Pneumonia Linked With 43% of Unexpected Infectious Deaths in Study

Infectious diseases can lead to rapid and unexpected deaths, highlighting the importance of prevention strategies, according to a study published in Open Forum Infectious Diseases by investigators at the Sunnybrook Health Sciences Center in Ontario, Canada.

"There is very little prior attention on sudden, unexpected deaths from infectious diseases," Nick Daneman, MD, FRCPC, MSc, a scientist with Sunnybrook Health Sciences Centre and an author of the report, told Contagion^®.

The population-wide cohort study examined all unexpected deaths in Ontario between January 2016 and December 2017 and found that infectious causes were responsible for 6% of all unexpected deaths.

"In our 2-year study of all coroner cases involving sudden unexpected deaths in Ontario, Canada, we found more than 400 cases caused by a variety of pathogens and infectious syndromes," Dr. Daneman told Contagion^®. "The most common pathogen was Staphylococcus aureus. The most common site of infection was pneumonia."

Bacterial pneumonia was the cause of 43% of unexpected infectious deaths, while 12% were attributed to disseminated infection with no clear focus, 10% to peritonitis, 6% to myocarditis, and 5% to pyelonephritis. In half of all cases, a pathogen was identified, including S aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Klebsiella spp, and Escherichia coli.

"Roughly two thirds of these patients had prodromal symptoms prior to their death, but only a third had health care contact in the week before death. We need to develop upstream strategies to prevent these deaths, such as vaccines, and public education about early warning signs of sepsis," Dr. Daneman told Contagion^®.

The study found that 52% of patients had underlying heart disease, 31% had liver disease, 29% had lung disease, 24% had kidney disease, and 24% had psychiatric conditions. Other considerations included a history of illicit drug use in 17% of cases, acute drug intoxication in 9%, a history of smoking in 30% of cases, and a history of alcohol use in 23%.

Prodromal symptoms were present prior to death in 68% of cases, with the median length of time being 1 day. The majority of patients died before receiving health care, but the study didn't provide data to explain why some people are more vulnerable to infectious death.

A study released last year found patients hospitalized with acute bacterial pneumonia to be at 60% greater risk of major adverse cardiovascular events than those diagnosed with viral pneumonia.

Because of the short length of time between symptoms presenting and death and the low rate of health care, the study suggests preventing the infection is more significant than diagnosis and treatment.

"Ideally, there should be a continual focus towards upstream strategies such as public education regarding warning signs of severe infections, promoting early access to urgent care facilities and phone triage systems, and preventing infection transmission through vaccine development and implementation," the study concludes.