Work ability and duration of certified sickness absence.

Aims: The aim of this study was to examine the association between assessed work ability and the duration of certified sickness absence.
Methods: A total of 549 patients and 52 doctors provided questionnaire data about 549 episodes of absence. The episodes were classified as new, one month, or three months according to their duration at the time of questionnaire completion. Their duration after that was used as outcome. Uni-and multivariate Cox regression analyses were performed.
Results: In the multivariate analyses, a "very much reduced" work ability assessed by patients was associated with a longer duration than a "moderately reduced" work ability, in both one- and three-month episodes. Musculoskeletal and psychological disorders were associated with a longer duration, and respiratory disorders with a shorter duration than other disorders in new episodes. Patient age above 50 years was associated with a longer duration than lower age in new and three-month episodes. The doctors' use of referral and tests in the consultations, and the presence of non-medical factors as judged by the patients, were associated with a longer duration than the absence of those factors in new episodes. The patients' degree of job satisfaction, and non-medical factors as judged by doctors. were significantly associated with duration only in univariate Cox regression analyses in new episodes. Work demands were not significantly associated with duration in any of the analyses.
Conclusions: Work ability assessed by patients may be a useful prognostic indicator of duration in prolonged episodes of certified sickness absence. Further studies using other outcomes, such as disability pensioning, would be of interest to enlighten the concepts of work ability.