Remission of Generalized Anxiety Disorder after 6 Months of Open-Label Treatment with Venlafaxine XR

Abstract

Background: Remission has become one of the leading outcome criteria in clinical trials. Data collected by this research group assessed the rate of remission after 6 months of treatment of generalized anxiety disorder (GAD) with venlafaxine XR, to search for predictors of remission and to define how early on in treatment later remission can be predicted. Method: Two hundred sixty-eight patients with a GAD diagnosis enrolled into an open-label 6-month-treatment trial with venlafaxine XR (75-225 mg/day). Remission was defined by a Hamilton anxiety scale total score ≤7. Logistic regression approaches were used to find out how early on in treatment later remission could be predicted, as well as to determine predictors of remission. In addition, adverse events were also followed over time. Results: While the total enrolled patient sample (n = 268) had a remission rate of 53%, 6-month completers (n = 159) had a remission rate of 79%. The only statistically significant predictor of remission, independent of baseline anxiety and depression levels, was a low Eysenck neuroticism score. The remission status outcome could best be predicted after 8 weeks of treatment when a CGI-I score of 1 or 2 predicted later remission with 78% accuracy and later nonremission with 91% accuracy. The incidence of adverse events decreased over the 6-month period, with sexual adverse events decreasing the least. Conclusion: The only significant predictor of remission was a low score on the Eysenck neuroticism scale. The earliest reliable prediction of later remission, based on improvement, could be made after 8 weeks of treatment with 91% accuracy.

The Items Predicting Non-Remission after 6 Months of Treatment of Patients with Generalized Anxiety Disorder Covered the Eysenck Neuroticism Components of Anxiety, Interpersonal Sensitivity and Depression

“…Rickels et al [4] used this EPI neuroticism scale when predicting remission in patients with generalized anxiety disorder after 6 months of treatment with venlafaxine. Using a remission criterion of <8 on the Hamilton Anxiety Scale (HAM-A), it was shown that the neuroticism scale had predictive validity, as non-remitters had a significantly higher neuroticism score at treatment baseline than the remitters.…”

“…gender, age, race, education, HAM-A), only the neuroticism scale was found to have predictive validity. The objective of the present analysis of the data set of Rickels et al [4] has been to perform an item analysis of the neuroticism scale to identify those items that produce the predictive validity.…”

“…A total of 268 patients received open-label venlafaxine treatment in a dosage range of 75-225 mg/day for up to 6 months [4]. Of these patients, 142 were remitters and 126 non-remitters when using a HAM-A score of <8 as the criterion of remission at the end point of 6 months.…”

“…Of these patients, 142 were remitters and 126 non-remitters when using a HAM-A score of <8 as the criterion of remission at the end point of 6 months. On the Eysenck neuroticism scale containing 24 dichotomously scored items (1 = yes, 0 = no), the mean (SD) score in the group of remitters was 14.75 (4.35) compared with 16.75 (4.23) in the group of non-remitters [4]. …”

“…Because the total score of the EPI neuroticism scale at treatment baseline had a very limited standard deviation (approx. 4 [4]), we used the Rasch item response theory model to test for scalability [5] and not the Mokken analysis, which is based on correlation coefficients [6]. According to the Rasch analysis, the scalability is accepted if the χ 2 statistic is low and the p value is ≥0.01.…”