To evaluate patient-reported health effects of an add-on structured goal planning and supportive telephone followup rehabilitation program compared with traditional rehabilitation programs in patients with rheumatic diseases. In this pragmatic stepped-wedge cluster-randomized controlled trial 389 patients with rheumatic diseases recruited from six rehabilitation centres received either traditional rehabilitation or traditional rehabilitation extended with an add-on program tailored to individual needs. The add-on program comprised a self-management booklet and usage of motivational interviewing in structured individualized goal planning and four supportive followup phone-calls after discharge. Data were collected by questionnaires on admission and discharge from rehabilitation stay, and 6 months and 12 months after discharge. Primary outcome was health-related quality of life (HR-QoL) measured by the Patient Generated Index (PGI, 0-100, 0=low). Secondary outcomes included patient-reported health status, self-efficacy, pain, fatigue, global disease activity and motivation for change. The main statistical analysis was a linear repeated measures mixed model performed on the intention to treat population using all available data. A significant treatment effect of the add-on intervention on HR-QoL was found on discharge (mean difference = 3.32 [95% CI: 0.27, 6.37], p=0.03). No significant between-group differences were found after 6 or 12 months. Both groups showed positive changes in HR-QoL following rehabilitation which gradually declined, although the values remained at higher levels after 6 and 12 months compared with baseline values. The add-on program enhanced the short-term effect of rehabilitation with respect to patient-specific HR-QoL, but it did not prolong the effect as intended. This article is protected by copyright. All rights reserved.