SAN DIEGO – In-hospital mortality in patients with aspergillosis plummeted nationally, according to data from 2001-2011, with the biggest improvement seen in immunocompromised patients traditionally considered at high mortality risk, Dr. Masako Mizusawa reported at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
The decline in in-hospital mortality wasn’t linear. Rather, it followed a stepwise pattern, and those steps occurred in association with three major advances during the study years: Food and Drug Administration approval of voriconazole in 2002, the FDA’s 2003 approval of the galactomannan serologic assay allowing for speedier diagnosis of aspergillosis, and the 2008 Infectious Diseases Society of America clinical practice guidelines on the treatment of aspergillosis (Clin Infect Dis. 2008 Feb 1;46[3]:327-60).
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Dr. Masako Mizusawa
“This was an observational study and we can’t actually say that these events are causative. But just looking at the time relationship, it certainly looks plausible,” Dr. Mizusawa said.
In addition, the median hospital length of stay decreased from 9 to 7 days in patients with this potentially life-threatening infection, noted Dr. Mizusawa of Tufts Medical Center, Boston.
She presented what she believes is the largest U.S. longitudinal study of hospital care for aspergillosis. The retrospective study used nationally representative data from the Agency for Healthcare Research and Quality’s Healthcare Utilization and Cost Project–Nationwide Inpatient Sample.
Dr. Mizusawa and coinvestigators defined aspergillosis patients as being at high mortality risk if they had established risk factors indicative of immunocompromise, including hematologic malignancy, neutropenia, recent stem cell or solid organ transplantation, HIV, or rheumatologic disease. Patients at lower mortality risk included those with asthma, COPD, diabetes, malnutrition, pulmonary tuberculosis, or non-TB mycobacterial infection.
The proportion of patients who were high risk climbed over the years, from 41% among the 892 patients with aspergillosis-related hospitalization in the 2001 sample to 50% among 1,420 patients in 2011. Yet in-hospital mortality in high-risk patients fell from 26.4% in 2001 to 9.1% in 2011. Meanwhile, the mortality rate in lower-risk patients improved from 14.6% to 6.6%. The overall in-hospital mortality rate went from 18.8% to 7.7%.
Of note, the proportion of aspergillosis patients with renal failure jumped from 9.8% in 2001 to 21.5% in 2011, even though the treatments for aspergillosis are relatively non-nephrotoxic, with the exception of amphotericin B. The outlook for these patients has improved greatly: In-hospital mortality for aspergillosis patients in renal failure went from 40.2% in 2001 to 16.1% in 2011.
While in-hospital mortality and length of stay were decreasing during the study years, total hospital charges for patients with aspergillosis were going up: from a median of $29,998 in 2001 to $44,888 in 2001 dollars a decade later. This cost-of-care increase was confined to patients at lower baseline risk or with no risk factors. Somewhat surprisingly, the high-risk group didn’t have a significant increase in hospital charges over the 10-year period.
“Maybe we’re just doing a better job of treating them, so they may not necessarily have to use a lot of resources,” Dr. Mizusawa offered as explanation.
She reported having no financial conflicts regarding this unfunded study.