Patients' satisfaction, successful treatment of diseases and cost-effectiveness are three of the main goals in healthcare, which in some cases are difficult to reconcile. Shared decision making (SDM) as a process of information exchange and negotiation can contribute as an essential lever to achieve these ambitious goals simultaneously (1). To successfully reach a shared decision, a positive and productive collaboration between physician and patient is needed (2). Physicians act as medical experts with their expertise in causes of disease, symptoms, treatment options with possible advantages and disadvantages. Based on the best available evidence they provide the information base for a meaningful physician-patient-conversation (3). The patient acts as an expert on himself, his preferences and his personal circumstances. Patients enrich the information exchange with their thoughts, experiences of disease, risk behavior and expectations—information that is not evident from any medical record (1). The active participation of both leads to a shared decision that is medically justifiable and provides the best fit for the individual patient. Such an exchange on equal terms meets patients need for better information, understanding and involvement in their medical decision making (4–6). In a study with more than 1.500 cancer patients in Germany over 80% of the participants preferred to take a collaborative or active role in decision making underlying the need for increased SDM-practice (7).

In addition to the arguments from the patient's point of view, SDM also offers advantages for physicians as well as the healthcare system: SDM strengthens patients' self-responsibility and knowledge of their disease, so that well-informed patients more rapidly recognize and communicate side-effects. This can be a protective factor against serious treatment complications, especially in complex decision-making situations with a multitude of treatment options, such as in the treatment of multiple sclerosis in neurology (8). Complementary, patients perceive themselves as more self-efficacious (6). In particular through the application of SDM, patients develop more realistic outcome expectations leading to increased patient satisfaction, greater treatment adherence, less decisional regret and less complaints (9–12).

In sum, there are many arguments in favor of SDM. This raises the question: How can SDM be successfully implemented in the hospital initially, and how can it be maintained so that SDM remains a matter of course in daily healthcare?

Only a limited number of SDM-interventions follow a comprehensive approach involving all relevant stakeholders, i.e., patients, physicians, nurses and other healthcare professionals (12). The SHARE TO CARE program (S2C) addresses each of these groups with a dedicated intervention module. Integrating four modules into a comprehensive implementation strategy, the S2C program aims to implement SDM within entire hospitals. The four S2C modules are:

(1) Training of all physicians. A minimum of 80% of physicians within each clinical department has to complete a multimodal training composed of an online-training session (13) and two individual feedback sessions based on videotaped patient consultations. Physicians first complete a 1-h online session presenting basic SDM knowledge and several simulations of physician-patient-interactions to demonstrate Do's and Don'ts in SDM. Subsequently, physicians take part in an individual SDM coaching session in a peer group setting (2–5 participants) based on their own videotaped patient consultations. Interaction of increased self-reflection through video excerpts and feedback from colleagues and experienced SDM coaches shall create an encouraging and constructive learning atmosphere. Later, physicians record another consultation and participate in a second small group training to further increase and consolidate their SDM skills. After successful training completion, physicians receive a certificate and education credits by the Physicians Chamber of the Federal State of Schleswig-Holstein.

(2) Activation of patients. To increase patients' participation and involvement in medical decision making, every patient receives information how to actively take part in their physician-patient consultations using the ASK-3 approach (14). By distributing various promotion/information material (e.g., SDM video clips on screens, roll ups, posters, flyers, promotional items, SDM web page, paper postcards and screen-based messages and media) inside each department, patients are encouraged to ask specific questions during their consultation to gain deeper understanding of their treatment opportunities.

(3) Implementation of evidence-based decision aids. Fostering patients' understanding of their condition and treatment opportunities is also done through online evidence-based Patient Decision Aids (EbPDA). These are developed within each department based on a literature and guideline review, in cooperation with physicians and patients. The evidence research team conducts a systematic review of best available evidence for all treatment opportunities available at the hospital. They also perform needs assessment interviews with patients to align with needs and preferences of patients in the specific decision situations. Methods are based on the German Standard of evidence-based patient information and the methods of evidence generation in patient information (15, 16). Considering EbPDA as a user-oriented interface, text information is complemented with video clips featuring local physicians explaining interventions and local patients who share their experience facing the same decision as the DA user. The process of DA development follows the International Patient Decision Aids Standards (17–19). Each EbPDA undergoes external review. The process of EbPDA development for the S2C program is described in detail elsewhere (20).

As decision aids will never cover every relevant decision within a hospital, clinical experts are to choose topics that are of relevance from a clinical perspective, preference-sensitive as well as sufficiently frequent. These topics are expected to induce a spill-over effect to decisions where no EbPDA is available in terms of a systematic consideration of benefits and harms of each treatment as well as the patient's preferences.

(4) Integration of nurses as SDM supporters. At least 80% of the nurses are educated how to integrate SDM within their own work and how to support patients and physicians regarding the application of the abovementioned modules. Beyond this, selected nurses (or physiotherapists, study nurses etc.) are trained as decision coaches to facilitate patients' decision processes with physicians. Training is designed in a similar way as physicians' coaching sessions: During 2 workshop days, healthcare professionals gain further knowledge about SDM, deep insight in the DAs of their specific department or section, and skills to support patients' decision making. Accompanied by the S2C trainer team, nurses complete decision coach training by recording coaching conversations with a patient twice and receiving individual feedback. Decision coaches function as emotional assistance to sensitize patients to unanswered questions and treatment preferences improving the physician-patient-consultation.

By completing all four modules, a department meets the criteria to be awarded with the S2C certificate. The fulfillment of the criteria is reviewed annually.

Initial findings from the hospital-wide implementation of SDM at the UKSH in Kiel indicate that the S2C program is feasible and effective (21).

Beyond the short-term effectiveness of SDM interventions, it is crucial that the effects are long-lasting, or can be maintained with reasonable effort. However, there is very limited research on the sustainability of SDM interventions. In a sample of patients with fibromyalgia, Bieber et al. (2) were able to show a diminished but still significantly enhanced SDM level 1 year after their SDM intervention. In a review by Martinez-Gonzalez et al. (22), only outcome parameters related to SDM—but not the SDM level itself—were reported, e.g., knowledge or perceived information level. No study was found with long-term effects (>3 months). Another study in outpatient asthma practices included data 1 year after implementation, but with poor comparability due to lack of a baseline survey (23).

In summary, there is no conclusive evidence on the sustainability of hospital wide implemented SDM interventions such as the S2C program. Although—given the substantial effort required for large-scale implementation of SDM—such evidence is particularly relevant as only a long-term effective intervention is cost-effective and reasonable for a hospital. To fill this research gap, the aim of this study was to examine the sustainability of the large-scale implementation of SDM with the S2C program at the UKSH in Kiel (24).

It had already been shown that the S2C program is feasible and can have positive effects on the SDM level right after full implementation: Immediately after the end of implementation, patients felt significantly more involved and better informed and prepared for decision-making (21). At that time, the healthcare professionals were trained recently and the learning content was fresh in their minds, the decision aids had been newly developed with a great deal of commitment from physicians, and patient activation had just been set up. In short, SDM was on everyone's agenda.

This new study is the first exploring the sustainability of a full S2C implementation in a hospital. The question was, how does the SDM level evolve months after the end of the initial implementation? Do departments deliberately invest resources to maintain the implementation, and does the effect on patient-reported SDM level and health literacy persist?

The results of this study show: Even 6–18 months after the end of the initial implementation of the S2C intervention, i.e., 2.5–3 years after the first physician has been trained, the SDM level is still significantly increased. Patients continue to perceive themselves as significantly more involved than before the intervention as indicated coherently by two different SDM measures, PICS and CollaboRATE. In addition, patients reported a higher health literacy while preparing for a decision. As patients were recruited regardless of their diagnosis, from acute and aftercare, from inpatient and outpatient care, in neurology and neurosurgery, these results seem exceptionally representative.

The sustained intervention effects can be attributed to at least two factors. On the one hand, it may be assumed that the effects from the initial intervention in terms of skills and attitudes have persisted among the healthcare professionals, and that they adhered to the procedures and pathways that were adapted to allow for SDM. In line with Légaré et al. (12), the comprehensiveness and intensity of a multifaceted program like S2C in combination with the fact that nearly all departments at the hospital in Kiel were transformed into SDM clinics simultaneously is supposed to have had enough impact to stimulate a cultural change that is more robust than a rather superficial adoption of SDM-related communication skills. On the other hand, the maintenance activity from the Neuromedical Center is regarded as important to secure sustainability. Within every hospital, let alone a university hospital, the turnover within the healthcare personnel requires constant introduction of new colleagues. The decision by the departments to continuously invest resources into SDM training and education, updates of decision aids etc. is both an important factor and a sign of appreciation of SDM. The intrinsic motivation to maintain SDM is further illustrated by the activities within the departments that exceeded the basic criteria required to renew the S2C certificate, such as ongoing scientific activity and public communication in cooperation with the National Competency Center for Shared Decision Making as well as the development of additional support models for patients regarding decision making.

Apart from the efforts within the hospital, an additional factor was established on the system level. In collaboration with the largest health insurance company in Germany, the Techniker Krankenkasse (TK), we managed to put in place a reimbursement scheme triggering an additional fee for every patient case within a department that is awarded with the S2C certificate at University Hospital Schleswig-Holstein. The motivation of the TK was to increase patient safety through enhancement of SDM, as it is recommended by the WHO (31). The reimbursement partly covers the costs for the professional SDM trainers, the updates of the decision aids etc. It is important to know that currently the departments have no financial benefits from this reimbursement; on the contrary, they invest own resources in terms of working hours of their staff. This corroborates their intrinsic motivation to maintain SDM by continuation of the S2C program. The amount of time needed to maintain SDM on a level that is sufficient for regular recertification is, however, much smaller than during the initial implementation phase.

Some possible limitations of this study have to be discussed. Firstly, the question may arise whether the results sustainability within two departments are sufficiently representative for the entire hospital. On the one hand, the Neuromedical Center is a large-volume center within the hospital, with a broad variety of diseases, treatments and patient characteristics. On the other hand, the S2C program has been successfully implemented in 15 other departments at the University Hospital Schleswig-Holstein simultaneously also using the standardized S2C approach (publications in preparation). There were no cues indicating that the implementation process in the Neuromedical Center was considerably different compared to the other departments. The reason the Neuromedical Center was chosen for examination of sustainability is that it was the first entire center that had started and fully completed the intervention. This allowed for the longest follow-up period during the overarching implementation project (24). Hence, it seems justified to interpret the results as proof of the sustainability of the S2C program in general. However, future results from other departments, and from other hospitals, should be gathered to underscore this conclusion.

Secondly, data might be biased by self-selection of responding patients. However, response rates of around 60% are to be viewed as comparably high indicating a rather low risk of selection bias. In addition, neither physicians nor the study group had any influence on the selection of patients enrolled in this study.

Thirdly, all outcome data on sustainability reflect the patients' point of view using PICS, PrepDM, and CollaboRATE as retrospective patient reported outcome instruments. It is indisputable, that the patient's experience is of major importance, especially when other patient-related variables like e.g., adherence are discussed. Nevertheless, the evaluation within other departments at the UKSH in Kiel also includes observer-based analyses of videotaped consultations using MAPPIN'SDM (32) and data on costs and quality of care as a result of the SDM implementation (24). With those future findings available, it will be possible to further corroborate the conclusions drawn from the current study.

Fourthly, data might also be biased by the occurrence of the Covid-19 pandemic. While the pre-intervention data (t₀) were collected during regular hospital operation, the long-term (t₂) data collection took place from May 2021 on, immediately after a multi-week lockdown for the majority of the German population. During this period, elective procedures and treatments were restricted or postponed, so that the patient sample must be expected to be different from the pre-intervention sample. However, a reduction of elective treatments at t₂ should result in a lower level of perceived SDM, not a higher one. Therefore, the positive effect in this study can hardly be explained by the influence of the pandemic. On the contrary, the pandemic in general made it even harder for all departments to adhere to the intervention program. Nevertheless, in view of the major influence of the pandemic on all levels of healthcare, post-pandemic replications of these findings are welcome.

Fifthly, in subsequent analyses of this study, we found a potential impact of age on both indicators of the SDM level indicating a smaller long-term effect among older patients. However, the size of some of the compared subgroups is very small. As such effects had not been found in previous data from the same population (21), the slightly differential effect among the subgroups should be interpreted cautiously until more long-term data are available.

In conclusion, this study is valuable as it provides long-term results from a hospital wide SDM implementation effort. It shows that the comprehensive, multifaceted S2C program has significant long-term effects on patient reported SDM and health literacy by inducing sustained intervention effects and the willingness among health professionals to actively maintain the SDM implementation. Future results from the ongoing S2C program in Kiel and in other hospitals will further broaden the knowledge on the sustainability of the program.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The study was approved by the Ethics Committee of Faculty of Medicine of Kiel University (reference number A111/18).

FG, KW, FS, JR, LS, and MLC contributed to conception and design of the study. CS-K and CB organized the database. LS, MC, and WS performed the statistical analysis. CS-K wrote the first draft of the manuscript. FG, FS, CB, and CS-K wrote sections of the manuscript. All authors contributed to manuscript revision, read, and approved the submitted version.

The SHARE TO CARE project was funded by the German Innovation Fund of the Federal Joint Committee (NVF170009) and the Medical Faculty of the Kiel University.

FG and FS are co-founders, JR is CEO and co-funder of SHARE TO CARE Patientenzentrierte Versorgung GmbH (Cologne/Germany). JR is CEO of TakePart Media + Science GmbH, Cologne, Germany. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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