It is not often that The Journal of Bone & Joint Surgery publishes an article about data-linkage efforts. To even raise the topic with most readers of The Journal would elicit a yawn and quick dismissal of the abstract without a second thought. With this fact duly noted, the possibility of linking health-system joint-replacement registries with Medicare claims data is a first step in a potentially game-changing approach to achieving the long-term clinical research our specialty needs.
In the June 20, 2018 issue of JBJS, Raman et al. detail their successful linkage of a total ankle arthroplasty (TAA) registry with Medicare data without the use of unique patient identifiers. Among 280 TAA patients over the age of 65, 250 had their registry data linked with their Medicare record with exact matches for date of procedure, date of birth, and sex. Of the linked records, 214 (76.4%) had ≥3 years of postoperative claims data.
Why are these findings so important? The answer is follow-up. Every clinician and/or researcher who has attempted to follow patients beyond the first year after a procedure understands how difficult long-term follow-up is. We live in a mobile society in which informative posttreatment data is easily lost. The younger the patient group, the more difficult it usually is to locate patients as time passes. If patients are doing well, many stop coming to our offices, no matter how strongly we recommend annual follow-ups. Everyone is busy—including retirees—and most have better things to do than drive to their surgeon’s office or even complete a web-based questionnaire. Additionally, some patients care only about their own outcomes; they are not as focused as we are on contributing to the advancement of the profession and improving outcomes at the population level.
By linking patient data from a local health-system registry to nationwide claims data, we can gain a better understanding of long-term patient progress. We can use the patient- and implant-specific data housed in the registry and essentially substitute the information from follow-up visits that did not take place within the registry system with the data contained within the Medicare system, which follows beneficiaries wherever they live.
The marriage of registry and claims data is not perfect, though, because patients who are still working probably have private insurance coverage that is not captured by the Medicare system. (Of course, if universal coverage were to come to pass, that issue would be eliminated.) Furthermore, any time claims data are used, uncertainty about the accuracy of coding must be considered. These real-world limitations notwithstanding, the linkage of registry data with claims data does have great potential for enhancing our ability to analyze—and improve—long-term orthopaedic outcomes.
Marc Swiontkowski, MD