Effect of the addition of a mental health specialist for evaluation of undiagnosed patients in centres for rare diseases (ZSE-DUO): a prospective, controlled trial with a two-phase cohort design

Abstract

Background: People with complex symptomatology but unclear diagnosis presenting to a centre for rare diseases (CRD) may present with mental (co-)morbidity. We hypothesised that combining an expert in somatic medicine with a mental health specialist working in tandem will improve the diagnostic outcome.

Methods: Patients aged 12 years and older who presented to one of the 11 participating German CRDs with an unknown diagnosis were recruited into this prospective cohort trial with a two-phase cohort design. From October 1, 2018 to September 30, 2019, participants were allocated to standard care (SC, N = 684), and from October 1, 2019 to January 31, 2021 to innovative care (IC, N = 695). The cohorts consisted mainly of adult participants with only a minority of children included (N = 67). IC included the involvement of a mental health specialist in all aspects of care (e.g., assessing medical records, clinic visits, telehealth care, and case conferences). Clinicaltrials.gov identifier: NCT03563677.

Findings: The proportion of patients with diagnoses established within 12 months after the first visit to the CRD explaining the entire symptomatology (primary outcome) was 19% (N = 131 of 672) in the SC and 42% (N = 286 of 686) in the IC cohort (OR adjusted for centre effects 3.45 [95% CrI: 1.99-5.65]). The difference was mainly due to a higher prevalence of mental disorders and non-rare somatic diseases in the IC cohort. The median time to explaining diagnoses was one month shorter with IC (95% CrI: 1-2), and significantly more patients could be referred to local regular care in the IC (27.5%; N = 181 of 659) compared to the SC (12.3%; N = 81 of 658) cohort (OR adjusted for centre effects 2.70 [95% CrI: 2.02-3.60]). At 12-month follow-up, patient satisfaction with care was significantly higher in the IC compared to the SC cohort, while quality of life was not different between cohorts.

Interpretation: Our findings suggested that including a mental health specialist in the entire evaluation process of CRDs for undiagnosed adolescents and adults should become an integral part of the assessment of individuals with a suspected rare disease.

Funding: The study was funded by the Global Innovation Fund from the Joint Federal Committee in Germany (Innovationsfonds des Gemeinsamen Bundesausschusses), grant number 01NVF17031.

Keywords: Diagnostic services; Medically unexplained symptoms; Mental health; Patient care team; Rare diseases.

Fig. 1

Flow diagram for the ZSE-DUO trial based on the reporting of observational studies in epidemiology (STROBE) checklist for cohort studies.

Fig. 2

Proportion of patients in the standard care and the innovative care cohorts for whom one or more diagnoses were confirmed during the evaluation process that explained the entire symptomatic spectrum presented by the patient (explaining diagnoses). A) Patients with any combination of newly established diagnoses (primary outcome). B) Patients clustered by diagnostic category. Please note, some participant received diagnoses from more than one diagnostic category and are included in each applicable category. C) Combinations of diagnostic categories explaining the full symptomatic spectrum RD = rare disease, MD = mental disorder, non-RD = non-rare somatic disease Main effects are presented as odds ratios with 95% credibility intervals based on basic statistical models.

Fig. 3

Time between first visit to the CRD and newly established explaining diagnoses in the standard care and innovative care cohorts. A) Patients with any combination of newly established and explaining diagnoses. B) Patients clustered by diagnostic category. Please note, some participants received diagnoses from more than one diagnostic category and are included in each applicable category. RD = rare disease, MD = mental disorder, non-RD = non-rare somatic disease. Boxplots show 10th, 25th, 50th, 75th, and 90th centiles. Differences between groups were tested using Mann–Whitney U-tests.

Fig. 4

Patient-reported outcomes. A and B) Change in health-related quality of life as indicated on the EQ-5D visual analogue scale at baseline and 12-month follow-up in the standard care and the innovative care cohorts (A: entire sample; B: separately for patients with and without explaining diagnoses). C and D) Patient satisfaction with care at 12-month follow-up in the standard care and the innovative care cohorts (C: entire sample; D: separately for participants with and without explaining diagnoses). Boxplots show 10th, 25th, 50th, 75th, and 90th centiles. Differences between groups were tested using Mann–Whitney U-tests.