Clinical characteristics, risk factors and outcomes of cancer patients with COVID‐19: A population‐based study

INTRODUCTION: Cancer patients may be susceptible to poorer outcomes in COVID‐19 infection owing to the immunosuppressant effect of chemotherapy/radiotherapy and cancer growth, along with the potential for nosocomial transmission due to frequent hospital admissions. METHODS: This was a population‐based retrospective cohort study of COVID‐19 patients who presented to Hong Kong public hospitals between 1 January 2020 and 8 December 2020. The primary outcome was a composite endpoint of requirement for intubation, ICU admission and 30‐day mortality. RESULTS: The following study consisted of 6089 COVID‐19 patients (median age 45.9 [27.8.1–62.7] years; 50% male), of which 142 were cancer subjects. COVID‐19 cancer patients were older at baseline and tended to present with a higher frequency of comorbidities, including diabetes mellitus, hypertension, chronic obstructive pulmonary disease, ischemic heart disease, ventricular tachycardia/fibrillation and gastrointestinal bleeding (p < 0.05). These subjects also likewise tended to present with higher serum levels of inflammatory markers, including D‐dimer, lactate dehydrogenase, high sensitivity troponin‐I and C‐reactive protein. Multivariate Cox regression showed that any type of cancer presented with an almost four‐fold increased risk of the primary outcome (HR: 3.77; 95% CI: 1.63–8.72; p < 0.002) after adjusting for significant demographics, Charlson comorbidity index, number of comorbidities, past comorbidities and medication history. This association remained significant when assessing those with colorectal (HR: 5.07; 95% CI: 1.50–17.17; p < 0.009) and gastrointestinal malignancies (HR: 3.79; 95% CI: 1.12–12.88; p < 0.03), but not with lung, genitourinary, or breast malignancies, relative to their respective cancer‐free COVID‐19 counterparts. CONCLUSIONS: COVID‐19 cancer patients are associated with a significantly higher risk of intubation, ICU admission and/or mortality.