Incidence and Risk of Post-COVID-19 Thromboembolic Disease and the Impact of Aspirin Prescription; Nationwide Observational Cohort at the US Department of Veteran Affairs. (preprint)

IntroductionCOVID-19 triggers prothrombotic and proinflammatory changes, with thrombotic disease prevalent in up to 30% SARS-CoV-2 infected patients. Early work suggests that aspirin could prevent COVID-19 related thromboembolic disorders in some studies but not others. This study leverages data from the largest integrated healthcare system in the United States to better understand this association. Our objective was to evaluate the incidence and risk of COVID-19 associated acute thromboembolic disorders and the potential impact of aspirin. MethodsThis retrospective, observational study utilized national electronic health record data from the Veterans Health Administration. 334,374 Veterans who tested positive for COVID-19 from March 2, 2020, to June 13, 2022, were included, 81,830 of whom had preexisting aspirin prescription prior to their COVID-19 diagnosis. Patients with and without aspirin prescriptions were matched and the odds of post-COVID acute thromboembolic disorders were assessed. Results10.1% of Veterans had a documented thromboembolic disorder within 12 months following their COVID-19 diagnosis. Those with specific comorbidities were at greatest risk. Preexisting aspirin prescription was associated with a significant decrease risk of post-COVID-19 thromboembolic disorders, including pulmonary embolism (OR [95% CI]: 0.69 [0.65, 0.74]) and deep vein thrombosis (OR [95% CI]: 0.76 [0.69, 0.83], but an increased risk of acute arterial diseases, including ischemic stroke (OR [95% CI]: 1.54 [1.46, 1.60]) and acute ischemic heart disease (1.33 [1.26, 1.39]). ConclusionsFindings demonstrated that preexisting aspirin prescription prior to COVID-19 diagnosis was associated with significantly decreased risk of venous thromboembolism and pulmonary embolism but increased risk of acute arterial disease. The risk of arterial disease may be associated with increased COVID-19 prothrombotic effects superimposed on preexisting chronic cardiovascular disease for which aspirin was already prescribed. Prospective clinical trials may help to further assess the efficacy of aspirin use prior to COVID-19 diagnosis for the prevention of post-COVID-19 thromboembolic disorders.

Risk of Suicide Attempts and Self-Directed Violence after SARS-CoV-2 Infection: Outcomes from an Emulated Trial of a Nationwide Observational Matched Cohort of US Veterans (preprint)

Importance: The negative health-related effects of SARS-CoV-2 infection may include increased risk for self-directed violence. Objective: To assess suicide attempts and other self-directed violence risk among US Veterans with a positive polymerase chain reaction (PCR) test for SARS-CoV-2 infection compared to matched uninfected Veterans. Design, Setting, and Participants: Using a target trial emulation design supported by comprehensive electronic health records from the US Veterans Health Administration, Veterans who had a positive PCR test between March 1, 2020 and March 31, 2021 were matched with non-infected comparators. Monthly matching was anchored to first positive PCR test for each patient. Groups were followed for one-year thereafter. Exposure: Positive SARS-CoV-2 PCR. Main Outcomes and Measures: Suicide attempts and self-directed violence documented in electronic health records by a VHA provider. Hazard ratios (HR) for time to first suicide attempt and self-directed violence (separate models) for the infected versus comparator group were measured using Cox regression models. Analyses were performed for short-term (days 1-30), long-term (days 31-365) and one-year (days 1-365) and further stratified by age and prior self-directed-violence history. Sensitivity analyses included censoring to address comparators crossing over by later testing positive for SARS-CoV-2. Results: Among the 1,190,974 Veterans included, during the one-year period after the index date; 3,078 (0.258%) had a suicide attempt and 2,887 (0.242%) had self-directed violence. Regardless of follow-up duration, the HRs for suicide attempts and self-directed violence were higher for the infected group. For suicide attempts, short-term HR=2.54 (95% Confidence Interval [CI]: 2.05 to 3.15), long-term HR=1.30 (CI: 1.19 to 1.43) and one-year HR= 1.41 (CI: 1.30, 1.54). For self-directed violence, short-term HR=1.94 (CI: 1.51 to 2.49), long-term HR=1.32 (CI: 1.20 to 1.45), and one-year HR=1.38 (CI:1.26, 1.51). Conclusions and Relevance: In matched cohorts, Veterans who had a positive SARS-CoV-2 PCR test had a higher risk of suicide attempt and self-directed violence that were greatest within the first 30 days and present for at least one year following. These findings highlight the importance of assessing patient experiences of suicide attempt and other forms of self-directed violence during different time periods post-infection to identify opportunities to augment prevention efforts and support those affected.

Effectiveness of COVID-19 treatment with nirmatrelvir-ritonavir or molnupiravir among U.S. Veterans: target trial emulation studies with one-month and six-month outcomes (preprint)

Background: Information about the effectiveness of oral antivirals in preventing short- and long-term COVID-19-related outcomes during the Omicron surge is limited. We sought to determine the effectiveness of nirmatrelvir-ritonavir and molnupiravir for the outpatient treatment of COVID-19. Methods: We conducted three retrospective target trial emulation studies comparing matched patient cohorts who received nirmatrelvir-ritonavir versus no treatment, molnupiravir versus no treatment, and nirmatrelvir-ritonavir versus molnupiravir in the Veterans Health Administration (VHA). Participants were Veterans in VHA care at risk for severe COVID-19 who tested positive for SARS-CoV-2 in the outpatient setting during January and February 2022. Primary outcomes included all-cause 30-day hospitalization or death and 31-180-day incidence of acute or long-term care admission, death, or post-COVID-19 conditions. For 30-day outcomes, we calculated unadjusted risk rates, risk differences, and risk ratios. For 31-180-day outcomes, we used unadjusted time-to-event analyses. Results: Participants were 90% male with median age 67 years and 26% unvaccinated. Compared to matched untreated controls, nirmatrelvir-ritonavir-treated participants (N=1,587) had a lower 30-day risk of hospitalization (27.10/1000 versus 41.06/1000, risk difference [RD] -13.97, 95% CI -23.85 to -4.09) and death (3.15/1000 versus 14.86/1000, RD -11.71, 95% CI -16.07 to -7.35). Among persons who were alive at day 31, further significant reductions in 31-180-day incidence of hospitalization (sub-hazard ratio 1.07, 95% CI 0.83 to 1.37) or death (hazard ratio 0.61, 95% CI 0.35 to 1.08) were not observed. Molnupiravir-treated participants aged [≥]65 years (n=543) had a lower combined 30-day risk of hospitalization or death (55.25/1000 versus 82.35/1000, RD -27.10, 95% CI -50.63 to -3.58). A statistically significant difference in 30-day or 31-180-day risk of hospitalization or death was not observed between matched nirmatrelvir- or molnupiravir-treated participants. Incidence of most post-COVID conditions was similar across comparison groups. Conclusions: Nirmatrelvir-ritonavir was highly effective in preventing 30-day hospitalization and death. Short-term benefit from molnupiravir was observed in older groups. Significant reductions in adverse outcomes from 31-180 days were not observed with either antiviral.

Design and Analysis of Outcomes following SARS-CoV-2 Infection in Veterans (preprint)

AO_SCPLOWBSTRACTC_SCPLOWO_ST_ABSBackgroundC_ST_ABSUnderstanding how SARS-CoV-2 infection impacts long-term patient outcomes requires identification of comparable persons with and without infection. We report the design and implementation of a matching strategy employed by the Department of Veterans Affairs (VA) COVID-19 Observational Research Collaboratory (CORC) to develop comparable cohorts of SARS-CoV-2 infected and uninfected persons for the purpose of inferring potential causative long-term adverse effects of SARS-CoV-2 infection in the Veteran population. MethodsIn a retrospective cohort study, we identified VA health care system patients who were and were not infected with SARS-CoV-2 on a rolling monthly basis. We generated matched cohorts utilizing a combination of exact and time-varying propensity score matching based on electronic health record (EHR)-derived covariates that can be confounders or risk factors across a range of outcomes. ResultsFrom an initial pool of 126,689,864 person-months of observation, we generated final matched cohorts of 208,536 Veterans infected between March 2020-April 2021 and 3,014,091 uninfected Veterans. Matched cohorts were well-balanced on all 38 covariates used in matching after excluding patients for: no VA health care utilization; implausible age, weight, or height; living outside of the 50 states or Washington, D.C.; prior SARS-CoV-2 diagnosis per Medicare claims; or lack of a suitable match. Most Veterans in the matched cohort were male (88.3%), non-Hispanic (87.1%), white (67.2%), and living in urban areas (71.5%), with a mean age of 60.6, BMI of 31.3, Gagne comorbidity score of 1.4 and a mean of 2.3 CDC high-risk conditions. The most common diagnoses were hypertension (61.4%), diabetes (34.3%), major depression (32.2%), coronary heart disease (28.5%), PTSD (25.5%), anxiety (22.5%), and chronic kidney disease (22.5%). ConclusionsThis successful creation of matched SARS-CoV-2 infected and uninfected patient cohorts from the largest integrated health system in the United States will support cohort studies of outcomes derived from EHRs and sample selection for qualitative interviews and patient surveys. These studies will increase our understanding of the long-term outcomes of Veterans who were infected with SARS-CoV-2.

Receipt of anti-SARS-CoV-2 pharmacotherapies among U.S. Veterans with mild to moderate COVID-19, January-February 2022 (preprint)

BackgroundOlder adults and persons with medical co-morbidities are at increased risk for severe COVID-19. Several pharmacotherapies demonstrated to reduce the risk of COVID-19-related hospitalization and death have been authorized for use. We describe factors associated with receipt of outpatient COVID-19 pharmacotherapies in the Veterans Health Administration. MethodsWe conducted a retrospective cohort study among Veterans with risk factors for severe COVID-19 who tested positive for SARS-CoV-2 during January and February 2022. We compared receipt of any COVID-19 pharmacotherapy, including sotrovimab, nirmatrelvir plus ritonavir, molnupiravir, or remdesivir versus no antiviral or monoclonal antibody treatment according to demographic characteristics, place of residence, underlying medical conditions, and COVID-19 vaccination using multivariable logistic regression. ResultsDuring January and February 2022, 16,546 courses of sotrovimab, nirmatrelvir, and molnupiravir were allocated across the Veterans Health Administration. Among 111,717 Veterans testing positive for SARS-CoV-2, 4,233 (3.8%) received any COVID-19 pharmacotherapy, including 2,870 of 92,396 (3.1%) in January and 1,363 of 19,321 (7.1%) in February. Among a subset of 56,206 Veterans with documented COVID-19-related symptoms in the 30 days preceding positive SARS-CoV-2 test, 3,079 of 53,206 (5.5%) received any COVID-19 pharmacotherapy. Untreated Veterans had a median age of 60 years (interquartile range [IQR] 46-71 years) and median 3 underlying medical conditions (IQR 2-5). Veterans receiving any treatment were more likely to be older (adjusted odds ratio [aOR] 1.66, 95% confidence interval [CI] 1.52-1.80, 65-74 versus 50-64 years; aOR 1.67, 95% CI 1.53-1.84 [≥]75 versus 50-64 years) and have a higher number of underlying conditions (aOR 1.63, 95% CI 1.48-1.79, 3-4 versus 1-2 conditions; aOR 2.17, 95% CI 1.98-2.39, [≥]5 versus 1-2 conditions). Persons of Black versus White race (aOR 0.65, 95% CI 0.60-0.72) and well as persons of Hispanic ethnicity (aOR 0.88, 95% CI 0.77-0.99) were less likely to receive treatment. Conclusions and RelevanceAlthough supply of outpatient COVID-19 pharmacotherapies during January and February 2022 was limited, prescription of these pharmacotherapies was underutilized, consistent with early national patterns in dispensing. Racial and ethnic minorities were less likely to receive any pharmacotherapy.

Effectiveness of mRNA COVID-19 vaccine boosters against infection, hospitalization and death: a target trial emulation in the omicron (B.1.1.529) variant era (preprint)

AbstractO_ST_ABSBackgroundC_ST_ABSThe effectiveness of a 3rd mRNA COVID-19 vaccine ("booster") dose against the omicron (B.1.1.529) variant is uncertain especially in older, high-risk populations. ObjectiveTo determine mRNA booster vaccine effectiveness (VE) against SARS-CoV-2 infection, hospitalization and death in the omicron era by type of booster, type of primary vaccine, time since primary vaccine, age and comorbidity burden. DesignTarget trial emulation study comparing booster vaccination versus no booster. SettingU.S. Department of Veterans Affairs (VA) healthcare system Participants and InterventionAmong persons who had received two mRNA COVID-19 vaccine doses at least 5 months earlier, we designed this retrospective matched cohort study to emulate a target trial of booster mRNA vaccination (BNT162b2 or mRNA-1273) versus no booster, conducted from 12/01/2021 to 03/31/2022. MeasurementsBooster VE. ResultsEach group included 490,838 well-matched persons, predominantly male (88%), mean age 63.0{+/-}14.0 years, followed for up to 121 days (mean 79.8 days). Booster VE >10 days after booster was 42.3% (95% CI 40.6-43.9) against SARS-CoV-2 infection, 53.3% (48.1-58.0) against SARS-CoV-2-related hospitalization and 79.1% (71.2-84.9) against SARS-CoV-2-related death. Booster VE was similar for different booster types (BNT162b2 or mRNA-1273), age groups or primary vaccination regimens, but was significantly higher with longer time since primary vaccination and with higher comorbidity burden. LimitationsPredominantly male population. ConclusionsBooster mRNA vaccination was highly effective in preventing death and moderately effective in preventing infection and hospitalization for up to 4 months after administration in the omicron era. Increased uptake of booster vaccination, which is currently suboptimal, should be pursued to limit the morbidity and mortality of SARS-CoV-2 infection, especially in persons with high comorbidity burden. Primary Funding Source: Department of Veterans Affairs