title: [Postoperative complication registration in gastric cancer surgery from 2005 to 2016: a learning curve in our institution].
abstract: OBJECTIVE
  To analyze the change in postoperative complication rate after gastric cancer surgery registered in the Peking University Cancer Hospital in recent 11 years and the learning curve of complication registration, and to investigate how to improve the complication registration and evaluation in gastric cancer surgery.
  
  
  METHODS
  Patients who underwent open or laparoscopic gastric cancer surgery between April 14, 2005 and February 15, 2016 in our institution were included in the study, and those without essential clinical and administrative data were excluded. Data were biennially collected, and linear regression was performed to investigate the changes of the following parameters, including overall complication rate, severe complication proportion (proportion of complications with Clavien-Dindo score ≥III(a in the total registered complications), re-operation rate and the major complication rate.
  
  
  RESULTS
  A total of 5 666 patients were included in the analysis, with 4 111 males (72.56%) and 1 555 females (27.44%). The average age was (58.87±11.50) years and average BMI was(23.15±3.30) kg/m2. There were 305 patients included in the 2005-2006 interval, 810 patients in 2007-2008, 957 patients in 2009-2010, 1 163 patients in 2011-2012, 1 421 patients in 2013-2014, and 1 010 patients in 2015-2016, respectively. The overall re-operation rate was 2.34%(133/5 666), postoperative mortality was 0.41%(23/5 666), registered complication rate was 19.66%(1 114/5 666), severe complication proportion was 32.28%(338/1 047), and the proportion of complication missing the Clavien-Dindo score was 6.01%(67/1 114). The linear regression showed the re-operation rate (r=0.13, P=0.801) and postoperative mortality (r=0.58, P=0.231) remained low (< 4% and < 1% respectively) since 2005, and showed no statistical significance. The registered complication rate showed evident increase from 3.93%(12/305) to 29.13%(414/1 421) between 2005 and 2014 (r=0.92, P=0.010), and slight decrease to 22.77%(230/1 010) in 2015-2016. The severe complication proportion significantly decreased from 6/9 in 2005-2006 to 22.73%(50/220) in 2015-2016 (r=0.90, P=0.014). The proportion of complication missing the Clavien-Dindo score significantly decreased from 25.00%(3/12) in 2005-2006 to 4.35%(10/230) in 2015-2016(r=0.82, P=0.044). The most common complications were infection (9.12%, 517 cases), effusions (6.26%, 355 patients), gastrointestinal motility disorder (4.45%, 252 cases), anastomotic leakage (3.19%, 181 cases) and bleeding (2.31%, 131 cases). The registered rates of these complications all increased since 2005, and the rates of leakage and effusions decreased since 2012 while the others decreased after 2014.
  
  
  CONCLUSIONS
  According to the data from our institution in the recent 11 years, a learning curve exists in our institution for complication registration in gastric cancer surgery. The administrative data appears to be more reliable than registered complication data in quality and safety evaluation during the learning period. A detailed classification with the Clavien-Dindo score aids to the use of complication data for the quality and safety measurement.
authors.forename: Zhouqiao
authors.initials: Z
authors.lastname: Wu
authors.forename: Jinyao
authors.initials: J
authors.lastname: Shi
authors.forename: Fei
authors.initials: F
authors.lastname: Shan
authors.affiliation: Department of Gastrointestinal Cancer Center, Ward I(, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital and Institute, Beijing 100142, China. ligregory@outlook.com.
authors.forename: Ziyu
authors.initials: Z
authors.lastname: Li
authors.forename: Jiafu
authors.initials: J
authors.lastname: Ji
mesh_terms: D000368:Aged; D057868:Anastomotic Leak / Q000209:etiology; D003625:Data Collection / Q000379:methods* / Q000706:statistics & numerical data*; D005260:Female; D005743:Gastrectomy / Q000009:adverse effects* / Q000401:mortality; D006801:Humans; D010535:Laparoscopy / Q000009:adverse effects*; D008297:Male; D008499:Medical Records / Q000706:statistics & numerical data*; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology*; D012042:Registries / Q000706:statistics & numerical data; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000150:complications / Q000601:surgery*