Characteristics of studies included in the meta-analysis.

Asterisk represents quality scores based on the Newcastle-Ottawa scale. aPatients who admitted for unstable angina, non-ST elevation myocardial infarction, and ST elevation myocardial infarction were included only. bPatients who admitted to intensive care unit were included only. cPatients with end-stage renal disease on hemodialysis were included only. dRenal transplant recipients were included only. Characteristics of studies included in the meta-analysis.