Patients with chronic lymphocytic leukemia (CLL) are at increased risk of having severe infections because both the disease and CLL treatments can suppress their immune system.1 Although the outbreak of COVID-19 has been a global health crisis affecting many different populations, early studies showed that patients with CLL were at particularly high risk of dying if they were hospitalized with the virus.1
Although these previous studies provided insights into the risks of COVID-19 for patients with CLL, they only included patients with disease severe enough to warrant hospitalization at the start of the pandemic.1 In addition, because they were large international studies, they were not able to provide a comprehensive analysis of the disease in any single region.1
In a recent study, investigators from 3 hematology centers in Stockholm, Sweden, reported data on all patients with CLL who were diagnosed with symptomatic COVID-19 during the first 13 months of the pandemic.1 Notably, more than 95% of patients with CLL in the region are followed at these 3 centers, meaning that this study provides one of the most comprehensive looks at the effects of COVID-19 on this population.1
During the first year of the pandemic, 60 patients with symptomatic COVID-19 and CLL were identified in the region.1 None had received COVID-19 vaccination during the study period, which spanned from March 2020 to March 2021.1 Half of the included patients were aged >71 years and 65% were men.1 Approximately 63% of patients had never received CLL treatment, 20% had received prior CLL treatment >1 year prior to being diagnosed with COVID-19, and 17% of patients were receiving ongoing CLL therapy.1
Overall, 77% of patients required hospitalization due to severe COVID-19, and 24% were admitted to the intensive care unit (ICU).1 The length of hospitalization ranged from 1 to 38 days (half of all patients were discharged by day 11), and the length of time in the ICU ranged from 4 to 21 days (half of all patients were discharged from the ICU within 10 days).1 Having a higher number or more severe comorbid health conditions was a predictor for developing severe COVID-19, but characteristics such as age, gender, body mass index, or CLL status were not.1
Twenty-three percent of patients in this study died, nearly all of whom had been admitted to the hospital.1 Being >75 years of age at the time of COVID-19 diagnosis was the only predictor of death that the investigators could identify, although they acknowledged that the low number of patients in this study limited their ability to find others.1
When comparing the first 6 months of the pandemic to the second 6 months, investigators found that the fatality rate was reduced from 32% to 18% and ICU admission was reduced from 37% to 15%, whereas hospitalizations remained frequent (86% vs 71%) for patients with CLL.1 Increased use of antivirals, such as remdesivir, and corticosteroids in the second 6 months likely played a role in improving patient outcomes, although the study was not designed to evaluate such treatment effects.1 Likewise, the study was not able to measure the effect of COVID-19 vaccination on disease severity or risk of death.
Notably, 82% of patients in this study who recovered from COVID-19 had formed antibodies against the virus, suggesting that, despite their suppressed immune system, they had developed immunity against subsequent infections.1 For most patients who had data available, these antibodies appeared to be long-lasting, and were still detectable after 1 year of follow-up.1
Overall, these data expand our understanding of the real-world impact of COVID-19 on patients with CLL, beyond studies that have only evaluated severe cases in hospitalized patients.
- Blixt L, Bogdanovic G, Buggert M, et al. Covid-19 in patients with chronic lymphocytic leukemia: clinical outcome and B- and T-cell immunity during 13 months in consecutive patients [published online ahead of print, September 25, 2021]. Leukemia. 2021;1-6.