Table 2

 Quality of cohort studies examining the effect of circumcision on urinary tract infection in male subjects

ReferenceDefinition of UTIDetermination of circumcision statusExclusion criteriaFollow upAdjustment for confounding variables
AgeSESEthnicity
ICD-9,International Classification of Diseases, 9th revision; KPNC, Kaiser Permanente Medical Care Program, Northern California, USA; OHIP, Ontario Health Insurance Plan; SES, socioeconomic status.
Schoen et al22>108/l pure growth in 90% from any means of collectionInpatients: ICD-9 coding for circumcision in neonatal hospital stayPatient not within health plan for full duration of study<1 yearNoNoNo
Source unknown in 4%Outpatients: ICD-9 from KPNC database for outpatient circumcision
Determined by retrospective database search and confirmed by review of case records of random selection of 52 cases
To et al1Inpatients: ICD-9 coding (kidney infection, cystitis, urethritis or urinary tract infection)The Canadian classification procedure code during the first month of lifeOlder than 1 month of age at time of circumcision, multiple birth, stillbirth, birth complications and lack of health care number2–3 years for inpatient casesNoYesNo
Outpatients: OHIP data<1 year for outpatient cases
Determined by retrospective database search
Wiswell and Hachey6Not specifiedUS Army patient administration systems and biostatistics activity databaseBag urine specimen, congenital abnormality, or predisposition to UTI (not specified)<1 yearNoNoNo
Determined by retrospective database search
Wiswell et al5Not specifiedUS Army patient administration systems and biostatistics activity databaseCongenital abnormality or predisposition to UTI (not specified)<1 yearNoNoNo
Determined by retrospective database search