Severe COVID-19 Cases ‘Rather Low’ Among CF Patients in France
Cases of severe COVID-19 remained low during the first year of the pandemic in people in France with cystic fibrosis (CF), a study reported.
Patients with severe lung disease or CF-related diabetes, as well as those who underwent a lung transplant, however, were at a higher risk of severe complications with SARS-CoV-2 infection, the virus that causes COVID-19.
“Given the serious respiratory complications caused by viral infections in CF,” these people “are expected to be at a higher risk of COVID-19 as well as at a higher risk of disease severity,” the researchers wrote. “However, the number of diagnosed COVID-19 cases in [patients] is rather low, though the risk is increased in adults vs. children similarly to the general population.”
The study, “Cumulative Incidence and Risk Factors for Severe COVID-19 in French People with Cystic Fibrosis,” was published in the journal Clinical Infectious Diseases.
CF is marked by the accumulation of thick mucus in organs that include the lungs, where it can block the airways to make breathing difficult. A progressive decline in lung function is worsened by cycles of airway inflammation and infections due to bacteria and viruses.
Given how CF affects the lungs, patients were expected to be at a higher risk of severe COVID-19, and particularly its impact on the airways. In parallel with ongoing efforts worldwide, CF centers across France monitor COVID-19 cases to identify factors associated with poorer outcomes.
Investigators who are part of a nationwide study group evaluated data on CF patients diagnosed with COVID-19 and followed at one of the country’s 47 CF centers over the first year of the pandemic, from March 2020 through April 2021.
A total of 223 people with CF were infected, and 34 of them (15%) were considered to have severe COVID-19. Most infections were in adults (85.3%) and individuals who had a lung transplant due to advanced disease (61.8%).
Compared to the overall CF population in France, those with COVID-19 were older and more frequently post-transplant. Having had a lung transplant alone was a risk factor for SARS-CoV-2 infection in CF patients compared with those without a transplant, 7.1% vs. 2.6% respectively.
Likewise, adults had a 2.52-times higher relative risk of SARS-CoV-2 infection over that year than did children with CF.
“Post-transplant pwCF [people with CF] were more likely to develop severe COVID-19 in congruence with their immunosuppression status, their older age and their more frequent comorbidities such as diabetes,” the researchers wrote.
Clinical characteristics consistent with older age and transplant status included poorer lung function, a greater likelihood of CF-related diabetes, and oral corticosteroid, azithromycin (antibiotic), and CFTR modulator use, along with long-term use of supplemental oxygen.
At infection onset, post-transplant patients were a median of eight years older than other CF patients, had higher rates of CF-related diabetes and high blood pressure, and were more likely to be taking oral steroids and azithromycin.
Among the 223 infection cases, no symptoms were evident in 56 (25.1%). Reported symptoms for the remaining 167 cases were similar to the general population, including fever (46.6%), fatigue (44%), and cough (37.6%). Beyond severe symptoms such as shortness of breath and poorer lung function, most COVID-19 symptoms among CF patients were comparable regardless of transplant status.
Sixty patients were hospitalized (26.9%), and this level of care was more frequent in people who were post-transplant than others (50.8% vs. 17.9%).
A risk of severe COVID-19 complications was six times higher for those with a transplant than for other CF patients. Hospitalization was also more frequent in post-transplant patients, as were longer hospital stays, more time in an intensive care unit, and a more frequent need for breathing support, additional antibiotics, and corticosteroids.
Five reported cases of acute respiratory distress syndrome due to COVID-19 — a severe complication marked by fluid buildup in the tiny air sacs (alveoli) of the lungs — were all in post-transplant patients.
Most of the 223 people infected fully recovered from COVID-19, with 16 (13%) followed for a possible ongoing illness. Three women, ages 34 to 48, died; all had lung transplants between 2017 and 2018 and were using immunosuppressive therapies. Two also had CF-related diabetes and liver disease, but all three had relatively preserved lung function, the researchers reported.
Among non-transplant patients, severe SARS-CoV-2 infection was more likely if initial lung function was poorer and CF-related diabetes present. Researchers found no relationship between pre-infection clinical characteristics and COVID-19 severity among transplant patients, or for long-term azithromycin use.
“After one year of the COVID-19 pandemic, we found that the cumulative incidence of COVID-19 remained low in pwCF, probably thanks to the fact that pwCF are acclimated to masks, hand hygiene, and social distancing to limit exposure and avoid infection,” the researchers wrote. Those without a transplant also “appear to have better COVID-19 outcomes than anticipated.”
As the pandemic is continuing and “new SARS-CoV-2 variants are arising that may result in differential expression of COVID-19,” they added, “close monitoring of CF cohorts [groups] is necessary to fully understand the consequences of COVID-19.”