Diabetes and COVID-19: New Findings on the Systemic Burden

Diabetes and COVID-19: New Findings on the Systemic Burden

Evidence from a large-scale systematic review and meta-analysis published in BMJ Open in 2025 provides new insight into the disproportionate impact of COVID-19 on patients with diabetes.

Drawing on data from over 1.15 million individuals across 25 observational studies, the findings suggest that COVID-19 significantly increases the risk of mortality, acute kidney injury, and glycemic dysregulation in this population. Patients with diabetes affected by COVID-19 are also likely to exhibit elevated biomarkers linked to inflammation and coagulation.

Here's a closer look at the findings.

Elevated Mortality and Kidney Complications

Patients with diabetes who were infected with COVID-19 faced more than double the risk of death (OR 2.52, 95 percent CI 1.45-4.36, I²=99 percent). While the study found no significant differences in ICU admissions or diabetic ketoacidosis rates between infected and non-infected patients, acute kidney injury stood out as a significant complication (OR 3.69, 95 percent CI 2.75-4.94, I²=0 percent).

Biomarkers and Glycemic Shifts

The meta-analysis revealed significant elevations in key biochemical markers among diabetic patients with COVID-19:

• C-reactive protein (+38.3 mg/L, 95 percent CI 4.79-71.82, I²=82 percent)
• D-dimer (+1.52 µg/mL, 95 percent CI 0.73-2.31, I²=0 percent)
• Serum creatinine (+0.12 mg/dL, 95 percent CI 0.04-0.19, I²=0 percent)

Additionally, the findings draw attention to short-term and long-term glycemic disruptions:

• Patients with type 1 diabetes experienced an average +20.4 mg/dL (95 percent CI 7.39-33.36, I²=0 percent) rise in random plasma glucose, likely reflecting acute stress and altered insulin sensitivity
• Patients with type 2 diabetes experienced a modest but significant HbA1c increase of +0.21 percent (95 percent CI 0.05-0.38, I²=13 percent), hinting at larger impacts on metabolic stability post-infection

Implications for Care

These findings on increased vulnerability among patients with diabetes are consistent with prior research. To mitigate risk and improve outcomes, clinicians should:

• Prioritize patients with diabetes, especially those with type 1 diabetes or evidence of diabetic complications, in vaccination campaigns
• Proactively monitor renal function and intensify glycemic surveillance during acute illness
• Tailor post-COVID care plans to assess potential long-term deterioration in metabolic and renal markers

While the pooled estimates stem from observational studies with high methodological heterogeneity and therefore warrant cautious interpretation, the overarching message remains clear: for patients with diabetes, COVID-19 is not just a respiratory virus. It’s a full-body stressor that exposes and amplifies pre-existing vulnerabilities, so adapting protocols and personalizing care is key in protecting this high-risk group.

Reference

Zhang J, Ma Y, To WL, et al. Impact of COVID-19 infection on mortality, diabetic complications and haematological parameters in patients with diabetes mellitus: a systematic review and meta-analysis. BMJ Open. 2025;15(3):e090986. Published 2025 Mar 27. doi:10.1136/bmjopen-2024-090986