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Type 2 diabetes: a risk factor for acquisition of and increased mortality from cryptococcal disease

November 02 2017

Cryptococcal infections are usually caused by Cryptococcus neoformans or Cryptococcus gattii and typically manifest as meningitis or pneumonia. Host conditions that impair cell-mediated immunity such as human immunodeficiency virus (HIV), malignancies and use of immunosuppressive therapy are key risk factors, as are autoimmune diseases, liver cirrhosis and lung diseases.

Type 2 diabetes mellitus has recently emerged as a putative risk factor for cryptococcal disease. In a retrospective study by Yingfang Li and colleagues throughout China, the hospital-based prevalence of cryptococcal disease in persons with type 2 diabetes mellitus was 0.21% (1 in 475 patients). 30 cases of cryptococcosis in persons with type 2 diabetes mellitus were found in mainland China from 1993-2015. The mean age of the patients was 56.1 years. All the cultured strains were identified as Cryptococcus neoformans and sequence type 5 by multilocus sequence typing (MSLT). Untreated or poorly-controlled blood glucose control prior to developing cryptococcal disease was found in 62% of the patients. A high rate of misdiagnosis and treatment delays was reported in 69% of patients with pulmonary cryptococcosis. Among patients diagnosed with cryptococcal meningitis, 60% received substandard antifungal therapy. A high overall mortality rate of 33% was identified.  

As vulnerable populations continue to expand, cryptococcosis is likely to cause more significant morbidity and mortality, if unchecked. Further research is required to describe the relationship between cryptococcus and type 2 diabetes mellitus. This fungal infection is one more reason for maintaining good blood glucose in those with type 2 diabetes mellitus.

Article: Li Y et al. Cryptococcosis in patients with diabetes mellitus II in mainland China: 1993-2015. Mycoses. 2017; 60(11):706-713.