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Feasibility, cost-effectiveness and patients' acceptance of point-of-care INR testing in a hospital-based anticoagulation clinic |
Kong MC, Lim TG, Ng HJ, Chan YH, Lee LH |
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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. CRD summary This study evaluated the costs, patient preferences, time at hospital, and safety with the CoaguChek portable point-of-care coagulometer, for monitoring a patient's international normalised ratio (INR). The authors recommended that point-of-care testing could be implemented, in busy hospital anticoagulation clinics, with mechanisms to address increased variation in INR at higher ranges. The methods and reporting aligned well with creating a monitoring protocol. For a formal economic evaluation, additional costs and outcomes should be considered. Type of economic evaluation Cost-effectiveness analysis Study objective This study evaluated the intervention costs, patient satisfaction, and time saved with the CoaguChek portable point-of-care coagulometer, for monitoring a patient's international normalised ratio (INR), in anticoagulation clinics. This information was used to develop a protocol for using the device. Interventions Point-of-care coagulometers were compared with routine laboratory INR testing. The coagulometers tested blood from a finger prick, while laboratory testing required a sample from a vein. With implementation of the protocol, the coagulometers were used to measure the INR up to a threshold of 3.5. If the INR was 3.5 or higher, patients were referred for laboratory testing. Location/setting Singapore/out-patient care. Methods Analytical approach:The costs and outcomes were from a clinical and cost study. The outcomes were evaluated after testing. The study perspective was not explicitly stated. Effectiveness data:The study was conducted in two phases; the first evaluated test agreement (validation phase), and the second implemented point-of-care testing. For validation, the laboratory test was assumed to be the most accurate test. Each patient received both tests, and test agreement was evaluated using a Bland-Altman plot. There were 253 samples for both tests, from 230 patients. In the six-month implementation phase, safety outcomes (including bleeding and thrombotic events), the rates of rejected laboratory testing, and the time spent attending the hospital clinic were assessed. At two-month follow-up, 232 patients attending the clinic, who received the point-of-care test, were asked which test they preferred. If they preferred point-of-care testing, they were asked for the reasons for their preference. Monetary benefit and utility valuations:Not relevant. Measure of benefit:Test agreement, patient preference, time spent at the hospital, and safety were used as measures of benefit. Cost data:The costs of the INR test, needles, citrated tube, alcohol swabs, and lancets were combined to calculate the cost of each test. The prices for the INR tests were from the vendor. The authors indicated that test strips for point-of-care testing were supplied at competitive prices. In addition to these cost data, patient charges were presented. The charges were identical for each testing method. The currency was Singapore dollars (SGD). Analysis of uncertainty:Confidence intervals were presented for the patient preference survey results and the safety data. Probabilities were presented for the correlations and for time spent in hospital. Results The correlation between the two INR results was 0.945 (p<0.05). There was increasing deviance in the results when the INR value was 3.5 or higher. In the implementation phase, 22 of 510 samples were referred for venous laboratory testing due to an INR above 3.5 (4.3%, 95% CI 3.3 to 5.5). The percentage of patients preferring point-of-care testing over venous sampling was 87.5 (95% CI 82.5 to 91.5). The reasons were: 136 for less time, 58 for less pain, 43 for less blood loss, and 39 for other reasons. The average time per visit for point-of-care testing was 35 minutes less (95% CI 25 to 45) than for laboratory assessment. Safety data indicated that during implementation, there were one major bleed, 11 minor bleeds, and three thrombotic events. For the 250 active patients, the rate of major bleeding was 0.4% (95% CI 0.01 to 2.2) and the rate of thrombotic events was 1.2% (95% CI 0.2 to 3.5). The total cost of the test equipment and materials was SGD 3.07 for laboratory testing, and SGD 3.17 for point-of-care testing. Authors' conclusions The authors recommended that point-of-care testing could be implemented, in busy hospital anticoagulation clinics, with mechanisms to address increased variation in INR at higher ranges. CRD commentary Interventions:The diagnostic tests were explained. The study set out to explore the feasibility and safety of the point-of-care test. The protocol where patients with INR values greater than 3.5 had to be retested using the usual laboratory test was evaluated, and a cost-effectiveness analysis comparing this with usual care would have been useful. Effectiveness/benefits:The validation study was sufficiently reported, as was the patient satisfaction survey. Since all the patients who responded to the survey had the point-of-care test as the most recent test, there was a possibility of bias. The outcomes were appropriate for the objective. Further comparison of the sensitivities and specificities and health consequences of true and false positives of the protocol versus usual care would have been useful. Safety results were only reported for the point-of-care test; a quantitative comparison with historical rates or with a control group would allow better evaluation of differences between protocols. The authors acknowledged that it was unclear whether the INR differences between the two testing methods were due to underestimation with laboratory methods or overestimation with point-of-care testing. Costs:The type of costs analysed indicate that the perspective of the hospital was taken. The cost estimates were from the setting. Due to the limited objective of the study, the costs excluded labour for conducting the tests, and did not include any savings or increases associated with adopting a new protocol. Patient time was assessed, so a societal perspective, valuing that time, would have been useful. The authors stated that they had received a very competitive price, and that in other settings the cost of test strips and the point-of-care devices might be prohibitive. This was an important caution to those considering establishing a point-of-care protocol. Analysis and results:The analysis appears to have been appropriate, and the results were adequately reported. The authors compared the concordance of their results with those from other published studies. They acknowledged that concerns about cost-effectiveness were not sufficiently addressed by their small study, and that further research was necessary. Concluding remarks:The methods and reporting aligned well with creating a reproducible point-of-care INR monitoring protocol. For a more formal economic evaluation, additional costs and outcomes should be considered. Funding Devices and test strips received from Roche Diagnostics, manufacturers of the CoaguChek device. No other funding received. Bibliographic details Kong MC, Lim TG, Ng HJ, Chan YH, Lee LH. Feasibility, cost-effectiveness and patients' acceptance of point-of-care INR testing in a hospital-based anticoagulation clinic. Annals of Hematology 2008; 87(11): 905-910 Indexing Status Subject indexing assigned by NLM MeSH Adolescent; Adult; Aged; Aged, 80 and over; Anticoagulants /therapeutic use; Cost-Benefit Analysis; Drug Monitoring; Feasibility Studies; Female; Humans; International Normalized Ratio /economics /instrumentation; Male; Middle Aged; Outpatient Clinics, Hospital; Patient Satisfaction; Point-of-Care Systems; Prothrombin Time /economics /instrumentation; Warfarin /therapeutic use AccessionNumber 22008102020 Date bibliographic record published 22/04/2009 Date abstract record published 11/09/2013 |
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