Table of ContentsView AllTable of ContentsWhy They HappenShared CausesOne Causes AnotherCoincidenceWhy They’re ImportantFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Why They Happen
Shared Causes
One Causes Another
Coincidence
Why They’re Important
Frequently Asked Questions
Comorbidities are distinct health conditions that are present at the same time. They may exist together for many reasons, including shared causes and risk factors.
Comorbidities can increase your risk of complications or developing a new health issue altogether. Being aware of possible comorbidities and how conditions interact can help your healthcare provider ensure you get the best possible care.
This article looks at the causes of comorbidities, provides examples of different types, and explains why it’s important to understand them for diagnosis, treatment, and prevention of disease.
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Also Known AsOther names for comorbidities include:Co-occurring conditionsCoexisting conditionsConcomitant conditionsConcurrent conditionsMultimorbidity is a similar term, but is generally used to describe the presence of more than one condition—neither of which is considered more of a focus of treatment than the other.
Also Known As
Other names for comorbidities include:Co-occurring conditionsCoexisting conditionsConcomitant conditionsConcurrent conditionsMultimorbidity is a similar term, but is generally used to describe the presence of more than one condition—neither of which is considered more of a focus of treatment than the other.
Other names for comorbidities include:
Multimorbidity is a similar term, but is generally used to describe the presence of more than one condition—neither of which is considered more of a focus of treatment than the other.
Causes of Comorbidities
Comorbidities can exist in many different combinations. It is also possible to have more than one comorbidity at the same time.
Conditions described as comorbidities can be physical or mental in nature. They’re typically chronic (long-term) concerns.
10 Reasons Why You Keep Getting Sick
Shared Risk Factors or Causes
Some illnesses share an underlying cause or risk factors that increase your odds of developing them.
Shared Risk Factors
Many serious and common comorbidities occur because of shared risk factors.
Example: Stroke and heart attack
Astrokehappens when the flow of blood and oxygen to the brain is interrupted.Aheart attackhappens when an artery is blocked and can’t deliver blood and oxygen to the heart.They’re different, but they both involve problems with moving blood through your body.
These medical events share risk factors including:
Because these risk factors make both stroke and heart attack more likely, some people may have both. In fact, the risk of a stroke is higher in the year following a heart attack.
Comorbid Conditions and Diabetes
Many conditions are believed to have the same underlying cause.
Example:Lupusandrheumatoid arthritis
Both of these conditions areautoimmune. That means the immune system mistakenly attacks healthy parts of your body as if they were disease-causing viruses or bacteria.
Because they involve the same process—just with different targets of the immune system—having one autoimmune disease means you’re at risk for another, or even several more.
Example: Fibromyalgia and irritable bowel syndrome (IBS)
Fibromyalgiais a common chronic pain disease that involves fatigue, pain, and cognitive dysfunction.IBSis a digestive disorder. So they may seem quite different.
But experts suspect fibromyalgia and IBS both involve something calledcentral sensitization. That means the central nervous system is hypersensitized and easy to irritate.
When sensitization affects the nerves, pain processing, and certain hormones/brain chemicals, it manifests as fibromyalgia. When those things affect the digestive organs, it manifests as IBS.
These conditions and othercentral sensitivity syndromes (CSS)are common comorbidities.Other CSS include:
Many people have several of these comorbidities due to their common underlying mechanisms.
Comorbidity in Fibromyalgia and ME/CFS
One Condition Causes the Other
Sometimes, one condition directly causes the other.
Example: High blood pressure (hypertension) andheart disease
Example:Depressionand chronic illness
Depression is comorbid with most chronic illnesses. In some cases, that may be partly due to common physiology, such as brain-chemical (neurotransmitter) abnormalities.However, it’s also due to the symptoms and stresses of living with a chronic illness.
Depression and Chronic Illness: The Connection
Example: Obesity and many conditions
A condition that can directly lead to numerous and varied comorbidities is obesity. It’s tied to approximately 236 medical problems. Common ones include:
Obesity is thought to be comorbid with these conditions because:
The Role of Symptoms and Treatments in Comorbidity
Sometimes, the symptoms of one illness can make you more likely to develop another.
Example: Mental health and substance use disorder
Anxietyand depression can lead someone to abuse drugs or alcohol in an attempt to feel better, which can lead tosubstance use disorder(addiction).
It’s also possible for a medication you take for one condition to cause a comorbidity.
Example: Hyponatremia
Depression and AnxietyOne of the most common examples of comorbidity in the mental health field is depression and anxiety disorder. Some sources estimate that nearly 60% of those with one of these diagnoses also have symptoms of the other.
Depression and Anxiety
One of the most common examples of comorbidity in the mental health field is depression and anxiety disorder. Some sources estimate that nearly 60% of those with one of these diagnoses also have symptoms of the other.
Coincidence is just two things happening that have nothing to do with each other. For example, you may have a peanut allergy and a genetic eye disease that are unrelated.
Also, comorbidities that sometimes have a cause and effect relationship may at other times be coincidental.
Example: Diabetes and heart disease
Diabetes is a well-recognized cause of heart disease. Excess blood sugar over time damages blood vessels and can lead to heart attack and stroke. But the two conditions may also be coincidental: If your diabetes is well controlled and you don’t have damaged blood vessels, you may have a heart attack for an unrelated reason (such as abirth defect in your heart.)
This can also be the case when you get them in the reverse order, such as having a heart attack before developing diabetes. In that case, one may not cause the other and it’s just a coincidence that you have both.
Why Recognizing Comorbidities Is Important
It’s important to recognize and understand comorbidities for several reasons, including disease prevention and issues with diagnosis and treatment.
Disease Prevention
If you have a diagnosis that can lead to comorbidities, you may be able to take steps to prevent those other conditions from developing.
Example: Hypertension
Say you’re diagnosed with hypertension. Your healthcare provider will likely advise you to improve yourdietand fitness level, and potentially take medications, to lower your risk of comorbidities such as heart attack and stroke.
Acute Conditions and Comorbidities
While comorbidities are usually chronic conditions, sometimes it’s important to recognize how some of them affect acute (short-term) infectious illnesses. Having one condition may mean you need to take extra precautions to prevent an infection.
Example:COVID-19
You’re more likely to have a serious or fatal case of COVID-19 if you also have:
Example:Influenza
The flu (influenza) also poses extra risks for people with many chronic illnesses, including:
In cases like this, it’s important for people with chronic diagnoses to take extra steps to prevent a comorbid acute illness or receive prompt treatment for it.
Acute and Chronic Illnesses: The Difference
Diagnosis
Example: Autoimmune diseases
Say you have an autoimmune disease that affects your eyes and you develop joint pain. It may make more sense for your healthcare provider to first consider autoimmune pain conditions, such as lupus or rheumatoid arthritis, rather than non-autoimmune diseases like osteoarthritis andgout.
Recognizing comorbidities can also help your healthcare provider properly diagnose and treat all of your conditions, which gives you a better chance of feeling and functioning well.
Example: Fibromyalgia and digestive symptoms
Fibromyalgia can involve some digestive symptoms, but if someone’s digestive symptoms get worse while other fibromyalgia symptoms are stable, it could mean they’ve developed IBS—which may require differenttreatments.
Treatment
When you have comorbidities, it can complicate treatment and management. Your healthcare team may monitor you more closely, as well.
In general, outcomes tend to be worse for people with comorbidities than for those with only one diagnosis. Close medical oversight can help improve outcomes.
Medication Considerations
When prescribing medications, your healthcare provider needs to consider all of your diagnoses and everything else you take. That includes prescription and over-the-counter (OTC) drugs and nutritional supplements.
This is important because:
Depending on your mix of diagnoses, possible comorbidities, and treatments, you may need medical tests to make sure nothing is having unintended effects.
Example: Liver disease and medications
If you haveliver diseaseor a condition that could cause comorbid liver disease, your provider may be extra cautious about giving you medications that can harm the liver. If you take one, they may regularlytest your liver enzymesso they can take action at the first signs of a problem.
Make sure every healthcare provider you see has a full, updated list of your medications and diagnoses. This is the first step toward avoiding problems.
When it comes to combining medications, it’s important to stick to one pharmacy as much as possible. Then your pharmacist can fulfill their intended role, which is to watch for potentially dangerous drug interactions.
Treating One to Cure AnotherWhen one condition causes another, treating the first condition may help with the second. If you have obesity, for instance, losing weight may lessen or even cure comorbidities like hypertension, diabetes, and sleep apnea.
Treating One to Cure Another
When one condition causes another, treating the first condition may help with the second. If you have obesity, for instance, losing weight may lessen or even cure comorbidities like hypertension, diabetes, and sleep apnea.
Consultation and Collaboration
The more comorbidities you have and the more medications you take, the more complicated the situation becomes. Your healthcare providers may need to consult with each other from time to time or regularly collaborate on your treatments.
It’s a good idea for you to be proactive about your treatment. If one healthcare provider prescribes a new treatment or makes a new diagnosis, you may want to check in with your other providers about how it may affect things.
The Price of IllnessHealthcare costs tend to be higher for people with multiple comorbidities. This is due to seeing more healthcare providers, needing more medical tests, and taking more medications.
The Price of Illness
Healthcare costs tend to be higher for people with multiple comorbidities. This is due to seeing more healthcare providers, needing more medical tests, and taking more medications.
Summary
Comorbidity means you have more than one illness at once. It has many causes.
Comorbidities are important for disease prevention, diagnosis, and treatment. Comorbid conditions may complicate each other or affect treatment and management strategies.
All of your healthcare providers need to know about all of your comorbidities and treatments.
A Word From Verywell
Comorbidities can be challenging to live with. You may need to see a few different types of healthcare providers before you can put together the right comprehensive treatment plan for you.
Being proactive, working closely with your healthcare providers, and putting together a strong healthcare team can help you feel better and be more functional.
Frequently Asked QuestionsNo. A comorbidity is a health condition that occurs at the same time as another. These issues can have shared causes or not. A complication is a direct consequence of a health condition, medication, or lack of treatment.Learn MoreComplications of Type 2 DiabetesYes. The number of comorbidities you have can go up as you get older. This is because people tend to develop more health problems as they age.The Charlson Comorbidities Index is a system used to predict mortality (how long someone will live) in people with comorbid conditions. That helps healthcare providers determine how aggressively a condition needs to be treated.
No. A comorbidity is a health condition that occurs at the same time as another. These issues can have shared causes or not. A complication is a direct consequence of a health condition, medication, or lack of treatment.Learn MoreComplications of Type 2 Diabetes
No. A comorbidity is a health condition that occurs at the same time as another. These issues can have shared causes or not. A complication is a direct consequence of a health condition, medication, or lack of treatment.
Learn MoreComplications of Type 2 Diabetes
Yes. The number of comorbidities you have can go up as you get older. This is because people tend to develop more health problems as they age.
The Charlson Comorbidities Index is a system used to predict mortality (how long someone will live) in people with comorbid conditions. That helps healthcare providers determine how aggressively a condition needs to be treated.
18 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Harvard University Medical School, Harvard Health Publishing.Stroke after a heart attack: What’s the risk?Centers for Disease Control and Prevention.About stroke.American Heart Association.What is a heart attack?Centers for Disease Control and Prevention.Chronic diseases.Versus Arthritis.What is lupus?Erdrich S, Hawrelak JA, Myers SP, Harnett JE.A systematic review of the association between fibromyalgia and functional gastrointestinal disorders.Therap Adv Gastroenterol. 2020;13:1756284820977402. Published 2020 Dec 8. doi:10.1177/1756284820977402Fleming KC, Volcheck MM.Central sensitization syndrome and the initial evaluation of a patient with fibromyalgia: a review.Rambam Maimonides Med J. 2015;6(2):e0020. Published 2015 Apr 29. doi:10.5041/RMMJ.10204Suzuki K, Suzuki S, Haruyama Y, et al.Central sensitization in migraine is related to restless legs syndrome.J Neurol. 2021;268(4):1395-1401. doi:10.1007/s00415-020-10295-7Carvajal-Oliveros A, Campusano JM.Studying the contribution of serotonin to neurodevelopmental disorders. Can this fly?.Front Behav Neurosci. 2021;14:601449. Published 2021 Jan 12. doi:10.3389/fnbeh.2020.601449Bobo WV, Grossardt BR, Virani S, St Sauver JL, Boyd CM, Rocca WA.Association of depression and anxiety with the accumulation of chronic conditions.JAMA Netw Open. 2022;5(5):e229817. Published 2022 May 2. doi:10.1001/jamanetworkopen.2022.9817Obesity Medicine Association.Diseases related to obesity.Salcedo B. National Association of Mental Illness (NAMI).The comorbidity of anxiety and depression.National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Congenital heart defects.American Heart Association.Healthy changes in diet, activity improved treatment-resistant high blood pressure.Washington State Department of Health.Are you at high risk for flu?National Institutes of Health, National Institute on Drug Abuse.Common comorbidities with substance use disorders research report: What are the treatments for comorbid substance use disorder and mental health conditions?Ording AG, Sorenson HT.Concepts of comorbidities, multiple morbidities, complications, and their clinical epidemiologic analogs.Clin Epidemiol.2013;5:199-203. doi:10.2147/CLEP.S45305Roffman CE, Buchanan J, Allison GT.Charlson Comorbidities Index.J Physiother.2016 Jul;62(3):171. doi:10.1016/j.jphys.2016.05.008Additional ReadingMeghani SH, Buck HG, Dickson VV, et al.The conceptualization and measurement of comorbidity: a review of the interprofessional discourse.Nurs Res Pract. 2013;2013:192782. doi:10.1155/2013/192782Valderas JM, Starfield B, Sibbald B, Salisbury C, Roland M.Defining comorbidity: implications for understanding health and health services.Ann Fam Med. 2009;7(4):357-363. doi:10.1370/afm.983
18 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Harvard University Medical School, Harvard Health Publishing.Stroke after a heart attack: What’s the risk?Centers for Disease Control and Prevention.About stroke.American Heart Association.What is a heart attack?Centers for Disease Control and Prevention.Chronic diseases.Versus Arthritis.What is lupus?Erdrich S, Hawrelak JA, Myers SP, Harnett JE.A systematic review of the association between fibromyalgia and functional gastrointestinal disorders.Therap Adv Gastroenterol. 2020;13:1756284820977402. Published 2020 Dec 8. doi:10.1177/1756284820977402Fleming KC, Volcheck MM.Central sensitization syndrome and the initial evaluation of a patient with fibromyalgia: a review.Rambam Maimonides Med J. 2015;6(2):e0020. Published 2015 Apr 29. doi:10.5041/RMMJ.10204Suzuki K, Suzuki S, Haruyama Y, et al.Central sensitization in migraine is related to restless legs syndrome.J Neurol. 2021;268(4):1395-1401. doi:10.1007/s00415-020-10295-7Carvajal-Oliveros A, Campusano JM.Studying the contribution of serotonin to neurodevelopmental disorders. Can this fly?.Front Behav Neurosci. 2021;14:601449. Published 2021 Jan 12. doi:10.3389/fnbeh.2020.601449Bobo WV, Grossardt BR, Virani S, St Sauver JL, Boyd CM, Rocca WA.Association of depression and anxiety with the accumulation of chronic conditions.JAMA Netw Open. 2022;5(5):e229817. Published 2022 May 2. doi:10.1001/jamanetworkopen.2022.9817Obesity Medicine Association.Diseases related to obesity.Salcedo B. National Association of Mental Illness (NAMI).The comorbidity of anxiety and depression.National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Congenital heart defects.American Heart Association.Healthy changes in diet, activity improved treatment-resistant high blood pressure.Washington State Department of Health.Are you at high risk for flu?National Institutes of Health, National Institute on Drug Abuse.Common comorbidities with substance use disorders research report: What are the treatments for comorbid substance use disorder and mental health conditions?Ording AG, Sorenson HT.Concepts of comorbidities, multiple morbidities, complications, and their clinical epidemiologic analogs.Clin Epidemiol.2013;5:199-203. doi:10.2147/CLEP.S45305Roffman CE, Buchanan J, Allison GT.Charlson Comorbidities Index.J Physiother.2016 Jul;62(3):171. doi:10.1016/j.jphys.2016.05.008Additional ReadingMeghani SH, Buck HG, Dickson VV, et al.The conceptualization and measurement of comorbidity: a review of the interprofessional discourse.Nurs Res Pract. 2013;2013:192782. doi:10.1155/2013/192782Valderas JM, Starfield B, Sibbald B, Salisbury C, Roland M.Defining comorbidity: implications for understanding health and health services.Ann Fam Med. 2009;7(4):357-363. doi:10.1370/afm.983
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Harvard University Medical School, Harvard Health Publishing.Stroke after a heart attack: What’s the risk?Centers for Disease Control and Prevention.About stroke.American Heart Association.What is a heart attack?Centers for Disease Control and Prevention.Chronic diseases.Versus Arthritis.What is lupus?Erdrich S, Hawrelak JA, Myers SP, Harnett JE.A systematic review of the association between fibromyalgia and functional gastrointestinal disorders.Therap Adv Gastroenterol. 2020;13:1756284820977402. Published 2020 Dec 8. doi:10.1177/1756284820977402Fleming KC, Volcheck MM.Central sensitization syndrome and the initial evaluation of a patient with fibromyalgia: a review.Rambam Maimonides Med J. 2015;6(2):e0020. Published 2015 Apr 29. doi:10.5041/RMMJ.10204Suzuki K, Suzuki S, Haruyama Y, et al.Central sensitization in migraine is related to restless legs syndrome.J Neurol. 2021;268(4):1395-1401. doi:10.1007/s00415-020-10295-7Carvajal-Oliveros A, Campusano JM.Studying the contribution of serotonin to neurodevelopmental disorders. Can this fly?.Front Behav Neurosci. 2021;14:601449. Published 2021 Jan 12. doi:10.3389/fnbeh.2020.601449Bobo WV, Grossardt BR, Virani S, St Sauver JL, Boyd CM, Rocca WA.Association of depression and anxiety with the accumulation of chronic conditions.JAMA Netw Open. 2022;5(5):e229817. Published 2022 May 2. doi:10.1001/jamanetworkopen.2022.9817Obesity Medicine Association.Diseases related to obesity.Salcedo B. National Association of Mental Illness (NAMI).The comorbidity of anxiety and depression.National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Congenital heart defects.American Heart Association.Healthy changes in diet, activity improved treatment-resistant high blood pressure.Washington State Department of Health.Are you at high risk for flu?National Institutes of Health, National Institute on Drug Abuse.Common comorbidities with substance use disorders research report: What are the treatments for comorbid substance use disorder and mental health conditions?Ording AG, Sorenson HT.Concepts of comorbidities, multiple morbidities, complications, and their clinical epidemiologic analogs.Clin Epidemiol.2013;5:199-203. doi:10.2147/CLEP.S45305Roffman CE, Buchanan J, Allison GT.Charlson Comorbidities Index.J Physiother.2016 Jul;62(3):171. doi:10.1016/j.jphys.2016.05.008
Harvard University Medical School, Harvard Health Publishing.Stroke after a heart attack: What’s the risk?
Centers for Disease Control and Prevention.About stroke.
American Heart Association.What is a heart attack?
Centers for Disease Control and Prevention.Chronic diseases.
Versus Arthritis.What is lupus?
Erdrich S, Hawrelak JA, Myers SP, Harnett JE.A systematic review of the association between fibromyalgia and functional gastrointestinal disorders.Therap Adv Gastroenterol. 2020;13:1756284820977402. Published 2020 Dec 8. doi:10.1177/1756284820977402
Fleming KC, Volcheck MM.Central sensitization syndrome and the initial evaluation of a patient with fibromyalgia: a review.Rambam Maimonides Med J. 2015;6(2):e0020. Published 2015 Apr 29. doi:10.5041/RMMJ.10204
Suzuki K, Suzuki S, Haruyama Y, et al.Central sensitization in migraine is related to restless legs syndrome.J Neurol. 2021;268(4):1395-1401. doi:10.1007/s00415-020-10295-7
Carvajal-Oliveros A, Campusano JM.Studying the contribution of serotonin to neurodevelopmental disorders. Can this fly?.Front Behav Neurosci. 2021;14:601449. Published 2021 Jan 12. doi:10.3389/fnbeh.2020.601449
Bobo WV, Grossardt BR, Virani S, St Sauver JL, Boyd CM, Rocca WA.Association of depression and anxiety with the accumulation of chronic conditions.JAMA Netw Open. 2022;5(5):e229817. Published 2022 May 2. doi:10.1001/jamanetworkopen.2022.9817
Obesity Medicine Association.Diseases related to obesity.
Salcedo B. National Association of Mental Illness (NAMI).The comorbidity of anxiety and depression.
National Institutes of Health, U.S. National Library of Medicine: MedlinePlus.Congenital heart defects.
American Heart Association.Healthy changes in diet, activity improved treatment-resistant high blood pressure.
Washington State Department of Health.Are you at high risk for flu?
National Institutes of Health, National Institute on Drug Abuse.Common comorbidities with substance use disorders research report: What are the treatments for comorbid substance use disorder and mental health conditions?
Ording AG, Sorenson HT.Concepts of comorbidities, multiple morbidities, complications, and their clinical epidemiologic analogs.Clin Epidemiol.2013;5:199-203. doi:10.2147/CLEP.S45305
Roffman CE, Buchanan J, Allison GT.Charlson Comorbidities Index.J Physiother.2016 Jul;62(3):171. doi:10.1016/j.jphys.2016.05.008
Meghani SH, Buck HG, Dickson VV, et al.The conceptualization and measurement of comorbidity: a review of the interprofessional discourse.Nurs Res Pract. 2013;2013:192782. doi:10.1155/2013/192782Valderas JM, Starfield B, Sibbald B, Salisbury C, Roland M.Defining comorbidity: implications for understanding health and health services.Ann Fam Med. 2009;7(4):357-363. doi:10.1370/afm.983
Meghani SH, Buck HG, Dickson VV, et al.The conceptualization and measurement of comorbidity: a review of the interprofessional discourse.Nurs Res Pract. 2013;2013:192782. doi:10.1155/2013/192782
Valderas JM, Starfield B, Sibbald B, Salisbury C, Roland M.Defining comorbidity: implications for understanding health and health services.Ann Fam Med. 2009;7(4):357-363. doi:10.1370/afm.983
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