Mental health symptoms as prognostic risk markers of all-cause and psychiatric sickness absence in office workers

Background: To investigate mental health symptoms as prognostic risk markers of all-cause and psychiatric sickness absence (SA). Methods: Mental health symptoms were measured in 1137 office workers with the Four-Dimensional Symptom Questionnaire (4DSQ), including scales for distress, depression, anxiety and somatization. The total number of SA days was accumulated prospectively on the individual level and high SA was defined as epsilon 30 SA days during 1-year follow-up. Psychiatric SA was also tallied on the individual level during 1-year follow-up. Baseline 4DSQ scores were associated with high all-cause SA and psychiatric SA by logistic regression analysis. The Hosmer-Lemeshow test and calibration slope were used to assess the accuracy of predictions by 4DSQ scores. The ability of 4DSQ scores to discriminate high-risk from low-risk employees was estimated by the area under the receiver operating characteristic curve. Results: Six hundred thirty-three office workers (56%) participated in the study. All 4DSQ scales were prospectively associated with high all-cause SA and with psychiatric SA. Distress and somatization scores showed acceptable calibration, but failed to discriminate between office workers with and without high all-cause SA. The distress scale did show adequate calibration (calibration slope = 0.95) and discrimination (area under the receiver operating characteristic curve = 0.71) for psychiatric SA. Conclusion: Distress was a valid prognostic risk marker for identifying office workers at work, but at risk of future psychiatric SA. Further research is necessary to investigate the prognostic performance of distress as risk marker of psychiatric SA in other working populations and to determine cut-off points for distress.