Linkage of a De-identified United States Rheumatoid Arthritis Registry with Administrative Data to Facilitate Comparative Effectiveness Research

File Size727.7 KiB
DateSeptember 9, 2015
AuthorCurts, J R, Chen L, Bharat A, Delzell E, Greenberg J D, Harrold L, Kremer J, Setoguchi S, Solomon D H, Xie F, Yun H.
Linkages between registries and administrative data may provide a valuable resource for comparative effectiveness research. However, personal identifiers that uniquely identify individuals are not always available. We describe methods to link a de-identified arthritis registry and U.S. Medicare data. The linked dataset was also used to evaluate the generalizability of the registry to the U.S. Medicare population.
Rheumatoid arthritis (RA) patients participating in the Consortium of Rheumatology Researchers of North America (CORRONA) registry were linked to Medicare data restricted to rheumatology claims or claims for RA. Deterministic linkage was performed using age, sex, provider identification number, and geographic location of the CORRONA site. We then searched for visit dates in Medicare matching visit dates in CORRONA, requiring at least 1 exact matching date. Linkage accuracy was quantified as a positive predictive value (PPV) in a sub-cohort (n=1581) with more precise identifiers.
CORRONA participants with self-reported Medicare (n=11,001) were initially matched to 30,943 Medicare beneficiaries treated by CORRONA physicians. A total of 8,431 CORRONA participants matched on at least 1 visit; 5,317 matched uniquely on all visits. The number of patients who linked and linkage accuracy (from the subcohort) was high for patients with >2 visits (n=3458, 98% accuracy), exactly 2 visits (n=822, 96% accuracy) visits, and 1 visit (n=1037, 79% accuracy) visit that matched exactly on calendar date. Demographics and comorbidity profiles of registry participants were similar to non-participants, except participants were more likely to use DMARDs and biologics.
Linkage between a national, de-identified outpatient arthritis registry and Medicare data on multiple non-unique identifiers appears feasible and valid.