Digital rehabilitation aftercare shows steeper initial work ability improvement that disappears after adjustment

PURPOSE: The primary aim of this study was to compare the effectiveness of digital rehabilitation aftercare (digIRENA) with conventional rehabilitation aftercare (IRENA) and a control group without organized aftercare in improving work ability among orthopedic patients. METHODS: A total of 1056 orthopedic rehabilitation patients were recruited from multiple rehabilitation clinics in Germany and randomly assigned to three groups: digIRENA (n = 405), IRENA (n = 352), or a control group (n = 299). Work ability was assessed using the short version of the Work Ability Index at four time points: baseline, 13, 26, and 43 weeks post-baseline. Repeated-measures ANOVA was conducted to examine longitudinal trends in work ability, with additional analyses to assess the impact of age, gender, and employment status on outcomes. RESULTS: Work ability improved significantly over time in all three groups (F = 37.6, p < 0.01, η = 0.045). In the unadjusted analysis, the interaction between time and group was significant (F = 2.2, p < 0.01, η = 0.006), indicating a steeper initial improvement in the digIRENA group compared to IRENA and control. However, when adjusting for age, gender, and employment status, this difference was no longer significant, suggesting that selection bias and baseline differences explain the unadjusted group effect. Across all groups, younger and unemployed participants showed greater improvements in work ability. CONCLUSION: In unadjusted comparisons, digital aftercare showed a steeper initial improvement in work ability. However, once key sociodemographic factors were controlled for, these group differences disappeared.