Michael Höhle: Evaluating quality of care using time-to-event endpoints based on patient follow-up data

Abstract: The recently founded Federal Institute for Quality Assurance and Transparency in Healthcare (IQTIG) is the central institution in Germany for the statutory quality assurance in health care. In accordance with its statutes, it is scientifically independent and works for, in particular, The Federal Joint Committee as well as the Federal Ministry of Health providing its expertise in various tasks of quality assurance of medical care.

One of the biostatistical tasks has been the development of new quality indicators for longitudinal data, where patient outcomes are tracked as subsequent operations after an initial surgery occur, i.e. so called patient follow-up data. We describe the development of two new indicator types for analysing such data within an survival context by taking censoring mechanisms of the data generating process into account: An un-adjusted Kaplan-Meier based survival rate indicator and a risk-adjusted standardized mortality ratio (SMR) based on the work of Breslow (1975). For each indicator type we discuss the construction of appropriate confidence intervals and how to embed the indicators into a sequential monitoring scheme applicable to the German hospital benchmarking performed at the IQTIG in the areas of cardiac pacemakers as well as hip and knee endoprosthesis. Results from a simulation study comparing the proposed methodology against other alternatives are also given.

The presented work is joint work with Johannes Hengelbrock, IQTIG.