3.1. Strength and limitations of the study
RLS
This study is the first to investigate 2 non-drug therapy options for RLS that could expand the current treatment spectrum through self-applicable, openly accessible, and cost-effective measures. On the one hand, both therapies can be implemented in addition to the existing routine therapy, and, on the other hand, they can potentially limit or prevent the side effects of the existing drug therapy by helping to reduce the dose. After instruction, patients are largely independent of therapists in the implementation of the intervention and gain self-efficacy in the best case.Limitations arise from the fact that this is an exploratory study designed to investigate feasibility and assess potential impact, but not a study with a design that allows the confirmation of a formal hypothesis, a primary outcome based on a valid sample size calculation. In this study, routine care alone is the control condition. This means that patients assigned to the control group do not receive additional intervention in their routine care, as is the case with the hydrotherapy and acupressure groups. This means that there is no comparison group for possible specific effects of acupressure or hydrotherapy, such as sham procedures, on both study interventions. Furthermore, the study physicians and patients are not blinded to the interventions, whereas the data analysts are. Therefore, if there are clinically relevant effects of the interventions, we cannot say that they are due to them. It could also be due to other factors, such as “doing something,” “taking time for oneself,” “relaxing,” and “participating in a study.” Patients in the control group could be frustrated about being assigned to a “waiting group” and could be influenced in their outcome evaluation by negative affect.However, self-applied acupressure and hydrotherapy are not easily blinded, making the sham control of the 2 study interventions difficult.Because outcome parameters are collected solely from patients and through subjective measures, behavioral change and dissatisfaction may occur if patients do not receive the desired intervention. These patients are also more likely to be lost to follow-up.Another critical point could be the training of the patients. Live training for the study interventions will occur only once at the beginning of the intervention, and there will be no personal visual inspection by the study physicians during the study to ensure that the applications are performed correctly. This can lead to a situation in which the possible effects of the interventions do not take effect because they were performed incorrectly. Therefore, in the case of missing effects, it is not possible to say with certainty whether this is due to incorrect execution or the lack of effect of the study intervention itself.Moreover, patients in the acupressure group have some freedom in choosing the quality of the pressure to be applied (e.g., constant pressure, pulsating massage), which could lead to different results according to the theory of Chinese medicine.This exploratory study can provide a better understanding of the effects of complementary and self-administered interventions in patients with RLS. This may bring new questions to light so that future research questions in the field of RLS therapy can be refined. This study can also be used to formulate hypotheses about the causal relationships between the study interventions and their impact on RLS severity and quality of life in patients with RLS. Another advantage of this study is that we can see how both interventions work in their natural environment, what problems occur, and whether it is safe to do them at home.