Rheumatoid arthritis (RA), a chronic inflammatory disorder affecting approximately 0.6% of the global population and up to 1.6% in Germany, is characterized by joint swelling, pain, and potential for severe functional limitations. Beyond the physical impact, psychosocial distress, including depression (25-40%), anxiety (up to 77%), and fatigue, is prevalent in RA patients. Even with effective disease-modifying antirheumatic drugs (DMARDs), psychosocial outcomes often remain suboptimal, predicting increased disease activity, reduced quality of life (QoL), work impairment, and higher mortality. Therefore, a holistic approach to RA care is crucial, incorporating mental health support. Cognitive behavioral therapy (CBT) has demonstrated positive effects on psychosocial outcomes in RA patients, but access is limited. Digital therapeutics offer a potential solution to address this access issue. This study aimed to evaluate the efficacy of *reclarit*, a fully automated digital therapeutic utilizing CBT methods and lifestyle counseling, on psychosocial outcomes in RA patients with impaired QoL compared to treatment as usual (TAU) plus educational materials (active control). The German Digital Healthcare Act (Digitale-Versorgung-Gesetz), enacted in 2019, allows for the reimbursement of digital therapeutics, creating a context for this study.

Existing literature strongly supports the benefits of cognitive behavioral therapy (CBT) in improving psychosocial outcomes for individuals with rheumatoid arthritis (RA). Multiple studies have shown positive effects of CBT on depression, anxiety, and fatigue in this population. These findings are consistent across various studies and methodologies, highlighting the efficacy of CBT as a non-pharmacological intervention for managing the psychological burden of RA. However, access to CBT remains limited due to factors such as specialist shortages and cost. This gap in access has motivated the exploration of digital therapeutics as an alternative delivery method for CBT, potentially broadening access and improving treatment outcomes for a larger number of RA patients.

This prospective, randomized, single-blind study compared *reclarit* plus treatment as usual (TAU) to TAU plus educational materials in adult RA patients in Germany (German Clinical Trials Register DRKS00025256). Participants (n=354) were recruited online between April 29, 2021, and April 20, 2022, with data collected until November 10, 2022. Inclusion criteria included age 18+, RA diagnosis (ICD-10 M05-M06), internet access, sufficient German language comprehension, and impaired QoL (SF-36 MCS and PCS scores <50). Exclusion criteria included suicide risk, psychoses, and non-RA chronic inflammatory diseases. Participants were randomized 1:1 to *reclarit* or control using online randomization software. Patient-reported outcome (PRO) data were collected online at baseline, 3 months, and 6 months. The primary endpoint was health-related QoL assessed by the SF-36 at 3 months. Secondary endpoints included SF-36 at 6 months and other PROs (PHQ-9 for depression, GAD-7 for anxiety, BRAF-MDQ for fatigue, WSAS for social/work functioning, NRS for pain, HAQ-DI for physical function) at 3 and 6 months. User satisfaction was assessed using the Net Promoter Score (NPS). Statistical analysis involved intention-to-treat (ITT) and per-protocol (PP) analyses, ANCOVA, multiple imputation for missing data, chi-square tests, and responder analyses (RCI, PHQ-9, GAD-7).

At 3 months, the *reclarit* group showed significantly improved SF-36 MCS scores compared to the control group (mean difference 3.3, 95% CI 0.7, 5.9; p = 0.014). This effect was sustained at 6 months. Responder rates for SF-36 MCS were also significantly higher in the *reclarit* group (36.7% vs 27.5%; p = 0.019). Significant improvements were observed in the *reclarit* group for depression, anxiety (at 3 months), fatigue, and social/work functioning at both 3 and 6 months. No significant differences were found between groups in SF-36 PCS scores, pain, or disability. Post-hoc analyses showed significantly more responders in the *reclarit* group for depression (25.6% vs 12.9%; p = 0.002) and anxiety (25.3% vs 16.4%; p = 0.048). User satisfaction with *reclarit* was high (NPS +19.8). Subgroup analyses did not reveal significant differences in treatment effects based on age, gender, DMARD use, physiotherapy, or psychotherapy.

This study demonstrates the clinical effectiveness of *reclarit*, a digital CBT intervention, in improving psychosocial outcomes in RA patients with impaired QoL. The observed effect sizes for depression, anxiety, and fatigue are comparable to those reported in meta-analyses of conventional psychological interventions for RA. The lack of significant improvement in physical QoL and pain-related outcomes aligns with findings from meta-analyses of other psychological interventions, suggesting that the improvements are specifically related to the psychosocial aspects of the condition. The high user satisfaction and sustained improvements at 6 months highlight the acceptability and potential long-term benefits of this digital therapeutic. The findings are particularly relevant given the limited access to traditional CBT for RA patients and the increasing need for scalable, accessible mental health solutions in chronic disease management. The results support the integration of digital therapeutics, like *reclarit*, into standard care for RA to address the significant psychosocial burden experienced by many patients.

This randomized controlled trial provides strong evidence for the efficacy of the digital therapeutic *reclarit* in improving key psychosocial outcomes in adult RA patients with impaired health-related quality of life. The significant and sustained improvements in mental health, alongside high user satisfaction, suggest that *reclarit* offers a valuable addition to standard RA care. Future research should focus on broader implementation, evaluating its effectiveness under routine care conditions and exploring potential preventive applications in less-impaired populations.

The study's limitations include relatively small sample sizes in some subgroups (men and patients over 65). The inclusion criteria focused on patients with impaired QoL, potentially limiting generalizability to broader populations. Attrition rates were slightly higher in the intervention group, which may be attributed to participants discontinuing use after achieving sufficient benefit. Future research should include a broader range of patients and incorporate other relevant outcomes such as self-efficacy and pain catastrophizing to provide a more comprehensive understanding of the intervention's impact.