Design and analysis of outcomes following SARS-CoV-2 infection in veterans.

BACKGROUND: Understanding 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. METHODS: In 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 within each month 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. RESULTS: From 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 39 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%). CONCLUSION: This 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.

Surveyed Enrollees in Veterans Affairs Health Care: How They Differ From Eligible Veterans Surveyed by BRFSS.

OBJECTIVES: We described differences in demographic and socioeconomic characteristics between Veterans enrolled in the Veterans Health Administration (VHA) and Veterans eligible to enroll for Veterans Affairs health care. Knowledge of these differences is important in planning better services for Veterans who enroll and in encouraging additional enrollment. METHODS: We compared characteristics of enrollees and eligible Veterans in 2012. To describe enrollees, we used aggregate data from administrative records and results from VHA's Survey of Veteran Enrollees' Health and Reliance Upon VA. To describe eligible Veterans, we analyzed individual-level data from the Behavioral Risk Factor Surveillance System. RESULTS: Elderly individuals are more heavily represented among enrollees than eligible Veterans, and elderly enrollees are less likely to describe their health as good to excellent. Enrollees are more than twice as likely as eligible Veterans to have annual household incomes below $16,000. Representation of minorities is roughly the same among enrollees as eligible Veterans. CONCLUSIONS: Our results are consistent with VHA as a safety net provider with respect to income, age, and disease burden.