I am just starting to analyze v1.3 of MIMIC-III data. I have two questions about the DIAGNOSES_ICD table.
According to the documentation  : "ICD diagnoses are ordered by priority - and the order does have an impact on the reimbursement for treatment." What does priority really mean in clinical settings? Also, does it mean the dataset does not have any information about when a diagnosis is confirmed? E.g. a patient may have some cancer on day 1 but acquire pneumonia on day 5?
There are 47 rows in this table where the ICD9_CODE is an empty string, what do they mean? Should I just remove them from my analysis?
Thank you very much.