title: Does early improvement predict endpoint response in patients with generalized anxiety disorder (GAD) treated with pregabalin or venlafaxine XR?
abstract: Many patients with generalized anxiety disorder (GAD) only respond to pharmacological treatment after a delay of some weeks, and approximately 35% of patients do not respond. Therefore, early identification of potential responders may have important implications for clinical decision-making. In order to identify early improvement criteria that optimally predict eventual response during short-term treatment of GAD with pregabalin or venlafaxine XR, data were pooled from four double-blind, placebo-controlled GAD treatment studies. A range of measures were analyzed using logistic regression models and receiver operator characteristic (ROC) curve analysis, to predict endpoint response. Results showed that early improvement (≥ 20% reduction from baseline score) on the Hamilton Anxiety Scale (HAM-A) was associated with a high probability of achieving an endpoint response at Weeks 1 and 2 among patients treated with pregabalin (~67%), and at Week 2 with venlafaxine XR (60%). A Clinical Global Impression - Improvement (CGI-I) score ≤ 3 at Week 2 was a reliable predictor of achieving endpoint response for pregabalin and venlafaxine XR (odds ratio [OR], 5.33 and 2.47, respectively) with high sensitivity (pregabalin, 0.91; venlafaxine XR, 0.86) and relatively low specificity (pregabalin, 0.33; venlafaxine XR, 0.29), indicating a high true positive rate, but relatively low true negative rate. These findings indicate that improvement by Week 2 on the single item CGI may be a simple and reliable way to predict treatment response with pregabalin or venlafaxine XR in patients with GAD, but a less reliable way to predict non-responders.
authors.affiliation: University of Southampton, UK. dsb1@soton.ac.uk
authors.forename: David S
authors.initials: DS
authors.lastname: Baldwin
authors.forename: Edward
authors.initials: E
authors.lastname: Schweizer
authors.forename: Yikang
authors.initials: Y
authors.lastname: Xu
authors.forename: Gavin
authors.initials: G
authors.lastname: Lyndon
mesh_terms: D000328:Adult; D000700:Analgesics / Q000627:therapeutic use*; D001008:Anxiety Disorders / Q000188:drug therapy*; D003511:Cyclohexanols / Q000627:therapeutic use*; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D000069583:Pregabalin; D011569:Psychiatric Status Rating Scales; D016896:Treatment Outcome; D000069470:Venlafaxine Hydrochloride; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D000700:Analgesics; D003511:Cyclohexanols; D003692:Delayed-Action Preparations; D000069583:Pregabalin; D005680:gamma-Aminobutyric Acid; D000069470:Venlafaxine Hydrochloride