Background At the start of the COVID-19 pandemic, several experts raised concerns about its impact on Multiple Sclerosis (MS) patients. Several small sample studies were published throughout the pandemic highlighting certain risk factors and outcomes. This study aims to provide a perspective using the biggest inpatient database from the United States. Method We screened for COVID-19 cases between April to December 2020, via the 2020 National Inpatient Sample (NIS). Characteristics of COVID-19 patients with and without MS were studied. The odds of mortality, mechanical ventilation and non-invasive ventilation were also analyzed. Finally, we investigated the risk factors of various outcomes among MS patients. Results We identified 1,628,110 hospitalizations with COVID-19, including 7620 (0.5%) MS patients. 68.6% of MS cases were Whites, and 63.3% were covered by Medicare. Compared to non-MS patients, MS patients with COVID-19 were mostly Females, had depression, peripheral vascular disease, and smoked. However, MS patients had lower cases of alcohol abuse, obesity, hyperlipidemia, diabetes, hypertension, CKD, or maintenance dialysis. MS patients with COVID-19 were also younger (mean age 60.65 years vs. 62.60 years, p<0.01). 8.9% of MS patients with COVID-19 did not survive their hospitalization, and it was lower than non-MS cases (12.9%, aOR 0.783, 95% CI 0.721-0.852, p<0.01). Less MS patients with COVID-19 needed non-invasive ventilation (4.5% vs. 6.4%, aOR 0.790, 95% CI 0.706-0.883, p<0.01) and mechanical ventilation (9.0% vs. 11.2%, aOR 1.017, 95% CI 0.937-1.104, p=0.687). Furthermore, MS patients with COVID-19 reported higher odds of non-invasive ventilation if they were of ages 60 and above (aOR 2.124, p<0.01), had chronic pulmonary disease (aOR 1.691, p<0.01), obesity (aOR 1.69, p<0.01), and diabetes (aOR 1.573, p<0.01). Private insurance beneficiaries showed reduced risk compared to Medicare (aOR 0.523, p<0.01). Similarly, for mechanical ventilation, those ages 60 and above (aOR 1.404, p<0.01), alcohol abuse (aOR 6.404, p<0.01), obesity (aOR 1.417, p<0.01), diabetes (aOR 1.992, p<0.01), hypertension (aOR 1.269, p=0.016), or dialysis (aOR 3.003, p<0.01) had higher odds, while females (aOR 0.700, p<0.01), smokers (aOR 0.588, p<0.01), and those with depression (aOR 0.698, p<0.01) or hyperlipidemia (aOR 0.711, p<0.01) showed reduced odds. Our study further found higher odds of mortality among those of age 60 and above (aOR 3.813, p<0.01), chronic pulmonary disease (aOR 1.739, p<0.01), obesity (aOR 1.425, p<0.01), CKD (aOR 1.982, p<0.01), or a history of old MI (aOR 1.864, p<0.01) while females (aOR 0.610, p<0.01), smokers (aOR 0.770, p<0.01), as well as those with depression (aOR 0.695, p<0.01), and hyperlipidemia (aOR 0.769, p<0.01) showed better outcomes. Blacks had lower odds of dying (aOR 0.636, p<0.01), whereas Hispanics had higher odds of dying (aOR 1.674, p<0.01), compared to Whites. Medicaid and Privately insured patients had lower odds of dying compared to Medicare i.e. (aOR 0.435, p<0.01), and (aOR 0.488, p<0.01), respectively. Conclusion We found several differences in patient characteristics among MS and non-MS patients with COVID-19. MS patients were also less likely to die or require non-invasive ventilation than non-MS patients. Further risk factors influencing the different outcomes among MS patients were also identified.
