Patient Referral for Device‐Aided Therapies in Parkinson's Disease is Suboptimal; A Dutch Survey

Patients with Parkinson's disease (PD) suffering from response fluctuations and/or troublesome dyskinesias insufficiently responding to optimized oral/transdermal therapy may benefit from device-aided therapy (DAT).1 The term DAT refers to deep brain stimulation (DBS), subcutaneous infusion of apomorphine and continuous infusion of levodopa/carbidopa intestinal gel with or without entacapone.2 However, timely referral for DAT remains challenging. Not all eligible patients are referred to a specialized center in time, while others may be referred too early, both attributable to a lack of clear and objective referral criteria.3 The knowledge and attitudes of referring neurologists may be part of this issue.4 Identification of relevant factors is necessary to effectively address the clinical need identified. In 2017–2018, we conducted a survey among general neurologists from 13 non-university hospitals in the northern part of the Netherlands to investigate their knowledge of DAT. Questions and agree/disagree statements on various aspects of DAT in PD were part of the anonymous paper-based questionnaire. We compared the agree/disagree statements between neurologists who had experience with DAT and those who had no experience. The main findings are discussed below, while the Appendix S1 provides a more detailed description of the methods and results. In total, 36 questionnaires were returned (response rate 59%; Fig. A1). Respondents had worked as neurologists for a mean of 12.5 years. Neurologists with DAT experience cared for a larger population of PD patients than neurologists without DAT experience (median: 100 vs. 30 PD patients per neurologist). Less than half of respondents (44%) considered the eligibility criteria for DAT to be clear (Table 1). A similar minority of respondents (47%) felt they had sufficient expertise to determine whether a patient would be eligible for any DAT. Experienced neurologists were more likely than neurologists without DAT experience to report having the necessary expertise to assess eligibility for DAT (81 vs. 18%, P < 0.001). The three clinical symptoms that respondents considered most important in assessing DAT eligibility were response fluctuations (78%), cognitive impairment (53%), and treatment-resistant tremor (50%). The results of this survey confirm that management of patients with advanced PD is perceived as difficult, especially by general neurologists who lack professional experience with DAT.4 Moreover, respondents ranked two factors particularly relevant to DBS (treatment-resistant tremor and cognitive impairment) in the top three most important selection criteria for any DAT. This may have a negative impact on referrals for DATs in general, as the exclusion criteria for pump therapies are less stringent than for DBS.3 Our study revealed a lack of competence among general neurologists in identifying PD patients possibly eligible for DAT. This knowledge gap partly explains the suboptimal referral practices, with evidence of both under- and over-referral (Table A4). Under-referral implies a missed opportunity to improve motor symptoms and quality of life in appropriate patients,1, 3 whereas over-referral may lead to false patient expectations and potentially overburden the referral network. Implementation of a user-friendly and validated screening tool is key to achieving timely referral for DAT without over-referral.5 (1) Research project: A. Conception, B. Organization, C. Execution; (2) Statistical Analysis: A. Design, B. Execution, C. Review and Critique; (3) Manuscript Preparation: A. Writing of the first draft, B. Review and Critique. H.R.M.: 1A, 1B, 1C, 2A, 2B, 2C, 3A, 3B J.M.t.K.: 1B, 1C, 2B, 3B E.B.: 1A, 2C, 3C T.v.L.: 1A, 1B, 2C, 3C The authors thank all neurologists who completed the survey. In addition, we thank neurologists who suggested relevant research topics when this project was still in a start-up phase. Moreover, the authors thanks Wim Simons and Martin van Schijndel from the Dutch Parkinson Patient's Association for their feedback on an earlier version of this manuscript. Ethical Compliance Statement: Medical Ethical Committee of the University Medical Center Groningen waived the need for ethical approval of the study protocol. Informed patient consent was not necessary for this work. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this work is consistent with those guidelines. Funding Sources and Conflicts of Interest: Harmen R. Moes received funding from the Dutch Parkinson Patient's Association to conduct this study (Parkinson Vereniging; grant number 2017-R04). The authors declare that there are no conflicts of interest relevant to this work. Financial Disclosures for the Previous 12 Months: Teus van Laar reports having received consulting fees from AbbVie, Britannia Pharm., Eurocept, and Clexio, and research grants from the Michael J. Fox Foundation, the Dutch Brain Foundation, and the University Medical Center Groningen; all unrelated to this work. Other authors declare that there are no additional disclosures to report. Appendix S1. Description of methods and results. Appendix S2. English translation of the questionnaire used in this study (originally in Dutch). Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.