Data extraction and quality assessment
For the data extraction and quality assessment, a
criteria catalogue developed by the Institute of
Health Economics and Clinical Epidemiology of
the University of Cologne [8] was used. The catalogue
was developed on the basis of current internationally
used quality tools (PREFFI, Closing the
Gap, IDM, QSP und Quintessenz) and contains 68
items. Among them, 8 are used to assess the quality