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Use of low molecular weight heparin (dalteparin), once daily, for the treatment of deep vein thrombosis: a feasibility and health economic study in an outpatient setting |
Lindmarker P, Holmstrom M |
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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 Low molecular weight heparin (LMWH) for the treatment of deep vein thrombosis in an outpatient setting.
Economic study type Cost-effectiveness analysis.
Study population Ambulant patients aged 18 years or older, with symptomatic DVT in the leg confirmed by phlebography or Duplex-Doppler ultrasound.
Setting Hospital. The economic study was carried out in Sweden.
Dates to which data relate Effectiveness and resource use data were mainly collected during 1994. The price year was not clearly stated.
Source of effectiveness data Effectiveness data were derived from a single study and a review of previously completed studies.
Link between effectiveness and cost data The costing was undertaken retrospectively on the patient sample included in the single clinical study.
Study sample A cohort of 434 (52.8% male) ambulant patients was included in the study. The mean age was estimated to be 65 years. The sample size calculations were made on the basis of a hypothesised frequency of major bleeding events and pulmonary embolism (PE) associated with the initial treatment with LMWHs of 2.0%.
Study design The case series study was conducted in 14 hospitals in central Sweden. The follow-up was at three months (+/- 2 weeks) after the discontinuation of dalteparin treatment.
Analysis of effectiveness The principle of the analysis was not relevant to the results. The primary health outcomes used in the analysis were the increasing severity of symptoms, PE, bleeding events and death during the initial phase and follow-up period.
Effectiveness results Of the 434 patients, 35% and 64% were treated in hospital within 24 and 72 hours, respectively, and, thereafter, were treated as outpatients. The majority of patients (80.2%) were treated as outpatients for at least part of the treatment period, with 19.8% being treated as inpatients throughout. During dalteparin treatment the overall rate of primary endpoints was 0.92%, with 4 events observed (3 PE and 1 major bleeding); the overall rate of secondary endpoints was estimated to be 4.8%, with 21 events (5 increasing severity of symptoms and 16 minor bleeding event) being recorded. During the follow-up period the overall rate of secondary endpoints was 2.5%, with 11 documented events (1 PE, 3 recurrent DVT, 3 major bleeding events and 4 deaths from causes other than bleeding).
Clinical conclusions Dalteparin, administered subcutaneously, once daily, for the initial treatment of DVT is well tolerated and effective in an outpatient setting.
Methods used to derive estimates of effectiveness Based on published evidence, the authors assumed the rate of complications for the comparator.
Estimates of effectiveness and key assumptions The overall rate of serious complications for the conventional in-hospital care was 2.8 - 7.1%.
Measure of benefits used in the economic analysis The measure of benefits used in the economic analysis was major events avoided (pulmonary embolism (PE), bleeding events and death) during the initial phase and follow-up period.
Direct costs The direct individual costs for the emergency room, diagnostic procedures, initial treatment and daily examinations, were included in the analysis. The quantities of resource use were not reported separately from the costs. The quantity/cost boundary adopted was the hospital. Mean unit operating costs were calculated separately at two hospitals in Sweden and then combined in order to price per patient resource use data. The price date was not clearly stated. Apparently no differential treatment of complication costs was made between the comparator and intervention strategies.
Currency Swedish kroner (SEK) (Conversion rate reported for June 1996, SEK6.2 = US$1.00).
Sensitivity analysis No sensitivity analysis was performed.
Estimated benefits used in the economic analysis For the intervention, the overall rate of serious complications was 0.92% during the initial phase and the corresponding figure for secondary endpoints at follow-up was 2.5%. The corresponding figure for the conventional in-hospital care was 2.8 - 7.1%.
Cost results The mean cost of diagnosis was estimated to be SEK3,249. Complications occurring during the initial period of treatment were estimated to have additional costs of 3.2%. The total cost reduction achieved with the intervention relative to the traditional care within hospital option was estimated to be SEK2,705,509, representing cost savings of 34.5%.
Synthesis of costs and benefits Since the intervention emerged as the dominant strategy, the costs and benefits were not combined.
Authors' conclusions Dalteparin, administered subcutaneously, once daily, for the initial treatment of DVT yields large cost reductions and is well tolerated and effective in an outpatient setting.
CRD COMMENTARY - Selection of comparators The reason for the choice of comparator is clear. The use of intravenous unfractionated heparin (UFH) was reported as the traditional in-hospital care option for the treatment of DVT.
Validity of estimate of measure of benefit The estimate of measure of benefit used in the economic analysis may be open to question due to the lack of a concurrent control in the effectiveness study. In addition, the authors noted that the study populations from the meta-analyses differ from that used in their study.
Validity of estimate of costs Adequate details of the methods of quantity/cost estimation were not given. In particular, the price date was not provided. Important cost items may have been omitted.
Other issues The authors' conclusions may not 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 cost results were not presented selectively.
Implications of the study Additional controlled studies may be necessary in order to validate the study results.
Bibliographic details Lindmarker P, Holmstrom M. Use of low molecular weight heparin (dalteparin), once daily, for the treatment of deep vein thrombosis: a feasibility and health economic study in an outpatient setting. Journal of Internal Medicine 1996; 240(6): 395-401 Indexing Status Subject indexing assigned by NLM MeSH Aged; Ambulatory Care; Anticoagulants /administration & Cost-Benefit Analysis; Dalteparin /administration & Drug Administration Schedule; Feasibility Studies; Female; Humans; Injections, Subcutaneous; Male; Middle Aged; Phlebography; Sweden; Thrombosis /diagnosis /drug therapy /economics; Treatment Outcome; Ultrasonography, Doppler; dosage /economics /therapeutic use; dosage /economics /therapeutic use AccessionNumber 21997000178 Date bibliographic record published 31/03/1999 Date abstract record published 31/03/1999 |
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