Researching COVID to enhance recovery (RECOVER) adult study protocol: Rationale, objectives and design (preprint)

Importance: SARS-CoV-2 infection can result in ongoing, relapsing, or new symptoms or other health effects after the acute phase of infection; termed post-acute sequelae of SARS-CoV-2 infection (PASC), or long COVID. The characteristics, prevalence, trajectory and mechanisms of PASC are ill-defined. The objectives of the Researching COVID to Enhance Recovery (RECOVER) Multi-site Observational Study of PASC in Adults (RECOVER-Adult) are to: (1) characterize PASC prevalence; (2) characterize the symptoms, organ dysfunction, natural history, and distinct phenotypes of PASC; (3) identify demographic, social and clinical risk factors for PASC onset and recovery; and (4) define the biological mechanisms underlying PASC pathogenesis. Methods: RECOVER-Adult is a combined prospective/retrospective cohort currently planned to enroll 14,880 adults aged [≥]18 years. Eligible participants either must meet WHO criteria for suspected, probable, or confirmed infection; or must have evidence of no prior infection. Recruitment occurs at 86 sites in 33 U.S. states, Washington, DC and Puerto Rico, via facility- and community-based outreach. Participants complete quarterly questionnaires about symptoms, social determinants, vaccination status, and interim SARS-CoV-2 infections. In addition, participants contribute biospecimens and undergo physical and laboratory examinations at approximately 0, 90 and 180 days from infection or negative test date, and yearly thereafter. Some participants undergo additional testing based on specific criteria or random sampling. Patient representatives provide input on all study processes. The primary study outcome is onset of PASC, measured by signs and symptoms. A paradigm for identifying PASC cases will be defined and updated using supervised and unsupervised learning approaches with cross-validation. Logistic regression and proportional hazards regression will be conducted to investigate associations between risk factors, onset, and resolution of PASC symptoms. Discussion: RECOVER-Adult is the first national, prospective, longitudinal cohort of PASC among US adults. Results of this study are intended to inform public health, spur clinical trials, and expand treatment options.

Association of Periodic Fasting with Lower Severity of COVID-19 Outcomes in the SARS-CoV-2 Pre-Vaccine Era: An Observational Cohort from the INSPIRE Registry (preprint)

Objectives: Intermittent fasting boosts some mechanisms of host defense against infection while modulating the inflammatory response. Lower-frequency periodic fasting is associated with greater survival and lower risk of comorbidities that exacerbate COVID-19. This study evaluated the association of periodic fasting with COVID-19 severity and, secondarily, initial diagnosis of infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Design: Prospective longitudinal observational cohort study. Setting: Single-center secondary care facility in Salt Lake City, Utah, USA with follow-up across a 24-hospital integrated healthcare system. Participants: Patients enrolled in the INSPIRE registry in 2013-2020 were studied if they had SARS-CoV-2 testing in March 2020-February 2021 and either tested positive (N=205) for the primary outcome evaluation or had a positive or negative test result for evaluation of the secondary outcome (n=1,524). Interventions: No treatment assignments were made; individuals provided information about their personal practice and history of engaging in routine periodic fasting across their lifespan. Main outcome measures: The association of periodic fasting with a composite of mortality or hospitalization as the primary outcome was evaluated by Cox regression through February 2021 and multivariable adjustments considered 36 covariables in INSPIRE patients diagnosed with COVID-19. Secondary analysis evaluated the association of fasting with testing positive for SARS-CoV-2 in INSPIRE patients evaluated for COVID-19 (n=1,524). Results: Subjects engaging in periodic fasting (n=73, 35.6%) did so for 40.4{+/-}20.6 years (max: 81.9 years) prior to COVID-19 diagnosis. The composite outcome occurred in 11.0% of periodic fasters and 28.8% of non-fasters (p=0.013), with HR=0.61 (95% CI=0.42, 0.90) favoring fasting. Multivariable analyses confirmed this association. Other predictors of hospitalization/mortality were age, Hispanic ethnicity, prior MI, prior TIA, and renal failure, with trends for race, smoking, hyperlipidemia, coronary disease, diabetes, heart failure, and history of anxiety, but not alcohol use. In secondary analysis, COVID-19 was diagnosed in 14.3% of fasters and 13.0% of non-fasters (p=0.51). Conclusions: Routine periodic fasting was associated with a lower risk of hospitalization or mortality in patients with COVID-19. Fasting may be a complementary therapy to vaccination that could provide immune support and hyperinflammation control during and beyond the pandemic. Trial registration: clinicaltrials.gov, NCT02450006 (the INSPIRE registry)