The Structured Delegation of Medical Care Services for Patients With Inflammatory Rheumatic Diseases

Findings of a Randomized Controlled Trial (the StärkeR Project)

Background: In some areas of Germany, there is a shortage of specialist physicians for patients with inflammatory rheumatic diseases. Delegating certain medical care services to qualified, specialized rheumatological assistants (SRAs) might be an effective way to supplement the available capacity for specialized medical care.

Methods: Patients under stable treatment for rheumatoid arthritis (RA) or psoriatic arthritis (PsA) were included in this trial, which was designed to demonstrate, in a first step, the non-inferiority of a form of care involving delegation of physicians’ tasks to SRAs (team-based care), in comparison to standard care, with respect to changes in disease activity at one year. “Non-inferiority,” in this context, means either superiority or else an irrelevant extent of inferiority. In a second step, in case non-inferiority could be shown, the superiority of team-based care with respect to changes in patients’ health-related quality of life would be tested as well. Disease activity was measured with the Disease Activity Score 28, and health-related quality of life with the EQ-5D-5L. This was a randomized, multicenter, rater-blinded trial with two treatment arms (team-based care and standard care). The statistical analysis was performed with mixed linear models (DRKS00015526).

Results: From September 2018 to June 2019, 601 patients from 14 rheumatological practices and 3 outpatient rheumatological clinics in the German states of North Rhine–Westphalia and Lower Saxony were randomized to either team-based or standard care. Team-based care was found to be non-inferior to standard care with respect to changes in disease activity (adjusted difference = −0.19; 95% confidence interval [−0.36; −0.02]; p <0.001 for non-inferiority). Superiority with respect to health-related quality of life was not demonstrated (adjusted difference = 0.02 [−0.02; 0.05], p = 0.285).

Conclusion: Team-based care, with greater integration of SRAs, is just as good as standard care in important respects. Trained SRAs can effectively support rheumatologists in the care of stable patients with RA or PsA.

In some areas of Germany, there are gaps in the care of patients with inflammatory rheumatic diseases (1). The comparatively small number of specialists working in rheumatology contributes to this, as shown in the memorandum of the German Society for Rheumatology (2). Yet there is also a misallocation of rheumatology manpower, considering that routine work, documentation, etc., could most likely be carried out by specialized rheumatological assistants (SRAs), without increasing disease activity or reducing patient health-related quality of life.

The European Alliance of Associations for Rheumatology (EULAR) recommended as early as 2012 a stronger involvement of nurses to improve the care of patients with chronic inflammatory arthritis (3) (updated 2018 [4]). While in other countries (for example in the Netherlands and England) team building to include the delegation of medical tasks to staff from non-physician healthcare professions is already quite advanced in some cases (4), in Germany it has so far been slow to develop, despite the fact that special courses for medical assistants have been available since 2006. Through cooperation between the BDRh (Professional Association of German Rheumatologists), the DGRh (German Society for Rheumatology) and the Rheumatism Academy (RhAk), a curriculum was created that qualifies for the title “Specialized Rheumatological Assistant DGRh”. In April 2021, the German Medical Association decided to extend this model curriculum of continuing education to include 120 teaching units.

The project “Structured Delegation of Physician Services as Part of a Concept Based Cooperation for the Management of Inflammatory Rheumatic Diseases” (acronym: “StärkeR”) was based on the hypothesis that adequately qualified SRAs can effectively take over certain aspects of patient care. A randomized, multicenter, rater-blinded trial assessed a new team-based form of care involving the increased delegation to SRAs and compared it with standard care in patients with rheumatoid arthritis (RA) or polyarticular psoriatic arthritis (PsA). The StärkeR study explored the following hypotheses:

1. The team-based form of care is not inferior to standard care as regards changes in disease activity.

2. Changes in patient health-related quality of life are better under team-based care than under standard care.

Method

SRA training and tasks

In the first year of the project, healthcare professionals were trained to become SRAs (if they were not already). This was followed by project-related training to prepare SRAs for the requirements associated with the delegation of tasks (see eMethods).

Under the team-based form of care with increased delegation to the SRAs, the SRA became the primary contact person for patients during a one-year period. SRA tasks included:

• Management of the three-monthly follow-up reviews, including history of disease progression, comorbidities and infections, vaccination status, medication use, adverse drug reactions, and capacity to work; calculation of a disease activity score (Clinical Disease Activity Index [CDAI] [5]) (eMethods).
• Optimization of the treat-to-target principle (6) by discussing the calculated CDAI score during the patient’s visit to the rheumatologist: review the need for treatment adjustment in the event of deviation of disease activity from the target range (CDAI >10) or, in cases of skin involvement, >10% of skin affected by psoriasis in patients with PsA (while still adhering to the delegation concept).
• Improvement of medication safety by discussing the current medication plan with the patient.

Inclusion and exclusion criteria

The study included adults

• with a diagnosis of RA according to an expert (rheumatologist) opinion, based on the EULAR criteria (7), and a disease course free of complications for three months with low disease activity in the last quarter as defined by a disease activity score (DAS) 28 <3.2 (28 joints assessed, as well as erythrocyte sedimentation rate [range 0–9.4]) (8), or
• with a diagnosis of polyarticular PsA according to an expert opinion, based on the CASPAR criteria (9) (CASPAR, Classification Criteria for Psoriatic Arthritis), and with a complication-free course for three months and low disease activity in the quarter before baseline (defined as for RA), and extent of skin affected by psoriasis ≤10%.

Exclusion criteria were limited legal capacity, insufficient knowledge of German, and a complicated comorbidity.

Primary endpoints

The primary endpoints were

1. change in disease activity (as measured with the DAS28) and

2. change in health-related quality of life (as measured with the EuroQol in five dimensions and five response levels [EQ-5D-5L]) (10), each after one year.

These endpoints were arranged hierarchically, meaning that examination of the second endpoint requires statistical significance of the first endpoint. We refer to the eMethods for details on determining sample size and the instruments used for assessment.

Randomization and measurement of primary and secondary endpoints

After informing the patients about the trial and obtaining their written consent, a telephone interview was conducted, followed by patient-by-patient randomization (1:1). Stratified randomization by center was used to ensure equal distribution of treatment groups within each center. The result was faxed from the data center to the practice/clinic.

At baseline and after one year, DAS28 and skin involvement due to psoriasis were assessed by a qualified assessor who was not a member of the practice team. The assessors were medical staff members of the Ruhr District Rheumatology Center and blinded to the randomization result. The EQ-5D-5L was obtained in a telephone interview by interviewers who were also blinded. The evaluating statistician was unblinded to group allocation only after database closure and finalization of the statistical evaluation plan.

Secondary analysis was conducted to determine the impact of form of care on functional capacity (11), physical activity (12), depressive tendency (13), pain intensity, fatigue, sleep disturbance, C-reactive protein (CRP), and patient satisfaction. In addition, resource use (14) was recorded in terms of health economics. The assessments took place every six months. Details regarding the assessment instruments for the secondary endpoints can be found in the eMethods.

Statistical analysis

The hierarchical evaluation of the two-part primary endpoint allows the tolerated error probability for a type-1 error to be reapplied at the second step if the previous step achieves statistical significance. For analysis of the first part of the primary endpoint, a linear mixed model was used for the data of the per-protocol population to assess non-inferiority (non-inferiority margin set at 0.4 [15], probability of error 2.5%) – in line with the recommendations of the European Medicines Agency (EMA) (16). The second part of the primary endpoint was analyzed in a linear mixed model (5% probability of error) for the intention-to-treat population. Sensitivity analyses were performed for the two primary endpoints in the other population. A more detailed description of the statistical evaluations can be found in the eMethods.

Ethical and administrative aspects

The project complied with good clinical practice. In addition to obtaining informed consent, this involved consultation with the ethics committees (in charge: Ethics Committee of the Medical Association of Westphalia-Lippe and the Westphalian Wilhelms University of Münster; file number: 2018–144-f-S, positive opinion on May 23, 2018) and monitoring of the centers. The project was funded by the Innovation Fund (grant number: 01NVF17004) and retrospectively registered with the German Clinical Trials Registry (DRKS00015526).

Results

Between September 2018 and June 2019, 650 patients from 14 specialist rheumatology practices and three rheumatology outpatient clinics in North Rhine-Westphalia and Lower Saxony were screened, and 601 were randomized, with 297 patients assigned to the team-based form of care and 304 to standard care. Of these, two patients in the team-based form of care group and five in the standard care group had to be excluded from the intention-to-treat analysis because they did not attend the baseline visit or had previously withdrawn their consent. Thus, 295 patients were included for the team-based form of care and 299 for standard care. Two hundred and seventy-eight patients from the team-based form of care and 280 from standard care were available for per-protocol analysis. One death occurred in each group (cause of death: traumatic brain injury under standard care and myocardial infarction under team-based care) (Figure 1).

Figure 1

Flowchart of the project “Structured Delegation of Physician Services as Part of a Concept Based Cooperation for the Management of Inflammatory Rheumatic Diseases” (StärkeR)

eFigure

CRF, case report form; SRA, specialized rheumatological assistant; RC, rheumatology center

Patient characteristics at baseline

There were no significant differences between the two types of care at the baseline examination. Average age was 62 years; 78% of the study participants were female, and 83% had RA. The average DAS28 score of 3.1 was in the low disease activity range (Table 1).

Table 1

Patient characteristics at baseline

Primary endpoints

The standard care group showed an average increase of 0.04 in the DAS28 score over the course of one year (standard deviation: 1.15), whereas the team-based form of care showed a decrease of 0.14 (1.07), resulting in a difference of −0.18 in favor of the team-based care group. After adjustment in the linear mixed model, this difference changed to −0.19 (95% confidence interval: [−0.36; −0.02]), and the p value for non-inferiority was <0.001. The additional test for superiority yielded a p value of 0.025, thus demonstrating superiority in a statistical sense (Table 2, Figure 2).

Figure 2

Estimated difference and 95% confidence interval (team-based model of care - standard care) of changes in the DAS28 after one year.

Table 2

Analysis of the primary endpoints

Analysis of changes in health-related quality of life over the course of one year showed an improvement in EQ-5D-5L of 0.01 (0.23) for standard care and 0.02 (0.21) for team-based care, resulting in an overall difference of 0.01 in favor of team-based care. The linear mixed model demonstrated an estimated difference of 0.02 [−0.02; 0.05] (p = 0.285) (Table 2). See eResults for full model results of the primary endpoints and sensitivity analyses.

Secondary endpoints

Statistical analysis for the secondary endpoints showed no relevant differences between the forms of care (Table 3; see eResults for sensitivity analysis in the per-protocol population).

Table 3

Analysis of the secondary endpoints

Over the course of the study, SRAs took progressively less time to perform delegated tasks; they ultimately required a mean of 16 minutes per patient instead of the initial 26 minutes. The median physician time spent per patient after one year in the team-based care setting was six minutes, compared with 14 minutes in the standard care setting.

In the final telephone interview, 64% of the 282 accessible patients in the team-based form of care and 66% of the 286 patients in standard care reported being “very satisfied” with the opportunity to ask questions, and 32% and 29%, respectively, were “satisfied” with this. Sixty-five percent and 67% of patients were “very satisfied” with the information they received, respectively, and 28% in both groups were “satisfied” . In the final questionnaire to all participating physicians and SRAs, 70% of physicians and 93% of SRAs reported that patients would have liked the SRAs to continue involvement in their care.

The questionnaire-based patient data on the use of healthcare services did not show relevant differences between the treatment groups, either for individual elements of the service or in terms of estimating total annual costs (Table 4, details in eTable 1).

Table 4

Estimated costs per year and patient based on resource use data

eTable 1

Estimated costs per year and patient based on resource use data

eTable 2

Check list for specialized rheumatological assistants (SRAs)

eTable 3

Calculation procedures of the cost types included in the total cost estimate and source of the reference cost amounts used

eTable 4

Analysis of the first primary endpoint DAS28—full model in the per-protocol population

eTable 5

Analysis of the second primary endpoint EQ-5D-5L—full model in the intention-to-treat population

eTable 6

Sensitivity analysis of the first primary endpoint DAS28—full model in the intention-to-treat population

eTable 7

Sensitivity analysis of the second primary endpoint EQ-5D-5L—full model in the per-protocol population

eTable 8

Sensitivity analysis of the secondary endpoints in the per-protocol population

Discussion

The aim of the StärkeR project to demonstrate the non-inferiority of team-based versus standard care in terms of disease activity in patients with stable RA or PsA in a randomized, multicenter, rater-blinded design was achieved by the present study. Several international studies (17, 18, 19) and a meta-analysis (20), as well as a German study also supported by the Innovation Fund, came to similar conclusions as the StärkeR project (21). However, the German study had a different design without blinding of the endpoint measurement, with quarterly alternating care by the SRA and the physician in the SRA group, and the possibility of including patients with high disease activity. Overall, it can be assumed that a team-based form of care with delegation of certain physician tasks to qualified SRAs is possible in the German healthcare system and is largely equivalent to standard care.

This offers several advantages, as the freed-up physician resources can result in an improved allocation of rheumatologic expertise to the benefit of patients with urgent treatment needs. Although the total treatment time of 22 minutes for the team-based model of care was slightly longer than that for standard care, there was a physician time gain of eight minutes per patient (14 minutes of physician treatment time in standard care, six minutes in team-based care). In the German study mentioned above, the mean physician treatment time was almost as long in the delegation group, at seven minutes (21). After the familiarization period, SRAs became more efficient in everyday care, although no refresher course was offered. As expected, SRAs initially required a relatively large amount of time (mean 26 minutes) per consultation; over time, however, this eventually decreased to 16 minutes per patient.

No evidence for superiority of the team-based form of care in terms of health-related quality of life was demonstrated with respect to the second study objective. Both groups showed only a slight, clinically insignificant, improvement in EQ-5D-5L over the course of one year.

There was no difference between the treatment groups with regard to the secondary endpoints. Patient satisfaction was also comparably high. Differences in patient satisfaction as in England (22) were not evident – this was possibly a reflection of the different healthcare systems.

While cost and efficiency studies of team-based care are already available from other European countries (17, 23), such studies have so far been lacking in Germany. Resource use as assessed by health economic analysis showed no relevant differences between the treatment strategies in the StärkeR project. In particular, the type of care provided had no impact on the costs associated with prescriptions for remedies or medications.

Limitations

Limitations arise on the one hand from restricting the study to patients with the diagnoses RA and PsA. However, similar results have already been shown for patients with spondyloarthritis (24, 25) and gout (26). On the other hand, only patients with a stable disease course, i.e. with low disease activity in the previous months and without complicating comorbidities, were included in the StärkeR project. The available reports on the delegation of SRAs for patients with higher disease activity at every other consultation (21) and in patients with stable co-morbidities (17, 19) showed similar good results for delegation in terms of disease activity to our study.

The exclusion of seven patients from the intention-to-treat population for the analysis of the second primary endpoint does not constitute a limitation in our view, because only those patients were excluded who did not present at the baseline visit or who withdrew their consent immediately after randomization and before baseline. This approach is consistent with the recommendations of the International Council for Harmonisation (27). The intention-to-treat evaluation principle was not violated because the randomization result was not announced before the baseline visit and was thus unknown to the patients.

Because this was not a cluster-randomized trial that assigns entire practice teams to a particular form of care in each case, it could not be ruled out in principle in the StärkeR project that standard care patients also encountered a trained SRA in the office or outpatient clinic, which could result in a convergence of the effects of the two forms of care. Despite this possible limitation, however, our study even showed statistical superiority of SRA treatment with respect to disease activity. This underlines the reliability of the results.

Conclusion

The principles and long-term advantages of delegation to non-physician health professionals were presented by an ad hoc committee of the DGRh in 2020 (28). The results of the StärkeR project constitute a further step towards more delegation of physician tasks to qualified SRAs with the aim of increasing the capacity of rheumatological care while maintaining quality.

Funding

The StärkeR project was funded by the Innovation Fund (funding code: 01NVF17004). The grant was applied for by Prof. Braun and Prof. Trampisch. Directly or indirectly, all authors were supported by Innovation Fund grants.

Acknowledgments

The authors would like to thank the patients, specialized rheumatological assistants, and assessors who participated in the StärkeR project. They would also like to thank the Rheumatism Academy (especially Prof. Erika Gromnica-Ihle MD), Dr. Gisela Reichmuth MD (for conducting the joints examination course), Dr. Ioana Andreica MD and Barbara Guminski (for organizing the assessor assignments), the AMIB employees Michelle Stein, Julien Stein, Silvia Stein, Achim Gursch, the BARMER employees Till Beckmann and Ulrich Walter as well as the employees of the call center, and finally the participating rheumatologists Dr. Ulrich Schoo MD, Dr. Ernst Gernot Scheibl MD and Dr. Albert Schmid MD.

Data sharing

Individual patient data (after anonymization) that support the findings reported in this article (text, tables, figures, and eSupplement) may be made available to academic researchers upon request in the period from three months to five years after publication of this article. Proposals should be directed to Dr. Anna Mai ([e-mail]). The application process includes scrutiny of the intended research question and research method. After approval, the data will be made available on an external website. Applicants must sign a data access agreement for access to data. The data may only be used for the purposes formulated in the evaluation plan.

Conflict of interest statement
Judith Günzel received reimbursement of participation fees for an event by Abbvie.

Dr. Elmar Schmitz received reimbursement of congress participation fees from Sandoz and Hexal.

The other authors confirm that there are no conflicts of interest.

Manuscript received on 5 October 2021, revised version accepted on 12 January 2022

Translated from the original German by Dr. Grahame Larkin, MD.

Corresponding author
Dr. Anna Mai PhD (Sport Science)

Department of Medical Informatics, Biometry and Epidemiology

Ruhr University Bochum, 44780 Bochum, Germany

Cite this as
Krause D, Mai A, Denz R, Johow J, Reese JP, Westerhoff B, Klaassen-Mielke R, Timmesfeld N, Rittstieg A, Saracbasi-Zender E, Günzel J, Klink C, Schmitz E, Fendler C, Raub W, Böddeker S, Dybowski F, Hübner G, Menne HJ, Lakomek HJ, Sarholz M, Trampisch U, Trampisch HJ, Braun J: The structured delegation of medical care services for patients with inflammatory rheumatic diseases—findings of a randomized controlled trial (the StärkeR project). Dtsch Arztebl Int 2022; 119: 157–64. DOI: 10.3238/arztebl.m2022.0109

►Supplementary material

eReferences, eMethods, eTables, eFigures, eBox:
www.aerzteblatt-international.de/m2022.0109

References

1. Albrecht K, Callhoff J, Edelmann E, Schett G, Schneider M, Zink A: Klinische Remission bei rheumatoider Arthritis. Daten aus der Früharthritiskohortenstudie CAPEA. Z Rheumatol 2016; 75: 90–6

2. Zink A, Braun J, Gromnica-Ihle E, et al.: Memorandum der Deutschen Gesellschaft für Rheumatologie zur Versorgungsqualität in der Rheumatologie – Update 2016. Z Rheumatol 2017; 76: 195–207

3. van Eijk-Hustings Y, van Tubergen A, Boström C, et al.: EULAR recommendations for the role of the nurse in the management of chronic inflammatory arthritis. Ann Rheum Dis 2012; 71: 13–9

4. Bech B, Primdahl J, van Tubergen A, et al.: 2018 update of the EULAR recommendations for the role of the nurse in the management of chronic inflammatory arthritis. Ann Rheum Dis 2020; 79: 61–8

5. Smolen JS, Aletaha D: Scores for all seasons: SDAI and CDAI. Clin Exp Rheumatol 2014; 32: S75–9.

6. Smolen JS, Aletaha D, Bijlsma JWJ, et al.: Treating rheumatoid arthritis to target: recommendations of an international task force. Ann Rheum Dis 2010; 69: 631–7

7. Aletaha D, Neogi T, Silman AJ, et al.: 2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Arthritis Rheum 2010; 62: 2569–81

8. Fransen J, van Riel PLCM: The disease activity score and the EULAR response criteria. Rheum Dis Clin North Am 2009; 35: 745–57, vii-viii

9. Taylor W, Gladman D, Helliwell P, Marchesoni A, Mease P, Mielants H: Classification criteria for psoriatic arthritis: development of new criteria from a large international study. Arthritis Rheum 2006; 54: 2665–73

10. Ludwig K, Graf von der Schulenburg JM, Greiner W: German value set for the EQ-5D-5L. Pharmacoeconomics 2018; 36: 663–74

11. Zochling J, Stucki G, Grill E, Braun J: A comparative study of patient-reported functional outcomes in acute rheumatoid arthritis. J Rheumatol 2007; 34: 64–9.

12. Trampisch US, Platen P, Moschny A, Wilm S, Thiem U, Hinrichs T: Messung körperlicher Aktivität bei älteren Erwachsenen. Übereinstimmung zwischen PRISCUS-PAQ und Akzelerometrie. Z Gerontol Geriatr 2012; 45: 212–7

13. Löwe B, Kroenke K, Gräfe K: Detecting and monitoring depression with a two-item questionnaire (PHQ-2). J Psychosom Res 2005; 58: 163–71

14. Seidl H, Bowles D, Bock JO, et al.: FIMA-Fragebogen zur Erhebung von Gesundheitsleistungen im Alter: Entwicklung und Pilotstudie. Gesundheitswesen 2015; 77: 46–52

15. Mai A, Braun J, Reese JP, et al.: Nurse-led care versus physician-led care in the management of rheumatoid arthritis and psoriatic arthritis (StaerkeR): study protocol for a multi-center randomized controlled trial. Trials 2019; 20: 793

16. Piaggio G, Elbourne DR, Altman DG, Pocock SJ, Evans SJ: CONSORT Group. Reporting of noninferiority and equivalence randomized trials: an extension of the CONSORT statement. JAMA 2006; 295: 1152–60

17. Ndosi M, Lewis M, Hale C, et al.: The outcome and cost-effectiveness of nurse-led care in people with rheumatoid arthritis: a multicentre randomised controlled trial. Ann Rheum Dis 2014; 73: 1975–82

18. Primdahl J, Sørensen J, Horn HC, Petersen R, Hørslev-Petersen K: Shared care or nursing consultations as an alternative to rheumatologist follow-up for rheumatoid arthritis outpatients with low disease activity—patient outcomes from a 2-year, randomised controlled trial. Ann Rheum Dis 2014; 73: 357–64

19. Bergsten U, Almehed K, Baigi A, Jacobsson LTH: A randomized study comparing regular care with a nurse-led clinic based on tight disease activity control and person-centred care in patients with rheumatoid arthritis with moderate/high disease activity: a 6-month evaluation. Musculoskeletal Care 2019; 17: 215–25

20. Thurah A de, Esbensen BA, Roelsgaard IK, Frandsen TF, Primdahl J: Efficacy of embedded nurse-led versus conventional physician-led follow-up in rheumatoid arthritis: a systematic review and meta-analysis. RMD Open 2017; 3: e000481

21. Hoeper JR, Zeidler J, Meyer SE, et al.: Effect of nurse-led care on outcomes in patients with ACPA/RF-positive rheumatoid arthritis with active disease undergoing treat-to-target: a multicentre randomised controlled trial. RMD Open 2021; 7: e001627

22. Hill J, Thorpe R, Bird H: Outcomes for patients with RA: a rheumatology nurse practitioner clinic compared to standard outpatient care. Musculoskeletal Care 2003; 1: 5–20

23. van den Hout WB, Tijhuis GJ, Hazes JMW, Breedveld FC, Vliet Vlieland TPM: Cost effectiveness and cost utility analysis of multidisciplinary care in patients with rheumatoid arthritis: a randomised comparison of clinical nurse specialist care, inpatient team care, and day patient team care. Ann Rheum Dis 2003; 62: 308–15

24. Kiltz U, Spiller I, Sieper J, Braun J: Ist eine Delegation ärztlicher Leistungen auf rheumatologische Fachassistenten bei der Evaluierung von Patienten mit Verdacht auf ankylosierende Spondylitis möglich? – Ergebnisse der PredAS-Studie. Z Rheumatol 2020; 79: 729–36

25. Molto A, Gossec L, Poiraudeau S, et al.: Evaluation of the impact of a nurse-led program of systematic screening of comorbidities in patients with axial spondyloarthritis: The results of the COMEDSPA prospective, controlled, one year randomized trial. Semin Arthritis Rheum 2020; 50: 701–8

26. Doherty M, Jenkins W, Richardson H, et al.: Efficacy and cost-effectiveness of nurse-led care involving education and engagement of patients and a treat-to-target urate-lowering strategy versus usual care for gout: a randomised controlled trial. Lancet 2018; 392: 1403–12

27. ICH harmonized tripartite guideline. Statistical principles for clinical trials: E9. 1998; www.database.ich.org/sites/default/files/E9_Guideline.pdf.

28. Krause A, Krüger K, Braun J, et al.: Delegation ärztlicher Leistungen in der Rheumatologie. Z Rheumatol 2020; 79: 47–8

e1. Sørensen J, Primdahl J, Horn HC, Hørslev-Petersen K: Shared care or nurse consultations as an alternative to rheumatologist follow-up for rheumatoid arthritis (RA) outpatients with stable low disease-activity RA: cost-effectiveness based on a 2-year randomized trial, Scand J Rheumatol 2015; 44: 13–21

e2. Johnson TM, Michaud K, England BR: Measures of rheumatoid arthritis disease activity. Arthritis Care Res (Hoboken) 2020; 72 (Suppl. 10): 4–26

e3. Bock JO, Brettschneider C, Seidl H, et al.: Ermittlung standardisierter Bewertungssätze aus gesellschaftlicher Perspektive für die gesundheitsökonomische Evaluation. Gesundheitswesen 2015; 77: 53–61 MEDLINE

e4. Ossendorf A: Krankheitskostenanalyse bei Patienten mit chronischen neuropathischen Schmerzen. Gesundheitsökonomie & Qualitätsmanagement 2019; 24: 42–50