Smokers and people with chronic obstructive pulmonary disease (COPD) are more likely to develop severe complications and die from COVID-19 infections than infected patients who do not smoke or have COPD, a recent meta-analysis shows.
This research, however, suggests that the prevalence of COPD patients and smokers among those infected is low.
The study, “Prevalence, Severity and Mortality associated with COPD and Smoking in patients with COVID-19: A Rapid Systematic Review and Meta-Analysis,” was published in the journal PLOS One.
COPD patients are believed to be highly vulnerable to infections with the new coronavirus, not only because their disease chronically affects the lungs, but also because of comorbidities such as high blood pressure or diabetes that appear to increase the risk of severe coronavirus infections.
A recent pre-print (a study available before peer review) suggested that this patient group is even more likely to develop severe disease or to be admitted to intensive care units than those with high blood pressure or diabetes.
To shed more light on the impact of coronavirus infections in COPD patients, researchers in the U.K. and Saudi Arabia conducted a meta-analysis of published and peer-reviewed studies investigating COVID-19 infections, and examined the prevalence of COPD in their analysis.
Among an initial pool of 123 studies, 15 were selected for additional analysis, including a total of 2,473 confirmed COVID-19 cases. Most of these studies were retrospective and all were conducted in China, except for one in the U.S.
Of the 2,473 examined patients, 58 had COPD, representing a prevalence of 2.3% — which is lower than the 10% prevalence of COPD patients in the general population.
Eight of the 15 studies reported the smoking status of participants. There were 193 current smokers, making up a prevalence of 9%.
Researchers then examined the severity and mortality due to coronavirus infections in COPD patients and smokers compared with non-COPD patients and non-smokers. Severe coronavirus disease was defined as the need for intensive care unit admission or mechanical ventilation, or death.
The team found that more COPD patients (63%) experienced severe disease than those without this condition (33.4%), with statistical analysis showing that COPD significantly increased by nearly twofold the risk of severe disease.
Two studies examined the mortality rate in these patients, which also appeared to be higher in COPD patients (60%) than in non-COPD patients (55%). These findings, however, did not reach statistical significance.
The same was seen for smokers, whose risk of severe disease was 1.45 times greater compared to those who never smoked or had quit smoking. About 38.5% of the smokers included in the study died due to COVID-19 infections.
“Our main outcomes show that the prevalence of COPD in COVID-19 patients was low, but that the risk of severity (63%) and mortality (60%) were high, which indicates COPD patients with confirmed COVID-19 are at a greater risk of severe complications and death,” the researchers wrote.
The team emphasized that the prevalence of COPD patients in coronavirus cases is much lower than the latest prevalence reported in China (13.6%), and the global prevalence of COPD (9%–10%). The prevalence of smokers in this population was also lower than the reported smoking prevalence in China (25%).
Still, “effective preventive measures are urgently required to reduce COVID-19 risk on COPD patients and current smokers,” the team concluded.
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