Why do some patients have no clinical notes in the first 48 hours in the MIMIC-III database?

Question

Using MIMIC-III (v1.4), it seems that some patients do not have any clinical (i.e. physician, nursing, respiratory, nutrition) text notes during the first 48 hours of their admission. The number ranges from 5-6 thousand depending on whether you use the CHARTTIME or CHARTDATE against the ADMITTIME. There are, however, radiology notes during this period. Additionally, there are about 15k unique HADM_IDs for which there are no such clinical notes at all.

Do these missing notes reflect missing data? An error in the date/time? Or were the patients in the ER, OR, or somewhere else where perhaps the clinical notes weren't captured?

Answer 1

While this may not be the definitive answer (disclosure: I am not the author of this dataset), further digging revealed that almost half of the missing notes were associated with admission source Clinic referral/Premature, while only 2-3% of this type are found in notes that do have clinical text notes present. I would hypothesize that the missing notes are due to some combination of 1) the admission dates of urgent clinic admits may falsely appear earlier than the "actual admission," thus the first 48h are actually in the outpatient setting 2) patients may end up boarding in some kind of obs or pre-admit area, where notes are not complete or perhaps not captured.

However, this still wouldn't explain the other half of the missing notes without the Clinic referral/Premature designation.