Correcting for dependent censoring in routine outcome monitoring data by applying the inverse probability censoring weighted estimator.

Censored data make survival analysis more complicated because exact event times are not observed. Statistical methodology developed to account for censored observations assumes that patients' withdrawal from a study is independent of the event of interest. However, in practice, some covariates might be associated to both lifetime and censoring mechanism, inducing dependent censoring. In this case, standard survival techniques, like Kaplan-Meier estimator, give biased results. The inverse probability censoring weighted estimator was developed to correct for bias due to dependent censoring. In this article, we explore the use of inverse probability censoring weighting methodology and describe why it is effective in removing the bias. Since implementing this method is highly time consuming and requires programming and mathematical skills, we propose a user friendly algorithm in R. Applications to a toy example and to a medical data set illustrate how the algorithm works. A simulation study was carried out to investigate the performance of the inverse probability censoring weighted estimators in situations where dependent censoring is present in the data. In the simulation process, different sample sizes, strengths of the censoring model, and percentages of censored individuals were chosen. Results show that in each scenario inverse probability censoring weighting reduces the bias induced in the traditional Kaplan-Meier approach where dependent censoring is ignored.

A cluster analysis of early onset in common anxiety disorders.

Early onset is regarded as an important characteristic of anxiety disorders, associated with higher severity. However, previous findings diverge, as definitions of early onset vary and are often unsubstantiated. We objectively defined early onset in social phobia, panic disorder, agoraphobia, and generalised anxiety disorder, using cluster analysis with data gathered in the general population. Resulting cut-off ages for early onset were ≤22 (social phobia), ≤31 (panic disorder), ≤21 (agoraphobia), and ≤27 (generalised anxiety disorder). Comparison of psychiatric comorbidity and general wellbeing between subjects with early and late onset in the general population and an outpatient cohort, demonstrated that among outpatients anxiety comorbidity was more common in early onset agoraphobia, but also that anxiety- as well as mood comorbidity were more common in late onset social phobia. A major limitation was the retrospective assessment of onset. Our results encourage future studies into correlates of early onset of psychiatric disorders.

Predictors of outcome in outpatients with anxiety disorders: the Leiden routine outcome monitoring study.

Little is known about the predictors of outcome in anxiety disorders in naturalistic outpatient settings. We analyzed 2-year follow-up data collected through Routine Outcome Monitoring (ROM) in a naturalistic sample of 917 outpatients in psychiatric specialty care in order to identify factors predicting outcome. We included patients with panic disorder with or without agoraphobia, agoraphobia without panic, social phobia, or generalized anxiety disorder. Main findings from Cox regression analyses demonstrated that several socio-demographic variables (having a non-Dutch ethnicity [HR = 0.71)], not having a daily occupation [HR = 0.76]) and clinical factors (having a diagnosis of agoraphobia [HR = 0.67], high affective lability [HR = 0.80] and behavior problems [HR = 0.84]) decreased chances of response (defined as 50% reduction of anxiety severity) over the period of two years. Living with family had a protective predictive value [HR = 1.41]. These results may imply that factors that could be thought to limit societal participation, are associated with elevated risk of poor outcome. A comprehensive ROM screening process at intake may aid clinicians in the identification of patients at risk of chronicity.

Effects of perceived control on the outcomes of workplace aggression and violence.

This study examined the role of perceived control in ameliorating the negative outcomes associated with the experience of violence at work, using 2 large samples of hospital staff (N = 187) and group home staff (N = 195). Exploratory and confirmatory factor analyses of the measure of perceived control converged in suggesting a 3-factor structure consisting of Understanding, Prediction, and Influence. Results of a series of moderated regression analyses suggested that perceived control did not moderate the relationships between violence and fear or between fear and emotional well-being, somatic health, or neglect. However, perceived control was directly associated with emotional well-being and indirectly associated with somatic health and neglect. In addition, training that targets workplace violence was found to be related to enhanced perceptions of control.