A new analysis of 100 million Medicare records from U.S. adults aged 65 and older reveals rising healthcare costs for infections associated with opportunistic premise plumbing pathogens. These disease-causing bacteria, such as Legionella, can live inside drinking water supply systems, including household and hospital water pipes.
A team led by researchers from the Friedman School of Nutrition Science and Policy at Tufts University and Tufts University School of Medicine found that between 1991 and 2006, more than 617,000 hospitalizations related to three common plumbing pathogens resulted in around $9 billion in Medicare payments–an average of $600 million a year.
According to the study authors, the costs may now exceed $2 billion for 80,000 cases per year. Antibiotic resistance, which can be exacerbated by aging public water infrastructure, was present in between 1% to 2% of hospitalizations and increased the cost per case by between 10% to 40%. The study was published in the Journal of Public Health Policy on Sept. 12.
“Premise plumbing pathogens can be found in drinking water, showers, hot tubs, medical instruments, kitchens, swimming pools–almost any premise where people use public water. The observed upward trend in associated infections is likely to continue, and aging water supply systems might soon be an additional reservoir of costly multi-drug resistance,” said lead study author Elena Naumova, Ph.D., professor at the Friedman School and Director of the Initiative for the Forecasting and Modeling of Infectious Disease at Tufts University.
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Opportunistic premise plumbing pathogens, such as the bacteria that causes Legionnaire’s disease, Legionella pneumophila, can thrive in low-nutrient conditions and grow as biofilms on the inner surfaces of pipes. Biofilms allow these pathogens to resist disinfectants and environmental stressors, and aid in the spread of antibiotic resistance and virulent genes. As water supply systems age, their susceptibility to contamination increases. However, few large-scale studies have examined the economic and public health burden of these bacteria.
To investigate, Naumova and her colleagues analyzed 100 million medical claims from 1991 through 2006 from the US Centers for Medicare and Medicaid Services. The team focused on hospitalizations related to three opportunistic premise plumbing pathogens: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa, which can cause a range of serious respiratory, systemic, or localized infections, particularly in vulnerable populations such as the elderly or immunocompromised individuals.
Based on clinical diagnostic codes, reported cases for all three infections totaled 617,291, with the majority due to pneumonia caused by Pseudomonas and related bacteria (560,504). Legionnaire’s disease and Mycobacteria infections accounted for 7,933 and 48,854 cases respectively. On average, each hospitalization represented $45,840 in Medicare charges and $14,920 in payments. Antibiotic resistance, recorded in a little under 2% of cases, increased the average costs to $60,870 in Medicare charges and $16,690 in payments per case.
Over the past decade, the US Centers for Disease Control and Prevention reported a substantial increase in incidence of opportunistic premise plumbing pathogens, with Pseudomonas alone accounting for 51,000 hospitalizations per year with more than 6,000 multi-drug resistant infections in 2011. Antibiotic resistance is likely underreported, and this number is a conservative estimate for the Medicare population based on the study findings and reported data on hospitalization costs per case, says Naumova.
The risk of becoming ill from drinking water is much less than the risk of becoming ill from food, but it is not zero,
“While public drinking water is safe, it is clearly more safe if you are healthy than if you have medical conditions that enhance your vulnerability to infections. The risk of becoming ill from drinking water is much less than the risk of becoming ill from food, but it is not zero,” said last author Jeffrey K. Griffiths, M.D., professor of public health and community medicine at Tufts University School of Medicine. Griffiths is also former chair of the Drinking Water Committee for the US Environmental Protection Agency’s Science Advisory Board. “These infections can cause a lot of illness and cost us a lot of money, and targeted disinfection of premise piping could save us from these consequences.”
The authors caution that their data cannot draw conclusions about the percentage of infections directly caused by contaminated water. The link between aging water supply systems and drug resistance is highly plausible, but has yet to be firmly established, say the authors. However, this study highlights the need for improved surveillance systems and targeted investigations of water-related outbreaks in order to determine the direct link between water contamination and drug-resistant infection.
For more information, visit: www.now.tufts.edu
