Using NAPIIA to improve the accuracy of Asian race codes in registry data

Misclassification of race/ethnicity, particularly for Asians and American Indians, has been an issue existing in cancer registry data for years. Over the past 10 years, the Asian population has increased noticeably in both the US and in Louisiana. Therefore, accurate recording of Asian races/ethnicities in cancer registry databases has become essential for disparity research. The objectives of this study were to demonstrate that using the North American Association of Central Cancer Registries (NAACCR) Asian/Pacific Islander Identification Algorithm (NAPIIA) could improve the coding accuracy of Asian ethnicities and to identify sources for manually verifying race/ethnicity.

We selected cases diagnosed in years 1995 to 2008 with first race (NAACCR item 160) coded to any Asians, other race, unknown race, or non-Asian race with birthplace in an Asian country. We then converted these races to Asian, Not Otherwise Specified (Asian NOS) race code 96 and applied NAPIIA on the records. The resultant Asian races/ethnicities assigned by NAPIIA were then compared to the original race. When the NAPIIA-assigned Asian codes were different from the original race, the cases were manually reviewed. Kappa statistic test was used to measure the interobserver agreement; sensitivity and positive predictive value (PPV) were used to assess the degree of discrepancy for each Asian racial/ethnic subgroup separately.

Of 2,147 cases run through the NAPIIA, 22.3% (479) were identified with coding discrepancies. Overall, the agreement on Asian subgroups between the original and NAPIIA-assigned was almost perfect (Kappa = 0.8682). When NAPIIA-assigned race and manually reviewed race were compared, the Vietnamese subgroup had the highest consistent rate (95%). Of the 237 cases where the original race was coded to Asian NOS, 93.7% were verified as having a more specific race/ethnicity. Slightly over 98% of deceased patients found in Louisiana online death certificate database had specific race/ethnicity information.

NAPIIA is an excellent tool to assist cancer registries in improving the coding accuracy of Asian subgroups and enhancing the data quality by reducing cases with Asian NOS and unknown race. The death certificate is a great source for identifying and/or verifying race/ethnicity based on several factors including patient's race code and place of birth as well as the parent's names and place of birth.