As we continue to monitor the COVID-19 pandemic, we track important outcomes to identify the course of the disease. Hospitalization is one of those metrics that can provide additional information to public health officials to target interventions and identify groups at higher risk for more severe disease.

We track hospitalization in several ways: 

  • Using syndromic surveillance to identify hospitalizations due to COVID-19-like Illness (CLI);
  • Monitoring trends in hospital utilization that is self-reported by hospitals; 
  • Tracking resource capacity through use of the Arizona Surge Line; and
  • Investigating reported COVID-19 cases to identify outcomes such as hospitalization.

Each of these methods provides public health with information we can use to determine the health of our health care system as well as the severity of the disease in our community. One of the important aspects of public health surveillance is data quality reviews. Epidemiologists at the state and local levels continuously review the data that is reported to public health to ensure it is being accurately reported. Corrections to the data are made when these experts identify systematic errors by reporters. 

The data reflected on our Hospitalization page is pulled from case investigations entered into our MEDSIS database. This information is gathered during case reporting and investigation by healthcare providers and case investigators who may directly interact with the patient. Healthcare providers, who diagnose COVID-19 in a patient, can electronically submit the case report to their local health department. Case investigators at the local health department may follow up with the cases to find out more about that individual’s disease, who they were in contact with, and other important information such as demographics and locations. 

Currently, the Hospitalization section of our dashboard shows the number of hospitalizations that occurred on a certain day and hospitalizations by age group, gender, and race/ethnicity. The largest share of hospitalized cases among the age ranges we track is those over the age of 65, a group that is known to be at higher risk of complications. The data shows slightly more men than women are hospitalized, and the two racial and ethnic groups most likely to be hospitalized include individuals who identify as white, non-Hispanic and Hispanic. We continue to reach out to cases to get a complete picture of their clinical course.

Recently, public health experts determined that a large healthcare provider was reporting an admission date for COVID-19 cases when these individuals were not actually hospitalized. The data being reported in the admission date field of the report form was actually the date the individual was seen by a healthcare provider. Because these cases were being reported with an admission date, they were being counted as hospitalized in the Hospitalization section of our data dashboard. 

Data reported prior to the end of August has been corrected to remove these cases from counts displayed in the Hospitalization section of the data dashboard. As a result, the number of hospitalized cases has decreased by 2,815, primarily in Maricopa County. Our epidemiologists continue to put data quality systems in place so all of the data reported is accurately characterized and used to identify interventions.