A group of researchers used data from St. Luke’s hospital network’s Sentinel Enhanced Dengue Surveillance Systems to investigate the association of asthma and the development of severe Dengue. Their findings were presented at the 2017 Annual Meeting of the American Academy of Allergy, Asthma & Immunology.
Although the same inflammatory cells that present in asthmatic individuals are also present in patients infected with severe Dengue, a research team failed to directly associate a history of severe asthma with an increased likelihood of developing Severe Dengue fever.
“Because secondary infections are also epidemiological risk factors for severe Dengue, including asthma, we wanted to compare [Dengue patients] with a more severe form of asthma, persistent asthma, to those with a milder form, acute, intermittent asthma,” explained Johanna Velez, MD, a physician at the Ponce Health Sciences University and St. Luke’s Episcopal Hospital in Ponce, Puerto Rico. Dr. Velez and her teamed hoped that information regarding the association of asthma and Severe Dengue fever “could lead to the exploration of other aspects of the pathogenesis of Dengue, including the role for mast cells,” she explained in a presentation on March 5, 2017, at the 2017 Annual Meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) in Atlanta, Georgia.
The group used data collected from patients via the St. Luke’s hospital network’s Sentinel Enhanced Dengue Surveillance Systems (SEDSS). They evaluated the medical histories of 1,691 patients enrolled in SEDSS between May 7, 2012 and May 6, 2015 who had a history of asthma. “Persistent asthma” was defined in the study as “[the need to] use two or more medications for control,” and “acute intermittent asthma” as “[the need to] use rescue medications and no use of control medications.” Of those patients, 186 patients with a history of asthma also had confirmed Dengue, and 39 had severe Dengue with a history of asthma. Of the group of 39 patients, 10 had severe Dengue and persistent asthma, while 29 had severe Dengue with acute intermittent asthma. An additional 81 patients had non-severe Dengue and a history of asthma. Within the whole study population, 39 had non-severe Dengue and persistent asthma, and 27 had non-severe Dengue and acute intermittent asthma. The remainder could not be reached for follow-up.
“Although medical literature has consistently reported an epidemiological link between comorbidities, including asthma, and severe presentations of Dengue,” the researchers did not find an association between the comorbidity of asthma and the development of severe Dengue. The researchers noted that there are also “no significant differences in the risk of developing severe Dengue between those with a history of mild versus those with severe (persistent) asthma.” However, Dr. Velez said, the study was limited by the relatively low number of cases available for analysis that had both Dengue and asthma severities and because the SEDSS study data required a retrospective classification of asthma severity.
Originally, the researchers had hoped that their research might shed light on the role of mast cells, which release histamine—a compound that causes many symptoms associated with asthma, allergies, and Dengue—in the progression of a Dengue infection to severe Dengue. “Given that Dengue is endemic [in] Puerto Rico and 15% of the population has asthma, especially in the pediatric age group, this research question was relevant,” Dr. Velez stated.
Although the group was not able to associate asthma and severe Dengue, they believe that it remains important to evaluate asthma and other comorbidities in the disease’s development. “SEDSS is in a unique position to study the burden of Dengue and to identify risk factors associated with the progress of Dengue from mild to severe,” they concluded.