What Is Comorbidity?

Medically Reviewed by Carol DerSarkissian, MD on November 17, 2021
5 min read

Comorbidity is a medical term that you may have heard your doctor use. It describes the existence of more than one disease or condition within your body at the same time. Comorbidities are usually long-term, or chronic. They may or may not interact with each other.

Doctors use the term comorbid to both understand and explain how the conditions might affect your physical and mental health, both together and separately. They may refer to comorbidities by other names, such as coexisting or co-occurring conditions. Other commonly used terms include “multimorbidity” or “multiple chronic conditions.”

For example, if you have diabetes and you’re later diagnosed with depression, then depression is a comorbidity. Both conditions have symptoms that can affect your quality of life. So when you see your doctor for diabetes, they’ll need to keep in mind that depression also affects your health overall.

It’s important to note that comorbidity is not the same thing as a complication. A complication is a side effect or medical problem that you may develop during a disease or after a procedure or treatment. It may be caused by the disease, procedure, or treatment, or not be related to them at all.

Comorbidity is a separate illness or disease you may have along with your primary health concern. A complication may or may not be related to the comorbid disease.

Older people are more likely to have them. This is because as you age, your body is more likely to develop health problems. According to research, in the U.S., about 80% of Medicare costs is spent on people with four or more chronic conditions.

But younger people can also have comorbidities. One 2012 study looked at data from more than 1 million people in Scotland. It found that many things can cause a person to have multimorbidity, or two or more diseases at the same time.

These include:

  • Disorder type (physical or mental)
  • Sex
  • Age
  • Socioeconomic status

The study found that those who lived in lower socioeconomic conditions were more likely to develop more than one health concern. They also developed them 10 to 15 years earlier than those who lived in more affluent areas with better access to care. It also found that the odds of a person having a mental health disorder went up as their number of comorbid conditions increased.

Common comorbid conditions in older people include:

  • Heart disease
  • High blood pressure
  • Respiratory disease
  • Mental health issues like dementia
  • Cerebrovascular disease
  • Joint disease
  • Diabetes
  • Sensory impairment
  • Arthritis

Comorbidities can complicate your overall disease management and treatment. When you’ve been diagnosed with more than one condition, it means that not only do you have different symptoms and triggers for each one, but you’ll also need different treatments plans to manage them.

Certain conditions may also increase your risk of developing others. For example, arthritis is more common among adults with other chronic issues such as obesity, heart disease, and diabetes. This means your body could build up several medical conditions that may or may not be related. This can make it complex to manage all your conditions at once.

When you have two or more conditions at the same time, you may have to take more than one type of prescription drug to manage them. This is known as polypharmacy, and it presents certain challenges. There’s a risk that one of your drugs will interact with a treatment for another problem or with the other condition in your body. These interactions could lower the drug’s effectiveness for you. In some cases, it can cause bad reactions.

In fact, if you have comorbidities, you’re at risk for bad health outcomes that may have nothing to do with your main concern.

This includes:

  • Functional limitations
  • Disability
  • Frailty
  • Nursing home placement
  • Lessened quality of life
  • Treatment complications
  • Emergency department visits
  • Adverse drug reactions
  • Avoidable hospitalizations
  • Death

If you have comorbidities and you’re visiting a specialist for one health concern, tell them about all of your medical history. This will help your doctor take all of your issues into account and come up with a treatment plan that suits your preference, tolerance, and needs.

Depending on your comorbidities and treatment needs, you may have to coordinate visits and care among different health care specialists and caregivers such as:

  • Different types of doctors in different health care settings
  • Nurses who provide care at rehabilitation centers, senior facilities, or in homes
  • Counselors
  • Physical therapists
  • Occupational therapists

Also, when you have more than one health issue, a 15- to 20-minute doctor’s appointment may not be enough time to address all of them. For example, you may want to talk to your doctor about your knee pain from arthritis, but the doctor may focus on your symptoms from diabetes. So when it comes to managing comorbidities, it’s important to plan ahead and keep everyone informed.

You can:

  • Establish a main doctor like a primary care provider. Depending on your health issues and care needs, they can point you to the appropriate specialist and work alongside them.
  • Discuss what health issue bothers you most or most affects your day-to-day quality of life. Your doctor may not have the time to address all of it but can start with the most important one.
  • During your doctor’s visit, discuss your overall health care goals with your doctor. This will help them tailor a treatment plan that works best for you.
  • Tell your doctor about any treatment side effects that you may have noticed.
  • Carry a list of all the medicines and doses you take to all your medical appointments. Include any over-the counter medications you take too.

Living with multiple chronic conditions can take a toll on your physical and mental health. A diet rich in fruits and vegetables and good lifestyle habits like physical exercise and sleep may boost your energy levels and lower the risk of certain side effects.

If you’re not sure how to start, ask your doctor, physical therapist, trainer, or a nutritionist. They can find diets or activities that will suit your health needs.