SSRI antidepressant use patterns and their relation to clinical global impression scores: a naturalistic study

Background: A cascade of events follows initial antidepressant selection wh ich includes the subsequent antidepressant use pattern, resultant clinical outcomes, and associated health care expenditures. Purpose: The purpose of this study using data from a clinical practice setting was to test whether the pattern of antidepressant use was correlated with patients' treatment r esponse as measured by the score on the Clinical Global Impression-Improvem ent scale. Data and Method's: A retrospective dataset of patients who initi ated therapy on fluoxetine, fluvoxamine, paroxetine, or sertraline in a pri mary care setting in Spain was used. A Cox proportional hazard analysis was used to predict the likelihood of treatment response based upon the patter n of initial antidepressant use, while minimizing the influence of other fa ctors. Results: After controlling for other observed baseline characteristi cs including initial disease severity, (a) patients who remained on their i nitial antidepressant therapy for at least 2 months with no switching, augm entation, or upward dose titration were 1.63 times more likely to experienc e a treatment response than patients who had an adjustment to therapy; and (b) patients who initiated therapy on sertraline were 0.46 times as likely to experience a treatment response as patients who initiated therapy on the most common study antidepressant, fluoxetine. Conclusion: The pattern of a ntidepressant use is an important determinant of treatment response among p atients initiating therapy on the newer antidepressants in clinical practic e. (C) 1999 Elsevier Science B.V. All rights reserved.