Diabetes associated with no improvement in COVID-19 patients

Type 2 diabetes mellitus (T2DM) appears to prevent improvement in patients with COVID-19 and contributes to a severe and critical condition of the infectious disease, according to a study.

“Furthermore, having a severe and critical condition and decreased lymphocyte count were independent risk factors that influence the improvement of patients with T2DM with COVID-19,” the researchers said.

A total of 663 consecutive patients with COVID-19 admitted to the Renmin Hospital of Wuhan University in China from 11 January to 6 February 2020 were included in the analysis. Of these, 67 (10.1 percent) had T2DM. [J Clin Endocrinol Metab 2020;105:dgaa535]

COVID-19 patients with T2DM, compared to those without, were older (aged 66 vs 57 years; p<0.001), were more likely to be male (62.7 percent vs 37.3 percent; p=0.019), and had higher prevalence of cardiovascular disease (61.2 percent and 20.6 percent; p<0.001) and urinary diseases (9 percent vs 2.5 percent; p=0.014).

Patients with T2DM also had a higher likelihood of developing severe (58.2 percent vs 46.3 percent; p=0.002) and critical COVID-19 (20.9 percent vs 13.4 percent; p=0.001) and having poor therapeutic response (76.1 percent vs 60.4 percent; p=0.017). No significant between-group difference was noted in mortality rates (4.5 percent vs 3.7 percent; p=0.732).

On multivariate logistic regression analysis, T2DM correlated with poor therapeutic effect in patients with COVID-19 (odds ratio [OR], 2.99, 95 percent confidence interval [CI], 1.07–8.66; p=0.04). In addition, having a severe and critical COVID-19 condition (OR, 3.27, 95 percent CI, 1.02–9.00; p=0.029) and decreased lymphocytes (OR, 1.59, 95 percent CI, 1.10–2.34; p=0.016) independently predicted poor therapeutic effect in those with T2DM.

These findings were consistent to those from studies examining other coronavirus infections, namely SARS-CoV and MERS-CoV. Diabetic patients with SARS-CoV had significantly higher mortality, intensive hospitalization, and mechanical ventilation rates than nondiabetic patients. In MERS-CoV, those with T2DM had poorer prognosis, significantly worse clinical outcomes, and a significantly higher mortality rate than other patients. [JAMA 2003;289:2801-2809; Emerg Infect Dis 2020;26:166-168]

The World Health Organization considers T2DM as a risk factor for MERS-CoV infection. [Pharmacol Res 2018;137:230-235]

“Patients with T2DM with COVID-19 are prone to a severe state, and the therapeutic effects are much poorer than in patients without T2DM,” for which there are several possible explanations, the researchers said.

“First, the pulmonary vascular bed and alveolar surfactants in patients with diabetes are often damaged... Second, hyperglycaemia and insulin deficiency in patients with diabetes will reduce synthesis of proinflammatory factors such as interferon-γ and interleukin 15 and have influence on downstream acute inflammatory responses. Therefore, it will impair the host’s innate and humoral immunity,” they explained. [Cold Spring Harb Perspect Med 2012;2:a007724]

“Third, chronic disease (such as diabetes) and infectious diseases and their complications share several common characteristics such as endothelial dysfunction, proinflammatory status, and innate immune response,” the researchers said. [PLoS Negl Trop Dis 2015;9:e0003741; Diab Vasc Dis Res 2008;5:213-214; Curr Hypertens Rep 2010;12:448-455]

The current study was limited by its single-centre design, the absence of data on body mass index, a number of covarying differences between patients with T2DM and control participants, and the lack of multivariate regression analysis with mortality as the dependent variable since only three deaths in diabetic COVID-19 patients were recorded.