Tele-Critical Care, Severity of Illness, and 30-Day Mortality Risk: A Retrospective, Cohort Analysis.

Introduction: Studies have shown that tele-critical care (TCC) improves outcomes in intensive care unit (ICU) settings with low baseline performance. Evidence also suggests that TCC outcomes may be modified by heterogenous baseline severity of illness. We examined the association of admission Acute Physiology and Chronic Health Evaluation IV (APACHE IV) score quartiles (APQ1-APQ4) and TCC exposure with 30-day mortality. Methods: Retrospective, cohort study of 151,780 consecutive ICU patients admitted to nine hospitals within Cleveland Clinic Health System from 2010 to 2019. Data were abstracted from an institutional ICU Datamart and APACHE IV registry. Analyses included summary statistics for demographics, unadjusted survival functions, and incidence rates across ascending APACHE quartiles (APQ1-APQ4). Multivariate Poisson regression modeled covariates associated with incidence rate ratio (IRR) for mortality, across quartiles including statistical interaction between TCC exposure and APACHE quartiles. Results: Unadjusted mortality risk ratios of TCC/no TCC were statistically different across APQ1 (0.83; 95% confidence interval [CI] 0.71-0.97), APQ3 (0.63; 95% CI 0.57-0.69), and APQ4 (0.77; 95% CI 0.74-0.82) (all p < 0.05) but not in APQ2 (0.98; 95% CI 0.88-1.10; p = 0.77). Multivariate Poisson modeling found reduced IRR with TCC (IRR 0.82; 95% CI 0.70-0.97). Relative to APQ1, risk was increased across quartiles, APQ2 (IRR 2.15; 95% CI 1.83-2.52), APQ3 (IRR 3.93; 95% CI 3.39-4.56), and APQ4 (IRR 9.30; 95% CI 8.10-10.67). Interaction with TCC significantly reduced risk in APQ3 (IRR 0.80; 95% CI 0.67-0.96). Conclusion: TCC exposure is associated with reduced 30-day mortality, affected by various clinical factors, to provide heterogenous impact. Mortality benefit appears to particularly accrue among patients with higher, but not the highest quartile for severity of illness, based on their APACHE IV scores.