PRELIMINARY RESULTS OF THE BHS COVID-19 REGISTRY

May 2021 Covid-19 T. Mercier

The global COVID-19 pandemic has had a major impact on all the aspects of the healthcare system in Belgium, and haematology departments were no exception to this. In order to get more insights into the risk for severe COVID-19 infections among patients with haematological conditions, the Belgian Hematology Society (BHS) set up the BHS COVID-19 registry. During the 2021 BHS general annual meeting preliminary results of this registry were presented.

The objective of the BHS COVID-19 registry was to collect data on the risk for severe COVID-19 (i.e. hospitalization, need for intensive care unit [ICU] transfer, death) in patients with haematological conditions. This would not answer the question whether patients with haematological conditions have a higher risk for severe COVID-19, but will also provide information on individual risk factors, such as a specific haematological malignancies, prior therapies or other patients- or disease characteristics. To this end, 47 centers across Belgium were asked to include all patients with a haematological disease who were hospitalized with a PCR-confirmed COVID-19 infection during the first wave, and out of these, 42 centers cooperated.

It turns out that one out of every 250 patients with a haematological malignancy in Belgium was hospitalized as a result of a COVID-19 infection during the first wave between mid-March and mid-June 2020.

In total, 220 patients coming from 42 centers were included in the registry. Of these patients, 205 had a malignant haematological condition, while the remaining 15 had a non-malignant disease. When extrapolating these data to the total number of patients with a haematological condition (data coming from the Belgian cancer registry), this means that 1 out of every 250 patients with a haematological malignancy in Belgium was hospitalized as a result of a COVID-19 infection during the first wave. This rate is significantly higher than what is seen in the general population, where the COVID-19 hospitalization rate is estimated at approximately 1/1,000.

Two thirds of all cases in the registry had a lymphoid malignancy. When comparing the distribution of haematological conditions in the registry to the general distribution in Belgium (data cancer registry) some remarkable differences can be observed. For example, while non-Hodgkin lymphomas make up 44% of all haematological conditions in Belgium, they only account for 26% of cases in the COVID registry.

However, the opposite is true for acute leukaemia and multiple myeloma, who make up 5% and 10% of haematological malignancies in Belgium, but respectively account for 9% and 18% of patients in the registry.

Similar to what is observed in the general COVID-19 population, the risk for hospitalization is highest in older patients, with a median age of 70.6 years. However, a younger age does not protect haematological patients from a severe COVID-19 disease course as all age groups are represented in the registry. Half of the patients in the registry had cardiovascular comorbidities, while a quarter of patients had renal problems, or diabetes.

Patients with haematological conditions not only have an increased risk for hospitalization following a COVID-19 infection, but once hospitalized they also have a higher risk to require ICU care.

The highest mortality risk was seen in the first 4–6 weeks after the hospitalization. After the first 6 weeks the mortality rate reaches a plateau phase. About one out of three patients in the registry had to be transferred from a general COVID ward to the intensive care unit. Again, this is much higher than the 20% of ICU need among the general COVID-19 population. As such, patients with haematological conditions not only have an increased risk for hospitalization following a COVID-19 infection, once hospitalized they also have a higher risk to require ICU care.

About 20% of patients in the registry had to be intubated. Overall, 60% of the hospitalized patients with a haematological condition in the registry survived their COVID-19 infection. In this respect, a huge difference was seen between patients in whom ICU care was foregone or shortened in favour of palliative care and patients who underwent regular ICU care (80% survival rate). The decision to forego on ICU care or shorten the ICU care occurred in about a quarter of patients.

Conclusions

These preliminary results of the BHS COVID registry during the first wave of the pandemic underscore that patients with haematological conditions have a higher risk of ending up in the hospital following a COVID-19 infection. Moreover, once hospitalized they also have a higher risk of requiring ICU support compared to the general hospitalized COVID-19 population. More detailed analyses from this registry will be presented at future meetings.

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