Table 3 Confounding variables controlled for in multivariate analysis in each study
Study | Covariates controlled |
|---|---|
Kreder et al (2003) | age, comorbidity, gender, diagnosis, hospital procedure volume |
Katz et al (2004) | age, gender, comorbidity, Medicaid eligibility, diagnosis, hospital procedure volume |
Katz et al (2007) | age, gender, race, education, diagnosis, income, comorbidity, preoperative patient reported outcome (WOMAC) |
Muilwijk et al (2007) | ASA class |
Manley et al (2009) | age, gender, race, diagnosis, hospital procedure volume, hospital teaching status, hospital ownership, hospital region, income |
Manley et al (2009) | age, gender, race, diagnosis, hospital procedure volume, hospital teaching status, hospital ownership, hospital region, income |
Ong et al (2009) | age, gender, comorbidity, race, diagnosis, Medicare eligibility, hospital teaching status, hospital ownership, hospital location, hospital size, hospital procedure volume |
Yasunaga et al (2009) | age, gender, BMI, diagnosis, comorbidity, hospital procedure volume |
Paterson et al (2010) | age, gender, comorbidity, diagnosis, hospital teaching status, hospital procedure volume |
Wei et al (2010) | age, gender, diagnosis, comorbidity, hospital ownership, hospital region |
Styron et al (2011) | age, gender, race, comorbidity, income, insurance status, geographic region, hospital region, hospital teaching status, hospital ownership, hospital size, hospital procedure volume |
Baker et al (2011) | age, surgeon volume, preoperative hemoglobin, gender, type of anaesthetic, ASA, surgeon experience, indication |