Cryptococcosis-Related Mortality, 2000-2010

Introduction: There are few specific reports of mortality burden of cryptococcosis, and none encompassing the entire United States (US). We examined the US mortality burden for this infection (both gattii and neoformans species) using the national multiple-cause-of-death (MCD) data. 

 

Methods: Cryptococcus-related deaths from 2000-2010 were identified from the MCD data set based on the ICD-10 coding for this disease. Crude and age-adjusted mortality rates were calculated by race/ethnicity, sex, and region. Poisson regression analysis was performed to model mortality trends over time. A matched case-control analysis was conducted to describe associations between this disease and other comorbid conditions that contributed to death.

Results: A total of 3,212 Cryptococcus-related deaths were identified (n=1,134 were underlying cases). A majority of deaths were in whites (53%, n=1,710) and blacks (29%, n=937).  The age-adjusted rate ratio for blacks, using whites as the referent group, was 2.89 (95% CI 3.71-4.09). Males comprised over two-thirds of cases (71%, n=2,288) and had a higher age-adjusted mortality rate than females (0.15 per 100,000 population, 95% CI 0.14-0.16). Mortality rates have trended downward over the 10-year study period, decreasing from 0.13 per 100,000 population in 2000 to 0.07 per 100,000 population in 2010.  A number of comorbid conditions were associated with cryptococcosis related deaths: HIV (MOR = 36.14; 95% CI 28.38-46.03), Leukemia (MOR = 16.10; 95% CI 11.24-23.06); non-Hodgkin’s Lymphoma (MOR = 7.18; 95% CI 5.39-9.57); Autoimmune/connective tissue disorders (MOR = 6.86; 95% CI 5.40-8.70).

Discussion: Despite a significant decline in mortality rates over the last ten years, cryptococcosis remains an important cause of death in the US. The dramatic decline in mortality is likely related to the improved control of HIV infection.