Why is there a "K." prefix on some endpoints?

We often use the K. prefix (from kuolinsyyrekisteri, the death registry) to denote that the endpoint represents death due to the disease.

K (from kuolema) means “death due to”. When endpoint follow-up is done, all endpoints are formed using only a specific registry (the death registry, in the case of K* endpoints). These intermediate data are dropped from the final endpoint files to keep file size to a minimum.