Presentation (CTI)

OBJECTIVES: Glycogen storage disease type Ia (GSDIa) is a rare genetic disorder of carbohydrate metabolism caused by a deficiency of glucose-6-phosphatase that can lead to acute and chronic complications, including life-threatening hypoglycemia, metabolic abnormalities, growth failure, renal dysfunction, and hepatocellular carcinoma. Other than dietary management with cornstarch, there are no treatments approved for GSDIa. However, promising therapies are in development, which may require health technology assessments. We aimed to develop and validate a conceptual cost effectiveness model that captures both short- and long-term manifestations of GSDIa, including potential impacts of future treatments.
METHODS: The de novo model conceptualization was based on a targeted literature review considering natural history of disease, epidemiology, clinical trials, quality-of-life (QoL), costs, and disease burden in GSDIa. No existing GSDIa model frameworks were identified. Therefore, cost-effectiveness models for progressive diseases with multi-comorbidities or complications (e.g. myasthenia gravis, metachromatic leukodystrophy and metabolic dysfunction-associated steatohepatitis) were reviewed. The model framework underwent validation by clinical and health technology experts.
RESULTS: Based on the review and feedback from experts, a de novo model framework was developed simulating i) current disease progression and ii) potential modified progression with GSDIa treatment. Within each state, recurring acute/short-term complications of GSDIa and cornstarch-related impacts were assessed using a Markov framework based on level of cornstarch dependence. In parallel, the occurrence and management of long-term complications would individually be tracked on a time-to-event basis with complication-specific costs, mortality and QoL.
CONCLUSIONS: A conceptual Markov model framework was considered the most appropriate to estimate the lifetime costs and benefits for patients with GSDIa and could be used to evaluate the cost-effectiveness of potential new treatments for GSDIa.