Improving Patient Follow-Up Information Through Data Linkages

Oregon State Cancer Registry

Each year, cancer patients who are residents of Oregon at the time of their diagnosis and are registered in the Oregon State Cancer Registry (OSCaR) move to a different state. If they die outside of Oregon, we have no systematic national process to access their follow-up heath information or update their vital status. This prevents us from presenting accurate survival statistics on our registered cases. A recent study concludes that complete death ascertainment is essential to producing reliable survival statistics.¹ In addition, inadequate follow-up information limited our capacity to provide accurate and complete follow-up data on these cases to researchers, policy makers, and other public health data users.

Our Social Security Death Index (SSDI) linkage was highly successful. Through this linkage, we identified about 10,000 OSCaR patients who were diagnosed between 1996 and 2010 and recorded in the SSDI database. This linkage provided their vital status and date of death, which we updated in our system. We also acquired previously missing Social Security numbers and corrected errors in dates of birth and death and Social Security numbers.

The National Death index (NDI) linkage provided death information on patients who were not recorded in the SSDI database. We had 1,541 matches with the NDI database, including 1,338 that were already known to be deceased. New vital status information was acquired for 208 cases. This linkage also helped us update cause of death, state of death, missing or inaccurate Social Security numbers, and date of birth for many other patient records.

OSCaR's goal is to provide high-quality, accurate, and complete cancer data to policy makers, researchers, and other public health data users. Accurate estimates of cancer incidence, prevalence, and survival are essential to evaluate the cancer burden among Oregon residents and to help reduce that burden. Periodic linkages with the SSDI and NDI databases, as well as monthly linkage with the Oregon death certificate files, help improve patient follow-up information by providing vital status and date and cause of death, improve the accuracy, quality, and completeness of OSCaR data.

¹Johnson CJ, Weir HK, Yin D, Niu X. The impact of patient follow-up on population-based survival rates. Journal of Registry Management 2010;37(3):86–103.