Qualitative analysis of patient interviews on the burden of neuronopathic Gaucher disease in Japan

Development and evaluation of a patient-reported outcome measure specific for Gaucher disease with or without neurological symptoms in Japan

BACKGROUND

Patients with Gaucher disease (GD), a rare lysosomal storage disorder, have reduced health-related quality of life (HRQOL). A patient-reported outcome measure (PROM) for HRQOL developed for type 1 GD (GD1) is not appropriate for patients with neuronopathic GD (nGD) types 2 (GD2) and 3 (GD3). In this study, we developed a new PROM for use in all GD types. We previously reported the qualitative analysis of interviews with Japanese patients with nGD, which was used to create nGD-specific PROM items. Here we evaluated the full PROM combining the type 1 questionnaire with the new nGD-specific items.

METHODS

Patients with confirmed GD were recruited (Association of Gaucher Disease Patients in Japan or leading doctors) for pre-testing (May 2021) or the main survey (October-December 2021). The PROM had three parts: Parts 1 and 2 were translated into Japanese from the pre-existing GD1 PROM, whereas Part 3 was newly developed. Patients (or their caregivers, where necessary) completed the PROM questionnaire on paper and returned it by mail. Mean scores were determined overall and by GD type. Inter-item correlations, content consistency (Cronbach's alpha), and test-retest reliability (Cohen's kappa; main survey only, taken 2 weeks apart) were calculated.

RESULTS

Sixteen patients (three with GD1; six with GD2; seven with GD3) and 33 patients (nine with GD1; 13 with GD2; 11 with GD3) participated in the pre-test and main survey, respectively. All GD2 patients and one-third (6/18) of GD3 patients required caregivers to complete the questionnaire. Mean scores indicated that the burden was highest in GD2 and lowest in GD1. In the main survey, internal consistency was high (Cronbach's alpha = 0.898 overall, 0.916 for Part 3), and test-retest reliability was high for Part 3 (kappa > 0.60 for 13/16 items) but low for Part 1 (kappa < 0.60 for 12/15 items).

CONCLUSIONS

We have developed a flexible and reliable PROM that can be tailored for use in all types of GD and propose using Parts 1 and 2 for GD1, Parts 2 and 3 for GD2, and Parts 1, 2, and 3 for GD3.

Burden of caregivers of patients with neuronopathic and non-neuronopathic Gaucher disease in Japan: A survey-based study

Background

Gaucher disease (GD), a rare lysosomal storage disorder, is associated with considerable patient and caregiver burden. We examined the applicability of existing caregiver questionnaires and assessed the level of burden in caregivers of patients with GD.

Methods

This cross-sectional, non-interventional study was conducted in Japan. Caregivers of patients with confirmed GD (any type) were recruited (patient association group and referral) for pre-testing (May 2021) or the main survey (October-December 2021). Caregivers completed the Caregiver Impact Questionnaire (CIQ; 30 items) and Zarit Caregiver Burden Interview (ZBI; 22 items) on paper. Total CIQ and ZBI scores and subscores were determined overall and by GD type. Inter-item correlations and test-retest reliability (2 rounds, 2 weeks apart) were calculated. The relationship between caregiving duration and caregiver burden was also analyzed.

Results

Nine caregivers (type 2 [GD2]: n = 6; type 3 [GD3]: n = 3) and 25 caregivers (type 1 [GD1]: n = 2; GD2: n = 17; GD3: n = 6) completed the pre-test and main survey, respectively. In the main survey, mean total CIQ score, all CIQ subscores (except emotional function), and total ZBI score were highest in caregivers of patients with GD2 compared with caregivers of patients with GD1/GD3. High test-retest reliability (Kappa >0.6) was observed for 15 CIQ items and 16 ZBI items. CIQ and ZBI scores appeared to be positively correlated with each other and negatively correlated with caregiving duration.

Conclusions

The CIQ and ZBI are applicable, reliable measures to assess burden in caregivers of patients with GD in Japan. Caregiver burden was highest in caregivers of patients with GD2 and decreased with caregiving duration.