Impaired glucose regulation, SARS-CoV-2 infections and adverse COVID-19 outcomes

Area of Science:

• Endocrinology
• Infectious Diseases
• Public Health

Background:

• Impaired glucose regulation (IGR) is globally prevalent and associated with Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
• Existing evidence linking IGR and SARS-CoV-2 is based on limited systematic reviews, with unknown strength of association.
• Understanding the interplay between glucose metabolism and COVID-19 is crucial for public health strategies.

Purpose of the Study:

• To systematically review and assess the evidence strength for associations between impaired glucose regulation and SARS-CoV-2.
• To identify limitations in current research regarding confounder adjustment, glycemic measures, and population-based data.
• To inform future research directions for clarifying the causal relationship and therapeutic targets.

Main Methods:

• Systematic literature review of studies investigating impaired glucose regulation and SARS-CoV-2.
• Critical appraisal of study methodologies, focusing on confounder adjustment and glycemic assessment.
• Synthesis of findings to evaluate the consistency and reproducibility of observed associations.

Main Results:

• Consistent associations were found between IGR and SARS-CoV-2, but with significant methodological limitations.
• Studies often lacked robust confounder adjustment and detailed glycemic data (e.g., HbA1c, glucose).
• The role of IGR as a risk factor for infection and SARS-CoV-2 as a risk factor for IGR onset remains uncertain.

Conclusions:

• While diabetes is a known risk factor for poor COVID-19 prognosis, causal links with IGR require further investigation.
• The effectiveness of interventions targeting dysglycemia for SARS-CoV-2 outcomes is not yet established.
• Future research should prioritize population-based studies with comprehensive pre-pandemic data collection and glycemic assessments.