[Treatment for an adjustment disorder after cancer: results of a Dutch study]. / Behandeling van een aanpassingsstoornis na kanker.

OBJECTIVE: To determine the effectiveness of treatment for an adjustment disorder in accordance with the Dutch guideline for an adjustment disorder in cancer survivor (i.e. people living with or after cancer) on distress, psychological symptoms and quality of life. DESIGN: Prospective cohort in which cancer survivors completed questionnaires prior to and after they received treatment for an adjustment disorder in accordance with the Dutch guideline 'adjustment disorder in patients with cancer'. METHOD: Using paired t-tests, the primary outcomes 'experienced distress' (Distress Thermometer) and 'psychological distress' (HADS) and secondary outcomes functioning, fatigue, and insomnia (EORTC-QLQ-C30) were compared before and after treatment. Clinically relevant improvement was also calculated for each outcome measure. The average costs per treatment were calculated based on the average number of sessions and the indexed NZA rate for the GGZ. RESULTS: A total of 563 cancer survivors received treatment and completed pre- and post-treatment questionnaires. They attended, on average, 11 treatment sessions. The average cost per treatment was €1.141. The results show a statistically significant decrease (p < .001) and a clinically relevant reduction in experienced distress, psychological distress, fatigue, insomnia and a clinically relevant improvement in functioning in cancer survivors following treatment for an adjustment disorder. CONCLUSION: Treatment for adjustment disorder for cancer survivors seems to lead to, at manageable cost, improved quality of life. Inclusion of the guideline in the quality register of the Dutch National Health Care Institute and treatment in accordance with this guideline is recommended.

Joint analysis of multiple longitudinal outcomes: application of a latent class model.

We address the problem of joint analysis of more than one series of longitudinal measurements. The typical way of approaching this problem is as a joint mixed effects model for the two outcomes. Apart from the large number of parameters needed to specify such a model, perhaps the biggest drawback of this approach is the difficulty in interpreting the results of the model, particularly when the main interest is in the relation between the two longitudinal outcomes. Here we propose an alternative approach to this problem. We use a latent class joint model for the longitudinal outcomes in order to reduce the dimensionality of the problem. We then use a two-stage estimation procedure to estimate the parameters in this model. In the first stage, the latent classes, their probabilities and the mean and covariance structure are estimated based on the longitudinal data of the first outcome. In the second stage, we study the relation between the latent classes and patient characteristics and the other outcome(s). We apply the method to data from 195 consecutive lung cancer patients in two outpatient clinics of lung diseases in The Hague, and we study the relation between denial and longitudinal health measures. Our approach clearly revealed an interesting phenomenon: although no difference between classes could be detected for objective measures of health, patients in classes representing higher levels of denial consistently scored significantly higher in subjective measures of health.