Table 2 Quality assessment based on evaluation of bias
From: Obstructive Sleep Apnea and the Risk of Perinatal Outcomes: A Meta-Analysis of Cohort Studies
study | Selection bias | Exposure bias | Outcome Assessment bias | Confounding factor bias | Analytical bias | Attrition bias | Overall likelihood of bias |
|---|---|---|---|---|---|---|---|
KoHS16 2013 | Minimal (Random survey by questionnaire) | Minimal (direct completion of survey) | Minimal (hospital records and specific definition used) | Minimal (adjusting for maternal age, BMI) | Minimal (Multivariable logistic regression model for the confounders) | Minimal (all subjects from initiation to final outcome accounted for) | minimal |
Louis J17 2012 | Minimal (Randomly selected) | Minimal (direct measurement of exposure) | Minimal (hospital records and specific definition used) | Minimal (adjusting for maternal age, race BMI) | Minimal (Multivariable logistic regression model for the confounders) | Minimal (<10% attrition and reasons for loss of follow up explained) | minimal |
Olivarea18 SA 2011 | Minimal (all gravidae in the Ben Taub General Hospital obstetrics clinic) | Minimal (direct completion of survey) | Minimal (hospital records and specific definition used) | Minimal (adjusting for age and BMI) | Minimal (Multivariable logistic regression model for adjusting confounders) | Minimal (no loss to follow up) | minimal |
Louis JM19 2010 | Minimal (randomly selected) | Low (validated prenatal database between January 2000-December 2008) | Low (assessment from administrative database) | Minimal (adjusting for maternal age, race BMI) | Minimal (Multivariable logistic regression model for the confounders) | Minimal (all subjects accounted for) | low |
Sahin FK20 2008 | Minimal (all pregnant women between May 2006 and June 2007 in Afyonkarahisar Kocatepe university hospital) | Minimal (direct measurement of exposure) | Minimal (hospital records and specific definition used) | Low (adjusting for BMI) | Low (Mann-Whitney U test and the chi-square or Fisher exact test were applied) | Minimal (no loss to follow up) | minimal |
