Objective: To develop outcome indicators for the implementation of comprehensive interventions targeting the multimorbidity of myopia and obesity in children and adolescents, providing a basis for the co-prevention of multimorbidity and the outcome measurement of implementation research in children and adolescents.

Methods: Based on the RE-AIM framework, a preliminary set of indicators was constructed. The Delphi method was employed, with experts scoring and providing feedback on the proposed indicators via questionnaires. After each round of consultation, expert enthusiasm index, authority coefficient, coordination degree, and consensus level were calculated. Expert opinions were collected and analyzed to modify, delete, or add indicators based on consultation results and screening criteria. Two Delphi rounds were conducted until consensus was achieved.

Results: A total of 28 experts participated actually in both rounds. The Kendall' s W coefficients for the two rounds of expert consultation were 0.352 (χ2=413.952, P < 0.001) and 0.499 (χ2=405.044, P < 0.001), both statistically significant. The final outcome indicators for implementation research on comprehensive interventions for myopia and obesity comorbidity in children and adolescents included five primary dimensions with 13 secondary and 20 tertiary indicators. The dimension of reach included the number of children and adolescents involved, participant representativeness, and full-course participation representativeness. The dimension of effectiveness included multimorbidity incidence, myopia incidence, spherical equivalent, body mass index (BMI), overweight and obesity prevalence, waist-to-height ratio, comprehensive health knowledge score, and comprehensive health behavior score. The dimension of adoption covered school representativeness and representativeness of school nurses and teachers involved in implementation. The dimension of implementation included fidelity, content modification, and cost. The dimension of maintenance included individual health outcomes and organizational sustainment.

Conclusions: This study developed implementation outcome indicators for comprehensive interventions targeting multimorbidity of myopia and obesity among the children and adolescents based on the RE-AIM framework. These indicators can serve as a reference for optimizing intervention research strategies related to common multimorbidity among children and adolescents in China.