Creation and Validation of Linkage Between Orthopedic Registry and Administrative Data Using Indirect Identifiers

Registries and administrative databases have unique and complementary strengths in device epidemiologic studies. We sought to develop, validate, and assess a sequential algorithm using indirect identifiers to link registry and administrative data.

Hip and knee arthroplasty procedures performed at 6 New York State hospitals enrolled in American Joint Replacement Registry in 2014 were included. After conducting a direct linkage using patient identifiers including name and social security numbers, we validated the methodology of indirect linkage using facility ID, patients' year and month of birth, sex, and zip code, and procedure date and site (hip/knee). We further evaluated the influence of absent indirect identifier(s) and compromised data quality on linkage success.

Using our sequential algorithm, 3739 of the 4063 directly linked records (92.03%) were matched with indirect identifiers, with an accuracy of >99.9%. Main reasons for nonmatching included discrepancies in procedure codes and dates. When one of the indirect identifiers was not available, the linkage algorithm still achieved over 90% sensitivity and 99.8% accuracy. Analyses showed that the algorithm was robust when quality of data was moderately compromised.

This study demonstrated high sensitivity and accuracy of an algorithm to create linkages between a registry and an administrative database using indirect identifiers. The methodology will enable long-term surveillance and outcome assessment of a wide variety of devices and procedures. Variations in the coding of procedures, availability of indirect identifiers, and their quality have limited impact on this algorithm.