Comparison of self-report data and medical records data: results from a case-control study on prostate cancer

Background Self-report and review of medical records are the most common me thods for the assessment of past exposures. However, information obtained f rom self-reports and medical records may not be consistent. This study comp ared information provided in a self-administered questionnaire with medical records data. Methods Self-report and medical records data came from a case-control study on prostate cancer. Cases were 181 patients with primary prostate cancer a nd controls were 297 men without the disease, enrolled in Group Health Coop erative (GHC) in Seattle. The consistencies between the two data sources we re examined. Results In general, agreement between the two data sources was almost perfe ct for demographic and anthropometric variables, substantial for the histor y of inguinal hernia and kidney stones, and moderate for vasectomy, family history of prostate cancer, smoking and alcohol consumption. However, the t wo data sources generally were poorly concordant for prior genitourinary di seases that have less explicit diagnostic criteria such as benign prostatic hyperplasia and prostatitis. Analyses of discordant data showed that men w ere more likely to report an exposure or medical condition that could not b e verified from medical records. No discernible patterns in the difference of agreement were found according to age, GHC membership length or case-con trol status. Conclusions This study suggests that agreement between self-reported data a nd medical records data varies depending upon the study variables. While bo th data sources are subject to some problems, self-report may provide more complete and comparable information, at least for variables unrelated to di agnosis.