The value of early functional improvement at week 2 for predicting subsequent functional outcomes at week 8 was assessed in a pooled analysis of patients with major depressive disorder (MDD) treated with desvenlafaxine (50 or 100 mg/d) or placebo.
Data were pooled from eight double-blind, placebo-controlled studies of desvenlafaxine 50 mg/d or 100 mg/d for the treatment of MDD. Optimal week-2 improvement thresholds in Sheehan Disability Scale (SDS) score, which best predicted week-8 treatment success, were determined using receiver operating characteristic (ROC) analysis. Four definitions of treatment success were established: (1) functional response, (2) functional/depression response, (3) functional remission, and (4) functional/depression remission. Odds ratios (ORs) of early improvement for prediction (based on thresholds determined in the ROC analysis) of week-8 treatment success were computed using logistic regression models.
Functional early improvement thresholds of 17%–32% were predictive of week-8 treatment success across treatment groups and definitions of treatment success. Optimal thresholds were higher for more stringent definitions. Negative predictive value exceeded positive predictive value, indicating that failure to achieve early functional improvement was more informative about later treatment success than was the achievement of early functional improvement. Early change in SDS was a highly significant predictor of functional response/remission (ORs, 4.981–8.737; all p < 0.0001); the interaction between treatment and early functional improvement was not significant.
Early improvement in SDS total score was predictive of functional outcomes for patients treated with desvenlafaxine 50 mg, desvenlafaxine 100 mg, or placebo.