Cervical cancer screening in rural NSW: Health Insurance Commission data compared to self-report

There are several sources of data for estimates of community Pap test rates, including self-report, pathology laboratory records and Health Insurance Commission (HIC) data. Estimates of screening rates can vary considerably according to the sampling frame and data source. This study aimed to compare the self-reported estimates of cervical cancer screening with HIC estimates for women in rural NSW towns. Self-report of a Pap test in the past two years from 2,498 women in 19 rural towns of NSW was compared to HIC-provided Pap test rates. Self-report levels were adjusted for non-HIC providers and HIC levels included data from the Victorian Cytology Register. Self-report estimates were significantly higher than HIC estimates in 18 of the 19 towns, with discrepancies ranging from 13% to 29%. HIC-recorded providers accounted for between 65% and 100% of Pap tests per town, according to self-report. The highest Pap test rate by self-report was 70.1%, the highest by HIC was 49.2%. The lowest Pap test rate by self-report was 45.2%, the lowest by HIC was 26.1%. There was significant variation in Pap test rates between towns for adjusted self-report estimates, but not for the crude self-report estimates. Researchers should always be aware of both the possible variations according to data source and the inherent biases for whichever data source is used. An extra caution is given to consider the public/private provider profile when exploring possible geographical differences in Pap test rates.