Cost of Antibiotic Resistance Shifting from Public to Private Payers
BETHESDA, Md. — The overall cost burden of antimicrobial resistance--as high as $38 billion in one 2009 hospital estimate--has shifted dramatically from Medicare to private payers over the last decade.
Medicare still pays the majority of the costs for excess length of stay, increased use of more expensive drugs, and poorer health attributable to treatment-resistant infections. However, the rise in infections caused by methicillin-resistant Staphylococcus aureus (MRSA), which largely affects younger, healthier individuals, has meant that the overall cost per patient has declined but more is being borne by private HMOs and PPOs, Susan D. Foster, Ph.D., said at the 2010 Conference on Antimicrobial Resistance sponsored by the National Foundation for Infectious Diseases.
"There's been a major shift in who's actually paying. I don't think the insurance companies are quite aware of this," said Dr. Foster, professor of international health at Boston University and director of public policy and education for the Alliance for the Prudent Use of Antibiotics, based at Tufts University, Boston.
Supported in part by an unrestricted educational grant from bioMérieux Inc., Dr. Foster analyzed data from three studies. The first study reviewed Massachusetts hospital discharge data from 2000 to 2007 to look for ICD9 "VO9" codes, which are specific for drug-resistant infections. Although these codes are complex and difficult to use and therefore represent a study limitation, they do allow for analysis of trends over time, she explained.
Overall, the number of hospital discharges reporting antibiotic resistance in Massachusetts increased from 3,861 in 2000 to 11,218 in 2007. The inflation-adjusted total cost more than doubled over the 7 years, from $135 to $285 million. However, the length of stay (LOS) per patient for drug-resistant infections dropped by 4.5 days, and the cost per patient fell by nearly $10,000.
In contrast, the length of stay for drug-susceptible infections didn't change during the study period (just under 5 days), while the cost per patient with susceptible infections rose only slightly.
The drop in LOS and cost per patient with drug-resistant infections is largely explained by the dramatic shift in patient age, particularly among 19- to 64-year-olds: In 2000, that age group accounted for 30% of drug-resistant infection discharges, whereas in 2007 the proportion had risen to 45.5%. At the same time, the 65- to 80-year-old group dropped from 38% to 25%. While the proportion of infections due to drug-resistant organisms rose in all age groups, the greatest rise was among working-age adults, Dr. Foster noted.