1 Division of Pharmacy, Central Institute of the Valais Hospitals, Sion; 2 Centre for Infectious Diseases and Epidemiology, Central Institute of the Valais Hospitals, Sion; 3 Valais Health Observatory, Sion; 4 Centre d'épidémiologie clinique, Institut Universitaire de Médecine Sociale et Préventive, Lausanne, Switzerland
Received 16 August 2004; returned 27 September 2004; revised 23 November 2004; accepted 15 December 2004
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Abstract |
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Materials and methods: The duration of antibiotic treatment, their cost, and the length of patient stay were compared in three secondary-care hospitals, before and after interventions that were designed to promote rational antibiotic use. After randomization, hospital A received no intervention (control), local practice guidelines were implemented in hospital B (low grade intervention), and these guidelines were reinforced by a clinical pharmacist in hospital C (high grade intervention). Adherence to the guidelines was measured in hospitals B and C. Multivariable statistical analyses were carried out to adjust for confounding factors.
Results: None of the outcomes measured in the 1200 included patients decreased between the two study periods in any hospital. Hospital A was significantly and independently associated with an increase in the duration of antibiotic treatments, the cost of antibiotics (acquisition and global costs), and the length of stay. Although these differences were not statistically significant, increases in hospital B were higher than in hospital C. Adherence to guidelines was significantly higher in hospital C.
Conclusions: Even though interdisciplinary interventions aiming at rationalizing antibiotic use could not diminish the duration of treatments, their costs or the length of stay, they proved useful to control the progression of these parameters.
Keywords: practice guidelines , antibiotic use , costs , interdisciplinary team , pharmaceutical services
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Introduction |
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Different interventions have been described to guide a more appropriate and cost-effective use of antibiotics in hospitals: some are restrictive (automatic stop orders, restricted antibiotic list, mandatory approval by infectious diseases specialists). Others focus on education (face-to-face discussion, conferences, distribution of printed material, audit with feed-back), or are based on tools to help physicians in their decision making (practice guidelines, computer programs). The importance of combining strategies to enhance the success of any intervention has been emphasized.3 Clinical practice guidelines are used to promote the rational use of antibiotics. They need to be adequately prepared, implemented and supported to have a positive impact.4 Several studies support the role of the clinical pharmacist as a drug therapy advisor in institutional settings,5 fewer demonstrate his/her impact on quality or cost in the implementation of antibiotic guidelines.6
The aim of this controlled beforeafter study was to evaluate the impact of the implementation of local practice guidelines, with and without their reinforcement by a clinical pharmacist, on the intra-hospital use of antibiotics.
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Materials and methods |
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The general medical wards and intensive care units of three comparable secondary-care non-university affiliated public hospitals in western Switzerland (100120 acute-care beds each, 50006000 admissions per year each, and similar case-mix indexes) were studied during two 6 month periods (November 2001 to April 2002 and November 2002 to April 2003). Over each period of time, the first 200 patients admitted to these wards of each hospital were enrolled into the study provided they received antibiotic therapy. Hospitals were randomly assigned to no intervention (hospital A, control), implementation of guidelines only (hospital B, low grade intervention), or implementation of guidelines with their reinforcement by a clinical pharmacist (hospital C, high grade intervention). Local practice guidelines, based on published recommendations, a common drug formulary, and regional antibiotic susceptibility patterns, were developed and implemented in hospitals B and C between the two study periods by infectious diseases physicians, pharmacists, and the heads of internal medicine of these two hospitals. In hospital C, a clinical pharmacist reviewed the medical charts and participated in clinical rounds twice weekly during the intervention period. She informed the physicians on any deviation from the guidelines, necessity to adjust dosages, and possibilities to narrow the spectrum of activity of antibiotics or to switch to oral therapy.
Data collection
Data were collected from the medical charts. The outcome variables were the length of hospital stay, the duration of the antibiotic treatment (distinguishing oral and intravenous administrations), and costs expressed as the cost of the substances and the global cost of treatment including substances, devices, and nursing time for the administration of the treatment. The adherence to guidelines in the second study period was evaluated, in hospitals B and C, by a blinded investigator.
Other collected variables included the age, the gender, the Charlson comorbidity index, microbiological results, the antibiotics used, their indication, dosage and route of administration.
Statistical analysis
Proportions and medians were compared between hospitals and study periods in univariate analysis by using 2, Fisher's exact, KruskalWallis or MannWhitney tests, as appropriate.
After exclusion of outliers based on the inspection of histograms and clinical appraisal, multivariable models were developed to obtain adjusted outcome comparisons between hospitals and study periods. Independent variables in the final models included the dummy-coded hospitals and study periods, and confounding factors remaining after a backward selection from the following variables: age, gender, Charlson comorbidity index, nosocomial infection, difficult-to-treat infection and difficult-to-treat pathogen, as defined in Table 1. P values were two-tailed; P 0.05 was considered to be significant.
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Results |
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Inter-hospital differences were however present in the baseline values of the measured outcomes. Hospital A (control) had lower median values for the total duration of antibiotic treatments (P < 0.001), costs of antibiotics (P=0.003), global costs of antimicrobial treatments (P < 0.001), and length of stay (P=0.003).
No decrease in the outcomes as defined in Table 2 was observed in any of the participating hospitals. However, significant increases were found only in hospital A (control) when comparing it with the two other participating institutions while adjusting for any potential changes in the patients' characteristics between the two study periods. Moreover, although the differences were not statistically significant, the observed increases in the parameters investigated were higher in hospital B (low grade intervention) than in hospital C (high grade intervention).
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Discussion |
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This study used a prospective, controlled, beforeafter design. The same months were chosen for each observation period to avoid seasonal biases. The different interventions were randomly allocated to different hospitals to avoid contamination biases. These institutions were similar in terms of size, activities, and case-mix indexes, thus minimizing the risk of inappropriate comparisons. In addition, the multivariable analyses took potential confounding factors into account, allowing us to estimate the independent association of each of the interventions with the measured outcomes.
Nevertheless, the control hospital had significantly lower baseline durations of antibiotic treatments, costs and length of stays than the others. In addition, although these parameters increased significantly in this hospital between the two study periods, they remained lower than in the others. As discussed by Avorn & Solomon,10 many factors, other than the patients' characteristics or their type of infection, may influence antibiotic use. Such factors that may be cultural or economical, are difficult to capture in a study on antibiotic use and could have played an unseen role in our results. Other limitations of this study suggest caution while interpreting its results. First, outcomes such as mortality, resistance rates to antibiotics or quality of care were not assessed and may vary independently from the costs, the duration of treatments or the length of stay. Second, this study addressed only in-hospital antibiotic use and did not include the treatments of patients transferred or discharged on antibiotics. Third, it was not designed to determine the cost-effectiveness of the implemented interventions.
In conclusion, this study illustrates the difficulties encountered when measuring the impact of interventions to promote the rational use of antibiotics. Nevertheless, it suggests a positive impact of the development and implementation of local guidelines, particularly when they are reinforced by a clinical pharmacist.
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Acknowledgements |
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References |
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