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Cost-effectiveness of various antibacterial therapies in hospitalised patients with lower respiratory tract infections |
Lucioni C, Ravasio R, Concia E |
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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 Different antibiotics (ceftriaxotone, piperacillin, cefotaxime, ceftazimine) for the treatment of patients suffering from lower respiratory tract infections (LRTIs).
Economic study type Cost-effectiveness analysis.
Study population The study population was based on patients suffering from LRTIs elected to the administration of antibacterials.
Setting The setting was community. The economic study was carried out in the Institute of Health Economics, Milan, Italy.
Dates to which data relate Effectiveness and resources use data were taken from patients' charts of individuals hospitalised before 1998 because of LRTIs. The charts were obtained from 14 public hospitals (located in three regions of Northen Italy: Veneto, Trentino Alto-Adige and Friuli-Venezia Giulia). The price year was 1998.
Source of effectiveness data Effectiveness data were derived from a single study.
Link between effectiveness and cost data The costing was undertaken retrospectively on the same sample of patients used to obtain effectiveness data.
Study sample A total of 1,993 patients' charts for individuals hospitalised because of LRTIs were included in the analysis. Of these, 446 patients were excluded because of important missing data in the charts, because they were aged under 16 years or they had been administered more than one antibiotic. The final study sample therefore totalled 1,547 and patients were divided into four groups: 554 for ceftriaxone, 543 for cefotaxime, 292 for piperacillin and 158 for ceftazidime. Given the large sample size, no power calculations were performed.
Study design This was a retrospective observational study performed in 14 public hospitals located in three regions of Northern Italy. The authors retrospectively selected the patients until they had obtained at least 100 cases of antibiotic administration for each hospital, but no information on the length of the follow-up was reported.
Analysis of effectiveness The primary clinical outcomes used in the analysis were recovery, improvement, and failure of the treatment. A patient was considered to have recovered when the antibiotic was successful in reducing his temperature, when a negative radiographic chest X-ray was obtained, and haematological indices of phlogosis were reduced. Improvement was defined as a partial amelioration of the elements previously mentioned (fever, chest X-ray, and index of phlogosis). If none of these elements improved, a failure of the treatment was reported. The effectiveness of the antibiotic was assessed as the percentage of patients who fully recovered, or who had improved by the end of the treatment.
The four patient groups were shown to be comparable in terms of age, sex, weight and incidence of concomitant pathologies, but no statistical analysis was reported.
Effectiveness results Ceftriaxone proved to be the most effective antibiotic (92.78% of patients fully recovered or improved), followed by cefotaxime (91.34%), piperacillin (84.25%) and ceftazidime (80.38%). The differences in terms of effectiveness were statistically significant (p<0.01) for ceftriaxone versus piperacillin, ceftriaxone versus ceftazidime, cefotaxime versus piperacillin and cefotaxime versus ceftazidime.
Clinical conclusions This observational study showed that ceftriaxone was the most effective antibiotic for patients suffering from LTRIs. However, the difference in terms of effectiveness was not statistically significant when ceftriaxone was compared to cefotaxime.
Measure of benefits used in the economic analysis The measure of benefits adopted was the percentage of patients successfully treated, i.e. percentage of patients who fully recovered or who had an improvement at the end of the treatment.
Direct costs The cost per gram of each antibiotic, the prescribed daily dose (PDD), the cost of each injection (both intravenous and intramuscular), the costs of hospital staff and disposable resources, and the average length of the therapy were reported. Apart from the unit costs of the hospital staff and disposable resources (obtained from the literature) all the other costs were based on actual data. Unit costs and resources used were reported separately. The total costs for each therapy were calculated as follow: the cost per gram (based on actual acquisition costs of the hospital) for each treatment was multiplied by the PDD and weighted on the basis of the type of injection (intravenous or intramuscular). The result was multiplied by the average length of the treatment in order to obtain the cost of the antibiotic for each cycle of therapy. Adding the cost of the injections (personnel plus disposable resources) the authors obtained the total average costs for each treatment. No discount rate was applied. All the costs were converted to the price year 1998.
Statistical analysis of costs No statistical analysis of costs was performed.
Indirect Costs No indirect costs were reported.
Sensitivity analysis A one-way sensitivity analysis was carried out on the level of efficacy of ceftriaxone and cefotaxime to assess the effects of changes from the baseline values on the average cost-effectiveness ratio.
Estimated benefits used in the economic analysis Ceftriaxone proved to be the antibiotic with the highest percentage of patients successfully treated (92.78%), followed by cefotaxime (91.34%), piperacillin (84.25%) and ceftazidime (80.38%). The differences in terms of effectiveness were statistically significant with respect to piperacillin and ceftazidime, (p<0.01) but not with respect to ceftriaxone and cefotaxime.
Cost results Ceftriaxone was the less expensive antibiotic for the treatment of patients suffering from LRTIs. The total costs of ceftriaxone (including the cost of the antibiotic for each cycle of therapy plus the total costs of the injections) were equal to L333,184, slightly less than the total costs of piperacillin (L333,634) and cefotaxime (L399,849). Ceftazidime was the most expensive therapy with total costs equal to L596,982. No discount rate was applied in the analysis.
Synthesis of costs and benefits Average cost-effectiveness ratios were calculated for each treatment but no incremental cost-effectiveness ratio was reported. However, ceftriaxone was dominant in terms of cost and effectiveness with respect to all the other therapies. The average cost of ceftriaxone per successfully treated case was L359,111, versus L396,004 for piperacillin, L438,383 for cefotaxime and L742,699 for ceftazidime. A one-way sensitivity analysis was performed on the level of clinical efficacy of ceftriaxone and cefotaxime. Assuming equal efficacy of the two antibiotics the authors recalculated the costs of the two therapies for each patient. Ceftriaxone remained the most-cost-effective (L332,958 versus L402,409) and the difference was statistically significant, (p<0.01).
Authors' conclusions Ceftriaxone appears to be the most cost-effective strategy for the treatment of patients suffering from LRTIs. Sensitivity analyses confirm the robustness of the results.
CRD COMMENTARY - Selection of comparators The four antibiotics analysed in the study are the most commonly used treatments for patients suffering from LRTIs in the North of Italy. Therefore, the reason for the choice of the comparators is clear and they were appropriate for the problem addressed. You should consider whether these are widely used therapies in your own setting.
Validity of estimate of measure of effectiveness Effectiveness data were derived from a retrospective observational study. The four patient groups were shown to be comparable in terms of age, sex, weight and incidence of concomitant pathologies in a narrative way. The use of statistical analyses might have been useful in order to exclude the risk of selection bias. However, despite the lack of randomisation, the internal validity of the effectiveness results was increased by the use of appropriate statistical tests.
Validity of estimate of measure of benefit Health benefits were drawn from the same sources used to obtain effectiveness evidence, raising the same issues considered for the measure of effectiveness. Moreover, the successfully treated patients were defined as percentage of individuals recovered plus improved, but no distinction was made between the two cases. It might have been useful to have distinguished between patients fully recovered and those who simply improved in order to have a clear understanding of the actual benefits related to each antibiotic.
Validity of estimate of costs The estimation of costs was based on very detailed actual data and all the relevant costs (given the perspective of the study) were included suggesting high internal validity. The cost estimates are, however, likely to be specific to the Italian setting.
Other issues Incremental cost-effectiveness ratios were not calculated although incremental analysis may not have been strictly necessary for ceftriaxone (dominant with respect to all the other strategies) and ceftazidime (dominated by all the other therapies), but it would have been interesting to have compared cefotaxime and piperacillin (less effective but less costly). The results of other published studies are in line with the findings of this work.
Implications of the study Antibiotics are one of the major items of pharmaceutical expenditure for Italian hospitals (25-30%). The use of ceftriaxone for the treatment of patients with LRTIs is likely to lead to savings without reducing the effectiveness of the therapy.
Bibliographic details Lucioni C, Ravasio R, Concia E. Cost-effectiveness of various antibacterial therapies in hospitalised patients with lower respiratory tract infections. Pharmacoeconomics - Italian Research Articles 2001; 3(1): 37-47 Indexing Status Subject indexing assigned by CRD MeSH Adult; Aged; Anti-Bacterial Agents /therapeutic use /economics /administration & Cefotaxime /therapeutic use /economics /administration & Ceftazidime /therapeutic use /economics /administration & Ceftriaxone /therapeutic use /economics /administration & Cost-Benefit Analysis; Female; Humans; Italy; Male; Piperacillin /therapeutic use /economics /administration & Respiratory Tract Infections /drug therapy /economics; dosage; dosage; dosage; dosage; dosage AccessionNumber 22001008139 Date bibliographic record published 28/02/2002 Date abstract record published 28/02/2002 |
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