A Registry in medical data systems is a specialized highly focused repo of medical information about specific patients. For example, a cancer registry will have unique diagnosis metadata on thousands of patients with a specific cancer. Registries in medicine started long before registries in computer science, so it's important not to confuse the two as equal. My grandfather ran a tumor registry in his file cabinet back in the 1940s. Think of a medical registry as a very specific EHR these days. Sometimes I get so frustrated with mainstream EHRs in hospitals and clinics I want to quit trying to improve the ecosystem. It's just madness until you realize it's a matter of Vendor Lock In Syndrome (VLIS) which sadly has no cure. This paper https://pmc.ncbi.nlm.nih.gov/articles/PMC10853080/ gives hope. Registries and FHIR integration are living proof that it's time to recognize it is not worth the effort to bring big EHRs to the table and expect progress; the cure for VLIS is to simply start over and innovate. Big EHRs are literally on life support without hope of recovery. It's time to pull the plug.