Unfortunately, it seems increasingly apparent that it is. It is especially common in clinical research to gather troves of data "anonymize" it, and release it publicly. I'm very curious how patient data can really be meaningfully anonymized if health conditions or treatments are combined with geographic data.

Recent history suggests we haven't really come up with effective, objective standards to truly anonymize health data. Certainly, this is not what most patients have in mind when they seek care.

https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2076397