Five-year review of Aspergillus ICD-9-CM coded infection in the Department of Veterans Affairs (VA), Veterans Healthcare System

BACKGROUND/OBJECTIVES: Aspergillus infection generally occurs in immunosuppressed patients and often leads to adverse outcomes. The VA healthcare system provides a convenient nationwide inpatient system in which to review data on Aspergillus epidemiology. METHODS: The national VA data warehouse for discharge diagnoses was reviewed for federal fiscal years (FYs) 2000 through 2004. ICD-9-CM codes for Aspergillus (117.3) and Aspergillus with pneumonia (117.3 with 484.6) were used as search parameters. Denominator data were defined as a unique person-inpatient episode of care. The numerator was defined as a unique-inpatient episode with an Aspergillus ICD-9-CM diagnosis. The rate is per 1000 inpatient episodes of care. RESULTS:Over the 5 years, the mean age of patients was 61.6 years, with a range from 59.1 to 63.5. The mean length of stay was 17 days, with a range from 14.2 to 19.7. In FY 2002, the rate for total Aspergillus exceeded the rate of the other 4 years (p = 0.02). Of the 11 facilities with the greatest number of Aspergillus with pneumonia episodes, only 5 (45%) had in-house transplant programs of any type. CONCLUSION: Aspergillus infection, based on ICD-9-CM coding, was relatively unchanged over a 5-year period with an increase during one fiscal year (FY 2002). This excess was traced to a single facility with a small cluster of Aspergillus ICD-9-CM coded inpatients during the year. Discharge diagnosis surveillance has yielded normative national case rates and retrospectively identified a cluster of discharges associated with an ICD-9-CM diagnosis for Aspergillus. Further work is necessary to clarify whether this methodology can be useful on a more contemporaneous basis.