Let’s get back to work: survival analysis on the return-to-work after depression

Abstract

Pepijn Vemer,1 Clazien A Bouwmans,1 Moniek C Zijlstra-Vlasveld,2 Christina M van der Feltz-Cornelis,2–4 Leona Hakkaart-van Roijen1 1Institute for Medical Technology Assessment, Erasmus University Rotterdam, Rotterdam, 2Institute of Mental Health and Addiction (Trimbos-institute), Utrecht, 3Tilburg University, Tranzo, Academic Centre 'Geestdrift', Tilburg, 4Clinical Centre for Body, Mind and Health, Tilburg, The Netherlands Purpose: Absence from work due to mental disorders is substantial. Additionally, long-term absence from work is associated with a reduced probability of return-to-work (RTW). Major depressive disorder (MDD) is a prevalent condition in Dutch occupational health care settings. An early estimate of the prognosis regarding RTW in patients with MDD could serve both as a point of departure for the identification of high-risk cases and as an instrument to monitor the course of the disorder and of RTW. In the current study, we aimed to assess the added value of health-related quality of life (HRQoL) and severity of depression to predict the time to RTW. Patients and methods: Data were derived from a prospective longitudinal study aimed to evaluate the cost effectiveness of a collaborative care treatment in sick-listed workers with MDD. We included demographic, job-related, and health-related variables. Severity of depression was measured using the Patient Health Questionnaire Depression Scale-9 (PHQ-9). HRQoL was measured using two generic preference-based instruments, the EuroQol 5-Dimension (EQ-5D™) and the Medical Outcomes Study Short Form Health Survey (SF-36). A survival model was constructed by applying different survival functions to assess the best fit for the data. Additionally, survival analyses were performed to assess the added value of the two HRQoL measures and depression severity for predicting RTW. Results: Females and older patients had a longer time to RTW. The same was true for patients with a full-time job and patients with more decision latitude. Patients in a management position and patients with more social support had a shorter time to RTW. Severity of depression was not predictive for the time to RTW. HRQoL measured by the SF-36 was a significant predictor for the time to RTW. Conclusion: HRQoL emerged as a significant predictor for the time to RTW. However, severity of depression was not predictive for the time to RTW. These results suggest the importance of assessing HRQoL in addition to severity of disease to assess functionality. Keywords: major depressive disorder, survival analyses, return-to-work, HRQoL