Impact of COVID 19 on Patients with Multiple Myeloma : A National Inpatient Sample Analysis

Introduction:

Multiple myeloma (MM) is characterized by the proliferation of clonal immunoglobulins and suppression of normal immunoglobulins. These patients are susceptible to infections due to multiple factors such as hypogammaglobulinemia, impaired lymphocyte function, steroid-related immunosuppression, and neutropenia secondary to chemotherapy. There is limited data on the association of COVID-19 infection with in-hospital outcomes of MM. We hypothesize that COVID-19 infection is associated with adverse outcomes.

Methodology:

We queried the National Inpatient Sample (NIS) Database 2020 for adult (aged ≥ 18 years) hospitalizations with a primary diagnosis of MM. The cohort was subcategorized based on the presence of COVID-19 infection. The primary outcome studied was in-hospital mortality. Multiple secondary outcomes were analyzed including length of stay, cost of hospital stay, and individual organ system failures. Multivariable logistic regression was performed adjusting for patient and hospital level characteristics to evaluate outcomes. An alpha error of 0.05 was accepted for all analyses.

Results:

A total of 111,540 MM hospitalizations were included in the study, of which 2,195 (1.96%) had concomitant COVID-19 infection. The mean age was almost similar in both groups. Patients with MM and concurrent COVID-19 infection, had significantly higher in-hospital mortality [adjusted odds ratio (aOR) 6.54, 95% CI 5.25-8.20, p<0.001], length of stay [aOR 4.12 (2.92-5.32), p<0.001] and hospitalization cost [$54,940 ($34,688-$75,191), p<0.001]. They had higher rates of cardiac arrest (2.9% vs 1.1%, p<0.001), acute renal failure (48.8% vs 31.3%, p<0.001), acute liver failure (2.5 % vs 1.1%, p<0.001), acute respiratory failure (50.8% vs 17.3%, p<0.001). They also required higher levels of care in terms of hemodialysis (14.8% vs 8.8%, p<0.001), non-invasive ventilation (8.4% vs 3.3%, p<0.001), and invasive ventilation (1.6 % vs 0.3%, p<0.001).

Discussion:

Patients with MM who were admitted with COVID-19 had higher odds of in-hospital mortality, and developing (end-organ)complications such as cardiac arrest, respiratory failure, renal failure, and liver failure. They also had longer and costlier stays. The development of COVID-19 in patients with MM causes such poor outcomes likely due to shared endothelial dysfunction, thrombosis, and hyperinflammation. Prior studies have also shown impaired response to mRNA vaccination in this population. Thus, as COVID-19 restrictions are now at ease, increased vigilance is required in this vulnerable population. The limitations of our study are retrospective use of the administrative database with a potential of missing or inaccurate data, lack of information on specific treatments in MM patients limiting the ability to assess treatment-related outcomes, and unknown vaccination status.