AbstractsBiology & Animal Science

Background: Depression accounts for more years lived with disability than any other medical condition. Major depressive disorder (MDD) may be present in 10-20% of patients in medical settings. Effective interventions to reduce the burden of depression exist, but most patients with depression do not receive adequate care. Screening for depression has been recommended to improve access to depression care. However, studies that have examined the diagnostic accuracy of depression screening tools typically have used data-driven, exploratory methods to select optimal cutoffs. Most often, these studies report results from a small range of cutoff points around whichever cutoff score is most accurate in that given study. When data from these published studies are combined in meta-analyses, estimates of accuracy for different cutoff points are often based on data from different studies, rather than having data from all studies for each possible cutoff point. As a result, traditional meta-analyses may generate exaggerated estimates of accuracy (i.e., sensitivity and specificity). Individual patient data (IPD) meta-analyses can address this problem by synthesizing data from all studies for each cutoff. Objective: To assess the degree to which selective reporting of results from well-performing cutoff thresholds may bias accuracy estimates in meta-analyses of depression screening tools. To do this, I examined results from studies of the Patient Health Questionnaire-9 (PHQ-9), a frequently used depression screening tool, comparing results from a traditional meta-analysis of published accuracy data to results from an IPD meta-analysis using original patient data from the same studies.Methods: Authors of studies included in a recently published meta-analysis on the PHQ-9 were invited to contribute patient-level data. For each dataset, we extracted the PHQ-scores and MDD diagnoses for each patient. Two sets of statistical analyses were performed: (1) a traditional meta-analysis where, for each cutoff between 7 and 15, we included data from the studies that reported accuracy results for the cutoff in the original publication; and (2) an IPD meta-analysis where, for each cutoff between 7 and 15, we included data from all studies.Results: We obtained data from 13 of 16 eligible datasets that were included in the original meta-analysis. Of the 13 studies, 11 (83% of patients) published accuracy results for the recommended cutoff score of 10 in the original report; accuracy results using traditional meta-analysis (sensitivity = 0.85, specificity = 0.88) were similar to those using IPD meta-analysis (sensitivity = 0.87, specificity = 0.88). For other cutoffs, the number of studies that published accuracy results for the particular cutoff ranged from 3 to 6 (21-46% of all patients) and results using the two different meta-analytic methods were more discrepant. Cutoffs below the standard cutoff of 10 tended to underestimate sensitivity in the traditional meta-analysis, whereas cutoffs above 10 tended to overestimate sensitivity. For…