The occurrence rate of COVID-19 infection among individuals with hematological malignancies (HM) varies from 1–3.9% (9). The high rates of illness and death related to COVID-19 in patients with HM, along with the additional difficulties caused by treatment delays or changes in chemotherapy schedules, pose significant obstacles for both patients and healthcare providers around the world, including Syria. Since randomized clinical trials were not feasible during the pandemic, observational studies can play a crucial role in helping us comprehend the various risk factors associated with COVID-19. These studies enable the implementation of suitable preventive measures and treatments more effectively in HM patients.
This study evaluated 150 hematology patients aged 16 to 78 years to determine their risk of acquiring COVID-19. It is important to highlight that in this sample, patients were mainly diagnosed with COVID-19 based on chest CT scan results, despite nearly half of them (52.7%) were negative for SARS-CoV-2 through RT-PCR laboratory tests. Several studies have demonstrated the high diagnostic accuracy of chest CT scans in identifying both typical and relatively atypical presentations of COVID-19, resulting in a minimal number of missed diagnoses (10). Additionally, research has shown that chest CT scans exhibit high accuracy in symptomatic patients suspected of having COVID-19 (11, 12). According to the previous literature, mild or asymptomatic presentations are common with COVID-19, with cough, fever, and dyspnea as the most frequent symptoms (13, 14). Likewise, the symptom profile in our hematologic malignancy cohort was dyspnea, being the most predominant, affecting 74% of patients - exceeding rates from prior studies in Italy (61%) and Turkey (33%) (15, 16). Meanwhile, less common symptoms such as diarrhea affected a smaller proportion (< 10%) of our hospitalized hematology patients, which is consistent with diarrhea rates reported in the general COVID-19 population (17). In contrast to general population studies that find 56–58% of infections to be asymptomatic, 100% of our cases were symptomatic (18).
During the COVID-19 pandemic, individuals with HM are considered to be at a higher risk due to factors such as inherent frailty, immunosuppressive treatments, and frequent hospital visits for treatment administration. In our research, we observed a mortality rate of 61.4% (92 out of 150 patients). This mortality rate is within the range of those reported in the literature among HM, ranging from 32–61% (9, 15, 19–22). Furthermore, a recent Italian study of 563 patients found that the mortality rate for patients with HM and COVID-19 was 41 times higher than for matched patients with hematological malignancies but without SARS-CoV-2 infection (20).
Our findings revealed a noteworthy correlation between patient age and the overall mortality rate, emphasizing that older individuals (those aged 50 years and above) with HM face a heightened risk of mortality. These results are consistent with previous studies (20, 23, 24). Moreover, a meta-analysis of 3,377 patients with HM and COVID-19 found that patients aged 60 years and older had a significantly higher risk of death than patients under 60 years, supporting our finding (25). This highlights the need of more protective measures in this group of age.
Furthermore, our data have revealed a profound clinical impact and the highest mortality rate among patients with acute leukemia, including AML (acute myeloid leukemia), ALL (acute lymphoblastic leukemia), and AML M4. Alarmingly, all patients in this subgroup succumbed to the infection. These findings align with previous studies (26–28), which reported increased morbidity and mortality associated with SARS-CoV-2 infection in individuals with acute HM, particularly AML. The high death rate in acute leukemia patients may stem from advanced age, profound immunodeficiency from disease and treatments, and the impossibility of delaying urgent therapy initiation. Delaying therapy has been suggested as a way to potentially improve COVID-19 survival in these patients, underscoring the need to balance competing health risks (26, 29). Notably, all 24 patients in our study with non-Hodgkin lymphoma survived, in contrast to the acute leukemia groups. This finding warrants further investigation to determine if non-Hodgkin lymphoma may confer a relatively lower mortality risk from COVID-19 versus other hematologic malignancies such as acute leukemias.
Moreover, we discovered higher mortality among those with more severe pulmonary infiltrate patterns on CT scans. This result aligns with other research linking abnormal radiographic findings and mortality, especially when ICU care is needed (16, 20). In our cohort, 37.3% required ICU admission. Regarding comorbid conditions, 67.3% of our patients had no pre-existing illnesses, with renal failure being the most common issue otherwise. This finding diverges from some literature indicating cardiovascular disease as the predominant COVID-19 comorbidity (19, 20). It is noteworthy that none of our hematology patients with underlying medical problems survived. However, Prior studies have conflicted on whether comorbidities influence COVID-19 mortality. Some studies (20) found no significant association, while others reported increased mortality risk with comorbidities (2, 16). Our findings suggest pre-existing conditions may contribute to poorer prognoses in HM patients infected with COVID-19.
In summary, the main findings of this study revealed that increased mortality rates were related to advanced age, severe infiltrates observed on CT scans, the presence of other medical conditions, and the specific type of HM. Ultimately, patients with HM still need special care, and protective measures must be maintained.
Strengths and limitations of the study:
This study represents the first investigation to examine the prevalence, risk factors, and outcomes among COVID-19 patients with hematological malignancies in Syrian population. Study limitations include missing data on cancer treatments and hematological malignancy details. Besides, the single-arm design prevented comparisons with non-COVID-19 hematologic cancer patients. Lastly, the relatively small sample size limits generalizability.
In conclusion:
This retrospective cohort study provides valuable real-world insights into the clinical characteristics and outcomes of COVID-19 infection in patients with hematologic malignancies. Our findings reveal a notably high mortality rate of 61.4% among 150 patients in Syria, highlighting the elevated risk faced by this population. Identifying key risk factors allows healthcare professionals to closely monitor patients, implement additional precautions, and make informed treatment decisions. Thorough COVID-19 screening and access to high-quality supportive care are crucial, given the unavailability of vaccines and antiviral treatments. It is imperative to prioritize preventive measures and maintain a vigilant approach in clinical practice. Continued research is essential for refining risk stratification and ensuring evidence-based care. Collaborative efforts across specialties and countries are necessary for addressing COVID-19 and comorbid conditions like hematologic cancers.