Cost-Effectiveness/Cost-Benefit Analysis of Newborn Screening for Severe Combined Immune Deficiency in Washington State

Abstract

Objective: To evaluate the expected cost-effectiveness and net benefit of the recent implementation of newborn screening (NBS) for severe combined immunodeficiency (SCID) in Washington State.

Study design: We constructed a decision analysis model to estimate the costs and benefits of NBS in an annual birth cohort of 86 600 infants based on projections of avoided infant deaths. Point estimates and ranges for input variables, including the birth prevalence of SCID, proportion detected asymptomatically without screening through family history, screening test characteristics, survival rates, and costs of screening, diagnosis, and treatment were derived from published estimates, expert opinion, and the Washington NBS program. We estimated treatment costs stratified by age of identification and SCID type (with or without adenosine deaminase deficiency). Economic benefit was estimated using values of $4.2 and $9.0 million per death averted. We performed sensitivity analyses to evaluate the influence of key variables on the incremental cost-effectiveness ratio (ICER) of net direct cost per life-year saved.

Results: Our model predicts an additional 1.19 newborn infants with SCID detected preclinically through screening, in addition to those who would have been detected early through family history, and 0.40 deaths averted annually. Our base-case model suggests an ICER of $35 311 per life-year saved, and a benefit-cost ratio of either 5.31 or 2.71. Sensitivity analyses found ICER values <$100 000 and positive net benefit for plausible assumptions on all variables.

Conclusions: Our model suggests that NBS for SCID in Washington is likely to be cost-effective and to show positive net economic benefit.

Figure 1

Tornado diagram of 1-way sensitivity analyses, showing the effect of range of individual variables on the outcome measure ICER for NBS of SCID. The vertical line in the diagram represents the base-case ICER of $35 998 per life year saved. Each horizontal bar indicates the range of ICER with the lower and upper values of each variable in Table I and Table II.

Figure 2

Two-way sensitivity analyses, showing ICER for NBS of SCID as a function of treatment cost per late-identified SCID who receive HCT as first-line therapy and cumulative survival in late-identified SCID.