Effects of Bias Adjustment on Actuarial Survival Curves

Abstract

Medical device companies report the performance of their products through actuarial survival curves. Analyses are based on “passive” databases. For pacemakers, a significant number of explanted devices may not be reported to manufacturers. Thus, expiant information is lost. High rates of underreporting of failures could result. Therefore, performance curves could indicate better survival rates than those that are actually occurring. Samples of closely-followed patients called active samples are used to adjust survival curves for underreported failures. Through simulations, this paper shows a need for a larger sample size for active components and what degree of underreporting failures would be necessary to assure better estimates using adjustments rather than estimates that ignore adjustments. The issues in this paper have a much broader context as pharmaceutical companies increasingly rely on medical devices to monitor patients ‘ health or deliver drugs. This can also apply to survival curves for adverse events in Phase 4 clinical trials.