June 07, 2017
2 min read

Mortality rate for Chagas disease higher than previously reported

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Blood donors who were seropositive for Chagas disease — whether known or not — were 2.3 times more likely to die than seronegative donors, with a noted underreporting of Chagas-related death in Brazilian mortality databases.

“One of the critical challenges for Chagas disease control is that many individuals with the indeterminate form of Chagas disease are not aware that they are infected, so that these individuals are potential onward Trypanosoma cruzi transmitters and may even die without being diagnosed with the disease,” Ligia Capuani, PhD, from the department of infectious diseases at the University of Sao Paulo School of Medicine, and colleagues wrote. “Mortality associated with Chagas disease is still inadequately estimated, particularly for those with this form of the disease.”

To compare the morality rates among blood donors in Sao Paulo who were seropositive for Chagas disease or a negative control in 1996 to 2000, the researchers led a retrospective cohort study in which the death status of individuals was gathered using probabilistic record linkage with the Brazil national mortality information system. The researchers evaluated record linkage in a prior study.

The cohort analyzed included 2,842 seropositive and 5,684 seronegative donors. Mortality was confirmed in 159 (5.6%) of seropositive donors and 103 (1.8%) of those without Chagas disease. The researchers determined that 26 of the deaths of seropositive patients were classified as ICD-10, with Chagas noted as the cause of death. Furthermore, 23 had ICD-10 codes linked to potential Chagas-related cardiac abnormalities. No other seropositive individuals had Chagas disease documented in part 1 of their death certificates.

Patients who were seropositive for the infection demonstrated a 2.3-times higher risk of mortality regarding all causes when compared with seronegative donors. If individuals who had confirmed Chagas-related death or cardiac abnormalities as a result of the disease were considered, seropositive donors had a 17.9% higher chance of death than those without Chagas disease.

“The fact that Chagas disease was not reported as an underlying or associated cause of death on the death certificate of 42% of seropositive donors that died due to cardiac causes demonstrates under ascertainment of Chagas disease pathogenesis, highlighting its status as a neglected disease,” Capuani and colleagues wrote. “… only those that returned to the blood bank to get their screening tests results would have been notified of being seropositive.” — by Katherine Bortz

Disclosure: The researchers report no relevant financial disclosures.