2D on key Covid-19 outcomes, including death rates, disease severity, and the requirement for mechanical ventilation.
For the study – findings were published in BMC Infectious Diseases – the researchers carried out a systematic review and meta-analysis following PRISMA guidelines. A broad literature search was performed across PubMed, Scopus, Web of Science and Embase, covering publications from December 2019 to March 2024.
The analysis included studies that examined the effect of T2D on adult Covid-19 patients.
The researchers employed a random-effects model to synthesise the data and used the I² statistic to assess heterogeneity. They also conducted robust assessments of publication bias, including Egger’s regression and the Fail-safe N test.
The results were consistent and clinically significant across several outcomes, they observed. Eighteen studies showed that T2D was linked with a markedly higher risk of mortality (odds ratio [OR]: 3.66; 95% CI: 2.20–5.11; p<0.001), while six studies found increased disease severity (OR: 1.97; 95% CI: 1.02–2.92; p<0.001). Furthermore, five studies indicated a greater need for mechanical ventilation in diabetic patients (OR: 2.34; 95% CI: 1.18–3.49; p<0.001).
Heterogeneity was high for mortality outcomes (I²=83.83%) but low for severity and ventilation measures (I²=0%), and no significant publication bias was detected.
These findings carry important implications for clinical practice. The robust association between T2D and poor Covid-19 outcomes highlights the urgency of tailored care strategies for diabetic individuals, including prioritisation in vaccination and early therapeutic interventions.
However, reports EMJ Reviews, the high heterogeneity in mortality data and reliance on observational studies are notable limitations. Further research is essential to uncover the biological mechanisms at play and to refine clinical guidelines for managing patients with T2D in the context of infectious diseases like Covid-19.
Study details
Type 2 diabetes mellitus as a predictor of severe outcomes in Covid-19 – a systematic review and meta-analyses
Fatoke B et al.
Published in BMC Infectious Diseases on 19 May 2025
Abstract
Background
The COVID-19 pandemic has posed significant challenges to global health, with type 2 diabetes mellitus (T2DM) emerging as a key risk factor for adverse outcomes. This study systematically reviews and quantifies the association between T2DM and COVID-19 outcomes, including mortality, severity, and need for mechanical ventilation.
Methods
A systematic review and meta-analysis were conducted that adhered to PRISMA guidelines. We searched PubMed, Scopus, Web of Science and Embase for studies published from December 2019 to March 2024. Eligible studies reported on the impact of T2DM on COVID-19 outcomes in the adult population. Data were extracted and analyzed using a random-effects model, and heterogeneity was assessed using the I2 statistic. Publication bias was assessed using Egger regression, Kendall’s Tau, and the Fail-safe N calculation.
Results
Eighteen studies were included in the meta-analysis for mortality, six for severity and five for mechanical ventilation. T2DM was significantly associated with higher mortality (OR = 3.66, 95% CI: 2.20–5.11, p < 0.001), higher severity (OR = 1.97, 95% CI: 1.02–2.92, p < 0.001), and higher need for mechanical ventilation (OR = 2.34, 95% CI: 1.18–3.49, p < 0.001). Heterogeneity was high for mortality (I2 = 83.83%) but low for severity and mechanical ventilation (I2 = 0%). No significant publication bias was found.
Conclusions
T2DM is associated with significantly worse outcomes in COVID-19 patients, including higher mortality, higher severity and a greater likelihood of needing mechanical ventilation. These findings emphasise the need for targeted interventions and management strategies for individuals with T2DM during the ongoing pandemic. Future research should focus on understanding the underlying mechanisms and exploring strategies to mitigate these risks.
See more from MedicalBrief archives:
Global database for research to examine link between Covid-19 and diabetes
Diabetes and hypertension most common comorbidities in Gauteng Covid-19 deaths
Undiagnosed diabetes added to Covid death toll