Analytical approach:
A multi-state time-dependent transition model was structured to simulate the course of patients undergoing aneurysm clipping. The time horizon was lifetime. The authors did not report the study perspective.
Effectiveness data:
The evidence was identified through a review of the literature, by searching MEDLINE and PubMed (Related Articles). The key clinical parameters were the probabilities of complications from clip aneurysm. The pooled transition probabilities were calculated mainly from a comprehensive review (Katz, et al. 2006, see 'Other Publications of Related Interest' below for bibliographic details).
Monetary benefit and utility valuations:
The utility estimates were obtained from the literature.
Measure of benefit:
The benefit measure was the number of quality-adjusted life-years (QALYs), which were discounted at 3% per year.
Cost data:
The cost categories included the costs of intra- or post-operative angiogram, elective re-clipping, admission, and clipping after re-bleed. Published Medicare and Medicaid reimbursements were used as proxies for these costs. All costs were reported in US dollars ($).
Analysis of uncertainty:
Univariate and two-way sensitivity analyses were performed on the major parameters. A Monte Carlo simulation was also conducted using 1,000 trials of 1,000 patients to calculate the mean outcome, 95% confidence intervals, and incremental differences between the various angiography strategies.