Predictors of Cryptococcus gattii clinical presentation and outcome: An international study

Background: Infection by Cryptococcus gattii can lead to pulmonary or central nervous system (CNS) disease, or both. Whether site of infection and disease severity are associated with C. gattii species and lineages or with certain underlying medical conditions, or both is unclear. We conducted a retrospective cohort study to identify factors associated with site of infection and mortality among C. gattii cases.

Methods: We extracted data on 258 C. gattii cases from Australia, Canada and the United States reported from 1999 to 2011. We conducted unadjusted and multivariable logistic regression analyses to evaluate factors associated with site of infection and C. gattii mortality among hospitalized cases (N=218).

Results: Hospitalized C. gattii cases with CNS and other extrapulmonary disease were younger, more likely to reside in Australia and be infected with VGI lineage but less likely to have comorbidities and die as compared to pulmonary cases. The odds of having CNS and/or other extrapulmonary disease were 9 times higher in cases with VGI infection (aOR=9.21, 95%CI=3.28-25.89). Age >70 years (aOR=6.69, 95%CI=2.44-18.30), chronic lung disease (aOR=2.62, 95%CI=1.05-6.51) and an immunocompromised status (aOR=2.08, 95%CI=1.05-6.51) were associated with higher odds of C. gattii mortality.

Conclusions: Among hospitalized cases, C. gattii species and lineage are associated with site of infection but not with the risk of death, whereas older age and comorbidities increase the risk of death.