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Variability in Rates of Use of Antibacterials Among 130 US Hospitals and Risk-Adjustment Models for Interhospital Comparison

  • Conan MacDougall (a1) and Ronald E. Polk (a2)

To describe variability in rates of antibacterial use in a large sample of US hospitals and to create risk-adjusted models for interhospital comparison.


We retrospectively surveyed the use of 87 antibacterial agents on the basis of electronic claims data from 130 medical-surgical hospitals in the United States for the period August 2002 to July 2003; these records represented 1,798,084 adult inpatients. Hospitals were assigned randomly to the derivation data set (65 hospitals) or the validation data set (65 hospitals). Multivariable models predicting rates of antibacterial use were created using the derivation data set. These models were then used to predict rates of antibacterial use in the validation data set, which was compared with observed rates of antibacterial use. Rates of antibacterial use was measured in days of therapy per 1,000 patient-days.


Across the surveyed hospitals, a mean of 59.3% of patients received at least 1 dose of an antimicrobial agent during hospitalization (range for individual hospitals, 44.4%-73.6%). The mean total rate of antibacterial use was 789.8 days of therapy per 1,000 patient-days (range, 454.4-1,153.4). The best model for the total rate of antibacterial use explained 31% of the variance in rates of antibacterial use and included the number of hospital beds, the number of days in the intensive care unit per 1,000 patient-days, the number of surgeries per 1,000 discharges, and the number of cases of pneumonia, bacteremia, and urinary tract infection per 1,000 discharges. Five hospitals in the validation data set were identified as having outlier rates on the basis of observed antibacterial use greater than the upper bound of the 90% prediction interval for predicted antibacterial use in that hospital.


Most adult inpatients receive antimicrobial agents during their hospitalization, but there is substantial variability between hospitals in the volume of antibacterials used. Risk-adjusted models can explain a significant proportion of this variation and allow for comparisons between hospitals for benchmarking purposes.

Corresponding author
Department of Pharmacy, School of Pharmacy, Virginia Commonwealth University, 410 N 12th Street, P.O. Box 980533, Richmond, VA 23298-053 (
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1.McGowan, JE JrAntimicrobial resistance in hospital organisms and its relation to antibiotic use. Rev Infect Dis 1983;5:10331048.
2.Interagency Task Force on Antimicrobial Resistance. A public health action plan to combat antimicrobial resistance. Part I. Domestic issues. Atlanta, GA: Centers for Disease Control and Prevention, 2001.
3.Avorn, J, Barrett, JF, Davey, PG, McEwen, SA, O'Brien, TF, Levy, SB. Antibiotic resistance: synthesis of recommendations by expert policy groups: a background document for the global strategy for containment of antimicrobial resistance. Boston, MA: Alliance for the Prudent Use of Antibiotics, 2001.
4.Guillemot, D. Antibiotic use in humans and bacterial resistance. Curr Opin Microbiol 1999;2:494498.
5.Shlaes, DM, Gerding, DN, John, JF Jret al.Society for Healthcare Epidemiology of America and Infectious Diseases Society of America Joint Committee on the Prevention of Antimicrobial Resistance: guidelines for the prevention of antimicrobial resistance in hospitals. Clin Infect Dis 1997;25:584599.
6.Goldmann, DA, Weinstein, RA, Wenzel, RP, et al.Strategies to prevent and control the emergence and spread of antimicrobial-resistant micro-organisms in hospitals: a challenge to hospital leadership. JAMA 1996;275:234240.
7.Zervos, MJ, Hershberger, E, Nicolau, DP, et al.Relationship between fluoroquinolone use and changes in susceptibility to fluoroquinolones of selected pathogens in 10 United States teaching hospitals, 1991-2000. Clin Infect Dis 2003;37:16431648.
8.Polk, RE, Johnson, CK, McClish, D, Wenzel, RP, Edmond, MB. Predicting hospital rates of fluoroquinolone-resistant Pseudomonas aeruginosa from fluoroquinolone use in US hospitals and their surrounding communities. Clin Infect Dis 2004;39:497503.
9.Monnet, DL, MacKenzie, FM, Lopez-Lozano, JM, et al.Antimicrobial drug use and methicillin-resistant Staphylococcus aureus, Aberdeen, 1996-2000. Emerg Infect Dis 2004;10:14321441.
10.Bhavnani, SM, Callen, WA, Forrest, A, et al.Effect of fluoroquinolone expenditures on susceptibility of Pseudomonas aeruginosa to ciprofloxacin in U.S. hospitals. Am J Health Syst Pharm 2003;60:19621970.
11.Bhavnani, SM, Hammel, JP, Jones, RN, Ambrose, PG. Relationship between increased levofloxacin use and decreased susceptibility of Streptococcus pneumoniae in the United States. Diagn Microbiol Infect Dis 2005;51:3137.
12.National Nosocomial Infections Surveillance (NNIS) System Report, data summary from January 1992 through June 2004, issued October 2004. Am J Infect Control 2004;32:470485.
13.Carling, PC, Fung, T, Coldiron, JS. Parenteral antibiotic use in acute-care hospitals: a standardized analysis of fourteen institutions. Clin Infect Dis 1999;29:11891196.
14.Lesch, CA, Itokazu, GS, Danziger, LH, Weinstein, RA. Multi-hospital analysis of antimicrobial usage and resistance trends. Diagn Microbiol Infect Dis 2001;41:149154.
15.Niland, JC, Rouse, L, Stahl, DC. An informatics blueprint for healthcare quality information systems. J Am Med Inform Assoc 2006;13:402417.
16.Platt, R. Toward better benchmarking. Infect Control Hosp Epidemiol 2005;26:433434.
17.Ellis, J. All inclusive benchmarking. J Nurs Manag 2006;14:377383.
18.Kislak, JW, Eickhoff, TC, Finland, M. Hospital-acquired infections and antibiotic usage in the Boston city hospital—January, 1964. N Engl J Med 1964;271:834835.
19.Scheckler, WE, Bennett, JV. Antibiotic usage in seven community hospitals. JAMA 1970;213:264267.
20.Roberts, AW, Visconti, JA. The rational and irrational use of systemic antimicrobial drugs. Am J Hosp Pharm 1972;29:828834.
21.Maki, DG, Schuna, AA. A study of antimicrobial misuse in a university hospital. Am J Med Sci 1978;275:271282.
22.Gonzales, R, Malone, DC, Maselli, JH, Sande, MA. Excessive antibiotic use for acute respiratory infections in the United States. Clin Infect Dis 2001;33:757762.
23.Fakih, MG, Hilu, RC, Savoy-Moore, RT, Saravolatz, LD. Do resident physicians use antibiotics appropriately in treating upper respiratory infections? A survey of 11 programs. Clin Infect Dis 2003;37:853856.
24.Hecker, MT, Aron, DC, Patel, NP, Lehmann, MK, Donskey, CJ. Unnecessary use of antimicrobials in hospitalized patients: current patterns of misuse with an emphasis on the antianaerobic spectrum of activity. Arch Intern Med 2003;163:972978.
25.Avorn, J, Solomon, DH. Cultural and economic factors that (mis)shape antibiotic use: the nonpharmacologic basis of therapeutics. Ann Intern Med 2000;133:128135.
26.Iezzoni, LI. Risk adjustment for measuring health care outcomes. 3rd ed. Chicago, IL: Health Administration Press, 2003.
27.Dellit, TH, Owens, RC, McGowan, JE Jr, et al.Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America guidelines for developing an institutional program to enhance antimicrobial stewardship. Clin Infect Dis 2007;44:159177.
28.Pennsylvania Healthcare Cost Containment Council. Public reports. Available at: Accessed July 30, 2007.
29. California Office of Statewide Planning and Development, Healthcare Quality and Analysis Division. Healthcare outcomes reports. Available at: Accessed July 30, 2007.
30.Polk, RE, Fox, C, Mahoney, A, Letcavage, J, MacDougall, C. Measurement of adult antibacterial drug use in 130 US hospitals: comparison of defined daily dose and days of therapy. Clin Infect Dis 2007;44:664670.
31.Hornbrook, MC. Hospital case mix: its definition, measurement and use. Part I. The conceptual framework. Med Care Rev 1982;39:143.
32.Concato, J, Feinstein, AR, Holford, TR. The risk of determining risk with multivariable models. Ann Intern Med 1993;118:201210.
33.Shapiro, M, Townsend, TR, Rosner, B, Kass, EH. Use of antimicrobial drugs in general hospitals. II. Analysis of patterns of use. J Infect Dis 1979;139:698706.
34.Janknegt, R, Wijnands, WJ, Caprasse, M, Brandenburg, W, Schuitenmaker, MG, Stobberingh, E. Antimicrobial drug use in hospitals in The Netherlands, Germany and Belgium. Eur J Clin Microbiol Infect Dis 1993;12:832838.
35.McDonald, LC, Yu, HT, Yin, HC, Hsiung, CA, Hung, CC, Ho, M. Correlates of antibiotic use in Taiwan hospitals. Infect Control Hosp Epidemiol 2001;22:565571.
36.Liem, TB, Filius, FM, van der Linden, PD, Janknegt, R, Natsch, S, Vulto, AG. Changes in antibiotic use in Dutch hospitals over a six-year period: 1997 to 2002. Neth J Med 2005;63:354360.
37.Blix, HS, Hartug, S. Hospital usage of antibacterial agents in relation to size and type of hospital and geographical situation. Pharmacoepidemiol Drug Saf 2005;14:647649.
38.Bhavnani, SM. Benchmarking in health-system pharmacy: current research and practical applications. Am J Health Syst Pharm 2000;57(Suppl 2):S13S20.
39.American Hospital Association. Available at: Accessed November 7, 2007.
40.Madaras-Kelly, K. Optimizing antibiotic use in hospitals: the role of population-based antibiotic surveillance in limiting antibiotic resistance. Insights from the society of infectious diseases pharmacists. Pharmacotherapy 2003;23:16271633.
41.Dalton, B, Sabuda, D, Conly, J. Trends in antimicrobial consumption may be affected by units of measure. Clin Infect Dis 2007;45:399400.
42.Campbell, SE, Campbell, MK, Grimshaw, JM, Walker, AE. A systematic review of discharge coding accuracy. J Public Health Med 2001;23:205211.
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