Two-month head-to-head clinical trials of escitalopram and venlafaxine demonstrated similar efficacy and better tolerability for escitalopram. However, as routine practice may differ from controlled trial, it is necessary to investigate the translation of clinical trial findings into real life. This work aims at comparing treatment early discontinuation (ED) at 1 and 2 months and its economic consequences at 6 months, under venlafaxine and escitalopram.

Using US denominator-based claims database PharMetrics (includes data from 86 managed care health plans covering 45 million patients), we included adult patients diagnosed with depression who started venlafaxine or escitalopram between January 1st and December 31st 2004. ED was compared at 1 and 2 months using Cox proportional hazard models and healthcare costs at 6 months, using log-linear regression. Propensity scoring was used to account for baseline differences.

13,227 patients started escitalopram; 5,922 patients started venlafaxine. ED at 2 months was 47% for venlafaxine, 45% for escitalopram. At 1 month, venlafaxine patients had 50% more risk of ED than escitalopram patients (Hazard Ratio=0.493 [95%CI 0.432-0.564]); while this difference decreased at 2 months, (Hazard Ratio=0.955 [95%CI 0.912-0.999]). Continuing treatment at 2 months doubled the chance of still being on treatment at 6 months. Moreover 1) ED at 2 months incurred more costs over 6 months (+US$173); 2) 6-month healthcare costs were higher with venlafaxine (+US$626, p<0.001).

Early discontinuation rate was higher with venlafaxine than escitalopram, possibly due to intolerance to venlafaxine. ED was shown to affect later continuation and incurred costs.