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Adults With Hematologic Malignancies and COVID-19 Fare Worse Than Children
Adults with hematologic malignancies and COVID-19 infection have a substantially higher risk of death compared with children with hematologic malignancies and COVID-19 , according to a study published in Blood .
“ While we don ’ t know for sure why this happens , it has been hypothesized that children may mount a more effective immune response to the SARS-CoV-2 virus ,” corresponding study author Lisa Hicks , MD , of St . Michael ’ s Hospital in Toronto , Ontario , told ASH Clinical News . “ There is also a body of literature suggesting that children may sometimes be infected with a lower ‘ dose ’ of the virus than adults due to differences in nasal receptors that the virus is thought to exploit .”
In this report , Dr . Hicks and colleagues conducted a systematic review and meta-analysis of studies published since January 2019 that reported outcomes of patients with cancer and COVID-19 . Only studies reporting data on patients with hematologic malignancies ( bone marrow failure syndromes such as myelodysplastic syndromes , acute leukemias , lymphomas , plasma cell dyscrasias , and / or myeloproliferative neoplasms [ MPNs ]) were eligible for inclusion in the final meta-analysis .
The pooled risk of death among patients with hematologic malignancies and COVID-19 comprised the primary outcome of the meta-analysis . The investigators examined this risk in both adult and pediatric patient populations . Additional secondary outcomes of interest were the proportion of hospitalized patients who required admission to the intensive care unit ( ICU ) and mechanical and noninvasive ventilation support .
The researchers identified 34 adult studies ( including a total of 3,240 adult patients ) and 5 pediatric studies ( including a total of 102 children and adolescents ). Overall , 3,377 patients had hematologic malignancies and COVID-19 .
In the adult studies , the pooled risk of death associated with hematologic malignancies and concomitant COVID-19 infection was 34 %. In an analysis restricted to mortality in hospitalized patients ( n = 2,361 ), the pooled risk of mortality was slightly higher , at 39 %.
The pooled risk of death associated with hematologic malignancies and COVID-19 was substantially lower in the pediatric studies : 4 %.
When the researchers stratified patients according to age , they found that younger patients (< 60 years ) had a lower pooled mortality risk compared with older patients ( ≥60 years ): 25 % vs . 47 % ( risk ratio [ RR ] = 0.55 ; 95 % CI 0.44-0.69 ; p < 0.01 ).
Race also appeared to affect mortality risk , the authors reported . In five studies that included race-based outcomes , non-white patients with hematologic malignancies and COVID-19 had a higher risk of death versus white patients ( RR = 2.2 ; 95 % CI 1.3-3.8 ; p = 0.003 ).
Mortality risk also varied according to type of hematologic malignancy :
• acquired bone marrow failure syndromes : 53 %
• acute leukemias : 41 %
• plasma cell dyscrasias : 33 %
• lymphomas ( including chronic lymphocytic leukemia [ CLL ]): 32 %
• lymphomas ( excluding CLL ): 32 %
• CLL specifically : 31 %
• MPNs : 34 %
Pooled mortality rates did not differ significantly from other factors , such as geographic region or recent systemic anticancer therapy . “ Importantly , despite a concerning risk of death , a majority of patients with hematologic malignancy and COVID-19 recover , even following recent [ cancer
“ Our findings also suggest that when patients [ with blood cancers ] become infected with COVID-19 , they need close monitoring and care as they may be at higher risk of deterioration than other patients .”
-Lisa Hicks , MD
treatment ],” the authors wrote . “ These data suggest that in patients who require urgent therapy for their hematologic malignancy , treatment can be delivered despite the risks of COVID-19 .”
Among hospitalized patients , the pooled risk
for ICU admission was 21 % ( as observed in 24 studies covering 2,192 patients ), the pooled risk for mechanical ventilation was 17 % ( as observed in 21 studies covering 1,320 patients ), and the pooled risk for noninvasive ventilation was 16 % ( as observed in 12 studies covering 373 patients ).
“ These results suggest that when patients with blood cancers are infected with COVID-19 , their risk of serious outcomes is substantial ,” said Dr . Hicks . “ Measures to prevent infection are extremely important in this population .” These types of measures include robust use of personal protective equipment , masking , social distancing , and prioritized access to COVID-19 vaccination for patients and their care givers .
“ Our findings also suggest that when patients become infected with COVID-19 , they need close monitoring and care as they may be at higher risk of deterioration than other patients ,” she added .
The investigators cited the significant heterogeneity in many of the pooled mortality estimates across studies as a major limitation of the meta-analysis . Dr . Hicks added that given the nature of the study ’ s design , the findings “ should be considered hypothesis-generating , rather than definitive .” ●
Study authors report no relevant conflicts of interest .
Reference Vijenthira A , Gong IY , Fox TA , et al . Outcomes of patients with hematologic malignancies and COVID-19 : a systematic review and meta-analysis of 3377 patients . Blood . 2020 ; 136 ( 25 ): 2881-2892 .
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