Introduction: Only 3 types of coronavirus cause aggressive respiratory disease in humans (MERS-Cov, SARS-Cov-1, and SARS-Cov-2). It has been reported higher infection rates and severe manifestations (ICU admission, need for mechanical ventilation, and death) in patients with comorbidities such as diabetes mellitus (DM). For this reason, this study aimed to determine the prevalence of diabetes comorbidity and its associated unfavorable health outcomes in patients with acute respiratory syndromes for coronavirus disease according to virus types. Methods: Systematic review of literature in Pubmed/Medline, Scopus, Web of Science, Cochrane, and Scielo until April of 2020. We included cohort and cross-sectional studies with no restriction by language or geographical zone. The selection and extraction were undertaken by 2 reviewers, independently. The study quality was evaluated with Loney’s instrument and data were synthesized by random effects model meta-analysis. The heterogeneity was quantified using an I2 statistic. Funnel plot, Egger, and Begg tests were used to evaluate publication biases, and subgroups and sensitivity analyses were performed. Finally, we used the GRADE approach to assess the evidence certainty (PROSPERO: CRD42020178049). Results: We conducted the pooled analysis of 28 studies (n = 5960). The prevalence analysis according to virus type were 451.9 diabetes cases per 1000 infected patients (95% CI: 356.74-548.78; I2 = 89.71%) in MERS-Cov; 90.38 per 1000 (95% CI: 67.17-118.38) in SARS-Cov-1; and 100.42 per 1000 (95% CI: 77.85, 125.26 I2 = 67.94%) in SARS-Cov-2. The mortality rate were 36%, 6%, 10% and for MERS-Cov, SARS-Cov-1, and SARS-Cov-2, respectively. Due to the high risk of bias (75% of studies had very low quality), high heterogeneity ( I2 higher than 60%), and publication bias (for MERS-Cov studies), we down rate the certainty to very low. Conclusion: The prevalence of DM in patients with acute respiratory syndrome due to coronaviruses is high, predominantly with MERS-Cov infection. The unfavorable health outcomes are frequent in this subset of patients. Well-powered and population-based studies are needed, including detailed DM clinical profile (such as glycemic control, DM complications, and treatment regimens), comorbidities, and SARS-Cov-2 evolution to reevaluate the worldwide prevalence of this comorbidity and to typify clinical phenotypes with differential risk within the subpopulation of DM patients.

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We have read with interest the editorial written by Papanas and Papachristou. 1 This article highlights some relevant aspects about the potential role of bidirectional cytokine imbalance due to SARS-Cov-2 (severe acute respiratory syndrome coronavirus 2) infections in diabetic foot patients referred to neuropathy, peripheral arterial disease, and improvement of injuries due to decrease of daily activities. Almost 8 months have passed since the SARS-CoV-2 outbreak began. We have witnessed how vulnerable populations, for example, patients with diabetes mellitus, are at major risk. In our hospital, we frequently treated patients with SARS-Cov-2 infected and diabetic foot simultaneously. Therefore, it is also relevant to discuss about corticoid therapy as an important pillar in the management and effect on wound healing. Both topical and systemic corticosteroids induce many changes on the skin. The treatment potency and duration have an effect on wound healing. 2 They reduce the proliferation of keratinocytes and fibroblasts 3 and decrease the expression of genes involved in collagen synthesis, such the human type VII collagen gene-COL7A1. 4 Moreover, collagen alterations have been observed by inhalation of lowdose corticosteroids for a short time. 5 Additionally, the presence of biofilms, which consist of encapsulated bacteria in a layer of extracellular polymeric substances that help their survival, is an important factor to take into account in wound healing. 6 The response mechanism of bacteria to steroids has remained unclear, but they have a direct action reducing biomass. 7 Another factor is the bacterial resistance, with different effects depending on the phenotype-gram positive or negative-and type of corticosteroids employed. 8 We conclude that continuous use of corticosteroids would have a negative effect in terms of wound healing. However, its use at low doses in critically ill patients with respiratory failure reduced the mortality rate; therefore, it is important that the physician take into account the doses and prescription of corticosteroids to adapt the ulcer therapy. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

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