The Cost-Effectiveness Of Screening For Severe Combined Immunodeficiency (SCID) In The UK NHS Newborn Bloodspot Screening Programme

Abstract

To assess the cost-effectiveness of including screening for severe combined immunodeficiency (SCID) in the NHS newborn bloodspot screening programme. A decision tree model with life-table estimates of outcomes was built. Model structure and parameterisation were informed by systematic review and expert clinical judgment. A public service perspective was used and lifetime costs and quality adjusted life years (QALYs) were discounted at 3.5%. Standard treatment following screening was hematopoietic stem cell transplantation with additional treatment options for adenosine deaminase deficiency SCID. The model estimated the number of non-SCID cases identified incidentally. Probabilistic sensitivity analyses was undertaken. An exploratory disbenefit analysis was conducted for false positives and those diagnosed with non-SCID T-cell lymphopenia (TCL) who would have presented as healthy at birth. Screening for SCID was estimated to result in 310 (72-811) presumptive positive cases per year including 260 (25-760) false positives cases, 7 (1-21) preterm cases, 26 (9-50) non-SCID TCL cases and 17 (14-22) SCID cases. Screening would increase overall QALYs and costs and result in an incremental cost-effectiveness ratio (ICER) of £17,642. The increase in QALYs was driven by improved survival in the screened cohort with mortality reducing from 8 (5.3-12) deaths to 1.7 (0.6-4.1). Results were sensitive to a number of parameters including the cost of the screening test, the incidence of SCID and quality of life estimates. The disbenefit analysis estimated that to push the cost-effectiveness over the £20,000 threshold the 6.5 (1.5-16) healthy at birth cases would need to experience a disbenefit of 2 QALYs and the false positive cases a disbenefit of over 12 quality adjusted days. Screening for SCID is potentially cost-effective at £20,000 per QALY, key uncertainties relate to the impact of false positives and the identification of children with non-SCID TCL.