Comorbidity refers to “a disorder that occurs simultaneously with another condition.” In the context of patients with rheumatoid arthritis (RA) specifically, comorbidities are diseases or disorders that commonly occur alongside RA in patients. Studies show that the most common comorbidities in RA are cardiovascular disease, serious infections, depression, respiratory conditions like COPD, and lymphoma. Let’s take a closer look at why these common comorbidities occur in patients with RA:

1. Heart disease and rheumatoid arthritis

The main mechanisms by which rheumatic diseases affect the cardiovascular system are damage to the heart muscle (cardiac hypertrophy) and blood vessels (vasculitis and vascular inflammation). These mechanisms are often exacerbated in patients with chronic diseases like rheumatoid arthritis. The elevated risk includes increased incident angina and myocardial infarction, as well as premature death through stroke or heart failure. Further, patients with RA are less likely to respond to treatments for these diseases, such as nitroglycerin. While the relationship between RA and cardiovascular disease is well established, its association with coronary heart disease (CHD) is less certain. Fractures of the collarbones or hips and other trauma to the skeleton are common in patients with RA. These fractures transmit significant force to the heart, possibly damaging it and increasing CHD risk.

2. Depression and RA

Depression is the most common mood disorder among patients with RA. Its prevalence in patients with RA is similar to that of other chronic diseases, such as coronary artery disease and hypertension. The onset of hopelessness is often abrupt in patients with chronic pain conditions, resulting in a longer duration of symptoms. Patients with RA report having more severe depressive symptoms and more difficulty than those without RA. Depression has been linked to disease onset and severity of RA. It is also associated with activity limitations, poorer health status, and decreased quality of life. Despair symptoms worsen during RA and are associated with higher disease activity.

3. Serious infections and RA

SAI, or sepsis-associated infections, describes potentially life-threatening infections in patients with rheumatoid arthritis. Patients who develop SAI are at risk for developing multiple organ system failure. SAI may be a complication of RA, as well as an independent risk factor for the development of RA. SAI is highly prevalent in patients with rheumatoid arthritis. Compared to healthy individuals, patients with RA have a 3-fold increased risk for developing SAI. Furthermore, less than half of patients with SAI have a recognized etiology in RA. The risk of developing SAI is increased by 5-fold in patients with RA compared to healthy individuals. For example, the risk of infection with the Gram-positive bacterium Staphylococcus aureus is more than 10-fold greater among RA patients.

4. Asthma and COPD with RA

Asthma and COPD have frequent comorbidity with RA. The association between asthma and RA is stronger than between COPD and RA. Asthma is a chronic inflammatory disorder that affects the airways, causing them to narrow. Chronic obstructive pulmonary disease (COPD) is a group of progressive diseases that involves damage to the lungs, leading to difficulty breathing. Both diseases have significant morbidity and mortality in patients with RA, as well as an additional burden on functioning and well-being.

5. Lymphoma and RA

Patients with RA have a greater risk for lymphoma, an abnormal proliferation of white blood cells. The overall disease incidence in RA patients differs by race, sex, and age. The condition may be associated with rheumatoid arthritis treatment or complications. Further animal studies indicate that the development of lymphoma may be related to the immune response to rheumatic inflammation and its medications.

Treatment of rheumatoid arthritis is focused on reducing the symptoms, inhibiting the progression of joint damage, minimizing and controlling inflammation, and restoring function. First-line treatment options for patients with rheumatoid arthritis include non-steroidal anti-inflammatory drugs (NSAIDs), disease-modifying anti-rheumatic drugs (DMARDs), glucocorticoids, biologic response modifiers, and analgesics. Each of these treatment options carries a risk for potentially serious adverse effects so please consult with your doctor before taking any medication.