Background: Hospitalizations to treat SARS-CoV-2 infected patients have strained health systems worldwide. Monitored outpatient management of select low-risk COVID-19 patients with isolated exertional hypoxia could help preserve hospital resources and reduce costs while aiming to maintain a high standard of care. In this retrospective cohort analysis, we aimed to evaluate the safety and effectiveness of the COVID-19 Remote Patient Monitoring with Home O2 (cRPM-O2) program across age groups.

Methods: This retrospective cohort study reports the outcomes of an algorithm to select emergency department (ED) patients with COVID-19 and exertional hypoxemia for disposition to discharge home with intermittent remote patient monitoring with low-flow home oxygen (cRPM-O2; Figure 1). The algorithm was implemented in a 24-hospital integrated healthcare system from November 2020 to April 2021. The primary outcome was inpatient hospital days associated with the first admission within 14 days following index ED encounter modeled by OLS regression. Secondary outcomes were intensive care unit (ICU) length of stay (LOS) and combined ICU admission or all-cause death within 28 days. Death was identified by EDW analysis and state death database review to ascertain any death occurring outside our system. ICU LOS was modeled in the same fashion as the primary outcome. The composite binary outcome of ICU admission or death was modeled using a logistic regression. Analyses applied multivariable regression to adjust for potential confounders and were stratified by age (< 70 versus ≥70 years) to evaluate differential outcomes among elderly patients.

Results: Analyses included 755 patients with laboratory confirmed COVID-19, of whom 171 (23%) were ≥70 years old. After adjustment, cRPM-O2 participation was associated with a reduction of 2.27 hospital days per patient (95% CI 1.53-3.01, p< 0.001). However, cRPM-O2 participation was associated with a numerical increase in combined ICU admission and mortality (OR 1.93, p=0.07, 95%CI 0.94-3.95) and ICU days were significantly increased in cRPM-O2 participants (0.33 days, 95%CI 0.00-0.65, p=0.05). In the preplanned sub-group analysis limited to patients ≥70 years old, hospital length of stay did not differ with cRPM-O2 participation (-0.50 days, 95%CI -3.44 to 2.44, p=0.74) and participation in cRPM-O2 was associated with increased ICU length of stay (1.05 days, 95%CI 0.07-2.0, p=0.04) and numerically increased odds of ICU admission or death (OR 5.44 95%CI 0.93-31.75, p=0.06). In this sub-group there were 4 deaths in the control group and 0 deaths in the cRPM-O2 group. In contrast, cRPM-O2 for patients < 70 years of age was associated with hospital length of stay reduction of 2.56 days (95%CI 1.84-3.30, p< 0.001), no change in ICU length of stay (+0.18 days, 95%CI -0.16-0.53, p=0.296), and no difference in the odds of combined ICU admission or mortality (OR=1.40, 95%CI 0.63-3.14, p=0.410).

Conclusions: Compared to hospital admission, low-risk ED patients age < 70 years with isolated ambulatory hypoxemia in the setting of COVID-19 who were discharged home with oxygen and telemonitoring support required fewer overall inpatient hospital days, without significant increase in combined ICU admission and mortality. By contrast, a concerning trend toward harm was observed among patients age ≥70 years, suggesting intermittent home monitoring programs may be inadequate for the care of elderly COVID-19 patients with exertional hypoxemia.

IMAGE 1: Figure 1. cRPM-O2 Triage Flow Diagram

IMAGE 2: Table 1. Baseline Characteristics of Patients and Outcomes by Group