Duloxetine compared with fluoxetine and venlafaxine: use of meta-regression analysis for indirect comparisons

BACKGROUND: Data comparing duloxetine with existing antidepressant treatments is limited. A comparison of duloxetine with fluoxetine has been performed but no comparison with venlafaxine, the other antidepressant in the same therapeutic class with a significant market share, has been undertaken. In the absence of relevant data to assess the place that duloxetine should occupy in the therapeutic arsenal, indirect comparisons are the most rigorous way to go. We conducted a systematic review of the efficacy of duloxetine, fluoxetine and venlafaxine versus placebo in the treatment of Major Depressive Disorder (MDD), and performed indirect comparisons through meta-regressions. METHODS: The bibliography of the Agency for Health Care Policy and Research and the CENTRAL, Medline, and Embase databases were interrogated using advanced search strategies based on a combination of text and index terms. The search focused on randomized placebo-controlled clinical trials involving adult patients treated for acute phase Major Depressive Disorder. All outcomes were derived to take account for varying placebo responses throughout studies. Primary outcome was treatment efficacy as measured by Hedge's g effect size. Secondary outcomes were response and dropout rates as measured by log odds ratios. Meta-regressions were run to indirectly compare the drugs. Sensitivity analysis, assessing the influence of individual studies over the results, and the influence of patients' characteristics were run. RESULTS: 22 studies involving fluoxetine, 9 involving duloxetine and 8 involving venlafaxine were selected. Using indirect comparison methodology, estimated effect sizes for efficacy compared with duloxetine were 0.11 [-0.14;0.36] for fluoxetine and 0.22 [0.06;0.38] for venlafaxine. Response log odds ratios were -0.21 [-0.44;0.03], 0.70 [0.26;1.14]. Dropout log odds ratios were -0.02 [-0.33;0.29], 0.21 [-0.13;0.55]. Sensitivity analyses showed that results were consistent. CONCLUSION: Fluoxetine was not statistically different in either tolerability or efficacy when compared with duloxetine. Venlafaxine was significantly superior to duloxetine in all analyses except dropout rate. In the absence of relevant data from head-to-head comparison trials, results suggest that venlafaxine is superior compared with duloxetine and that duloxetine does not differentiate from fluoxetine

Cost Effectiveness of Insulin Glargine plus Oral Antidiabetes Drugs Compared with Premixed Insulin Alone in Patients with Type 2 Diabetes Mellitus in Canada

Background: Several treatment options are available for patients with type 2 diabetes mellitus who are making the transition from oral antidiabetes drugs (OADs) to insulin. Two options currently recommended by the Canadian Diabetes Association for initiating insulin therapy in patients with type 2 diabetes who are no longer responsive to OADs alone are insulin glargine plus OADs, and premixed insulin therapy only. Because of differences in efficacy, adverse events (such as hypoglycaemia) and acquisition costs, these two treatment options may lead to different long-term clinical and economic outcomes. Objective: To determine the cost effectiveness of insulin glargine plus OADs compared with premixed insulin without OADs in insulin-naive patients with type 2 diabetes in Canada. Methods: Using treatment effects taken from a published clinical trial, the validated IMS-CORE Diabetes Model was used to simulate the long-term cost effectiveness of insulin glargine with OADs, versus premixed insulin. Input treatment effects for the two therapeutic approaches were based on changes in glycosylated haemoglobin A1c (HbA1c) at clinical trial endpoint, and hypoglycaemia rates. The analysis was conducted from the perspective of the Canadian Provincial payer. Direct treatment and complication costs were obtained from published sources (primarily from Ontario) and reported in $Can, year 2008 values. All base-case costs and outcomes were discounted at 5% per year. Sensitivity analyses were conducted around key parameters and assumptions used in the study. Outcomes included direct medical costs associated with both treatment and diabetes-related complications. Cost-effectiveness outcomes included total average lifetime (35 years) costs, life expectancy (LE), QALYs and incremental cost-effectiveness ratios (ICERs). Results: Base-case analyses showed that, compared with premixed insulin only, insulin glargine in combination with OADs was associated with a 0.051-year increase in LE and a 0.043 increase in QALYs. Insulin glargine plus OADs showed a very slight increase in total direct costs ($Can343 ± 2572), resulting in ICERs of $Can6750 per life-year gained (LYG) and $Can7923 per QALY gained. However, considerable uncertainty around the ICERs was demonstrated by insulin glargine having a 50% probability of being cost effective at a willingness-to-pay threshold of $Can10 000 per QALY, and a 54% probability at a $Can20 000 threshold. Base-case results were most sensitive to assumed disutilities for hypoglycaemic events, to the assumed effect of insulin glargine plus OADs on HbA1c, and to its assumed acquisition costs. Conclusions: These findings should be interpreted within the context of a large degree of uncertainty and of several study limitations that include a single clinical trial as the source for primary treatment assumptions and a single province as the source for most cost inputs. Under current study assumptions and limitations, insulin glargine plus OADs was projected to be a cost-effective option, compared with premixed insulin only, for the treatment of insulin-naive patients with type 2 diabetes unresponsive to OADs. Additional work is needed to examine the generalizability of the findings to individual jurisdictions of the Canadian healthcare system.cost-utility, glimepiride, therapeutic use, insulin-glargine, therapeutic use, insulin-suspension-isophane/insulin, therapeutic use, metformin, therapeutic use, type-2-diabetes-mellitus, treatment.