Medical entities that co-occur with psoriatic arthritis
Dr. Gladman says comorbid conditions are those are medical "entities" that co-occur in patients with psoriatic arthritis. The list includes diabetes, metabolic syndrome, fatty liver, coronary artery disease, depression, hyperuricemia or excess uric acid in the blood, usually implicated in the painful arthritis called gout. She explains more here.
1) Diabetes: This is directly related to the inflammatory condition psoriatic arthritis, and people with more inflammation in their joints are more likely to get diabetes, she says. A 2017 study in the Journal of Rheumatology, for which Dr. Gladman was a co-author, found that prevalence of diabetes is higher in patients with psoriatic arthritis than for the general population. Moreover, the degree of inflammation was a predictor for the development of diabetes.
2) Cardiovascular or heart disease: "We know from a mortality study done 20 years ago that the major cause of death with psoriatic arthritis patients was heart disease — but it's also true in the general population. In another study done almost 10 years ago, we found increased risk of heart attacks, angina, and hypertension or high blood pressure in patients with psoriatic arthritis. In addition to the usual risk factors, the extent of psoriasis was also a predictor of developing cardiovascular disease."
There's no shortage of scientific literature that confirms the association between psoriatic arthritis and heart disease. See the International Journal of Rheumatology from 2012, and from 2014, a study in the Annals of Rheumatic Diseases, with Dr. Gladman as a co-author, that found exposure to an increased burden of inflammation associated with more severe atherosclerosis in patients with psoriatic arthritis.
3) Depression: It is more common in patients with psoriatic arthritis than those who only have psoriasis. "The number of actively inflamed joints is associated with anxiety and depression," she says, citing a 2014 report in the Journal of Rheumatology that she helped develop. "But even in patients with psoriasis without arthritis, depression is related to the degree of inflammation. "
The presence of anxiety and depression interferes with patients' ability to achieve minimal disease activity, she says. "We want to have close to remission. We don’t know what the relationship is in terms of causation, but we know there is an association between psoriasis, psoriatic arthritis and depression. Maybe it's the effect of the disease, which is understandable."
Please don't ignore depression, she says. "It interferes with the ability to treat and to achieve treatment goals."
4) Hyperuricemia: Researchers have wondered whether this condition and gout are more common in people with psoriatic arthritis. "Psoriasis has a very high turnover of skin cells that may increase uric acid in the body as it's released from cells," says Dr. Gladman. "We ask, 'Do patients get more gout because of that turnover, or because they have diabetes and metabolic syndrome?'"
An early 2018 study in the Journal of Rheumatology, which Dr. Gladman co-authored, confirms that hyperuricemia is common in patients with psoriatic arthritis, especially when they've had the disease for a long time, and when they're obese. The researchers urged "proper control" of the condition and of metabolic diseases.
5) Obesity: Obesity is a risk factor for psoriasis and psoriatic arthritis, and people who are obese are likely to be more resistant to treatment, she says. Obesity interferes with the response to medications.
Dr. Gladman participated in a 2015 study published in the Annals of Rheumatic Disease that confirmed that overweight and obesity make it harder to achieve sustained minimal disease activity versus normal-weight patients.
"Fat cells produce cytokines that promote inflammation," she says. "If a person is genetically predisposed to psoriasis or psoriatic arthritis, all they need 'is one more thing.'"
A 2016 Turkish study in the journal Postępy Dermatologii i Alergologii also documented a relationship between psoriatic arthritis and high BMI (body mass index), high waist circumference, meaning the measurement of your waist, and "psoriasis area and severity index." An earlier 2008 paper in the Annals of Rheumatic Disease also cited increasing BMI as being associated with increased heart disease risk in patients with rheumatic diseases.