Of the 6257 patients admitted during the study period, 778 received IVT (12.4%). One hundred two patients were excluded due to unavailable door-to-needle times. Of the 676 included, the median age was 70 (IQR 58–81), 313 (46.3%), were female, and the median NIHSS was 8 (IQR 4–16). The simplified demographic, treatment and clinical outcomes are summarized in Table 1.
There were 62 (9.1%) patients out of the 676 included with an unfavorable disposition of in-hospital death or discharge to hospice during the study period. There was no significant increase in death or hospice discharge during COVID-19 when compared to the preceding period (10.1% vs. 8.9%, p = 0.68). A majority (73%) were discharged to a favorable disposition throughout the study period, with no difference across the two periods (69.8% [COVID-19] vs. 74.1% [Pre-COVID-19], p = 0.30). Patients treated during COVID-19 had a median delay of 8 min from door-to-needle in comparison with the preceding period (median 46 [IQR 29–64] vs. 38 [IQR 26–56], p = 0.01).
In univariate analysis, age, white race, atrial fibrillation, heart failure, baseline NIHSS, door-to-needle time, and sICH were associated with in-hospital death or discharge to hospice (Table 2). Every hour delay in IVT was associated with 8% higher odds of death/hospice (OR per hour 1.08, 95% CI 1.01–1.17, p = 0.03). In the multivariable logistic regression model, including all variables significantly associated in univariate analysis, including an interaction term for treatment delay on COVID-19 period), the association between delay in IVT was strengthened, with every hour corresponding to 15% higher odds of discharge to hospice/death (aOR 1.15, 95% CI 1.07–1.24, p < 0.001). There was no significant interaction between treatment delay and admission during the COVID-19 period on the outcome of death/hospice in this model (p = 0.65 for interaction). Model performance was similar with and without the interaction term (AIC 284.28 vs. 284.31). In subgroup analyses, after multivariable adjustment and clustering by site, delays in IVT remained independently associated with higher odds of in-hospital mortality/hospice prior to the COVID-19 pandemic (aOR 1.17, 95% CI 1.06–1.28, p = 0.001) and during the pandemic (aOR 1.10, 95% CI 1.02–1.19, p = 0.017).
With regard to the secondary outcome of favorable discharge to home or IRF, in the univariate analysis, older age, female sex, atrial fibrillation, heart failure, NIHSS, door-to-needle time per hour and sICH (all negative predictors), along with tobacco use (positive predictor) were associated with discharge to a favorable disposition of home or IRF. Longer delays to IVT remained associated with a non-significantly lower probability of discharge to a favorable discharge disposition (OR per hour 0.95, 95% CI 0.89–1.007, p = 0.089). In multivariable model, including all variables significantly associated with favorable discharge in univariate regression, and clustering by site, every one-hour delay in IVT was associated with a 7% reduction in the odds of being discharged to home or IRF (aOR 0.93, 95% CI 0.89–0.97, p < 0.001).