Is a Problem-Solving Intervention with Workplace Involvement for Employees on Sickness Absence Due to Common Mental Disorders More Effective, than Care as Usual, in Reducing Sickness Absence Days? Results of a Cluster-Randomised Controlled Trial in Primary Health Care.

The planned sample size of 220 employees was not reached, with only 197 participants, increasing the risk of a type II error (missing a true effect). Only 13% of eligible employees consented to participate, and those who refused may have differed in symptom severity or workplace conflict, limiting generalisability. The study population was mostly highly educated females, which may not represent all employees with common mental disorders. The analysis was conducted at the employee level rather than the cluster level because one cluster had only one employee, which may have increased the risk of a type I error. Baseline imbalances existed, with more adjustment disorder diagnoses in the intervention group and more depression diagnoses in the control group, which may have affected the distribution of absence days.

The study was funded by Forskningsrådet om Hälsa, Arbliv och Välfärd and Karolinska Institute. No other conflicts of interest were declared.

Do not conclude that workplace involvement is ineffective for reducing sickness absence based on this null result. The intervention was delivered in primary health care by coordinators with limited training in work-focused interventions, and the study was underpowered, so the lack of effect may reflect the setting and implementation rather than the intervention itself.