Prevalence of diabetes in the 2009 influenza A (H1N1) and the Middle East respiratory syndrome coronavirus: a systematic review and meta-analysis

Over the past two decades a number of severe acute respiratory infection outbreaks such as the 2009 influenza A (H1N1) and the Middle East respiratory syndrome coronavirus (MERS-CoV) have emerged and presented a considerable global public health threat. Epidemiologic evidence suggests that diabetic subjects are more susceptible to these conditions. However, the prevalence of diabetes in H1N1 and MERS-CoV has not been systematically described. The aim of this study is to conduct a systematic review and meta-analysis of published reports documenting the prevalence of diabetes in H1N1 and MERS-CoV and compare its frequency in the two viral conditions. Meta-analysis for the proportions of subjects with diabetes was carried out in 29 studies for H1N1 (n=92,948) and 9 for MERS-CoV (n=308). Average age of H1N1 patients (36.2±6.0 years) was significantly younger than that of subjects with MERS-CoV (54.3±7.4 years, P<0.05). Compared to MERS-CoV patients, subjects with H1N1 exhibited 3-fold lower frequency of cardiovascular diseases and 2- and 4-fold higher prevalence of obesity and immunosuppression, respectively. The overall prevalence of diabetes in H1N1 was 14.6% (95% CI: 12.3- 17.0%; P<0.001), a 3.6-fold lower than in MERS-CoV (54.4%; 95% CI: 29.4-79.5; P<0.001). The prevalence of diabetes among H1N1 cases from Asia and North America was ~two-fold higher than those from South America and Europe. The prevalence of diabetes in MERS-CoV cases is higher than in H1N1. Regional comparisons suggest that an etiologic role of diabetes in MERS-CoV may exist distinctive from that in H1N1

Prevalence of comorbidities in the Middle East respiratory syndrome coronavirus (MERS-CoV): a systematic review and meta-analysis

The Middle East respiratory syndrome coronavirus (MERS-CoV) is associated with life-threatening severe illnesses and a mortality rate of approximately 35%, particularly in patients with underlying comorbidities. A systematic analysis of 637 MERS-CoV cases suggests that diabetes and hypertension are equally prevalent in approximately 50% of the patients. Cardiac diseases are present in 30% and obesity in 16% of the cases. These conditions down-regulate the synthesis of proinflammatory cytokines and impair the host's innate and humoral immune systems. In conclusion, protection against MERS-CoV and other respiratory infections can be improved if public health vaccination strategies are tailored to target persons with chronic disorders

Prevalence of chronic comorbidities in chikungunya: A systematic review and meta-analysis

Background: Epidemiologic evidence suggests that patients with chikungunya virus (CHIKV) infection may be at risk of severe disease complications when they also have comorbidities such as obesity, diabetes, cardiac diseases, and/or asthma. However, the prevalence of these co-existing medical conditions in severe CHIKV cases has not been systematically reported. Objective: The aim of the present study is to conduct a systematic review and meta-analysis to describe the prevalence of chronic comorbidities in CHIKV and evaluate their possible contributions to disease severity. Methods: A search strategy was developed for online databases. Search terms used were “Chikungunya” AND “Diabetes, Hypertension, Stroke, Cardiovascular Diseases, Coronary Artery Diseases, Obesity, OR Asthma”. Only 11 articles documenting the frequency of comorbidities in CHIKV were included. Meta-analyses were conducted to evaluate the overall prevalence of comorbidities in the CHIKV infection and stratify the estimates by severity. Results: Among 2,773 CHIKV patients, hypertension was the most prevalent comorbidity (31.3%; 95%CI: 17.9-48.8%) followed by diabetes (20.5%; 95%CI: 12.7-31.3%), cardiac diseases (14.8%; 95%CI: 8.1-25.5%) and asthma (7.9%; 95%CI: 3.3-17.7). There was 4- to 5-fold significant increased prevalence of diabetes, hypertension and cardiac diseases in CHIKV patients over 50 years of age compared to their younger counterparts. Severe CHIKV cases had a significantly higher proportion of diabetes than non-severe cases (p < 0.05). CHIKV patients with diabetes had OR of 1.2 (95%CI: 1.05-1.48; p = 0.0135) for developing severe infection outcome compared to those with no diabetes. Conclusion: Hypertension, diabetes and cardiac diseases may contribute to the severe outcome of CHIKV. Diabetic subjects may be at higher risk of severe infection. These findings may be relevant in developing public health measures and practices targeting CHIKV patients with comorbidities to avert the severe outcome of the infectious disease

Prevalence of chronic comorbidities in dengue fever and West Nile virus: A systematic review and meta-analysis

<div><p>Background</p><p>Flavivirus diseases such as dengue fever (DENV), West Nile virus (WNV), Zika and yellow fever represent a substantial global public health concern. Preexisting chronic conditions such as cardiovascular diseases, diabetes, obesity, and asthma were thought to predict risk of progression to severe infections.</p><p>Objective</p><p>We aimed to quantify the frequency of chronic comorbidities in flavivirus diseases to provide an estimate for their prevalence in severe and non-severe infections and examine whether chronic diseases contribute to the increased risk of severe viral expression.</p><p>Methods</p><p>We conducted a comprehensive search in PubMed, Ovid MEDLINE(R), Embase and Embase Classic and grey literature databases to identify studies reporting prevalence estimates of comorbidities in flavivirus diseases. Study quality was assessed with the risk of bias tool. Age-adjusted odds ratios (ORs) were estimated for severe infection in the presence of chronic comorbidities.</p><p>Results</p><p>We identified 65 studies as eligible for inclusion for DENV (47 studies) and WNV (18 studies). Obesity and overweight (i.e., BMI> 25 kg/m², prevalence: 24.5%, 95% CI: 18.6–31.6%), hypertension (17.1%, 13.3–21.8%) and diabetes (13.3%, 9.3–18.8%) were the most prevalent comorbidities in DENV. However, hypertension (45.0%, 39.1–51.0%), diabetes (24.7%, 20.2–29.8%) and heart diseases (25.6%, 19.5–32.7%) were the most prevalent in WNV. ORs of severe flavivirus diseases were about 2 to 4 in infected patients with comorbidities such as diabetes, hypertension and heart diseases. The small number of studies in JEV, YFV and Zika did not permit estimating the prevalence of comorbidities in these infections.</p><p>Conclusion</p><p>Higher prevalence of chronic comorbidities was found in severe cases of flavivirus diseases compared to non-severe cases. Findings of the present study may guide public health practitioners and clinicians to evaluate infection severity based on the presence of comorbidity, a critical public health measure that may avert severe disease outcome given the current dearth of clear prevention practices for some flavivirus diseases.</p></div

Flowchart of study selection and systematic literature review process.

<p>The flow diagram describes the systematic review of literature on the prevalence of comorbidities in flavivirus infections. A total of 65 unique studies were identified (47 studies for dengue fever and 18 for West Nile virus from an initial 1373 examined titles). aSome studies reported on more than one flavivirus disease. Studies drawn from the same population were not included in the meta-analyses.</p

Characteristics of studies included in meta-analysis for prevalence of chronic comorbidities in flavivirus infections.

<p>Characteristics of studies included in meta-analysis for prevalence of chronic comorbidities in flavivirus infections.</p

Meta-analysis for the prevalence of clinical symptoms in flavivirus infections in the selected studies.

<p>Meta-analysis for the prevalence of clinical symptoms in flavivirus infections in the selected studies.</p

Keywords for the search related terms and synonyms.

<p>Keywords for the search related terms and synonyms.</p

Pooled prevalence estimates of comorbidities in severe and non-severe cases of flavivirus infections dengue fever and West Nile virus.

<p>Pooled prevalence estimates of comorbidities in severe and non-severe cases of flavivirus infections dengue fever and West Nile virus.</p

Meta-analysis for the frequency of clinical features in severe flavivirus infections in the selected studies.

<p>Meta-analysis for the frequency of clinical features in severe flavivirus infections in the selected studies.</p