Table 2.

Criteria for assessment of quality of studies using the Newcastle-Ottawa Scale adapted for cross-sectional studies

Scale of coding
Representativeness of sample
Truly representative = 3
Somewhat representative = 2
No description of sampling strategy = 1
Sample size
Justified and acceptable = 2
Not justified = 1
Sample selection
Hospital/volunteer = 3
Databases = 2
Not reported = 1
Standardisation of images
American Society for Echocardiography guidelines/other = 2
Not reported = 1
Statistical methods
Rigorous with clear exclusion criteria of abnormal cases = 3
Acceptable = 2
Not appropriate or incompletely described = 1
Total score
11–13 = good quality
8–10 = acceptable
5–7 = poor