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“For any antidepressant medication trial, it is important to identify as early as possible whether the patient is likely to achieve remission …,” wrote Paul B. Hicks, M.D., Ph.D., of Texas A&M College of Medicine and colleagues. “The present study bolsters the proposed use of the lack of early improvement as a predictor of failure to achieve remission with the current medication.”
The researchers conducted a secondary analysis of data from the Veterans Affairs Augmentation and Switching Treatments for Improving Depression Outcomes (VAST-D) study, which involved 1,552 veterans aged 18 and older whose major depressive disorder was unresponsive to at least one course of antidepressant treatment. The study participants were randomly assigned to one of three medication treatment groups: augmentation with bupropion sustained release, augmentation with aripiprazole, or switch to a different antidepressant. The dosage remained relatively constant throughout the trial, though the researchers allowed adjustments to doses as early as the end of the first week. The researchers evaluated participants at baseline and at the end of weeks 1, 2, 4, 6, 8, 10, and 12.
Early improvement was defined as a drop from the baseline depression severity score of 20% or more, as measured by the Quick Inventory of Depressive Symptomatology-Clinician Rated (QIDS-C), within the first two weeks of the treatment modification. The researchers then calculated positive and negative predictive values by evaluating whether the participants showed early improvement by the end of the second week and whether they then achieved remission by the end of week 12. The values were determined by categorizing participant outcomes based on whether the patient had a true positive (they showed early improvement and achieved remission), false positive (they showed early improvement but did not achieve remission), true negative (they neither achieved early improvement nor remission), and false negative (they did not show early improvement but achieved remission).
The researchers found that early improvement in patients resulted in a positive predictive value of 38.2% and a negative predictive value of 92.6%; the latter means that if the patient does not show improvement by the end of the second week on a medication, the chance of achieving remission at the end of the 12th week is less than 8%. “The odds of achieving remission, response, and greater than minimal improvement was higher among individuals who exhibited early improvement,” the authors wrote.
They noted, however, that it is also important to analyze the characteristics of the patients who did not experience early improvement but did ultimately achieve remission by the end of the 12 weeks. Those patients were more likely to have lower baseline scores, fewer adverse childhood experiences, lower baseline Beck Anxiety Inventory Score, lower Columbia-Suicide Severity Rating Scale scores, and a higher baseline quality of life.
“A lack of early improvement at the end of week 2 of antidepressant therapy can be used to inform clinical decisions on the likelihood of nonremission of depression during the subsequent 10 weeks, even when dosage optimization is incomplete,” the authors concluded.
For related information, see the American Journal of Psychiatry article “General Predictors and Moderators of Depression Remission: A VAST-D Report.”
(Image: iStock/FilippoBacci)
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