Screening instruments for predicting return to work in long-term sickness absence.

Background: Multiple somatic symptoms are common and may cause prolonged sickness absence (SA) and unsuccessful return to work (RTW).

Aims: To compare three instruments and their predictive and discriminative abilities regarding RTW.

Methods: A longitudinal cohort study of participants recruited from two municipal job centres, with at least 8 weeks of SA. The instruments used were the Symptom Check List of somatic distress (SCL-SOM) (score 0-48 points), the Bodily Distress Syndrome Questionnaire (BDSQ) (0-120 points) and the one-item self-rated health (SRH) (1-5 points). The instruments' predictive value was explored in a time-to-event analysis. Different cut-points were analysed to find the highest number of correctly classified RTW cases, identified in a register on public transfer payments.

Results: The study involved 305 subjects. The adjusted relative risk regarding prediction of RTW was 0.89 [95% confidence interval (CI) 0.83-0.95], 0.89 (95% CI 0.83-0.95) and 0.78 (95% CI 0.70-0.86) per 5-, 10- and 1-point increase in the SCL-SOM, BDSQ and SRH, respectively. After mutual adjustment for the three instruments, only the prediction of RTW from SRH remained statistically significant 0.81 (95% CI 0.72-0.92). The highest sensitivity (86%) was found by SRH at the cut-point ≤5, at which 62% were correctly classified.

Conclusions: All three instruments predicted RTW, but only SRH remained a significant predictor after adjustment for the SCL-SOM and BDSQ. The SRH provides an efficient alternative to more time-consuming instruments such as SCL-SOM or BDSQ for estimating the chances of RTW among sickness absentees.