Electronic death records effective influenza surveillance tool

The use of electronic death certificates may be an effective means of monitoring influenza outbreaks, according to new data.

Unlike traditional methods of surveillance, an electronic death reporting system (EDRS) does not require medical records to track the severity of influenza seasons. Therefore, it requires fewer resources and would be less taxing on hospitals and public health personnel, researchers reported in Emerging Infectious Diseases.

Elizabeth A. Bancroft, MD, and Sun Lee, MPH, of Los Angeles County Department of Public Health, California, compared information gathered from electronic death certificates with information retrieved from individual case reports (ICRs) in Los Angeles County during the 2009 influenza A(H1N1) pandemic and two subsequent influenza seasons.

According to the researchers, surveillance using electronic death certificates was “timely, matched the demographics and the epidemiologic curve of traditional influenza-related death surveillance in Los Angeles County, and had a moderate positive predictive value.”

During the 2009-2010 influenza season, 105 influenza-related deaths were reported in Los Angeles County through ICRs vs. 85 by the EDRS.

Demographic information pulled from the two surveillance methods was similar, specifically pertaining to female patients (53% for ICRs vs. 54% for EDRS), Hispanic patients (51% vs. 56%) and the median age of patients (47 and 49 years).

However, risk factors for influenza death were recorded in 97% of the ICRs, whereas only 62% of electronic death certificates contained that information.

The dates of influenza-related deaths were also similar between the EDRS and ICRs; both methods showed peak influenza activity between October 18 and December 5, 2009, and low activity during 2010.

The median lag time for deaths reported by ICR was 4 days, compared with 11 days using electronic death certificates.

Sixty of the 85 deaths identified by the EDRS met the ICR definition of influenza-related death, with a positive predictive value of 71%.

Bancroft told Infectious Disease News that the EDRS is effective, but clinicians need to “think before they write” the information submitted on death certificates.

"Our research found that many death certificates did not mention serious secondary conditions (like obesity with a BMI of >40) that might have played a role in a patient's death,” she said. “Death certificates can be a valuable tool for medical and public health research, but they are only as good as the clinician who filled them out.” — John Schoen

Elizabeth A. Bancroft, MD, can be reached at eabancroft@post.harvard.edu.

Disclosure: The researchers report no relevant financial disclosures.