Limitations and Recommendations for Future Research and Practice
RECRUITMENT
Although this study used the gold standard with a randomized controlled trial between the IG and the ACG, it should be kept in mind that the CompG was only matched but not randomized. The reason was that there were ethical concerns to not administer the intervention to patients with PACS in the same recruitment in which other patients received the intervention. It was anticipated that many of the potential patients with PACS would have already sought help or treatment, and we did not want to cause substantial frustration and despair when randomizing them to a passive control group. Due to the different recruitment pathways, patients could be immediately informed that they would only receive questionnaires. To statistically control for differences between groups, we chose the PSM approach.The inclusion criteria were largely the same for all groups, including patients who had the same symptoms of PACS, were between 18 and 60 years old, had not received previous treatment, and did not work in the health care sector. Nevertheless, patients in the CompG were recruited from the whole country of Germany, not just Bavaria, to reach a potentially larger pool of participants. In the future, randomization and completely similar inclusion criteria should be applied to allocate patients to all groups, including a passive control group. This would be beneficial to ensure the comparability of patients across groups as well as the generalizability of findings.In this study, the follow-up period after completing the digital assessments was only 6 weeks due to the total funding period of 12 months. Despite the apparently stable improvements in both the IG and the ACG, this period is too short to conclude that the program caused sustainable improvements. This is especially true due to the dynamic and fluctuating nature of PACS symptoms that many patients experience. Furthermore, no effects of the diagnostic assessment were found, which might have been, among other reasons, because of a too short follow-up period. Patients received recommendations for future interventions, such as rehabilitation after the diagnostic assessment, which was approximately 12 weeks before the follow-up measure. During that time, most patients could not apply for and complete rehabilitation, so the long-term effects of the diagnostic assessment were potentially underestimated. Despite the limited follow-up period that should be addressed in future intervention evaluations, we believe that as one of the first studies examining an intervention aimed at treating PACS, our research provides valuable insights into potential treatment approaches during this pressing health care challenge.In addition, digital interventions and the support of personal pilots could not be evaluated independently in this design, but the results indicated that a combined approach is effective in treating PACS. It is possible that the patients took part in other interventions, as the personal pilots empowered them to find effective medical treatment. This can also be seen as a strength of this evaluation as it examines an applied approach in a realistic health care setting. However, it is possible that some of the effects that we found were caused by the placebo effect rather than specific intervention effects, as indicated in the discussion. In this study, we did not have a placebo control arm, which would be beneficial for future research. This group could include unspecific interventions (eg, information about the COVID-19 pandemic and PACS symptoms) as well as counseling that is not focused on symptom management).Finally, all outcome assessments were taken at a subjective level only and need to be validated with objective measurements. This is also true for the condition of PACS, as only patients in the IG and ACG were assessed for whether they had PACS. More objective assessments should be applied to carefully diagnose PACS and and improvements in the condition (eg, spirometry or electrocardiography).