Pre-Autopsy Rates of Diagnosis of Aspergillosis Still Low

Review report by Dignani (2014) looks at currently available tools used for the estimation of the rate of aspergillosis amongst immunocompromised patients. One such tool is the rate of diagnosis established by looking at large numbers of patients - i.e epidemiological data. Unfortunately aspergillosis is often not diagnosised until an autopsy is performed so many (50%?) cases are missed and the estimates of rate of occurrence by invasive fungal disease (IFD) are thus calculated to be lower than they should be.

The authors of this paper have attempted to get a more accurate estimate of the frequency aspergillosis in this patient group and to try to identify the most reliable signs of aspergillosis while the patient is still alive - thus making effective treatment more likely. They have assessed both by looking at the autopsy data in 11 healthcare centres around the world between 2008 & 2013 (9187 invasive fungal infection diagnosed out of 193,093 autopsies).

Patients were looked at in groups according to type and scored for frequency of invasive fungal disease (in all cases except AIDS Aspergillus was the main infecting organism):

Patient population % IFD % Aspergillus
General population 5 46
Oncohaematology 25 56
Stem cell transplant 24 67
AIDS 18 29

 

Conclusions

What do the current autopsy reports say worldwide?

The current worldwide autopsy reports say that IFDs have a median prevalence of 9 per 100 autopsies, being highest among patients with hematological disorders or stem cell transplantation. The top three etiological agents are Aspergillus-like organisms (meaning culture negative hyalohyphomycetes plus confirmed Aspergillus spp.) followed by Candida spp. and agents of mucormycosis.

It is interesting to see the emergence of mucormycosis in patients younger than 1 year old across different centers and the high prevalence of invasive aspergilosis in autopsies of AIDS patients.

 

What is the current expected pre-mortem diagnosis of invasive fungal disease?

The current expected pre-mortem diagnosis of IFD is 46 patients per 100 autopsies, and this may vary according to the etiology of the IFD and the type of underlying disease of the deceased patient. Therefore, in 2013, we

still missed the diagnosis in around half of IFDs. However, we should also consider that this number might be higher in reality since the percentage of patients with IFDs diagnosed only at autopsy might have been

biased by including patients in terminal stages of chronic underlying diseases in which diagnostic procedures were not performed (as changes would not have been made in patient management).

 

How can we improve the quality of autopsy reports in autopsied patients?

The quality of data on IFD obtained from autopsy reports can certainly be improved by addressing the following issues: a) establishing standard procedures for diagnosis (pathology and microbiology or pathology and polymerase chain reaction (PCR)  plus clinical information); b) establishing standard inclusion criteria (with or without including Pneumocystis jirovecii disease); and c) increasing the autopsy rate over the suggested minimum of 30% .