Temporal Changes in Clinical Practice with COVID-19 Hospitalized Patients: Potential Explanations for Better In-Hospital Outcomes

Background/Aims: We reviewed demographic and clinical profiles, along with measures of hospital-based clinical practice to identify temporal changes in clinical practice that may have affected in-hospital outcomes of patients with COVID-19. Methods: Data consisted of sociodemographic and clinical data captured in University of Pittsburgh Medical Center (UPMC) electronic medical record (EMR) systems, linked by common variables (deidentified). The analysis population included hospitalized patients (across 21 hospitals) with a primary diagnosis of COVID-19 infection during the period March 14-August 31, 2020. The primary outcome was a composite of in-hospital mechanical ventilation/mortality. We compared temporal trends in patient characteristics, clinical practice, and hospital outcomes using 4 time-defined epochs for calendar year 2020: March 14-March 31 (epoch 1); April 1-May 15, (epoch 2), May 16-June 28 (epoch 3); and June 29-August 31 (epoch 4). We report unadjusted survival estimates, followed by propensity score analyses to adjust for differences in patient characteristics, to compare in-hospital outcomes of epoch 4 patients (recently treated) to epoch 1-3 patients (earlier treated). Results: Mean number of hospital admissions was 9.9 per day during epoch 4, which was ~2- to 3-fold higher than the earlier epochs. Presenting characteristics of the 1,076 COVID-19 hospitalized patients were similar across the 4 epochs, including mean age. The crude rate of mechanical ventilation/mortality was lower in epoch 4 patients (17%) than in epoch 1-3 patients (23% to 35%). When censoring for incomplete patient follow-up, the rate of mechanical ventilation/mortality was lower in epoch 4 patients (p<0.0001), as was the individual component of mechanical ventilation (p=0.0002) and mortality (p=0.02). In propensity score adjusted analyses, the in-hospital relative risk (RR) of mechanical ventilation/mortality was lower in epoch 4 patients (RR=0.67, 95% CI: 0.48, 0.93). For the outcome being discharged alive within 3, 5, or 7 days of admission, adjusted odds ranged from 1.6- to 1.7-fold higher among epoch 4 patients compared to earlier treated patients. The better outcomes in epoch 4 patients were principally observed in patients under the age of 75 years. Patient level dexamethasone use was 55.6% in epoch 4 compared to 15% or less of patients in the earlier epochs. Most patients across epochs received anticoagulation drugs (principally heparin). Overall steroid (81.7% vs. 54.3%, p<0.0001) and anticoagulation use (90.4% vs. 80.7%, p=0.0001) was more frequent on the day or day after hospitalization in epoch 4 patients compared to earlier treated patients. Conclusions: In our large system, recently treated hospitalized COVID-19 patients had lower rates of in-hospital mechanical ventilation/mortality and shorter length of hospital stay. Alongside of this was a change to early initiation of glucocorticoid therapy and anticoagulation. The extent to which the improvement in patient outcomes was related to changes in clinical practice remains to be established.