Quality of morbidity coding in general practice computerized medical records: a systematic review

Background. Increased use of computers and morbidity coding in primary care delivery and research brings a need for evidence of the quality of general practice medical records. Objective. Our aim was to assess the quality, in terms of completeness and correctness, of morbidity coding in computerized general practice records through a systematic review. Methods. Published studies were identified by searches of electronic databases and citations of collected papers. Assessment of each article was made by two independent observers and discrepancies resolved by consensus. Studies were reviewed qualitatively due to their heterogeneity. Results. Twenty-four studies met the inclusion criteria for the review. There was variation in the methodology and quality of studies, and problems in generalizability. Studies have attempted to assess the completeness and correctness of morbidity registers by reference to a gold standard such as paper notes, prescribing information or diagnostic tests and procedures, each of which has problems. A consistent finding was that quality of recording varied between morbidities. One reason for this may be in distinctiveness of diagnosis (e.g. coding of diabetes tended to be of higher quality than coding of asthma). Conclusions. This review highlights the problems faced in assessing the completeness and correctness of computerized general practice medical records. However, it also suggests that a high quality of coding can be achieved. The focus should now be on methods to encourage and help practices improve the quality of their coding.