Epidemiological studies in incidence, prevalence, mortality, and comorbidity of the rheumatic diseases

Table 1 Examples of comorbid conditions by their relationship with rheumatoid arthritis

Estimated relationship to RA	Comorbid condition	Mechanism of relationship
High	Anemia	RA activity
	Osteoporosis	CS, RA, decreased function
	Bacterial infection	RA, CS, smoking, (TNF?)
Medium	Lymphoma	RA activity, (TNF?)
	GI ulceration	NSAIDs, CS
	Myocardial infarction	RA, CS
	Heart failure	RA, CS
Low	Stroke	RA
	Depression	Chronic pain
	Fracture	CS, decreased function
	Skin cancer	RA, TNF
	Any cancer
No relationship	Appendicitis

CS, corticoid steroid treatment, GI, gastrointestinal; NSAID = Non-steroidal anti-inflammatory drug treatment; RA, rheumatoid arthritis; TNF, antitumor necrosis factor treatment.

ISSN: 1478-6362