Accumulating Impact of Smoking and Co-morbidities on Severity and Mortality of COVID-19 Infection: A Systematic Review and Meta-analysis

Abstract

Background: High prevalence, severity, and formidable morbidity have marked the recent emergence of the novel coronavirus disease (COVID-19) pandemic. The significant association with the pre-existing co-morbid conditions has increased the disease burden of this global health emergency, pushing the patients, healthcare workers and facilities to the verge of complete disruption.

Methods: Meta-analysis of pooled data was undertaken to assess the cumulative risk assessment of multiple co-morbid conditions associated with severe COVID-19. PubMed, Scopus, and Google Scholar were searched from January 1^st to June 27^th 2020 to generate a well-ordered, analytical, and critical review. The exercise began with keying in requisite keywords, followed by inclusion and exclusion criteria, data extraction, and quality evaluation. The final statistical meta-analysis of the risk factors of critical/severe and non-critical COVID-19 infection was carried out on Microsoft Excel (Ver. 2013), MedCalc (Ver.19.3), and RevMan software (Ver.5.3).

Results: We investigated 19 eligible studies, comprising 12037 COVID-19 disease patients, representing the People's Republic of China (PRC), USA, and Europe. 18.2% (n = 2200) of total patients had critical/severe COVID-19 disease. The pooled analysis showed a significant association of COVID-19 disease severity risk with cardiovascular disease (RR: 3.11, p < 0.001), followed by diabetes (RR: 2.06, p < 0.001), hypertension (RR: 1.54, p < 0.001), and smoking (RR: 1.52, p < 006).

Conclusion: The review involved a sample size of 12037 COVID-19 patients across a wide geographical distribution. The reviewed reports have focussed on the association of individual risk assessment of co-morbid conditions with the heightened risk of COVID-19 disease. The present meta-analysis of cumulative risk assessment of co-morbidity from cardiovascular disease, diabetes, hypertension, and smoking signals a novel interpretation of inherent risk factors exacerbating COVID-19 disease severity. Consequently, there exists a definite window of opportunity for increasing survival of COVID-19 patients (with high risk and co-morbid conditions) by timely identification and implementation of appropriately suitable treatment modalities.

Keywords: COVID-19; Co-morbidity; SARS-CoV-2; acute cardiac injury; hypertension; risk factor; smoking.

Fig. (1)

Flow chart of the study selection. (A higher resolution / colour version of this figure is available in the electronic copy of the article).

Fig. (2)

Pooled prevalence of mortality and recovery rate in critical/severe patients. (A higher resolution / colour version of this figure is available in the electronic copy of the article).

Fig. (3)

Forest plot of the relative risk in smoking habits and cancer associated with COVID-19 infected cases. (A higher resolution / colour version of this figure is available in the electronic copy of the article).

Fig. (4)

Forest plot of the relative risk in hypertension and diabetes associated with COVID-19 infected cases. (A higher resolution / colour version of this figure is available in the electronic copy of the article).

Fig. (5)

Forest plot of the relative risk in cardiovascular and liver diseases associated with COVID-19 infected cases. (A higher resolution / colour version of this figure is available in the electronic copy of the article).

Fig. (6)

Forest plot of the relative risk in comorbidities associated with COVID-19 infected cases. (A higher resolution / colour version of this figure is available in the electronic copy of the article).

Fig. (7)

Funnel plot for Meta-analysis of the relative risk of underlying disease in COVID-19 infected cases, [A] Smoking, [B] Cancer, [C] Hypertension, [D] Diabetes, [E] Cardiovascular disease, [F] Liver disease [G] Cumulative effect. (A higher resolution / colour version of this figure is available in the electronic copy of the article).