Infections Avoided, Excess Costs Averted, and Changes
in Mortality Rate
- The project
carried out a systematic review of the cost of CLABSI. After reviewing almost
850 abstracts and over 150 articles in full, 6 articles met inclusion criteria.
- After weighting
and adjusting to 2012 dollars, the average CLABSI cost reported in the
literature was $70,696 with a range (± two standard deviations) of $40,412–$100,980.
- Assuming baseline
rates would have remained stable without the study intervention, an estimated
total of 2,187–2,419 CLABSIs were prevented over the course of the project.
- An estimated 290–605
deaths were prevented during the course of the project assuming a 12–25 percent
- An estimated $97,756,628–$244,270,620
in excess costs were averted during the course of the project.
versions of this analysis reported the excess cost per CLABSI at $16,550, an
estimate used by the CDC.6 However, to better assess the estimated excess costs averted as a result of the
improvement project, a systematic review of the literature was conducted. Although
prior systematic reviews have been conducted, this review differed in that it
focused solely on the U.S. experience. As such, studies conducted outside of
the United States were excluded. In addition, we assumed that the cost of
treating adult versus pediatric CLABSIs differs and as such did not include
studies solely examining NICU, PICU, or pediatric units.
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PubMed, EconLit, Biological Abstract
and Science Direct were searched. First, articles were reviewed at the abstract
level. Abstracts believed to have appropriate CLABSI cost calculations were
retrieved to be reviewed in full. Retrieved articles were then reviewed against
inclusion criteria and included articles were abstracted (for a full list of a
priori inclusion criteria, go to Appendix
A). Costs identified in
included studies were adjusted to reflect May 2012 dollars using the consumer
price index (CPI) inpatient hospital services index.7 When authors
did not indicate what dollar year their estimates were based upon, the year of
publication was assumed. A clear consensus does not exist for cost adjustment.8 As such, both
the all urban CPI (CPI-U) and CPI inpatient adjustments were calculated and
reflected in the summary table. After adjusting to 2012 dollars, a weighted
mean was calculated. The number of patients with a CLABSI (i.e., cases) was used
to weight the final mean. Although more robust methodologies exist, we were
limited by the detail of statistical data reported by authors. This limitation
resulted in the use of two standard deviations (plus/minus) to estimate the
range of costs based upon the estimated mean.
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A total of 841 unique abstracts were
identified. Forty-nine articles were retrieved after being deemed relevant at
the abstract level, and 109 additional articles were retrieved after conducting
a reference review. A total of six articles satisfied inclusion criteria and
can be found in Table 11. A flowchart of the article review
process can be found in Appendix
B, and all excluded
articles and reason for exclusion can be found in Appendix C.
Table 11. Articles satisfying
stay and charges associated with health care acquired bloodstream infections
costs of enterococcal bloodstream infections in a nonsurgical hospital cohort
from reduced catheter-related bloodstream infection after simulation-based
education for residents in a medical intensive care unit
of central line-associated bloodstream infections
costs of catheter-associated bloodstream infections among intensive care
patients in a nonteaching hospital
stringent inclusion/exclusion criteria were applied, the six included articles
differed significantly in both estimated costs as well as the methods utilized
to derive the costs. Variation can be attributed to factors such as sample size
(range: 12-100,851 cases), setting (single hospital site estimate in four
studies vs. multi-site estimate), costs considered (e.g., costs billed, actual
costs, etc.), and estimation model utilized (e.g., matching procedure). Although
a weighted mean was calculated, only one study utilized a large, national
administrative database, thereby resulting in greater cases and a larger weight
in the averaging process.9
costs per CLABSI in each study as well as relevant CPI adjustment weights and
adjusted costs can be found in Table
12. The average cost per
CLABSI after using the weight and May 2012 CPI inpatient hospital service index
adjustment was estimated at $70,696 with a range (plus/minus two standard deviations)
of $40,412 to $100,980. This range is similar to that found on the Johns
Hopkins CLABSI Opportunity Estimator Web site (range of $40,000 to $117,000 per
Table 12. Cost per CLABSI of
studies meeting inclusion criteria*
||Cost in Year
|CPI IP Weight
et al. (2012)
et al. (2008)
et al. (2006)
consumer price indexes utilized May 2012 tables.
reflect the number of observed CLABSIs utilized in the study's cost estimate.
= all urban consumer price index; CPI IP = consumer price index inpatient
hospital services index
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the deaths prevented, a range in mortality was assumed (12-25 percent).11 For each 100
CLABSIs prevented, 12-25 deaths are prevented. To estimate the excess costs
averted, the mean cost per CLABSI (using CPI inpatient hospital service
adjustment) was utilized: $70,696. Thus, for each CLABSI prevented, $70,696 in
treatment costs were averted. To estimate the number of CLABSIs prevented, the
number of actual CLABSIs reported was compared with the number of CLABSIs that
would have occurred if the pre-intervention ("baseline") rate of CLABSIs per
1,000 line days had persisted:
# CLABSIs prevented =
(baseline rate – observed rate) * (#central line days)
calculations were done on a quarterly basis and totaled over all quarters.
The project quarters
considered were eight quarters post-intervention, or 24 months. Not all units
reported data for all 24 months (to be distinguished from units that reported
zero central line days). Thus, it is useful to calculate savings based not only
on months of reported data, but under the assumption that for each unit,
non-reported months were similar to reported months. In order to estimate the
total number of central line days (CLDs) and CLABSIs over the project quarter,
these were interpolated for each unit using the available reported data. Mean
interpolation was used. For example, if one unit did not report data for the
eighth month, the numbers of CLDs and CLABSIs for that month were estimated as
the average of the numbers for the seventh and ninth months. If the month with
missing data was at the end of the project quarter (i.e., month 24), the numbers
of the last available month were carried forward, and if at the beginning of
the project quarter (i.e., month 1), the numbers of the first available month
were carried back (go to Appendix
D for an example). Since
CLABSI rates declined over the course of the intervention, using the study
average would underestimate projected savings. Thus, data from quarters five
and six were used to estimate monthly costs and lives saved over time after the
project. Estimates are based on all adult ICU units that participated in the
project and had not formally withdrawn. Units that never submitted data but did
not formally withdraw were excluded.
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Table 13 presents estimated CLABSIs and
deaths prevented and excess costs averted using all available data as well as
missing data imputation. An estimated total of 2,187 CLABSIs were prevented
over the course of the study with a projected continuation of 114 CLABSIs
prevented monthly moving forward. After missing values were imputed, this
number increased to an estimated total of 2,419 CLABSIs prevented over the
course of the study with a projected continuation of 121 CLABSIs prevented monthly.
of deaths prevented varied as a function of the underlying assumption: 12
percent mortality rate to 25 percent mortality rate. Using all available data,
an estimated range of 262–547 deaths were prevented over the course of the
study with 14–28 deaths prevented monthly moving forward. After missing value
imputation, this number increased to an estimated range of 290–605 deaths
prevented over the course of the study with 14–30 deaths prevented monthly
range of estimates for excess costs averted can be found in Table 14. Using all available data and the
CPI inpatient hospital service adjusted weighted cost, an estimated $154,612,152
in excess costs were averted with an estimated $8,057,594 in excess costs
averted monthly moving forward. After missing value imputation, this number
increased to $171,013,624 in excess costs averted with an estimated $8,533,375
in excess costs averted monthly moving forward. In previous reports, using the
estimate of $16,550 per CLABSI the estimated excess costs averted would range
from $36,194,850 to $40,034,450 (Table 13).
the cost estimate is based on an estimated mean, a more conservative approach
would be to consider a range of costs. Using all available data and a range
that is two standard deviations from the mean, excess costs averted are
estimated at between $88,381,044 and $220,540,320. Every month moving forward
this translates into an estimated cost savings range of $4,606,015 to $11,509,172.
After imputing missing values the total range estimate becomes $97,756,628 to $244,270,620
with every month moving forward estimated at averting $4,877,989 to $12,188,760
It should be noted that the finalized
estimate of costs is from the hospital perspective, not the patient. As such,
excess costs averted such as wages lost were not considered. In addition,
estimates do not include costs of death in terms of the value of statistical
life which would increase the overall economic impact of the project (see the
National Center for Environmental Economics for more information12). Finally,
estimated costs do not reflect reductions in CLABSI rates found in non-ICU and
pediatric units participating in the project.
Table 13. Estimation of infections and deaths prevented and excess costs averted among
participating adult ICUs using all data ("reported") and data after missing
value imputation ("estimated") using CDC estimates
Prevented represents the sum of Q1 to Q8 and does not include savings outside
‡ Center of Disease
Control and Prevention Morbidity and Mortality Weekly Report (Go to: http://www.cdc.gov/mmwr/pdf/wk/mm60e0301.pdf) [Plugin Software Help].
Table 14. Estimation of excess
costs averted among participating adult ICUs using all data ("reported") and
data after missing value imputation ("estimated")
|CLABSIs Reported/ Estimated
|Excess Costs Averted
represents the sum of Q1 to Q8 and does not include savings outside the
based upon data from Q5 to Q6.
estimates utilize ± two standard deviation from the mean.
6. Morbidity and Mortality Weekly Report (MMWR)
March 2011. Vital Signs: Central Line-Associated Blood Stream Infections—United States, 2001, 2008, and 2009. Accessed on: October 18, 2012. Access at: http://www.cdc.gov/mmwr/pdf/wk/mm6008.pdf [Plugin Software Help].
7. Bureau of Labor Statistics, Consumer Price
Indexes. Accessed on: October 18, 2012. Access at: http://www.bls.gov/cpi/
8. Scott RD. The Direct Medical Costs of
Healthcare-Associated Infections in U.S. Hospitals and the Benefits of
Prevention—Centers for Disease Control and Prevention. 2009 Accessed on:
October 18, 2012. Access at: http://www.cdc.gov/hai/pdfs/hai/scott_costpaper.pdf [Plugin Software Help].
9. Al-Rawajfah OM, et al. Length of stay and
charges associated with health care-acquired bloodstream infections. Amer J
Infec Contr 2012;40:227-232.
10. Johns Hopkins CLABSI Opportunity Estimator.
Accessed on October 18, 2012. Access at: http://www.hopkinsmedicine.org/quality_safety_research_group/our_projects/stop_bsi/toolkits_resources/clabsi_estimator.html .
11. Morbidity and Mortality Weekly Report (MMWR)
March 2011. Vital Signs: Central Line-Associated Blood Stream Infections—United States, 2001, 2008, and 2009. Accessed on: October 18, 2012. Accessed
at: http://www.cdc.gov/mmwr/pdf/wk/mm60e0301.pdf [Plugin Software Help].
12. National Center for Environmental Economics: http://yosemite.epa.gov/ee/epa/eed.nsf/webpages/homepage.
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