Purpose: The complexity and severity of rare genetic conditions pose substantial burden to families. While the importance of spillovers on carers' health in resource allocation decisions is increasingly recognised, there is significant lack of empirical evidence in the context of rare diseases. The objective of this study was to estimate the health spillovers of paediatric rare genetic conditions on parents.
Methods: Health-related quality-of-life (HRQoL) data from children with rare genetic conditions (genetic kidney diseases, mitochondrial diseases, epileptic encephalopathies, brain malformations) and their parents were collected using the CHU9D and SF-12 measures, respectively. We used two approaches to estimate parental health spillovers. To quantify the 'absolute health spillover', we matched our parent cohort to the Australian general population. To quantify the 'relative health spillover', regression models were applied using the cohort data.
Results: Parents of affected children had significantly lower HRQoL compared to matched parents in the general public (- 0.06; 95% CIs - 0.08, - 0.04). Multivariable regression demonstrated a positive association between parental and child health. The mean magnitude of HRQoL loss in parents was estimated to be 33% of the HRQoL loss observed in children (95% CIs 21%, 46%).
Conclusion: Paediatric rare genetic conditions appear to be associated with substantial parental health spillovers. This highlights the importance of including health effects on family members and caregivers into economic evaluation of genomic technologies and personalised medicine. Overlooking spillover effects may undervalue the benefits of diagnosis and management in this context. This study also expands the knowledge of family spillover to the rare disease spectrum.
Keywords: Economic evaluation; Genomic medicine; Informal care; Quality of life; Rare disease.