Newborns with suspected occult spinal dysraphism: A cost-effectiveness analysis of diagnostic strategies

Objective. To assess the clinical and economic consequences of different di agnostic strategies in newborns with suspected occult spinal dysraphism. Methods. A decision-analytic model was constructed to project the cost and health outcomes of magnetic resonance imaging (MRI), ultrasound (US), plain radiographs, and no imaging in newborns with suspected occult spinal dysra phism. Morbidity and mortality rates of early versus late diagnosis of dysr aphism and the sensitivity and specificity of MRI, US, and plain radiograph s were obtained from the literature. Cost estimates were obtained from a ho spital cost accounting database and from the Medicaid fee schedule. Results. We found that the choice of imaging strategy depends on the underl ying risk of occult spinal dysraphism. In low-risk children with interglute al dimple or newborns of diabetic mothers (pretest probability: 0.3%-0.34%) , US was the most effective strategy with an incremental cost-effectiveness ratio of $55100 per quality-adjusted life year gained. For children with l umbosacral dimples, who have a higher pretest probability of 3.8%, US was l ess costly and more effective than the other 3 strategies considered. In in termediate-risk newborns with low anorectal malformation (pretest probabili ty: 27%), US was more effective and less costly than radiographs and no ima ging. However, MRI was more effective than US at an incremental cost-effect iveness of $1000 per quality-adjusted life year gained. In the high-risk gr oup that included high anorectal malformation, cloacal malformation, and ex strophy (pretest probability: 44%-46%), MRI was actually cost-saving when c ompared with the other diagnostic strategies. For the intermediate-risk gro up, we found our analysis to be sensitive to the costs and diagnostic perfo rmances (sensitivity and specificity) of MRI and US. Lower MRI cost or grea ter MRI diagnostic performance improved the cost-effectiveness of the MRI s trategy, whereas lower US cost or greater US diagnostic performance worsene d the cost-effectiveness of the MRI strategy. Therefore, individual or inst itutional expertise with a specific diagnostic modality (MRI versus US) may influence the optimal diagnostic strategy. Conclusion. In newborns with suspected occult dysraphism, appropriate selec tion of patients and diagnostic strategy may increase quality-adjusted life expectancy and decrease cost of medical work-up.