Association between postoperative atrial fibrillation and the levels of hemoglobin or hematocrit: a systematic review and metaanalysis

Abstract

Objective: Postoperative atrial fibrillation is the most commonly observed arrythmia following cardiac
surgery. Both atrial fibrillation and preoperative anemia hve been related to high rate of mortality and
postoperative morbidity. In this systematic review and meta-analysis, we aimed to analyze whether levels
of preoperative hemoglobin or hematocrit were useful biomarkers for development of postoperative
atrial fibrillation after cardiac surgery or not.
Methodology: The literature screening was performed from PubMed database without any date limitation.
All patients who underwent open cardiac surgery procedures were considered.
Outcome measures included the association between preoperative levels of hemoglobin/hematocrit and
atrial fibrillation after cardiac surgery. The results of trials were evaluated with random or fixed effect
model according to the heterogeniety. The statistical evaluation was performed by using Open Meta
Analyst programme.
Results: A total of 9948 articles were found after database searching. 17 articles were included in metaanalysis
consisting of 5934 patients who fulfilled inclusion criteria. The rate of postoperative atrial
fibrillation was 35.6% (2114 cases out of 5934). Effect size was observed as heterogenous for studies
including hematocrit (Q(df): 30.76, p <0.001, I2: 73.99%). However, it was not observed as heterogeneous
for studies including hemoglobin (Q(df): 11.10, p: 0.26, I2:18.96%). Analysis results of studies including
hematocrit according to random effect model were SMD: 0.013, 95% CI -0.21-0.18 and p: 0.89 (p >0.05).
And analysis results of studies including hemoglobin according to fixed effect model were SMD: 0.172,
95% CI -0.23- -0.11 and p <0.001.
Conclusion: The results of quantitative analysis showed that preoperative hemoglobin is associated
with development of atrial fibrillation, but hematocrit is not. However, more studies may be required
including both hemoglobin and hematocrit in the same trials to clearly establish this association.