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Antimicrobial central venous catheters: a qualitative review of the literature and economic assessment |
Oinonen M J, Ratko T A, Cummings J P, Matuszewski K A |
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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 The use of antimicrobial central venous catheters (CVC) in critical care patients. The CVCs were either impregnated with the antiseptic combination chlorhexidine-silver sulfadiazine (CSS catheters), or bonded with the antibiotic agents minocycline and rifampin (MR catheters).
Type of intervention Treatment and secondary prevention.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised critical care patients requiring the insertion of CVCs for the administration of intravenous fluids, medications, blood products, total parenteral nutrition, and/or monitoring of haemodynamic and haematologic status.
Setting The setting was secondary care. The study was carried out in the USA.
Dates to which data relate The effectiveness data were collected from studies published between 1996 and 1999. The cost data related to studies published between 1994 and 2000, and from a retrospective review of data encompassing the period of the fourth quarter of 1998 through to the third quarter of 1999. The price year was not reported.
Source of effectiveness data The effectiveness data were derived from a review of published studies, which appeared to be systematic. A retrospective analysis of patient data derived from a database was also performed.
Outcomes assessed in the review The primary health outcomes assessed were the rates of catheter colonisation and the incidence of catheter-related bloodstream infections (CR-BSIs) for each of the individual randomised controlled trials (RCTs) included in the review. These outcomes were reported for the following comparisons:
MR catheters versus standard catheters for hospitalised patients; and
CSS catheters versus standard catheters for medical or surgical intensive care patients, patients requiring total parenteral nutrition, immunocompromised patients, and overall.
The authors also evaluated the mortality rates associated with intensive care patients requiring CVC who had bacteraemia or septicaemia versus those who did not. These rates were obtained from a retrospective analysis, which was performed by the authors and based on data from the University HealthSystem Consortium database.
Study designs and other criteria for inclusion in the review RCTs were included in the systematic review. Only studies published in English were considered.
Sources searched to identify primary studies MEDLINE was used to identify published RCTs. The authors also identified articles related to the relevant articles included in the review.
Criteria used to ensure the validity of primary studies Methods used to judge relevance and validity, and for extracting data The authors did not report the methods used to assess the validity of the primary studies. However, the results of one meta-analysis and one cohort study were compared with the results obtained in the review.
Number of primary studies included Thirteen RCTs, one cohort study, and one meta-analysis were reviewed. A retrospective analysis performed by the authors was also included in the study.
Methods of combining primary studies A narrative method appears to have been used to report the results of the individual studies. Although the authors did not report that a meta-analysis had been carried out, a composite measure of outcome was estimated.
Investigation of differences between primary studies The results of the included studies were reported according to the type of patients integrated in the RCTs. However, no statistical tests of homogeneity were reported.
Results of the review The rates of catheter colonisation were:
between 2 and 40% with CSS catheters versus 18% and 52% with standard catheters for medical or surgical intensive patients, (p<0.05);
5.8% with CSS catheters versus 22% with standard catheters for hospitalised patients who required a CVC, (p<0.001);
23% with CSS catheters versus 71% with standard catheters for immunocompromised patients, (p<0.002); and
8% with MR catheters versus 26% with standard catheters, (p<0.001) for hospitalised patients.
The composite incidence of CR-BSI was 5.2% for standard catheters versus 3.2% for CSS catheters.
The incidence of CR-BSI was significantly lower with MR catheters (i.e. no patients presented infection in the individual study reviewed) than with standard catheters (i.e. 5% of incidence; p<0.01).
The results of one study showed that MR catheters were superior to CSS catheters in terms of lower rates of CR-BSI (3% with CSS catheters versus 1% with MR catheters; p<0.002), and a lower likelihood of being colonised (8% versus 23%; p<0.001).
The authors' retrospective analysis showed that mortality rates associated with intensive care patients requiring CVC were 40% for those with bacteraemia or septicaemia, versus 19% for patients who did not have these infections.
Methods used to derive estimates of effectiveness To derive the summary measure of benefit, the authors made several assumptions about the values of the effectiveness estimators.
Estimates of effectiveness and key assumptions The authors assumed that a CSS catheter would lower the absolute incidence of CR-BSI by 2% in comparison with standard catheters, while an MR catheter would lower this incidence by 4%.
Measure of benefits used in the economic analysis The summary measure of benefit used was the number of CR-BSI cases avoided by using CSS or MR catheters instead of standard catheters in a hypothetical cohort of 300 patients. This measure of benefit was derived from some authors' assumptions, which appear to have been based on the results of the review. The period considered for the estimation of the health benefits was not reported.
Direct costs The direct costs considered in the economic analysis appear to have been those of the hospital. Some of the costs included were for the catheters, catheter tray, hospital stay and intensive care. Some of the resource quantities were reported separately from the unit costs, although not all of them were identified. The sources of the cost estimation were a retrospective review of the University HealthSystem Consortium database, the studies reviewed for the effectiveness analysis, and some other published studies. The price year was not reported. Discounting does not appear to have been performed, but it was not relevant since the time horizon considered for the economic analysis was less than 2 years. The authors did not report the total cost or the cost per patient for each of the catheters compared. They reported instead the mean, median, and ranges of costs for adult intensive care patients, according to whether or not the patients had bacteraemia or septicaemia. They also reported the incremental costs per 300 patients of using MR catheters or CSS catheters in comparison with standard catheters.
Statistical analysis of costs The costs of adult intensive care patients were treated stochastically since mean, median, ranges and standard deviations (SDs) were reported. Unique statistical analyses of the costs were performed to compare the costs of patients with and without bacteraemia or septicaemia.
Indirect Costs The indirect costs were not reported.
Sensitivity analysis Although it was not clearly stated, sensitivity analyses might have been performed. The authors seem to have performed threshold analyses to identify the minimum absolute risk reduction and the difference in the acquisition costs between CSS or MR catheters and the standard catheters, which would make the use of CSS and MR catheters remain cost-neutral.
Estimated benefits used in the economic analysis The results of the incremental analysis of the estimated benefit showed that:
if CSS catheters were used instead of standard catheters, 6 cases of CR-BSI would be avoided per 300 patients; and
if MR catheters were used instead of standard catheters, 12 cases of CR-BSI would be avoided per 300 patients.
Cost results The average costs of adult intensive care patients were $65,577 (SD=66,223; median 45,925, range: 1,644 - 881,627) if the patients had bacteraemia or septicaemia, and $41,444 (SD=43,686; median 28,542, range: 514 - 1,304,658) if the patients did not have bacteraemia or septicaemia, (p<0.001).
The incremental costs per 300 patients of using CSS or MR catheters, compared with standard catheters, were $7,500 (CSS) and $15,900 (MR), respectively.
Synthesis of costs and benefits Incremental cost-effectiveness ratios were calculated as the additional cost incurred with the use of CSS or MR catheters to avoid a further case of CR-BSI, compared with the use of standard catheters. Compared with standard catheters, the incremental costs per additional avoided case of CR-BSI were $1,250 with the use of CSS catheters versus $1,325 with the use of MR catheters.
The results of the sensitivity analyses showed that the difference in the acquisition costs of CSS or MR catheters, and the standard catheters, could be up to $75 and $159, respectively, and the absolute risk of CR-BSI could be up to a minimum of 0.3% and 0.64%, respectively, for the use of CSS and MR catheters to remain cost-neutral in comparison with standard catheters.
Authors' conclusions The authors did not provide a conclusion that combined the effectiveness and cost results. They concluded that antimicrobial-associated central venous catheters (CVCs) represent an effective approach to reducing the incidence of catheter colonisation when they are inserted under full barrier precautions and are maintained using scrupulous infection control procedures. Some data indicate that these devices also reduce the incidence of CVC-associated bacteraemia or septicaemia, although the evidence for this conclusion is not as strong.
CRD COMMENTARY - Selection of comparators A justification was given for the comparator chosen. Untreated CVCs were the standard practice in the authors' setting. You should decide whether this type of CVCs is widely used in your own setting.
Validity of estimate of measure of effectiveness Although it was not clearly specified by the authors, a systematic review of the literature appears to have been carried out. Some further studies were also reviewed. Some relevant studies might not have been included, as only one electronic database was consulted, and this might have biased the results of the review. Apart from the study design and language publication, no information was given on how the studies were selected and assessed. Although RCTs were the main source of the effectiveness estimators, there may be uncertainty surrounding the internal validity of the results because of the limitations the RCTs presented (i.e. small sample sizes, differences in morbidity, differences in catheter type). A narrative method was used to derive most of the estimates of effectiveness. The authors calculated composite incidences from the review, although they did not report the methods used for this calculation. The study population included in the individual studies appeared to be rather heterogeneous. Some authors' assumptions were formulated, based on the results of the review, which tried to summarise the conclusions of the review and were used for the estimation of the measure of benefit.
Validity of estimate of measure of benefit The estimation of benefits was obtained directly from the effectiveness analysis. The choice of the measure was not justified, but it seems reasonable when compared with those used in similar studies.
Validity of estimate of costs The estimation of costs was confusing since several sources were combined. In addition, methods used for the cost estimation were not clearly detailed. The costs included may not have been exclusively related to the use of one or another type of CVC, but rather with the morbidity of the patients considered at analysis. Moreover, the authors did not comment that sensitivity analyses were performed, although some of the information reported in the study suggested that such analyses were carried out. The costs and the quantities were not reported separately, thus limiting the generalisability of the authors' results to other settings. The date to which the prices referred was unclear and this prevents future reflation exercises. The authors reported further limitations associated with the cost analysis. For example, the impossibility of identifying the type of catheter used in the retrospective review, and the differences in the population included (more critically ill than populations evaluated in the literature review). Therefore, there is considerable uncertainty surrounding the cost results, and this should be considered when interpreting the study findings.
Other issues The authors compared the effectiveness findings with those from other studies. However, no comparisons of the cost-effectiveness results with those from other studies were reported. In terms of the issue of the generalisability of the results, the authors suggested that a local analysis be performed in terms of patient characteristics, acquisition costs and infection rates, before deciding whether to implement the use of antimicrobial CVCs.
Implications of the study The authors did not make any explicit recommendations for policy change or practice resulting from their study. They also did not suggest any areas for further research. The results of this study should be interpreted with caution given the caveats highlighted.
Bibliographic details Oinonen M J, Ratko T A, Cummings J P, Matuszewski K A. Antimicrobial central venous catheters: a qualitative review of the literature and economic assessment. Journal of Clinical Outcomes Management 2000; 7(12): 42-48 Other publications of related interest Veenstra DL, Saint S, Sullivan SD. Cost-effectiveness of antiseptic-impregnated central venous catheters for the prevention of catheter-related bloodstream infection. JAMA 1999;282:554-60.
Veenstra DL, Saint S, Saha S, et al. Efficacy of antiseptic-impregnated central venous catheters in preventing catheter-related bloodstream infection: a meta-analysis. JAMA 1999;281:261-7.
Indexing Status Subject indexing assigned by CRD MeSH Antibiotic Prophylaxis; Catheterization, Central Venous /instrumentation /economics /trends /utilization; Costs and Cost Analysis AccessionNumber 22001007669 Date bibliographic record published 30/06/2005 Date abstract record published 30/06/2005 |
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