Validity of data in the Danish Colorectal Cancer Screening Database

Abstract

BackgroundIn Denmark, a nationwide screening program for colorectal cancer was implemented in March 2014. Along with this, a clinical database for program monitoring and research purposes was established.ObjectiveThe aim of this study was to estimate the agreement and validity of diagnosis and procedure codes in the Danish Colorectal Cancer Screening Database (DCCSD).MethodsAll individuals with a positive immunochemical fecal occult blood test (iFOBT) result who were invited to screening in the first 3 months since program initiation were identified. From these, a sample of 150 individuals was selected using stratified random sampling by age, gender and region of residence. Data from the DCCSD were compared with data from hospital records, which were used as the reference. Agreement, sensitivity, specificity and positive and negative predictive values were estimated for categories of codes “clean colon”, “colonoscopy performed”, “overall completeness of colonoscopy”, “incomplete colonoscopy”, “polypectomy”, “tumor tissue left behind”, “number of polyps”, “lost polyps”, “risk group of polyps” and “colorectal cancer and polyps/benign tumor”.ResultsHospital records were available for 136 individuals. Agreement was highest for “colorectal cancer” (97.1%) and lowest for “lost polyps” (88.2%). Sensitivity varied between moderate and high, with 60.0% for “incomplete colonoscopy” and 98.5% for “colonoscopy performed”. Specificity was 92.7% or above, except for the categories “colonoscopy performed” and “overall completeness of colonoscopy”, where the specificity was low; however, the estimates were imprecise.ConclusionA high level of agreement between categories of codes in DCCSD and hospital records indicates that DCCSD reflects the hospital records well. Further, the validity of the categories of codes varied from moderate to high. Thus, the DCCSD may be a valuable data source for future research on colorectal cancer screening.

Colonoscopy-related complications in a nationwide immunochemical fecal occult blood test-based colorectal cancer screening program

“…The DCCSD was established to monitor the screening program and consists of data from existing data sources: the IAM, the Danish National Patient Registry (DNPR), and the National Pathology Registry. 6 The DNPR is a national registry that collects data on all in- and outpatient somatic admissions including CPR number, dates of admission and discharge, and codes for diagnoses (using the ICD-10) and procedures (Health Care Service Classification System). 10 Thus, all clinical data, including screening-related diagnoses (eg, type of lesion and complication) and procedures (eg, number of polyps observed and completion of colonoscopy), are reported to DNPR from the departments or emergency rooms providing the colonoscopy or follow-up treatment, and subsequently assembled in the DCCSD.…”

“…In Denmark, the CRC screening program consists of an immunochemical fecal occult blood test (iFOBT) followed by colonoscopy for participants who tested positive for occult blood. 6 Mass screening targets apparently healthy individuals. Thus, it is crucial that the involved procedures cause minimal harm.…”

“…As recommended by the European guidelines, 4 the quality of the Danish CRC screening program is monitored, and data for this purpose are assembled in the Danish Colorectal Cancer Screening Database (DCCSD). 6 In the first annual report of the DCCSD, the overall incidence of hospital-registered complications (perforation, bleeding, medical complications during colonoscopy, and post-polypectomy syndrome) after screening-related colonoscopy was 3.0 per 1,000. However, the validity of these data is unknown, and the incidence of complications is potentially underreported as they may occur with a delay, that is, hours or days after the individual has been discharged from the colonoscopy department.…”

“…In addition, along with the establishment of the screening program, novel codes for registration of complications were introduced, which likely prompted underreporting, especially in the starting period. 6 …”

Effectiveness of Colorectal Cancer Screening in Detecting Earlier-Stage Disease—A Nationwide Cohort Study in Denmark

“…22,23 Information on the date of screening invitation was retrieved from the Danish CRC Screening Database, which monitors the quality of the screening program. 17,24 Those who were a priori randomized to be invited to CRC screening from March 1, 2014 to June 30, 2015 were classified as invited to screening, and those randomized to be invited from January 1, 2016 to December 31, 2017 were classified as not yet invited.…”