METHODS: We analyzed data from the PATH (Population Assessment of Tobacco and Health) study wave 4 (2016-2018) and wave 5 (2018-2019). Based on questionnaires from wave 4, we categorized tobacco use as: 1) non-use, 2) exclusive e-cigarette use, 3) combustible cigarette use, and 4) dual use. Presence of established cardiovascular disease was examined at wave 4, and participants aged >40 years were asked about chest pain during wave 5. We used binary logistic regression models to determine the association between tobacco exposures and self-reported chest pain.

RESULTS: We evaluated a total of 11254 adults. The rates of chest pain were 1518 out of 7055 non-users, 49 from 208 exclusive e-cigarette users, 1192 from 3722 combustible cigarette users, and 99 out of 269 dual users. In the multivariable models adjusted for relevant covariates, combustible cigarette users (adjusted odds ratio, AOR=1.77; 95% CI: 1.56-2.01) and dual users (AOR=2.22; 95% CI: 1.61-3.05) had higher odds of reporting ever having chest pain, as well as having chest pain in the past 30 days. Conversely, exclusive e-cigarette users had similar odds of reporting chest pain compared to non-users (AOR=1.03; 95% CI: 0.69-1.54) and lower odds than combustible and dual users. In sensitivity analyses, categorizing individuals based on their reported history of cardiovascular disease, overall findings were similar.

OBJECTIVE: To evaluate the likelihood of improvement among persons with likely LC.

DESIGN: Prospective, multisite cohort study (RECOVER-Adult [Researching COVID to Enhance Recovery]).

SETTING: 83 U.S.-based sites across 33 states; Washington, DC; and Puerto Rico.

PARTICIPANTS: 1019 persons in RECOVER-Adult with likely LC (LC Research Index [LCRI] ≥11) 12 months after first SARS-CoV-2 infection.

MEASUREMENTS: The primary outcome was time until 2 consecutive study visits with LCRI less than 11. Secondary outcomes were time until LCRI measure reduced 50% or more and quality of life was good or better, and LCRI decreased to 0. Unadjusted estimates of cumulative incidence and adjusted marginal cumulative incidence by age, sex, SARS-CoV-2 wave, and LC subtype were reported across all follow-up time points.

RESULTS: An estimated 36.2% (95% CI, 33.0% to 39.5%) met the primary outcome by 24 months after infection, and 50.1% (CI, 46.1% to 54.0%) met the primary outcome by 36 months. An estimated 56.4% (CI, 52.2% to 60.4%) and 26.9% (CI, 23.3% to 30.5%), respectively, met the 2 secondary outcomes by 36 months. Among persons who still reported likely LC at 18 months and 24 months after first infection, relative timing of subsequent symptom improvement was similar.

LIMITATION: Findings in this observational cohort are interpretable in a population with prevalent likely LC and do not address causal relationships between individual characteristics and symptom improvement.

CONCLUSION: Among persons with likely LC 12 months after initial SARS-CoV-2 infection, one half experience meaningful reductions in symptoms by 36 months, whereas a quarter experience complete remission of symptoms. These findings underscore both the potential for natural recovery and the urgent need for placebo-controlled therapeutic intervention trials.