Table 3. Quality assessment.
| Author | Q1 | Q2 | Q3 | Q4 | Q5 |
| Poli, et al.[9] | Y | N | Y | U | U |
| Lip, et al.[4] | Y | N | Y | U | U |
| Lip, et al.[10] | Y | N | Y | N | N |
| Olesen, et al.[11],* | Y | N | Y | U | U |
| Olesen, et al.[11],# | Y | N | N | U | U |
| Olesen, et al.[11],† | Y | N | N | U | U |
| Lin, et al.[12] | Y | N | Y | U | U |
| Sandhu, et al.[13] | Y | N | Y | U | U |
| Van Staa, et al.[14] | Y | N | Y | U | U |
| Friberg et al.[15] | Y | N | Y | N | N |
Q1: Did the included patients have different disease severities? Q2: Did the patient selection process exhibit bias? Internal authenticity: Q3: Was the dropout rate lower than 20%? Q4: Was the predictor to be evaluated blinded to the endpoint events? Q5: Were the endpoint events blinded to predictors? The study of Olesen was divided into three periods of follow-up: *1 year, and #5 years, †10 years. Y: Yes; N: No; U: unclear.