Prevalence, clinical and economic burden of mucormycosis-related hospital admissions in the US
January 23 2017
There were 555 cases of mucormycosis in hospital among 47 million inpatient episodes, a prevalence of 0.16 per 10,000 discharges. The median length of stay was ~17 days and mean cost was $112,419.
Mucormycosis is an uncommon, opportunistic fungal infection primarily caused by Mucorales, a filamentous fungus of the Mucormycetes class. This fungal infection particularly affects patients with diabetes mellitus (especially following ketoacidosis), or those with hematologic malignancies on chemotherapy (especially with neutropenia), stem cell and solid organ transplants.
The study used the Premier’s Perspective™ Comparative Database, a large, U.S hospital based database covering more than 560 participating hospitals across the U.S and 104 million patients. Data was collected from January 2005 to June 2014. Mucormycosis related-hospitalisations were identified with an ICD-9 code of 17.7 or a positive laboratory microbiology result for Mucorales. Laboratory results were only available from 2009 and for about 37% of the hospitals. All eligible encounters needed at least one prescription of amphotericin B or posaconazole to qualify for a mucormycosis-related hospitalisation. The clinical and economic outcomes assessed included death at discharge, length of stay, and re-admission rates at 1 and 3 months. The cost for hospitalisation included all supplies, labour, depreciation of equipment, etc. All costs were inflated to 2014 USD.
A total of 555 mucormycosis-related hospitalisations were identified among 47,131,360 total inpatient encounters from 177 hospitals. The estimated prevalence was 0.12 per 10,000 discharges during the study period. When the definition of mucormycosis-related hospitalisations was relaxed to not require anti-fungal use, the overall prevalence increased to 0.16 per 10,000 discharges. Most hospitals were large (67%), with a bed size over 300, and 42% were affiliated with teaching facilities. The average age of patients was 51.7 years. About 29% were aged 65 years or older. 63% of the patients were male and approximately 61% were white. The most common underlying condition was diabetes (52%) followed by haematological malignancies (40%).
The median length of stay was approximately 17 days, ranging from 1 to 259 days. 225 (41%) patients were admitted to Intensive care during the hospitalisations. The overall death rate was 23%. Death rates were higher in patients with hematologic malignancies than those with diabetes (23% vs. 19%). 30% of patients were readmitted within a month after discharge, 37% were readmitted within 3 months of discharge. Treatment wise, amphotericin B lipid complex was used in 52%, Liposomal Amphotericin B in 45%, and posaconazole in 45%.
The average cost per hospital stay was $112,419 with a range from $1,912 to $1,395,163. The mean per diem cost was $4,096 ( range $ 768 to $19,728) The mean daily cost for patients with and without intensive care admission during the hospitalisation was $5,107 and $3,407 respectively.
The projected total costs associated with mucormycosis could amount to $48 million per year. The antifungal therapies fluconazole and voriconazole are not effective against mucormycosis.
The authors advised some caution in interpreting the results. First, only a subset of hospitals submitted microbiology results, and no microbiology data were available before 2009. Some mucormycosis-related hospitalisations that did not receive anti-fungals or who were diagnosed will have been omitted. Due to lack of histopathology data, cases identified by histopathology only could have been missed as well.