Severe MUPS in a sick-listed population: a cross-sectional study on prevalence, recognition, psychiatric co-morbidity and impairment

Background: Medically unexplained physical symptoms (MUPS) have a high prevalence in the general population and are associated with psychiatric morbidity. There are indications that MUPS are an important determinant of frequent and long-term disability. The primary objective was to assess the prevalence of MUPS in sick-listed-employees and its associations with depressive disorders, anxiety disorders, health anxiety, distress and functional impairment. Secondary objectives were to investigate the classification of the occupational health physicians (OHPs), their opinions about the causes as well as the attributions of the employee. Methods: In a cross- sectional study of 489 sick-listed employees from 5 OHP group practices, MUPS, depressive disorders, anxiety disorders, health anxiety, distress and functional impairment were assessed with the Patient Health Questionnaire (PHQ), the Whitely Index (WI), the Four-Dimensional Symptom Questionnaire (4DSQ) and the Short-Form 36 Health Survey (SF-36). We used a cut off score of 15 on the PHQ for the categorisation of severe MUPS. The opinions of the OHPs were evaluated by means of a separate questionnaire with regard to the presence of employees physical symptoms, and the symptoms attributions, and the diagnoses of the OHPs. Results: Severe MUPS had a prevalence of 15.1% in this population of sick-listed employees. These employees had 4-6 times more depressive and anxiety disorders, and were more impaired. Female gender and PHQ-9 scores were determinants of severe MUPS. Most of the time the OHPs diagnosed employees with severe MUPS as having a mental disorder. The employees attributed their physical symptoms in 66% to mental or to both mental and physical causes. Conclusion: The prevalence of severe MUPS is higher in long-term sick-listed employees than in the non-sick-listed working population and at least equals the prevalence in the general practice population. Severe MUPS are associated with psychiatric morbidity and functional impairment and must therefore be specifically recognised as such. Validated questionnaires, such as the PHQ-15, are useful instruments in order to help OHPs to recognise severe MUPS.