Editing Case mix (section)

{{Refimprove|date=October 2016}}
'''Case mix''', also '''casemix''' and '''patient mix''', is a term used within [[epidemiology]] as a synonym for [[Cohort (statistics)|cohort]]; essentially, a case mix groups statistically related patients.<ref name="NCO">{{cite web|title=NHS National Casemix Office|url=http://digital.nhs.uk/casemix|accessdate=3 September 2016|archive-url=https://web.archive.org/web/20160909221255/http://digital.nhs.uk/casemix|archive-date=9 September 2016|url-status=dead}}</ref> An example case mix might be male patients under the age of 50, who present with a [[myocardial infarction]] and also undergo emergency [[coronary artery bypass surgery]].

At a local level, such as a single hospital; the data within a case mix may relate to the activity of an individual consultant, a specific [[Specialty (medicine)|speciality]] or a particular unit (such as a ward). On a wider level; it is possible to compare the case mix of hospitals, regions, and even countries.<ref name="NCO" /> Whilst a case mix will often include a condition or diagnosis, as well as any treatment received; it can also include demographics, such as gender or age, and a specific time range.{{citation needed|date=September 2016}}

Conditions and treatments are often captured using a [[medical classification]] system, such as [[ICD-10]], in a process called [[clinical coding]]. The practice of coding, essentially groups patients using statistical codes. The coded data can be grouped further into [[Diagnosis-related group|Diagnosis-Related Groups]] (DRGs), which are used in the [[medical billing|billing]] process by hospitals and practices; as the "cost per item" of healthcare is based on the casemix.{{citation needed|date=September 2016}}