Relationship between modeling technique and reported outcomes: case studies in models for the treatment of...

Complex modeling techniques such as discrete-event simulation and simpler Markov or decision-tree models have been used to estimate the cost-effectiveness of treatment for chronic diseases such as schizophrenia. A systematic literature review of MEDLINE, EconLit, Embase, and the Cochrane Library identified schizophrenia modeling studies presenting incremental cost-effectiveness ratios. The relationship between modeling technique used and reported outcomes was examined. Fifty-four studies reporting results of 69 pairs of drug comparisons were identified. Of the paired-drug comparisons, 27 were conducted in at least two studies; in 14 of the 27, the results agreed (i.e., drug A cost-effective compared with drug B) despite differences in modeling techniques. Thirteen of the 27 paired-drug comparisons had contradictory study results even when the same modeling technique was used. Different modeling techniques did not appear to explain different findings about cost-effectiveness.