Publication patterns of cancer cost-effectiveness studies presented at major conferences

Abstract

Objective: To be useful to policymakers and stakeholders, cost-effectiveness analyses (ceas) should be published in a timely manner and without bias. The aims of the present study were to examine the time between conference abstract presentation and subsequent publication, to determine the factors associated with time to publication, to evaluate potential publication bias, and to examine discrepancies in the results between abstract and publication.

Methods: Abstracts of ceas presented at the annual meetings of the American Society of Clinical Oncology (asco), the American Society of Hematology (ash), and the International Society for Pharmacoeconomics and Outcomes Research (ispor) between 1997 and 2007 were reviewed. Time-to-event analysis was performed to assess the timeliness of publication and to examine factors associated with time to publication. Summary statistics were used to assess discrepancies in incremental cost-effectiveness ratios (icers) between abstract and publication.

Results: Of 164 abstracts identified, 65 (39.6%) were subsequently published. The 1-, 2-, 3-, and 5-year publication rates were 12.8%, 25%, 34.2%, and 40.5% respectively. Abstracts were more likely to be published if presented at asco than at ispor (hazard ratio: 1.94; p = 0.038). There was no direct evidence of publication bias for abstracts with favourable icers. Comparing icers between abstracts and publications, the mean absolute difference was 23.8%; 50% of studies had a change in icer exceeding 10%.

Conclusions: Publication rates for ceas were low, and publication was not timely with respect to informing the decision-making process for funding. Abstract results often differed from publication results and cannot reliably be used in the decision-making process for funding.

Keywords: Cost-effectiveness analyses; abstracts; publication bias; time to publication.

FIGURE 1

Time from abstract presentation to publication. The solid line represents the Kaplan–Meier plot for time from abstract presentation to manuscript publication. The dashed lines represent the limits of the 95% confidence band.

FIGURE 2

Publication rates by conference. Each line represents the Kaplan–Meier plot for time from abstract presentation to manuscript publication for a specific conference. asco = American Society of Clinical Oncology; ash = American Society of Hematology; ispor = International Society for Pharmacoeconomics and Outcomes Research.

FIGURE 3

Percentage change in the incremental cost-effectiveness ratio (icer) from abstract to publication for forty-eight cost–utility analyses. Each bar represents a cost–utility study, and the height of the bar represents the percentage change in icer from abstract to publication. Twenty-three studies reported a decrease, fourteen reported an increase, and eleven reported no change in icer.