Table 1

Characteristics and methodological summary of studies

ReferenceStudy characteristicsOutcomes measured
YearCountryPeriodData typeNo of patientsNo of hospitalsLow* High* MortalityComplications (breakdowns)TransfusionLOSConversionsOthersCase mixQuality score (18)
Radical nephrectomy
Hjelle29 2016Norway2008–2013Admin327340204030 day+Demographics, tumour stage, nephrectomy type8
Becker30/Sun31 2014/
USA1998–2007Admin48 172N/S516In-hospital+ (17 events including haemorrhage, cardiac arrest, infection, wound disruption, seroma, pneumothorax, VTE, etc)++Demographics, comorbidity, nephrectomy type, laparoscopy, payer/hospital type9
Hanchanale32 2010England1998–2005Admin20 67211811435In-hospital+Demographics9
Yasunaga33 2010Japan2006–2007Admin79886462665In-hospital+ (11 events including surgical site infection, UTI, VTE, sepsis, ileus, stroke, cardiac events, renal, failure, peritonitis, etc)Demographics, comorbidity, laparoscopy, hospital type, tumour location9
Mitchell34 2009USA2003–2007Clinical42 98813499/4.5 year500/4.5 yearIn-hospital+ (not specified)+ICU admissionNone9
Yasunaga18 2008Japan2006–2007Clinical1704461940In-hospital+ (wound infection, pneumonia, ileus, renal dysfunction, others)OT, EBLDemographics, comorbidity, laparoscopy, tumour stage and location11
Davenport35 2005England2004Clinical59848<1/month>1/monthN/S+ (12 events including bleeding, bowel injury, GI bleed, renal failure, pneumothorax, VTE, MI, splenic injury, etc)++OTNone4
Keoghane41 2004England2001–2002Clinical2632556-+ (16 events including renal failure, sepsis, wound infection, bowel injury, incisional hernia, peri hepatic collection, etc)+None3
Taub36 2004USA1993–1997Admin16 8589621434In-hospital+Demographics, comorbidity, admission acuity9
Birkmeyer37 2002USA1994–1999Admin58 990329263330 day or in-hospitalDemographics, comorbidity, admission acuity7
Partial nephrectomy
Couapel38 2014France2010Clinical570534/7 month19/7 monthN/S+ (medical and surgical events, not further specified)++OT, EBL, totalisation, +ve marginN/S8
Monn42 2014USA2009–2011Admin17 5833221335+ (organ-based complications not further specified, pain, seroma, shock, haematoma, hypotension, VTE, pneumothorax)++Hospital costDemographics, comorbidity, payer, region, hospital type9
Abouassaly39 2012Canada1998–2008Admin4292181146/10 year797/10 yearIn-hospital+ (not specified)Demographics, comorbidity, region12
Taub36 2004USA1993–1997Admin11729621434In-hospital+Demographics, comorbidity, admission acuity9
Nephrectomy with venous thrombectomy
Toren40 2013Canada1998–2008Admin816120N/SN/SIn-hospital+ (40 medical and surgical events including MI, CHF, PE, infection, organ injury, pneumothorax etc)+Demographics, comorbidity, region11
Yap19 2012Canada1995–2004Admin433N/S2/10 year8/10 year30 dayDemographics11
  • *Low, cut-off value for lowest volume group; high, cut-off value for highest-volume group. Volume units are cases per year unless specified.

  •  †Becker and Sun were equal in the data source used, outcomes evaluated, periods covered and quality scores, but employed different analyses to evaluate the benefit of regionalisation and volume–outcome relationship in nephrectomy.30 31 We therefore treated them as one single cohort, with no duplicates in our analysis.

  • Admin, administrative; CHF, congestive heart failure; EBL, estimated blood loss; GI, gastrointestinal; ICU, intensive care unit; LOS, length of stay; MI, myocardial infarction; N/S, not specified; OT, operating time; PE, pulmonary embolism; UTI, urinary tract infection; VTE, venous thromboembolism.