JMIR Publications

ABSTRACT

Background:

Accurately assessing regional activity of diseases such as COVID-19 is important in guiding public health interventions. Leveraging electronic health records (EHR) to monitor outpatient clinical encounters may lead to the identification of emerging outbreaks.

Objective:

To investigate whether excess visits where the word “cough” was present in EHR reason for visit, and hospitalizations with acute respiratory failure were more frequent December 2019 to February 2020, compared with 5 preceding years.

Methods:

A retrospective observational cohort was identified from a large U.S. health system with 3 hospitals, over 180 clinics and 2.5 million patient encounters annually. Data from patient encounters from July 1, 2014 to February 29, 2020 were included. Seasonal autoregressive integrated moving average (SARIMA) time-series models evaluated if the observed winter 2019/2020 rates were higher than the forecast 95% prediction intervals. Estimated excess number of visits or hospitalizations in winter 2019/2020 were calculated comparing to previous seasons.

Results:

The percent of patients presenting with the EHR reason for visit containing “cough” to clinics exceeded the 95% prediction interval the week of December 22, 2019 and was consistently above the 95% prediction interval all ten weeks through the end of February 2020. Similar trends were noted for emergency department visits and hospitalizations starting December 22, 2019, where observed data in 6 and 7 of the 10 weeks, respectively, exceeded the 95% prediction interval. The estimated excess over the three winter months of 2019-2020, subtracting the maximum or subtracting the average of the five previous seasons from the current season, were 1.6 or 2.0 excess visits for cough per 1,000 outpatient visits, an excess of 11.0 or 19.2 per 1,000 emergency department visits, and an excess of 21.4 or 39.1 /1,000 hospitalizations with acute respiratory failure, respectively. The total number of excess cases above the 95% predicted forecast interval were 168 cases in the outpatient clinics, 56 cases for the emergency department and 18 hospitalized with acute respiratory failure.

Conclusions:

A significantly higher number of patients with respiratory complaints and diseases starting late December 2019 and continuing through February 2020 suggests community spread of SARS-CoV-2 prior to established clinical awareness and testing capabilities. This provides a case example of how health system analytics combined with EHR data can provide powerful and agile tools in identifying when future trends in patient populations are falling out of the expectations.