Estimating the burden of invasive and serious fungal disease in the United Kingdom

Background The burden of fungal disease in the UK is unknown. Only limited data are systematically collected. We have estimated the annual burden of invasive and serious fungal disease. Methods We used several estimation approaches. We searched and assessed published estimates of incidence, prevalence or burden of specific conditions in various high risk groups. Studies with adequate internal and external validity allowed extrapolation to estimate current UK burden. For conditions without adequate published estimates, we sought expert advice. Results The UK population in 2011 was 63,182,000 with 18% aged under 15 and 16% over 65. The following annual burden estimates were calculated: invasive candidiasis 5142; Candida peritonitis complicating chronic ambulatory peritoneal dialysis 88; Pneumocystis pneumonia 207–587 cases, invasive aspergillosis (IA), excluding critical care patients 2901–2912, and IA in critical care patients 387–1345 patients, <100 cryptococcal meningitis cases. We estimated 178,000 (50,000–250,000) allergic bronchopulmonary aspergillosis cases in people with asthma, and 873 adults and 278 children with cystic fibrosis. Chronic pulmonary aspergillosis is estimated to affect 3600 patients, based on burden estimates post tuberculosis and in sarcoidosis. Conclusions Uncertainty is intrinsic to most burden estimates due to diagnostic limitations, lack of national surveillance systems, few published studies and methodological limitations. The largest uncertainty surrounds IA in critical care patients. Further research is needed to produce a more robust estimate of total burden.