Newborn Screening and Treatment of Phenylketonuria: Projected Health Outcomes and Cost-Effectiveness

Abstract

The objective of this study was to evaluate the cost-effectiveness of newborn screening and treatment for phenylketonuria (PKU) in the context of new data on adherence to recommended diet treatment and a newly available drug treatment (sapropterin dihydrochloride). A computer simulation model was developed to project outcomes for a hypothetical cohort of newborns with PKU. Four strategies were compared: (1) clinical identification (CI) with diet treatment; (2) newborn screening (NBS) with diet treatment; (3) CI with diet and medication (sapropterin dihydrochloride); and (4) NBS with diet and medication. Data sources included published literature, primary data, and expert opinion. From a societal perspective, newborn screening with diet treatment had an incremental cost-effectiveness ratio of $6400/QALY compared to clinical identification with diet treatment. Adding medication to NBS with diet treatment resulted in an incremental cost-effectiveness ratio of more than $16,000,000/QALY. Uncertainty analyses did not substantially alter the cost-effectiveness results. Newborn screening for PKU with diet treatment yields a cost-effectiveness ratio lower than many other recommended childhood prevention programs even if adherence is lower than previously assumed. Adding medication yields cost-effectiveness results unlikely to be considered favorable. Future research should consider conditions under which sapropterin dihydrochloride would be more economically attractive.

Keywords: cost-effectiveness; newborn screening; phenylketonuria; sapropterin dihydrochloride.

Figure 1

Model framework.

Figure 2

Proportion of Hypothetical Cohort of PKU Patients by Health State and Age–diet treatment only (no medication), partial adherence. ¹ Individuals with PKU that are untreated or identified through clinical identification start with mild or moderate/severe impairment. ² These figures only reflect the proportion of individuals alive at that age and does not include those that have died.

Figure 3

One–way sensitivity analysis for NBS/diet when compared with CI/diet, ICER. * For these variables, when the value decreased to a certain threshold, the reference case switched to NBS/diet and becomes a cost–saving strategy when compared to CI/diet the ICER is negative with NBS/diet as reference case, therefore, 0 is used here to indicate that NBS/diet is the more cost–effective strategy when the value is lower, i.e., when the cost of NBS decreases, when the probability of NBS screened positive decreases, and when the probability of true positive decreases, all these would turn NBS/diet to a more favorable strategy.