3.2 – Study Characteristics
Key characteristics of the 12 studies are included in Table 1 and
assessed quality of studies is shown in Appendix 1. All the studies were
case-control studies and cumulatively included 4960 patients (min 125
max 1424) across eight countries and it is unlikely that this involved
any duplicated patients due to the geographical and chronological spread
of the studies. For each study the case population was well described as
patients undergoing coronary angiography. Most studies reported
relatively consistent definitions of DELC. This was typically a deep
crease extending obliquely from the tragus towards the outer border of
the ear lobe although the distance varied from a third to complete. All
studies defined the presence of coronary artery disease as
>50% stenosis of at least one major epicardial vessel,
except for three studies which used a threshold of >70%
stenosis(6, 12, 13).