Literature review (table)
Data from the first epidemiologic studies of the COVID-19 pandemic in
China apparently did not identify asthma as a risk factor of severe
COVID-19.10,11 Of 171 children treated at Wuhan
Children’s Hospital (Wuhan, China), three (1.8%) required intensive
care and mechanical ventilation; all of those had underlying diseases
but there was no asthma reference.12 The same data was
found in a cross-sectional multicenter study carried out in 10 hospitals
across Hubei province (China), including hospitalized children with
COVID-19.13
Dong et al (China) in a nationwide case series of 2135 pediatric
patients (mean age 7 years) with COVID-19 reported to the Chinese Center
for Disease Control and Prevention from January 16, 2020, to February
8,2020 (Hubei Province), did not report any asthma
case.14
In a survey of 140 adult-aged admitted with COVID-19 (China), the
clinical characteristics and allergy status of patients was
investigated. All patients were community-acquired cases. Hypertension
(30.0%) and diabetes mellitus (12.1%) were the most common
comorbidities. Drug hypersensitivity (11.4%) and urticaria (1.4%) were
self-reported by several patients. Asthma or other allergic diseases
were not reported by any of the patients and the authors concluded that
allergic diseases and asthma were not risk factors for SARS-CoV-2
infection. Older age and high number of comorbidities, namely
cardiovascular and metabolic diseases, were associated with COVID-19
severity.15 The same authors studied a larger sample
of 290 confirmed COVID-19 adult patients hospitalized, and found only
one patient with asthma (0,3%); once again hypertension and diabetes
mellitus were the most frequently found
comorbidities.16
In another retrospective, multicenter cohort study that included 191
adult inpatients with confirmed COVID-19 (Wuhan, China), 48% had at
least one comorbid disease, hypertension being the most common, followed
by diabetes and coronary heart disease, with no asthma
reference.17 In a survey of 70 adult patients admitted
with COVID-19 in the Tongji Hospital (Wuhan, China), a 0.9% asthma
prevalence was found, markedly lower than that in the adult population
of this region (6.4%).18 In this study, asthma was
not identified as a risk factor for disease severity, in contrast with
hypertension.18
A nationwide analysis from China,19 including 1,590
COVID-19 cases from 575 hospitals in 31 provincial administrative
regions were collected, with an overall rate of severe cases and
mortality of 16.0% and 3.2%, respectively. The most prevalent
comorbidity was hypertension (16.9%), followed by diabetes (8.2%). 130
(8.2%) patients reported having two or more comorbidities. None of the
cases had physician-diagnosed asthma. After adjusting for age and
smoking status, COPD [hazards ratio (HR) 2.681, 95% confidence
interval (95%CI) 1.424-5.048], diabetes (HR 1.59, 95%CI 1.03-2.45),
hypertension (HR 1.58, 95%CI 1.07-2.32) and malignancy (HR 3.50, 95%CI
1.60-7.64) were identified as significant severity risk factors,
including for ICU admission, mechanical ventilation and
death.19
In Europe, in a sample of 355 patients with COVID-19 who died in Italy
(with a mean age of 79.5 years), it was reported that comorbidities were
associated with increased mortality risk. 30% had ischemic heart
disease, 35.5% had diabetes, 20.3% had active cancer, 24.5% had
atrial fibrillation, 6.8% had dementia, and 9.6% had a history of
stroke. Once again, no reference to chronic respiratory diseases was
made, namely asthma or chronic obstructive pulmonary disease
(COPD).20
Also in a retrospective case series of 1591 consecutive patients with
laboratory-confirmed COVID-19 admitted in ICUs from 72 hospitals of the
Lombardy Region, Italy, between February 20 and March 18, 2020, 68% of
patients had at least 1 comorbidity. Hypertension was the most common
comorbidity, affecting 49% of 1043 patients with available data. The
second most common comorbidities were cardiovascular disease (21%) and
hypercholesterolemia (18%). Only 4% had a history of COPD, with no
reference with patients with asthma.21
In the CONFIDENCE study22 that included 100 pediatric
COVID-19 cases also from Italy (median age 3,3 years), 58% with mild
disease and only 1% with severe disease, there was no reference to
chronic respiratory diseases as it was found in previous pediatric
Chinese surveys by Lu et al12 and Dong et
al.14
Barobia et al23 from La Paz University Hospital,
Madrid, Spain, in a sample of 2226 adult patients (median age 61 years)
admitted to the hospital who either died (20,7%) or were discharged
(79,3%), identified that the most common comorbidity was hypertension
(41.3%), followed by other chronic cardiovascular diseases (19,3%) and
diabetes (17,1%); asthma was identified in 5,2% of COVID-19 patients,
with a lower prevalence of 3,7% in the fatal cases. COPD affected 6,9%
of the population with a prevalence of 14,1% in the fatal cases. Also
from Spain, in Catalonia, Prieto-Alhambra et al24analyzed a primary care database covering >6 million
people, including 121,263 COVID-19 patients, both hospitalized and
outpatients. Most common comorbidities were hypertension (24.3%) and
obesity (19.9%). Asthma was present in 6,8% of the patients and COPD
in 3,2%. 10,7% of all patients were treated with inhalers.
In 200 COVID-19 patients hospitalized in the Lausanne University
Hospital, Switerzland,25 an asthma prevalence of 4,0%
was found, being 2,7% the asthma prevalence in those patients that
required mechanical ventilation.
In the United States of America (USA), Bhatraju et
al26 (Seattle) reported 24 patients with COVID-19
admitted to the intensive care unit (ICU) with a mortality rate of 50%.
As coexisting disorders, 58% had diabetes, 22% were current or former
tobacco smokers, 21% had chronic kidney disease, and 14% had asthma,
corresponding to three cases with mild asthma who had been treated with
systemic corticosteroids in the week before ICU admission, as
outpatients, for a presumed asthma exacerbation. These patients were
subsequently admitted to the ICU with severe respiratory failure
requiring invasive mechanical ventilation.26
Arentz et al27 (Washington, USA), describe in a case
series the characteristics and outcomes of 21 cases of COVID-19 admitted
to the ICU at Evergreen Hospital, with a mean age of 70 years-old (range
43-92 years), being the more common comorbidities identified chronic
kidney disease (47,6%), congestive heart failure (42,9), diabetes
(33,3%) and COPD (33,3%). 2 patients had asthma (9,5%).
Data also from the USA regarding 345 cases in children (< 18
years) reported that 23% had at least one
comorbidity.28 Chronic respiratory diseases, namely
asthma, were the most common associated diseases, although the authors
did not quantify the prevalence. Comorbidities were more frequently
present in pediatric cases that required hospitalization compared to
those that were not admitted to hospital (77% versus 12%), but there
was no reference of asthma as a significant risk
factor.28
In a sample of 377 adult COVID-19 patients admitted in California
Hospitals (USA), 7,4% had non discriminated asthma or
COPD.29 Data analysis of patients hospitalized in 14
states of the USA with COVID-19, during March 2020
(n=1,482),30 confirmed that hospitalization was much
more frequent in adults (74.5% with ≥ 50 years). Among patients with
information on underlying conditions (n=120), 89% had one or more
comorbidities. The most common were hypertension and other
cardiovascular diseases (77.5%), followed by obesity (48.3%) and
diabetes mellitus (28.3%). 17,0% of the COVID-19 positive patients had
asthma and 10,7% COPD. According the Centers for Disease Control and
Prevention (CDC) report, in admitted patients aged 18-49 years, obesity
was the most prevalent underlying condition (59,0%), followed by asthma
(27,3%).30
A report from eight hospitals (Georgia, USA), also summarized medical
data for 305 adult patients with confirmed COVID-19 who were admitted
during March 2020. Overall, 225 (73.8%) patients had underlying
conditions. Hypertension (67.5%), diabetes (39.7%), other
cardiovascular diseases (25.6%) and severe obesity (body mass index
≥40), which was present in 12.7% of patients. Asthma was identified in
10.5% of all patients (13.5% in patients aged 18-49 years-old, 13.1%
in those aged 50-64 years-old and 6.0% in those aged ≥65 years-old,
with no statistically significant differences) and COPD in
5.2%.31
In the large sample of hospitalized COVID-patients (>99%
adults), that included 5700 patients hospitalized with COVID-19 in the
New York City Area (NY), 14.2% were treated in the ICU, 12.2% received
invasive mechanical ventilation and 21% died.32Asthma prevalence was found in 9,0% (with no reference of asthma
severity / control) and COPD in 5,4%; most common comorbidities were
hypertension (56,6%), obesity (41,7%) and diabetes
(33,8%).32
In the NY Mount Sinai Hospitals an 8,2% prevalence of asthma was found
in 2199 hospitalized patients, that was not significantly different in
those that died (7,4%).33 Also in NY, in the first
1000 consecutive adult patients with a positive SARS-CoV-2 PCR test
presented to the emergency department or were hospitalized at New
York-Presbyterian/Columbia University Irving Medical Center between
March 1 and April 5, 2020, an asthma prevalence of 11,3% was found,
that was also not significantly different in those that were ICU
admitted (12,3%).34
In the ISARIC Prospective Observational Cohort Study35with near real-time analysis, with the participation of 166 United
Kingdom (UK) hospitals, 16,749 COVID-19 hospitalized patients were
included between 6th February and 18th April 2020, mostly adults. The
commonest comorbidities were chronic cardiac disease (29%),
uncomplicated diabetes (19%), non-asthmatic chronic pulmonary disease
(19%) and asthma (14%); 47% had no documented reported comorbidity.
Increased age and comorbidities including obesity were associated with a
higher probability of mortality.35
Very recent data from the OpenSAFELY Collaborative
Study,36 identified asthma as a significant risk
factor of death from COVID-19 in England, United Kingdom (UK). The
authors conducted a cohort study that included 17,425,445 adults using
national primary care electronic health record data linked to
in-hospital COVID-19 death data (from the 1st February 2020 to the 25th
April 2020). Increasing age was strongly associated with risk, with the
≥80 year-age group having more than 12-fold increased risk compared with
those aged 50-59 years; most comorbidities were associated with higher
risk of COVID-19 hospital death, including asthma (fully adjusted hazard
risk (HR); 95% CI = 1,11(1.02-1.20, with a greater HR for those with
recent use of an oral corticosteroid -
1,25(1,08-1.44)).36
Data from the UK Biobank,37 in a prospective
case-control study, found an asthma prevalence of 17,9% in 605 COVID-19
hospitalized patients, mostly of them adults (asthma prevalence was of
13,5% in the control population) but the disease was not identified as
an independent risk factor for COVID-19 hospitalization / severity, in
contrast with hypertension and COPD. In the oldest population (≥65
year-old) included in the UK Biobank,38 the same
tendency on asthma prevalence was found between patients COVID-19
hospitalized versus controls (18,2% versus 13,0%), but again asthma
was not identified as an independent risk factor for severity.
In a report from the Middle East (Saudi Arabia)39 that
included 150 hospitalized adult patients (mean age 46,1 years), it was
found that 28.8% and 26.0% of the COVID-19 population had hypertension
and diabetes respectively. The asthma prevalence was 2,7%, and one
patient with asthma was admitted in the ICU.
In a study aiming to estimate the risk factors for hospitalisation and
death in the Mexican population40 infected by
SARS-CoV-2 (n=10554, mean age 46,5 year-old, 39,4% hospitalized and
9,2% fatal cases), hypertension was the most prevalent comorbidity
found (21.7%), followed by obesity (20.15%) and diabetes (17.7%).
Asthma prevalence was 3,6% of this population (3,1% in the
hospitalized patients and in 3,2% in the fatal cases). Patients with
hypertension, obesity, and diabetes were more likely to be hospitalised
and die than people without these comorbidities. Once again asthma was
not identified as an independent risk factor for hospitalization and/or
mortality.40