Electronic health record data for assessing risk of hospitalization for COVID-19: Methodological considerations applied to multiple sclerosis.

INTRODUCTION: During the COVID-19 pandemic, electronic health record (EHR) data has been used to investigate disease severity and risk factors for severe COVID-19 in people with multiple sclerosis (pwMS). Methodological challenges including sampling bias, and residual confounding should be considered when conducting EHR-based studies. We aimed to address these limitations related to the use of EHR data in order to identify risk factors, including the use of disease modifying therapies (DMTs), associated with hospitalization for COVID-19 amongst pwMS. METHODS: We performed a retrospective cohort study including a sample of 47,051 pwMS using a large US-based EHR and claims linked database. Follow-up started at the beginning of the pandemic, February 20th 2020, and continued until September 30th 2020. COVID-19 diagnosis was determined by the presence of ICD-10 diagnostic code for COVID-19, or a positive diagnostic laboratory test, or an ICD-10 diagnostic code for coronaviruses. We used Cox regression modeling to assess the impact of baseline demographics, MS disease history and pre-existing comorbidities on the risk of hospitalization for COVID-19. Then, we identified 5,169 pwMS using ocrelizumab (OCR) and 3,351 pwMS using dimethyl fumarate (DMF) at baseline, and evaluated the distribution of the identified COVID-19 risk factors between the two groups. Finally, we used Cox regression models, adjusted for the identified confounders, to estimate the risk of hospitalization for COVID-19 in pwMS treated with OCR compared to DMF. RESULTS: Among the pwMS cohort, we identified 799 COVID-19 cases (1.7%) which resulted in 182 hospitalizations for COVID-19 (0.4%). Population differences between the pwMS and COVID-19 cohorts were observed. Statistical modeling identified older age, male gender, African-American race, walking with assistance, non-ambulatory status, severe relapse requiring hospitalization in year prior to baseline, and specific comorbidities to be associated with a higher risk of COVID-19 related-hospitalization. Comparing the COVID-19 risk factors between OCR users and DMF users, MS characteristics including ambulatory status and MS subtype were highly imbalanced, likely arising from key differences in the labelled indications for these therapies. Compared to DMF use, in unadjusted (HR 1.58, 95% CI 0.73 - 3.44), adjusted (HR 1.28, 95% CI 0.58 - 2.83), propensity score weighted (HR 1.25, 95% CI 0.56 - 2.80), and doubly robust models (HR 1.29, 95% CI 0.57 - 2.89), no significantly increased risk of hospitalization for COVID-19 was associated with OCR use. CONCLUSION: We observed significant population differences when comparing all pwMS to COVID-19 cases, as well as significant differences in key confounders between OCR and DMF treated patients. In unadjusted analyses we did not observe a statistically significant higher risk of COVID-19 hospitalization in pwMS treated with OCR compared to DMF, with further attenuation of risk when adjusting for the key confounders. This study re-emphasises the importance to appropriately consider both sampling and confounding bias in EHR-based MS research.

COVID-19 in ocrelizumab-treated people with multiple sclerosis.

BACKGROUND: There are limited data on the impact of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on people with multiple sclerosis (MS). OBJECTIVE: To better understand SARS-CoV-2 infection in ocrelizumab-treated people with MS. METHODS: Internal Roche/Genentech data sources: Cases of COVID-19 from ongoing Roche/Genentech clinical trials and from post-marketing use of ocrelizumab until July 31, 2020 were identified and assessed using descriptive statistics. External real-world data (RWD) source: An MS COVID-19 cohort and an ocrelizumab-treated MS COVID-19 cohort were identified and assessed from the OPTUMⓇ de-identified COVID-19 electronic health record (EHR) database. RESULTS: Roche/Genentech clinical trial data: There were 51 (1.3%) suspected or confirmed cases of COVID-19 identified from 4,000 patients ongoing in 10 Roche/Genentech clinical trials. Of these, 26 (51%) were confirmed COVID-19 and 25 (49%) were suspected COVID-19. Sixteen (31.4%) patients were hospitalized. COVID-19 severity was mild to moderate in most patients (35, 68.6%). Ten (19.6%) patients had severe disease and there were three (5.9%) fatal cases. Most patients (43, 84.3%) recovered or were recovering. There was no association apparent between duration of exposure to ocrelizumab and COVID-19. Among COVID-19 patients with previous serum immunoglobulin status (27/51, 52.9%), all (27/27, 100%) had IgG levels within the normal range. Roche/Genentech post-marketing safety database data: There were 307 post-marketing cases of COVID-19 in the Roche/Genentech global safety database. Of these, 263 (85.7%) were confirmed and 44 (14.3%) were suspected COVID-19. 100 (32.6%) patients were hospitalized. COVID-19 was asymptomatic, mild or moderate in 143 (46.6%) patients, severe in 52 (16.9%) patients, and critical in 15 (4.9%) patients. There were 17 (5.5%) fatal cases. Information on severity was not reported in 80 (26.1%) cases. Most patients (211, 68.7%) recovered or were recovering at the time of the report. External RWD data source: As of July 13, 2020, the OPTUMⓇ database included EHRs for almost 1.2 million patients with suspected COVID-19, 130,500 of whom met the criteria for confirmed/clinically diagnosed COVID-19. A total of 357 patients with MS with confirmed COVID-19 were identified. Forty-eight (13.4%) were treated with ocrelizumab, of whom 12 (25.0%) were hospitalized and one died (2.1%). Similar rates of hospitalization, invasive ventilation, and death were observed in the ocrelizumab-treated and non-ocrelizumab-treated MS cohorts. Across the Roche/Genentech and RWD sources assessed, age, male sex, and the presence of comorbidities such as hypertension were associated with a more severe disease course of COVID-19. There was a higher number of comorbidities present in hospitalized versus non-hospitalized patients. CONCLUSIONS: This assessment provides evidence that COVID-19 in ocrelizumab-treated people with MS is predominantly mild to moderate in severity with most patients not requiring hospitalization; in line with data reported from the general population and MS datasets. Risk factors known to be associated with severe COVID-19 outcomes in the general population also appear to influence COVID-19 severity in ocrelizumab-treated people with MS. Case fatality rates for ocrelizumab-treated people with MS were within published ranges for the general population and other MS cohorts.