A cost-effectiveness analysis of screening for intracranial aneurysms in persons with one first-degree relative with subarachnoid haemorrhage

Abstract

Introduction: Although persons with one first-degree relative with aneurysmal subarachnoid haemorrhage have an increased risk of aneurysm formation and aneurysmal subarachnoid haemorrhage, screening them for unruptured intracranial aneurysms was not beneficial in a modelling study from the 1990s. New data on the risk of aneurysmal subarachnoid haemorrhage in these persons and improved treatment techniques call for reassessment of the cost-effectiveness of screening.

Patients and methods: We used a cost-effectiveness analysis using a Markov model and Monte Carlo simulation comparing screening and preventive aneurysm treatment with no screening in persons with one first-degree relative with aneurysmal subarachnoid haemorrhage. We analyzed the impact on quality-adjusted life years, costs and net health benefit of single screening (at varying screening age) and serial screening (with varying screening age and intervals) using a cost-effectiveness threshold of €20,000/quality-adjusted life year.

Results: In 17 of the 24 strategies assessed, additional costs for screening for unruptured intracranial aneurysm were <€20,000 per quality-adjusted life year gained. The strategy with highest net health benefit was screening at age 40 and 55. Screening every five years from age 20 to 70 yielded the highest health benefits at the highest additional costs.

Discussion: Based on current risks of aneurysmal subarachnoid haemorrhage and complications of preventive treatment, several strategies to screen for unruptured intracranial aneurysm in persons with one first-degree relative with aneurysmal subarachnoid haemorrhage are cost effective compared with no screening, when applying a cost-effectiveness threshold of €20,000/quality-adjusted life year.

Conclusion: We recommend discussing with persons at risk the option of screening twice, at age 40 and 55, which will result overall in substantial health benefits at acceptable additional costs.

Keywords: Subarachnoid haemorrhage; cost-effectiveness; first-degree relatives; intracranial aneurysms; screening.

Figure 1.

The figure represents the screening arm of the model. For the no screening arm, please see supplementary Figure I. On the left the different health states (death, disabled, healthy with known small aneurysm, healthy with aneurysm, healthy) are displayed. The tree emerging from each health state composes the possible transitions (at each ^) and subsequent health state (Δ). In time steps of one year persons progress through the decision model and can move from one health state to another based on transition probabilities. Costs and utility values are linked to the health states and interventions during each cycle and aggregated until persons reach the death state. Clone 1–3 refer to different parts of the model which should be copied at that point.

Figure 2.

The figure shows the impact of screening on untreated UIA and aSAH incidence compared to natural history simulated in our Markov model with a single cohort of 10,000 patients. Three examples of different screening strategies are shown. Panel (a) reflects screening from age 20 to 70 every five years, panel (b) reflects screening from age 30 to 60 every 15 years and panel (c) a single screening at age 45. After every screening moment there is a visible decrease in number of untreated UIA. Frequent screening produces repeated small reductions in untreated UIAs (a) and a constant lower aSAH number. Less intensive screening programmes have much larger impact per screening moment on untreated UIA prevalence and can be highly effective in aSAH prevention when screening is performed shortly before the peak incidence of aSAH at age 50 (c). As panels (a) to (c) reflect analyses of three separate cohorts, the number of untreated UIAs and aSAHs in natural history as a function of age is similar but not identical, due to random variation. aSAH: aneurysmal subarachnoid haemorrhage; UIA: unruptured intracranial aneurysms.