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A pharmacoeconomic evaluation of major depressive disorder |
Casciano J, Arikian S, Tarride J, Doyle J J, Casciano R |
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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 venlafaxine XR (vXR), a particular type of serotonin norepinephrine reuptake inhibitor, for the treatment of major depressive disorders (MDD).
Economic study type Cost-effectiveness analysis.
Study population The study population comprised patients suffering from MDD.
Setting The setting was a hospital and the community. The economic study was carried out in Italy.
Dates to which data relate The dates during which the effectiveness data were obtained, and the price year, were not reported. The resource use data were generally gathered between 1996 and 1997.
Source of effectiveness data The effectiveness data were derived from a meta-analysis.
Modelling A decision tree was used to model the inpatient and outpatient management of patients suffering from MDD, for a timeframe of 6 months. The tree paths were identified with the support of a panel of physicians, who were experts in MDD treatment.
Outcomes assessed in the review The input parameters assessed were the estimates of success rate for inpatients and outpatients, and the drop-out rate. The success rate was defined as a 50% reduction in the depression scores on the Hamilton Depression Scale or the Montgomery-Asberg Depression Rating Scale. Drop-outs occurred on account of adverse drug reactions and the patients' perceived lack of effect. Due to the lack of studies for inpatients, the rates of success and drop-out for vXR were based on a published meta-analysis of 274 inpatients treated with venlafaxine IR (see of Related Interest).
Study designs and other criteria for inclusion in the review The meta-analysis was based on the data from clinical trials. Studies were included in the meta-analysis if they involved patients diagnosed with MDD, where MDD was defined as a score of at least 15 on the Hamilton Depression Scale or at least 18 on the Montgomery-Asberg Depression Rating Scale.
Sources searched to identify primary studies Criteria used to ensure the validity of primary studies Methods used to judge relevance and validity, and for extracting data Number of primary studies included Forty-four trials with a total of 4,033 patients were included in the review.
Methods of combining primary studies A meta-analysis was used to combine primary studies.
Investigation of differences between primary studies Results of the review The rate of success for outpatients was 73.7% (95% confidence interval, CI: 68.9 - 78.4) for vXR, 61.4% (95% CI: 55.7 - 67.0) for SSRIs, and 59.3% (95% CI: 50.1 - 68.6) for TCAs. The difference was statistically significant for vXR compared with the other two drugs.
The rate of success for inpatients was 62.3% (95% CI: 49.7 - 74.9) for vXR, 58.6% (95% CI: 48.2 - 69.0) for SSRIs, and 58.2% (95% CI: 43.0 - 73.5) for TCAs.
The drop-out rate due to lack of efficacy was 4.8% (95% CI: 1.8 - 7.8) for vXR, 8.4% (95% CI: 4.6 - 12.3) for SSRIs, and 6.8% (95% CI: 4.6 - 9) for TCAs. The drop-out rate due to adverse drug reactions was 10.9% (95% CI: 7.9 - 13.9) for vXR, 17.4% (95% CI: 17.4 - 21.3) for SSRIs, and 23.1% (95% CI: 16.2 - 30.0) for TCAs.
Measure of benefits used in the economic analysis The measures of benefits were the expected success rate and the number of expected symptom-free days; these were derived from the decision tree. While the success rate was based on the estimates obtained from the review, the number of expected symptom-free days was obtained by calculating the time from treatment success until the end of the 6-month period. This parameter was considered as a proxy for patient utility.
Direct costs The costs were not discounted since they were incurred in a 6-month time period. The quantities and costs were analysed and reported separately. The analysis included the costs of medication, physician services, laboratory services, facility (hospital) services, electroconvulsive therapy, and psychosocial care. The quantity/cost boundary was that of the health service. The estimation of the costs and resources used was derived from the decision model. The sources of the costs were based on official data published by the Italian Ministry of Health, and were compiled in collaboration with local health economists. Several costs were measured between 1996 and 1997. The price year was not reported. The decision model yielded the total expected cost for each drug strategy adopted.
Statistical analysis of costs No statistical analysis of costs was carried out.
Indirect Costs Indirect costs were not included.
Sensitivity analysis Sensitivity analyses were performed to test for variability in the data and to generalise the results of the model. Univariate analyses were conducted using rank order stability analysis, whilst multivariate analyses were conducted using Monte Carlo simulations. These varied key model variables such as success and drop-out rates, and drug prices.
Estimated benefits used in the economic analysis In the outpatient setting, the expected success rate was 83.1% for vXR, 74.4% for SSRIs, and 73.2% for TCAs. The number of expected symptom-free days were 110.06 for vXR, 94.38 for SSRIs, and 91.5 for TCAs. In the inpatient setting, the corresponding expected success rates were 78.0% (vXR), 74.2% (SSRIs) and 72.9% (TCAs). The numbers of expected symptom-free days were 100.0 (vXR), 93.25 (SSRIs) and 30.9 (TCAs). In both settings, the estimated benefits of the vXR strategy were always higher than for the SSRIs and TCAs.
Cost results In the outpatient setting, the expected total costs were 1,576,843.8 L for vXR, 1,670,851.93 L for SSRIs, and 1,595,384.8 L for TCAs. The corresponding values in the inpatient setting were 15,423,853.24 L (vXR), 16,043,353.62 L (SSRIs) and 16,330,681.56 L (TCAs). The adoption of the treatment with vXR would yield savings of 94,008 L per outpatient when compared with SSRIs, and 18,541 L when compared with TCAs. The savings in the inpatient setting would be 619,500 when compared with SSRIs, and 906,828 L when compared with TCAs.
Synthesis of costs and benefits The costs and benefits were combined by calculating the expected cost per success and per symptom-free day. An incremental analysis was also performed; this represented the differences between the cost per success or symptom-free day of the three strategies.
In the outpatient setting, the expected cost per success was 1,898,187.13 L for vXR, 2,245,544.49 L for SSRIs, and 2,180,888.14 L for TCAs. The corresponding values in the inpatient setting were 19,784,487.81 L (vXR), 21,624,798.08 L (SSRIs) and 22,406,800.84 L (TCAs).
In the outpatient setting, the expected cost per symptom-free day was 14,326.7 L for vXR, 17,704.32 L for SSRIs, and 17,436.34 L for TCAs. The corresponding values in the inpatient setting were 154,238.13 L (vXR), 172,055.36 L (SSRIs) and 179,654.32 L (TCAs).
vXR was more cost-effective for both inpatients and outpatients with respect to the expected cost per success and per symptom-free day, when compared with SSRIs and TCAs. The difference in expected cost per symptom-free day for vXR and the second ranking comparator (SSRIs) was 3,378 L for outpatients and 17,817 L for inpatients.
The authors also assessed the local budgetary impact of a shift in utilisation from the SSN current portfolio of antidepressant spending, to one with a greater utilisation of vXR. The results demonstrated that the Italian government could save between 963 million and 3,210 million L, depending on the treated prevalence estimates. The results from the sensitivity analysis indicated that the study's findings were fairly robust with respect to the assumptions in the base-case.
Authors' conclusions The authors concluded that vXR was the most cost-effective strategy for the treatment of MDD. The superior pharmacoeconomic profile of vXR was due to its high effectiveness compared to other antidepressants. This effectiveness was interpreted in terms of cost-savings arising from the non-requirement of health care services.
CRD COMMENTARY - Selection of comparators The selection of the comparators was clearly based on drug treatments routinely adopted in current practice.
Validity of estimate of measure of effectiveness The estimates of effectiveness measures were derived from a meta-analysis. However, the methodology and the conduct of the review were not reported satisfactorily.
Validity of estimate of measure of benefit The estimation of benefits was modelled. However, as the authors recognised, the decision tree was constructed on the basis of the opinions of an expert panel. This panel should be representative of the typical practice in Italy, but it is a potential source of bias, especially given that the number of physicians in the panel was quite small.
Validity of estimate of costs The study included all the cost categories relevant to the perspective adopted, and the quantities and costs were reported separately. Sensitivity analyses were performed on the costs and quantities. These showed that the model's assumptions were robust for wide variations in the parameters.
Other issues The authors acknowledged the limited external validity of their study, given that the analysis seemed to reflect the implication of drug selection for the average patient. It should be noted that in the management of MDD, there are significant variations between individual patients and differences in practice patterns. The authors also recognised that the timeframe of the study, i.e. 6 months, seemed too short to take into account the problems related to long-term MDD therapy.
Implications of the study The cost-savings of the vXR strategy could be enhanced by also considering indirect costs, such as productivity losses, given the high impact of MDD on the number of days of work lost. Einarson TR, Arikian SR, Casciano J, Doyle JJ. Comparisons of extended-release venlafaxine, selective serotonin reuptake inhibitors, and tricyclic antidepressants in the treatment of depression: a meta-analysis of randomized controlled trials. Clinical Therapeutics 1999;21:296-308.
Source of funding Supported by Wyeth-Lederle Italia SPA.
Bibliographic details Casciano J, Arikian S, Tarride J, Doyle J J, Casciano R. A pharmacoeconomic evaluation of major depressive disorder. Epidemiologia e Psichiatria Sociale 1999; 8(3): 220-231 Indexing Status Subject indexing assigned by NLM MeSH Antidepressive Agents /economics /therapeutic use; Costs and Cost Analysis; Depressive Disorder, Major /diagnosis /drug therapy; Humans; Italy AccessionNumber 22001008092 Date bibliographic record published 31/03/2002 Date abstract record published 31/03/2002 |
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