Comorbidity in psoriatic arthritis and rheumatoid arthritis

Comorbid conditions are common and impact outcomes in people with rheumatoid arthritis (RA), but less data are available for psoriatic arthritis (PsA).

To describe baseline demographics and prevalence of comorbidities in participants with PsA in an Australian cohort using data from the Australian Rheumatology Association Database (ARAD) and to compare the prevalence of comorbidities in ARAD participants with PsA with those with RA.

ARAD is a voluntary national registry for inflammatory arthritis. Data, including demographic details, medication use, history of comorbid medical illnesses and patient-reported outcomes, all self-reported, were extracted from questionnaires completed at the time of database enrolment for participants with PsA and RA. Demographic information and prevalence of comorbidities were summarised using descriptive statistics. Prevalence of comorbidities in PsA and RA were compared using logistic regression, adjusting for age, gender, disease duration, education, employment and prednisone use.

There were 490 participants with PsA, 59.2% female, mean (standard deviation (SD)) age 50.4 (21.1) years and disease duration 16.4 (9.7) years, and 57.8% reported having two or more comorbidities. Hypertension (38.2%) and depression (35.9%) were the most common. Compared with RA, participants with PsA had greater odds of depression (adjusted OR (95% CI): 2.1 (1.7-2.6)), hypertension (1.7 (1.4-2.1)), hyperlipidaemia (2.0 (1.6-2.5)), diabetes (2.2 (1.6-3.0)) and a history of ischaemic heart disease (2.0 (1.3-2.9)).

High rates of comorbidity were found in ARAD participants with PsA. The prevalence of depression, cardiovascular risk factors and other comorbidities were higher in PsA than RA participants in our Australian cohort.