Disagreement of ICD-10 Codes Between a Local Hospital Information System and a Cancer Registry

Background: In the field of cancer, the ICD-10 coding convention is based on the site of a neoplasm in the bodyand usually ignores the morphology, thus the same code may be assigned to tumors of different morphologic typesin an organ. Nowadays, all general (provincial) and center hospitals in Thailand are equipped with the hospitalinformation system (HIS) database.
Objective: This study aimed to find the characteristics and magnitude ofagreement represented by the positive predictive value (PPV) of provisional cancer diagnoses in the HIS databasein Pattani Hospital in Thailand in comparison with the final cancer diagnosis of the ICD-10 codes generatedfrom a well established cancer registry in Songklanagarind Hospital, the medical school hospital of Prince ofSongkla University. Materials and
Methods: Data on cancer patients residing in Pattani province who visitedPattani Hospital from January 2007 to May 2011 were obtained from the HIS database. The ICD-10 codes ofthe HIS computer database of Pattani Hospital were compared against the ICD-10 codes of the same personrecorded in the hospital-based cancer registry of Songklanagarind Hospital. The degree of agreement or positivepredictive value (PPV) was calculated for each sex and for both sexes combined.
Results: A total of 313 cases(15.9%) could be matched in the two databases. Some 222 cases, 109 males and 113 females, fulfilled the criteriaof referral from Pattani to Songklanagarind Hospitals. Of 109 male cancer cases, 76 had the same ICD-10 codesin both hospitals, thus, the PPV was 69.7% (95%CI: 60.2-78.2%). Agreement in 76 out of 113 females gave a PPVof 67.3% (95%CI: 57.8-75.8%). The two percentages were found non-significant with Fisher’s exact p-value of0.773. The PPV for combined cases of both sexes was 68.5% (95%CI: 61.9-74.5%).
Conclusions: Changes in finaldiagnosis in the referral system are common, thus the summary statistics of a hospital without full investigationfacilities must be used with care, as the statistics are biased towards simple diseases able to be investigated byavailable facilities. A systematic feedback of patient information from a tertiary to a referring hospital shouldbe considered to increase the accuracy of statistics and to improve the comprehensive care of cancer patients.