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Clinical and cost comparison of ibutilide and direct-current cardioversion for atrial fibrillation and flutter |
Murdock D K, Schumock G T, Kaliebe J, Olson K, Guenette A J |
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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 study compares using first-line ibutilide for cardioversion with direct-current cardioversion (DCC) for recent onset of atrial fibrillation (AF) or atrial flutter (AFl) in patients undergoing anticoagulation for 3 to 4 weeks before elective cardioversion.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised patients referred for elective cardioversion with their first episode of AF or AFl, the duration of which was confirmed to be greater than 48 hours and less than 90 days.
Setting The setting was secondary care. The economic study was carried out in the Wausau Hospital, Wisconsin, USA.
Dates to which data relate The authors did not report the dates during which the effectiveness and resource data were gathered. The price year was not reported.
Source of effectiveness data The effectiveness data were derived from a single study.
Link between effectiveness and cost data Cost data were prospectively collected alongside the effectiveness data in the same patient sample.
Study sample No calculations to estimate the sample size required to detect statistically significant differences were reported. A total of 30 patients were randomly assigned to one of two treatment groups: Group A (n=17), who received intravenous ibutilide, and Group B who underwent DCC (n=13). All 30 patients were included in the final analysis. The authors reported that the exclusion criteria included: the presence of de-compensated heart failure, unstable angina, haemodynamic instability (systolic blood pressure less than 90mm Hg or diastolic pressure greater than 105mm Hg) or use of class I or class III antiarrhythmic agents. The authors did not report the method of patient selection for the study or details about patients who refused to participate or who were excluded from the study.
Study design The study was a single centre, randomised, controlled trial carried out in Wausau Hospital, Wisconsin. No details of the method of randomisation were reported. The duration of follow up was 3-4 weeks after the initial procedure for conversion to normal sinus rhythm. There was no loss to follow up. The authors did not report any methods used to mask patients, health care providers or researchers to treatment allocation.
Analysis of effectiveness The analysis was conducted on an intention to treat basis. The primary outcomes used in the economic analysis were: successful conversions of AF and AFl (%); mean time spent in hospital (hours); adverse reactions (%); and relapse at 3-4 weeks. The authors reported that the two patient groups were comparable in most respects (sex, rhythm, congestive heart failure, left atrial size, ejection fraction, associated heart disease, and cardiac medications), but also reported that there was a non-significant trend for group B to be older than group A. The mean age of patients in group A was 69 +/-5 (years), compared to an average age in group B of 73 +/-9 (years) (p=0.08). The authors did not report any adjustments for confounding variables.
Effectiveness results The effectiveness results were as follows:
The percentage of successfully converted patients in group A was 100% (17/17), compared to 92% (12/13) in group B, (p=0.25). However, only 24% of patients (4/17) were successfully converted with ibutilide alone.
The mean time spent in hospital by patients in Group A was 5.9 +/-1.3 (hours), compared to 3.9 +/-0.5 hours in group B, (p=0.004).
Adverse reactions were suffered by 6% (1/17) of patients in Group A, in contrast to 0% (0/13) in group B, (p=0.45).
The percentage of patients who relapsed at 3-4 weeks was 65% (11/17) in group A, and 54% (7/13) in group B, (p=0.55).
Clinical conclusions The authors reported that ibutilide produced a low rate of converting recent-onset AF and AFl in patients scheduled for cardioversion after 3 to 4 weeks of anticoagulation.
Measure of benefits used in the economic analysis No summary measure of health benefit was used in the economic analysis. The outcomes were reported in a disaggregated fashion and, as such, this was a cost-consequences analysis.
Direct costs The authors reported that the following direct costs were included in the economic analysis:
The hospital: admittance charge, hourly charge, IV supplies.
Physician: cardiology level 1, cardiology DCC, anaesthesiology.
Pharmaceutical: ibutilide 1 mg dose, sodium metho-hexital.
The authors did not report resource use and costs separately. The authors obtained the cost of the hospital component of treatment from charge data adjusted by cost-to-charge ratios appropriate for each cost centre at Wausau Hospital. The physician costs were obtained by summing the Medicare charges submitted by cardiology and anaesthesiology departments according to standard Medicare current procedural codes. Pharmaceutical costs were calculated by obtaining the average wholesale costs for each drug used. Discounting was not performed because of the short time frame of the study, and the authors did not report the price year.
Statistical analysis of costs The authors reported that, for continuous variables, group A was compared with group B using an F test, and that for categorical data a chi-square test was used. A p value equal to or less than 0.05 was considered statistically significant.
Indirect Costs No indirect costs were included in the analysis.
Currency US dollars ($). No currency conversions were reported.
Sensitivity analysis No sensitivity analysis was reported.
Estimated benefits used in the economic analysis See effectiveness results above.
Cost results The total treatment cost in group A was $978 +/- 121, compared to $622 +/- 4 in group B, (p<0.0001). The cost of adverse reactions was not reported.
Synthesis of costs and benefits No synthesis of costs and benefits was carried out and no incremental analysis was reported.
Authors' conclusions The authors reported that ibutilide produced a low rate of converting recent-onset AF and AFl in patients scheduled for cardioversion after 3 to 4 weeks of anticoagulation. The authors also stated that treating non-acute AF and AFl of recent onset with first-line ibutilide, followed by DCC for patients who failed to convert was far more costly than proceeding directly to DCC.
CRD COMMENTARY - Selection of comparators A justification was given for the choice of comparator, namely that it represented common practice in the authors setting. You, as a user of this database should decide if DCC is widely used as a first line therapy in your own setting for patients with recent onset of AF or AFl.
Validity of estimate of measure of effectiveness The analysis was based on a randomised controlled trial that was appropriate for the study question. The study sample appeared to be representative of the study population. However, the authors did not report details about patients who refused to participate or who were excluded from the evaluation. The patient groups were shown to be statistically comparable at analysis. The authors noted that the small size of the study sample (30 patients) was a limitation to the study, although they did not present any power calculations to indicate whether the sample size was sufficient to detect statistically significant differences. The authors did not report whether the participants (patients or health care providers) or researchers were masked to treatment allocation. Knowledge of treatment allocation may have introduced bias into the assessment of outcomes by participants or researchers, or choice of subsequent treatment by participants. The authors included adverse reactions and relapse into AF or AFl states. The duration of follow up was short (3-4 weeks). You, as a user of this database, should consider whether the duration of follow up was sufficient to detect all relevant adverse events and accurately estimate the relapse rate for this population.
Validity of estimate of measure of benefit The authors did not derive a summary measure of health benefit. The study should therefore be categorised as a cost-consequences analysis.
Validity of estimate of costs All categories of cost relevant to the perspective adopted were included in the analysis. Although some costs were omitted from the analysis, these are unlikely to affect the authors' conclusions. Costs and quantities were not reported separately. The authors performed a statistical analysis of both costs and prices but did not perform sensitivity analysis. No currency conversions were reported and discounting was not undertaken because of the short time frame of the study.
Other issues The authors made appropriate comparisons of their findings with those from other studies, but did not fully address the issue of generalisability to other settings. The main limitation of the study reported by the authors was that the sample size of 30 was too small. The authors stated that this is particularly the case with respect to AFl, as this arrhythmia accounted for only 10% of patients. The authors reported that their study is similar to all other published data in this sense, as the other available data also include far more patients with AF than AFl.
Implications of the study The authors report that ibutilide produced a low rate of converting recent-onset AF and AFl in patients scheduled for cardioversion after 3 to 4 weeks of anticoagulation. Furthermore the authors also state that treating non-acute AF and AFl of recent onset with first-line ibutilide, followed by DCC for patients who fail to convert was far more costly than proceeding directly to DCC.
Source of funding Supported in part by The CARE Foundation Inc, Wausau, Wisconsin, The Wausau Hospital, Wausau, Wisconsin.
Bibliographic details Murdock D K, Schumock G T, Kaliebe J, Olson K, Guenette A J. Clinical and cost comparison of ibutilide and direct-current cardioversion for atrial fibrillation and flutter. American Journal of Cardiology 2000; 85(4): 503-506 Indexing Status Subject indexing assigned by NLM MeSH Aged; Anti-Arrhythmia Agents /administration & Atrial Fibrillation /economics /therapy; Atrial Flutter /economics /therapy; Cost-Benefit Analysis; Electric Countershock /economics; Electrocardiography; Female; Heart Rate; Hospital Costs; Humans; Injections, Intravenous; Male; Medicare /economics; Sulfonamides /administration & Treatment Outcome; United States; dosage /economics /therapeutic use; dosage /economics /therapeutic use AccessionNumber 22000000461 Date bibliographic record published 30/04/2002 Date abstract record published 30/04/2002 |
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