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A randomized, prospective evaluation of an interventional program to discontinue intravenous antibiotics at two tertiary care teaching institutions |
Bailey T C, Ritchie D J, McMullin S T, Kahn M, Reichley R M, Casabar E, Shannon W, Dunagan W C |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology A labour-intensive, pharmacist intervention aimed at discontinuing intravenous antibiotics or switching patients from intravenous to oral agents in inpatients receiving antibiotics for at least 3-4 days.
Economic study type Cost-effectiveness analysis.
Study population Inpatients receiving antibiotics for at least 3-4 days. The excluded patients consisted of those in intensive care units, those with signs of uncontrolled infection, neutropenia, positive blood cultures within 2 days or positive cerebrospinal fluid cultures within 10 days, those who were unable to take oral drugs, and those for whom clinical pharmacists judged oral antibiotics to be clinically inappropriate (e.g., endocarditis).
Setting Hospital. The economic study was carried out in the USA.
Dates to which data relate The effectiveness and resource use data were collected between 16 May and 3 November 1994 at hospital A (a 400-bed teaching hospital) and between 15 August and 23 November 1994, at hospital B (a 1000-bed teaching hospital). The price year was not explicitly specified.
Source of effectiveness data The evidence for final outcomes was based on a single study.
Link between effectiveness and cost data Costing was prospectively undertaken on the same patient sample as that used in the effectiveness analysis.
Study sample Power calculations were not used to determine the sample size (a retrospective power calculation was performed indicating that, given the mean and SD of post-randomisation length of stay, and the size of the sample, the study would have had a power of 80% to detect a 0.4-day difference at the 0.05 level of significance). The study sample consisted of 102 inpatients meeting eligibility criteria. The patients were randomised to either the intervention group (n=41 in hospital A with a mean age of 65 (95% CI: 59-62) years and n=10 in hospital B with a mean age of 66 (95% CI: 51-81) years) or to the control group (n=38 in hospital A with a mean age of 70 (95% CI: 65-75) years and n=13 in hospital B with a mean age of 63 (95% CI: 52-74) years). The selection of eligible patients by the clinical pharmacists was performed by reviewing 1,150 medical records in hospital A and 801 in hospital B.
Study design This was a prospective randomised controlled trial, carried out in 2 centres. The duration of the follow-up appears to have been until discharge from the hospital. The study appears to have had no loss to follow-up. The clinical pharmacists in consultation with an infectious disease physician performed the selection of potential candidates for randomisation. Physicians of patients considered being candidates for intervention were randomised to be contacted by the clinical pharmacist with suggestions to change therapy or to be observed. Stratified randomisation was performed according to six categories employing National Nosocomial Infection Surveillance definitions, viz.: infections of the urinary tract, respiratory tract, skin or soft tissue, gastrointestinal tract, unidentified infection, or no infection present.
Analysis of effectiveness The principle used in the analysis of effectiveness was intention to treat. The clinical outcomes were; need to restart intravenous antibiotics, in-hospital mortality, and 30-day readmission. Other clinical outcomes reported were; percentage of patients for whom discontinuation was achieved within 24 hours, and the mean number of intravenous antibiotic days after randomisation. The study groups were found to be comparable in terms of demographic data and prognostic features. In comparison between the two study sites, the patients in hospital B had a longer pre-randomisation duration of antibiotics and different types of infections. An adjustment was made for the institution-specific effects.
Effectiveness results The percentage of patients for whom discontinuation was achieved within 24 hours in the intervention group was 73% at hospital A and 90% at hospital B. The percentage of patients for whom discontinuation was achieved within 24 hours in the control group was 55% at hospital A and 46% at hospital B. (p=0.01, intervention versus control, adjusting for hospital site).
The mean number of intravenous antibiotic days after randomisation in the intervention group was 1.04 days (95% CI: 0.60-1.48) versus 2.02 (1.30-2.73) in the control group (p=0.01, intervention versus control, adjusting for hospital site).
Need to restart intravenous antibiotics and in-hospital mortality were not significantly different between the two study groups.
The intervention group had a 30-day readmission rate of 29% versus 9.8% in the control group (p=0.02, adjusting for hospital site), but infection-related readmissions were not significantly different (4/51 versus 3/51).
Clinical conclusions At hospital A, the 30-day readmission rate was significantly higher in the intervention group. Although readmission did not seem to be directly related to the intervention, the authors stated that they could not rule out the possibility of an indirect effect that led to this adverse outcome. As a result of these summary findings, the authors have not continued the programme at either institution.
Measure of benefits used in the economic analysis No summary benefit measure was adopted in the economic study, and only separate clinical outcomes were reported.
Direct costs Costs were not discounted, as the time frame of the cost analysis was less than one year. Quantities were reported separately from the costs in terms of mean length of stay (LOS) and mean intravenous antibiotic days. The cost analysis covered the costs of antibiotic therapy (antibiotic acquisition and preparation) and the labour costs associated with operating the programme. The perspective adopted in the cost analysis was not explicitly specified. The calculation of annual antibiotic costs was based on the extrapolation of the mean post-randomisation costs during the study period to a full year. The date of the price data was not explicitly specified. The cost analysis did not cover the cost of personnel time for preparing and administering antibiotics since they were deemed to be fixed costs and, hence, not affected drastically by the results of this study.
Statistical analysis of costs Analysis of variance (ANOVA) was used to compare the study groups in terms of antibiotic costs adjusting for hospital site.
Estimated benefits used in the economic analysis Cost results The mean antibiotic cost was $19.82 (95% CI: $9.86-29.77) in the intervention group versus $35.84 (95% CI: $23.42-48.27) in the control group (p=0.03, adjusting for hospital site).
The antibiotic cost saving estimated for a 200 patient/year in hospital A was $1,600 (95% CI: $6300-$3100) while it was estimated that labour expenses of $15,000 would be required to run the intervention programme at hospital A.
The corresponding saving for 100 patients/year in hospital B was $4,200 (95% CI: $9,000 saving to $700 loss) with an estimated labour cost of $7,200.
Synthesis of costs and benefits Authors' conclusions In conclusion, a labour-intensive intervention aimed at discontinuing intravenous antibiotics or switching patients from intravenous to oral agents was not cost-effective at either of two academic teaching hospitals.
CRD COMMENTARY - Selection of comparators The reason for the choice of the comparator (not using any specific intervention) is clear, it appears to represent current practice in the authors' setting.
Validity of estimate of effectiveness:
The effectiveness results are likely to be internally valid given the randomised nature of the study design. The study sample was deemed representative of the patients treated in urban academic institutions with specific pattern of infection types. The study groups were comparable in terms of demographic and prognostic features. It was conjectured that it was unlikely that the study intervention could have affected the phlebitis or other potential complications of intravenous antibiotics.
Validity of estimate of measure of benefit The authors did not derive a summary measure of health benefit and the study may therefore be regarded as a cost-consequences analysis.
Validity of estimate of costs Quantities were reported separately from the costs in terms of general categories. Some details of methods of cost estimation were given. Statistical analysis was performed on the resource use data. The perspective adopted in the cost analysis and price year was not explicitly specified. No important cost items appear to have been omitted other than staff time for antibiotic preparation and administration, which was assumed to be an element of fixed costs. Statistical analysis was performed on antibiotic costs. Cost results may not be generalisable to other settings.
Other issues The authors' conclusions appear to be justified given the uncertainties in the data. The issue of generalisability to other settings was not addressed. Appropriate comparisons were made with other studies. The authors do not appear to have presented their results selectively.
Implications of the study The authors recommend that similar evaluations are conducted for institutions with such programmes in place, or which are contemplating instituting them. It is certainly possible that different implementation strategies, which are less labour intensive than the programme tested by the authors, or which evaluate different patient populations, could work and be cost-effective. Because the utility of these programmes is likely to be institution specific, the authors recommend that they be evaluated by randomised, controlled studies before they are implemented.
Bibliographic details Bailey T C, Ritchie D J, McMullin S T, Kahn M, Reichley R M, Casabar E, Shannon W, Dunagan W C. A randomized, prospective evaluation of an interventional program to discontinue intravenous antibiotics at two tertiary care teaching institutions. Pharmacotherapy 1997; 17(2): 277-281 Indexing Status Subject indexing assigned by NLM MeSH Administration, Oral; Aged; Anti-Bacterial Agents /administration & Communicable Diseases /drug therapy /economics /mortality; Costs and Cost Analysis; Drug Costs; Female; Hospitals, Teaching; Humans; Injections, Intravenous; Length of Stay; Male; Middle Aged; Missouri; Pharmacists; Prospective Studies; dosage /economics /therapeutic use AccessionNumber 21997000510 Date bibliographic record published 30/11/2000 Date abstract record published 30/11/2000 |
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