DISEASE BURDEN OF CEREBELLAR ATAXIA IN HONG KONG: A RETROSPECTIVE COST-UTILITY ANALYSIS

S. Winser¹, K.L.K. Chan¹, C.C. Tung¹, T. Wai Lok¹, T.m.K. Ringo¹, Y.K. Ho¹, R. Cheung¹

Background: Cerebellar ataxia affects the coordination and balance of patients. The impact of this disease increases burden in patients, caregivers and society. Costs and the burden of this disease have not been investigated in Hong Kong. 

Purpose: (1) To estimate the socioeconomic cost of cerebellar ataxia in Hong Kong for the base year 2019,
(2) to assess the health-related quality of life (HRQoL) and severity of ataxia and
(3) to establish the correlation between the severity and cost of cerebellar ataxia and to examine the correlation between the severity of cerebellar ataxia and HRQoL.

Methods: A retrospective cross-sectional study was conducted amongst 31  patients with cerebellar ataxia. Cost-related data were obtained through self-reported questionnaires. The severity of ataxia was assessed using the Scale for Assessment and Rating of Ataxia, and HRQoL was assessed using the Short Form (36) Health Survey (SF-36). Pearson correlation was used for normally distributed data, whereas Spearman correlation was used otherwise. We conducted two adjusted analysis, first, we excluded participants with acquired cerebellar ataxia such as ataxia secondary to stroke, multiple sclerosis or  cerebral palsy as these diseases may have a different clinical course of that of degenerative and hereditary ataxias. Second, we constructed a Tornado plot to geographically represent the degree to which each of the items within the direct and indirect costs influences the total cost of ataxia. The minimum and maximum range of the cost was set at the 25th and 75th percentile and the model was run for each adjusted extreme cost value while keeping the remaining fixed at their mean and median.

Results: The mean severity of ataxia was 21 out of 40. The average direct and indirect costs of a patient with ataxia in 6 months were HKD 51,371 and HKD 93,855, respectively. The mean difference between the independent to minimally dependent in activities of daily living (ADL) group and the moderate to maximally dependent in ADL group for direct and indirect costs was HKD 33,829 and HKD 51,444, respectively. Significant expenditure was related to production lost (42%), caregiver salary (17%) and in-patient care (16%). The physical functioning (r=−0.58) and general health (r=−0.41) of SF-36 were negatively correlated with disease severity (p<0.05). A significant, positive correlation was found between disease severity and direct cost (Spearman’s rho=0.39) and the cost of hiring a caregiver (Spearman’s rho=0.43). Nearly all the patients had one or more falls in the last 6 months and the majority of the patients with cerebellar ataxia (87%) are frequent fallers.

Conclusion(s): The average estimated costs for each patient with cerebellar ataxia was HKD 146,832 (HKD 70956 and HKD 158073 for independent to minimally dependent patients and moderate to maximally dependent patients, respectively) for 6 months. Direct costs accounted for 35% of the expenses, and indirect costs was 65%.

Implications: Additional support, including  employment, access to specialist consultants, informal home care and community participation, are some areas that should be addressed. Future study on a larger population with a prospective design is necessary to confirm the aforementioned claims.

Funding, acknowledgements: This study was funded by the Start-up fund for Early Careers, Hong Kong Polytechnic University.

Keywords: Cerebellar ataxia, Cost-utility, Falls

Topic: Neurology

Did this work require ethics approval? Yes

Institution: The Hong Kong Polytechnic University

Committee: Human Subjects Ethics Committee of the Hong Kong Polytechnic University

Ethics number: (HSECS reference number: HSEARS20190524001).