Cost-Consequence Analysis of Nitisinone for Treatment of Tyrosinemia Type I.

Background: Tyrosinemia type I is a rare but severe genetic metabolic disorder. Nitisinone combined with a diet low in tyrosine and phenylalanine became first-line therapy in 1994.

Objectives: To estimate the direct medical costs of health care services related to the treatment of tyrosinemia type I, taking into consideration the real-life efficacy of nitisinone.

Methods: A cost-consequence analysis was performed for all children with a confirmed diagnosis of tyrosinemia type I who were treated in Quebec between January 1, 1984, and January 1, 2009. The costs of care were compared for 3 consecutive historical groups: no nitisinone (1984 to 1994), late intervention with nitisinone (first dose received between 1994 and 1997), and early intervention with nitisinone (first dose received between 1997 and 2008). Data were derived from patient charts, hospital databases, and the Régie de l'assurance maladie du Québec and MED-ÉCHO administrative databases. Costs were reported in 2008 Canadian dollars.

Results: Nitisinone treatment was associated with significant reductions in the number and duration of hospital admissions, the number of admissions to a pediatric intensive care unit, and the number of liver transplants. The cost of hospitalization per person-year was significantly lower in the 2 groups treated with nitisinone: $673 and $5 590 for the early-intervention and late-intervention groups, respectively, as compared to $12 980 for the no-nitisinone group (p < 0.001). Hospital costs per person-year for liver transplant were $3 198 for the late-intervention group and $5 044 for the no-nitisinone group: there were no transplants in the early-intervention group. The cost of nitisinone per person-year was $51 493 for the early-intervention group and $64 895 for the late-intervention group.

Conclusions: Nitisinone treatment significantly improved the outcomes of patients with tyrosinemia type I, while decreasing utilization of health care resources, liver transplants, and associated costs.