Psychometric Assessment of the Swedish version of the Work Ability Index in Patients with Chronic Pain in Specialized Care.

The sample was small, with 118 participants analysed. The analysis of how the items grouped was exploratory rather than confirmatory, and the authors note that the limited sample size might have affected the grouping. Non-working people were more likely to lack complete index answers, 75% compared with 49% in the sample with complete answers. The version used added an instruction for people not working to estimate work ability from current or previous work or studies, and the authors could not determine how this affected how the index measured work ability. Work status was self-reported, and the study did not use official sick-leave records. The study did not check whether the score would be stable if measured twice, or whether it predicted later outcomes. The sample had poor work ability and high rates of non-working status, so the findings may not transfer to other pain groups.

The authors declared no conflicts of interest.

Do not conclude that the Work Ability Index predicts treatment benefit or future disability pension. This study checked how the Swedish index behaved in one pain clinic sample and did not test outcomes over time.