CF Patients With COVID-19 at Higher Risk of Poor Outcomes
Cystic fibrosis (CF) patients infected with the virus that causes COVID-19 are at a higher risk of hospitalization, a need for intensive care, and kidney injury relative to COVID-19 patients without this disease, according to a large, multi-center study in the U.S.
While previous research reported that CF patients appear to have a similar COVID-19 disease course to the general population, that work lacked long-term follow-up and a matched population for comparison — features that allow the current study to draw stronger conclusions.
Its findings indicate that COVID-19-related outcomes are likely to be poorer in people with CF, and emphasize the importance of continued preventive measures and vaccination in this patient population, the researchers noted.
The study, “Outcomes of SARS-CoV-2 infection in patients with cystic fibrosis: A multicenter retrospective research network study,” was published in the journal Respiratory Medicine.
COVID-19 severity and mortality across are known to generally increase with older age and the presence of simultaneous health conditions (comorbidities), such as cardiovascular disease, lung disease, obesity, diabetes, chronic kidney disease, cancer, and smoking.
Severe complications that may require ventilatory support and intensive care are typically associated with an abnormal, excessive inflammatory response, known as a cytokine storm.
Due to pre-existing lung disease, additional risk factors — such as diabetes — and disease-associated inflammation and immune system dysregulation can put CF patients at risk of severe COVID-19 infection.
However, few studies have analyzed the course of COVID-19 disease in these patients, and available data indicated that its course may actually be milder than in the general population.
In this study, a team of researchers at West Virginia University retrospectively analyzed COVID-19-related clinical outcomes in a large group of CF patients, and compared them with outcomes in a matched group of people without CF.
Patients’ data were collected from TriNETX’s de-identified database, which provides access to electronic health records of more than 40 million people treated at more than 40 U.S. academic centers with tertiary care and outpatient office locations.
The study’s main goal was to assess changes in a composite event of death or the need for mechanical ventilation, while secondary goals included changes in mortality, hospitalization, and critical care. All outcomes were assessed within 30 days following either a positive test for SARS-CoV-2, the virus that causes COVID-19, or a COVID-19 diagnosis based on clinical symptoms.
Researchers conducted unmatched and matched analyses, with the latter consisting of a comparison between CF patients and people without the disease matched for age, sex, race, body mass index, and co-existing conditions.
Based on the database, 507,810 people, age 16 and older, were infected with COVID-19 between January 2020 and January 2021, and were subsequently included in the analysis. A total of 422 of these patients (0.08%) had a CF diagnosis (CF group), while 507,388 (99.92%) did not have CF.
Most (73.22%) CF patients were Caucasian, and 53.32% were female. Their mean age at COVID-19 diagnosis was 46.6 years. A total of 58 CF patients (14%) had a history of lung transplant, and 68 (16.15%) had documented use of a CFTR potentiator therapy before COVID-19 infection.
Co-existing conditions that included high blood pressure, lung disease, diabetes, heart disease, nicotine dependence, and chronic kidney disease were significantly more common among the CF patients than among people without CF.
Results showed that 22 (5.21%) deaths and 37 (8.77%) composite outcomes — death or mechanical ventilation — were reported among CF patients in the 30-day period after a COVID-19 diagnosis.
In the unmatched analysis, people with CF had higher rates of a composite outcome, mortality, hospitalization, critical care need, mechanical ventilation, and kidney damage than those in the non-CF group.
Notably, even after matching with people without the disease, CF patients still showed higher hospitalization rates, a need for intensive care, and kidney injury.
Mortality, which was 3.74 times higher among CF patients relative to the non-CF group, was also 1.83 times higher in the matched analysis, but this difference failed to achieve statistical significance.
Interestingly, there was a trend toward lower hospitalization rates among CF patients with prior CFTR potentiator use (19.12% vs. 29.46%), but this difference also did not reach statistical significance.
These findings highlight that people with CF “are at risk of poor outcomes with COVID-19,” as “5.2% of these patients died within one month of COVID-19 diagnosis, and more than one in 10 patients required critical care,” the researchers wrote.
As such, “the relatively young median age of cystic fibrosis patients, and lower prevalence of obesity do not protect these patients from severe disease contrary to prior reports,” the team added.
The researchers noted that previous studies did not have follow-up data for many patients, and lacked a control group or a matched population without CF, which may explain the distinct differences in their findings.
This study “adds important comparative data to the existing scientific pool and owing to robust follow-up data as well as a match control allows for drawing of important conclusions,” the researchers wrote.
Results also emphasize that “continued preventative measures will be important” in this patient population, and “may hold implications for measures such as prioritization for vaccination,” they added.
The study was supported by the National Institute of General Medical Sciences of the National Institutes of Health.