Editing Comorbidity (section)

== Definition ==
The term "comorbid" has three definitions:
# to indicate a medical condition existing simultaneously but independently with another condition in a patient.
# to indicate a medical condition in a patient that causes, is caused by, or is otherwise related to another condition in the same patient.<ref>{{cite journal |last1=Valderas |first1=Jose M. |last2=Starfield |first2=Barbara |last3=Sibbald |first3=Bonnie |last4=Salisbury |first4=Chris |last5=Roland |first5=Martin |year=2009 |title=Defining Comorbidity: Implications for Understanding Health and Health Services |journal=Annals of Family Medicine |volume=7 |issue=4 |pages=357–63 |doi=10.1370/afm.983 |pmc=2713155 |pmid=19597174}}</ref>
# to indicate two or more medical conditions existing simultaneously regardless of their causal relationship.<ref>{{cite journal |vauthors=Jakovljević M, Ostojić L |date=June 2013 |title=Comorbidity and multimorbidity in medicine today: challenges and opportunities for bringing separated branches of medicine closer to each other |journal=Psychiatr Danub. |volume=25 Suppl 1 |issue=25 Suppl 1 |pages=18–28 |pmid=23806971}}</ref>
Comorbidity can indicate either a condition existing simultaneously, but independently with another condition or a related derivative medical condition. The latter [[word sense|sense]] of the term causes some [[semantic field|overlap]] with the concept of [[complication (medicine)|complications]]. For example, in longstanding [[diabetes mellitus]], the extent to which [[coronary artery disease]] is an independent comorbidity versus a [[complications of diabetes mellitus|diabetic complication]] is not easy to measure, because both diseases are quite multivariate and there are likely aspects of both simultaneity and consequence. The same is true of [[intercurrent disease in pregnancy|intercurrent diseases in pregnancy]]. In other examples, the true independence or relation is not ascertainable because [[syndrome]]s and [[genetic association|associations]] are often identified long before [[pathogenesis|pathogenetic]] commonalities are confirmed (and, in some examples, before they are even [[hypothesis|hypothesized]]). In psychiatric diagnoses it has been argued in part that this "'use of imprecise language may lead to correspondingly imprecise thinking', [and] this usage of the term 'comorbidity' should probably be avoided."<ref name="pmid_15738496">{{Citation |last=Maj |first=M |title='Psychiatric comorbidity': an artefact of current diagnostic systems? |journal=Br J Psychiatry |volume=186 |issue=3 |pages=182–84 |year=2005 |postscript=. |doi=10.1192/bjp.186.3.182 |pmid=15738496 |doi-access=free}}</ref> However, in many medical examples, such as comorbid diabetes mellitus and coronary artery disease, it makes little difference which word is used, as long as the medical complexity is duly recognized and addressed.

=== Difference from multimorbidity ===
Comorbidity is often referred to as [[multimorbidity]] even though the two are considered distinct clinical scenarios.<ref name=":07">{{Cite book |url=https://acmedsci.ac.uk/file-download/82222577 |title=Multimorbidity: a priority for global health research |publisher=Academy of Medical Sciences |year=2018}}</ref><ref>{{Cite journal |last1=Nicholson |first1=Kathryn |last2=Makovski |first2=Tatjana T. |last3=Griffith |first3=Lauren E. |last4=Raina |first4=Parminder |last5=Stranges |first5=Saverio |last6=van den Akker |first6=Marjan |date=22 September 2018 |title=Multimorbidity and comorbidity revisited: refining the concepts for international health research |url=https://linkinghub.elsevier.com/retrieve/pii/S0895435618305432 |journal=Journal of Clinical Epidemiology |language=en |volume=105 |pages=142–146 |doi=10.1016/j.jclinepi.2018.09.008|pmid=30253215 |s2cid=52825086 }}</ref><ref name=":322">{{Cite journal |last1=Harrison |first1=Christopher |last2=Fortin |first2=Martin |last3=van den Akker |first3=Marjan |last4=Mair |first4=Frances |last5=Calderon-Larranaga |first5=Amaia |last6=Boland |first6=Fiona |last7=Wallace |first7=Emma |last8=Jani |first8=Bhautesh |last9=Smith |first9=Susan |date=2021-01-01 |title=Comorbidity versus multimorbidity: Why it matters |journal=Journal of Multimorbidity and Comorbidity |language=en |volume=11 |pages=263355652199399 |doi=10.1177/2633556521993993 |issn=2633-5565 |pmc=7930649 |pmid=33718251}}</ref>

Comorbidity means that one 'index' condition is the focus of attention, and others are viewed in relation to this. In contrast, multimorbidity describes someone having two or more long-term (chronic) conditions without any of them holding priority over the others. This distinction is important in how the healthcare system treats people and helps making clear the specific settings in which the use of one or the other term can be preferred. Multimorbidity offers a more general and [[Person-centered care|person-centered concept]] that allows focusing on all of the patient's symptoms and providing a more holistic care. In other settings, for example in pharmaceutical research, comorbidity might often be the more useful term to use.<ref name=":14">{{Cite journal |last1=Marengoni |first1=Alessandra |last2=Angleman |first2=Sara |last3=Melis |first3=René |last4=Mangialasche |first4=Francesca |last5=Karp |first5=Anita |last6=Garmen |first6=Annika |last7=Meinow |first7=Bettina |last8=Fratiglioni |first8=Laura |date=12 March 2011 |title=Aging with multimorbidity: A systematic review of the literature |url=https://linkinghub.elsevier.com/retrieve/pii/S1568163711000249 |journal=Ageing Research Reviews |language=en |volume=10 |issue=4 |pages=430–439 |doi=10.1016/j.arr.2011.03.003|pmid=21402176 |s2cid=40912813 }}</ref><ref name=":322"/>