In this single-center, cross-sectional study, we selected patients with CHD who underwent cardiac surgery at the age of 18 years or older at the German Heart Center Munich between 2004 and 2013. For patients who underwent repeated operations in adulthood, the most recent operation was considered the reference point. Patients who had undergone isolated aortic valve procedures without prior cardiac intervention or operation before the age of 18 years were excluded from the patient selection. Furthermore, patients who had undergone cardiac transplantation, transvenous implantation of a pacemaker or implantable cardioverter-defibrillator (ICD) as an isolated procedure, and non-German-speaking patients were also excluded. Eligible subjects were invited to take part in the study. The recruited patients completed the surveys digitally via the Heartbeat Medical online platform (HRTBT Medical Solutions GmbH, Berlin, Germany). Patients’ clinical data were obtained after a review of the internal medical database.

The severity of CHD was defined according to the Bethesda classification (5). As not all were available in German, the surveys differed slightly from those of the APPROACH-IS (3, 6–12). The following surveys (German version) were selected for the assessment of the corresponding PROs: 1.

Perceived health status and life satisfaction: a.

Veterans RAND 12-item mental and physical scores (VR-12)

Continuous variables were reported as medians with interquartile ranges. Categorical variables were reported as frequencies with percentages. Score results were reported as medians with ranges (minimum–maximum) and mean with standard deviations. Demographic, medical, and surgical factors affecting a relevant percentage of subjects were selected as potential explanatory variables for the variation in score results. These included gender, severity of CHD, number of previous cardiac operations, age at first cardiac operation, age at last cardiac operation, age at study, presence of pacemaker or ICD, anticoagulant and beta-blocker therapy. As the scores of the scales in their original form have varying values and polarities, all scores were rescaled from 0 to 100 (0 being the worst subjective value and 100 being the best) to better illustrate their relationship with the clinical factors. The effect size was estimated using Pearson's correlation coefficient. P-values <0.05 were considered statistically significant.

To refine the granularity of the information reported by this study on ACHDs with different diagnoses and medical histories, we divided the patients into three groups according to the complexity of their primary diagnosis defined by the Bethesda classification: simple, moderate, or severe CHD. A comparison of patient characteristics and PROs between the groups was performed using a Kruskal–Wallis test or a pairwise Fisher's exact test as appropriate.

As absolute score values provide limited information, we compared the data obtained with those available in the literature on healthy subjects. However, the Health-Behavior Scale—Congenital Heart Disease was compared with young adults with CHD (median age 16.3 years), as the questionnaire was not administered to healthy subjects. After selecting studies with documented sample sizes, mean values, and standard deviations of the scores, we compared the results using Welch's t-test (11, 13–17). For the PHQ-8, a two-proportion Z-test was applied for patients reporting a score ≥10, which corresponds to the cut-off point for depression (16). Due to the mismatch between the questionnaires and the geographical diversity, we refrained from statistical comparisons with the APPROACH-IS and only reported its results for information. For better comprehension, the score results have also been rescaled from 0 to 100 for their graphical representation.

Statistical analysis and graphs were conducted and created with R, respectively (R Foundation for Statistical Computing, Vienna, Austria).

This study was approved by the Institutional Review Board of the Technical University of Munich (No. 145/20 S-KH on 28/04/2020). All recruited patients consented to the anonymous processing and publication of their data.

After pre-selection, according to the criteria set out in the Methods section, 670 subjects were deemed eligible and invited to participate in the study. In total, 196 patients completed the questionnaires (participation rate of 29%). Patient characteristics with between-group comparisons are listed in Table 1. The median age at the time of the study was 43 years (37–53 years), and the median time since the last cardiac operation was 13.4 years (10.6–15.5 years). Approximately half of the patients had undergone more than one cardiac operation in their lifetime (55%). The severity of CHD was evenly distributed. Patients with severe CHD had a notably higher number of previous cardiac surgeries, were younger at the time of their first operation, and had a higher incidence of pacemaker or ICD implantation. Female patients were more represented in the group with simple CHD. The most frequent primary cardiac diagnoses were atrial septal defect (n = 34, 17%), tetralogy of Fallot (n = 22, 11%), and mixed aortic valve disease (n = 11, 6%). The most frequent cardiac procedures in adulthood were patch repair of an atrium septum defect (n = 31, 16%), replacement of a right ventricle-to-pulmonary artery conduit (n = 21, 11%), and mitral valvuloplasty (n = 20, 10%). Supplementary Tables S2, S3 provide complete lists of the patients’ primary cardiac diagnoses and cardiac procedures in adulthood, respectively. The analysis of the following data of the patients who were contacted but did not respond to the questionnaires (n = 474) revealed no statistically significant differences with the study sample: sex (male patients 47% vs. 46%, P = 0.9), age at last heart operation [30 (23–40) vs. 30 (24–41) years, P = 1], age at the time of the study [43 (36–53) vs. 43 (37–53) years, P = 0.9], and complexity of the congenital heart defect according to the Aristotle comprehensive complexity score [9.5 (7.0–11.5) vs. 9.5 (6.2–11.0) points, P = 1, the Bethesda score not being available for these patients].

Details of sociodemographic characteristics, as reported by the patients, are listed in Table 2. The majority of patients were married or in a partnership (70%), were engaged in a professional activity (85% with full-time or part-time jobs), and had a driver's license (94%). The patients in the group with simple CHD were more likely to be married or in a partnership and had more children than the other two groups.

Score results are detailed in Table 3 and plotted in Figure 1. According to the institutional questionnaire, most patients reported improved wellbeing after the cardiac operation and were in functional NYHA class I or II. Except for the EQ-5D-5l (visual analog scale, VAS), which was slightly lower for the severe CHD group, the results regarding the patients’ perceived health status and life satisfaction, psychological functioning, and health risk behaviors were similar between the patient groups. Illness perception showed the most significant variation between the groups, with patients with severe CHD reporting significantly inferior results in all items except “Personal Control.”

The results of the correlation analysis are depicted in Figure 2. Older age at last cardiac surgery, older age during the study, having a pacemaker, and beta-blocker medication were all associated with worse perceived physical health. Aging was associated with better perceived mental health and greater coherence. Female patients reported significantly lower risks in overall health behavior and dental hygiene.

Of all the factors, the PROs from the IPQ-R showed the most remarkable occurrence of statistically significant associations with the investigated variables, especially the “Consequences” (i.e., the believed impact of the disease on various aspects of the patient's life), “Timeline acute/chronic” (i.e., the perceived duration of the disease), and “Identity” (i.e., the symptoms the patient attributes to the illness) items. The severity of CHD, number of previous cardiac operations, and beta-blocker medication had the strongest substantial negative correlations with illness perception. In contrast, older age at first cardiac surgery had the most significant positive correlation.

Details of the comparison of patient-reported outcomes with representative samples are listed in Table 4, and the results are plotted in Figure 3. The study population presented significantly better physical health perceptions and a sense of coherence than the available data on healthy subjects. Furthermore, the data showed a lower risk of dental hygiene compared with the selected sample of young adults with CHD. The results reported by APPROACH-IS for scores equivalent to our study are also listed in Table 4 as a reference.