The consortium project INTEGRATE-ADHD - comparison and integration of administrative and epidemiological ADHD diagnostic data by clinical assessment: study description, non-responder analysis, and sample characteristics

This paper aims to describe the study design, methodological approach, conduct, and sample characteristics of the data linkage project INTEGRATE-ADHD. The project was designed to evaluate the concordance and validity of administrative versus epidemiological and clinical ADHD diagnoses, thereby providing insights for health care and health care planning. The assessment of treatment satisfaction among families with children with ADHD, as well as the health economics of ADHD, is also part of the project. A total of 24,880 parents of children and adolescents statutorily insured with DAK-Gesundheit, who had at least one confirmed administrative ADHD diagnosis in one quarter of the 2020 insurance year, were invited to complete an online survey. The survey included questions on ADHD diagnosis, disorder-specific and comorbid psychopathology, health care utilisation, and both the quality of and satisfaction with health care. A random sampling procedure was applied to select 202 participants for a guideline-based clinical online assessment. Administrative, survey, and clinical diagnostic data were subsequently linked at the individual level. Non-responder analyses and sample characteristics were examined with descriptive statistics. Group differences were tested with chi-square and t-tests. Sample representativeness was evaluated. A total of 5,461 parents of youths (mean age = 12.5 years; 25.4% girls) participated in the survey (response rate: 21.5%). A guideline-based clinical ADHD decision could be made for a subsample of 201 participants (mean age = 12.1 years; 27.9% girls). Non-responder analyses indicated only minor differences in sociodemographic and health care–related variables, parents of more severely affected children and adolescents were more likely to participate in the survey. Weighting factors were calculated to adjust for these deviations. Non-responder analyses and comparisons with nationwide outpatient diagnostic data suggest that the results are broadly generalisable to German children and adolescents with an administrative ADHD diagnosis. By linking administrative, epidemiological, and clinical ADHD diagnostic data at the individual level, INTEGRATE-ADHD facilitates an individual-level evaluation of how administrative ADHD diagnoses relate to epidemiological and clinical assessments.