Comorbidities such as depression and cardiovascular risk factors are common in psoriatic arthritis (PsA) with the potential to contribute to disease progression or impact on response to therapy.
An analysis of 490 patients with PsA from the Australian Rheumatology Association Database (ARAD) found more than half (57.8%) had two or more comorbidities; 41.8% had three or more comorbidities.
Depression (35.9%), hypertension (38.2%) and gastrointestinal disease (31.6%) were most common, with other features of the metabolic syndrome – hyperlipidaemia (25.3%) and diabetes (12.9%) – also prominent.
In comparison to patients with rheumatoid arthritis from the same database, patients with PsA were more likely to have cardiovascular and other comorbidities.
The adjusted odds ratio of having hypertension, hyperlipidaemia, a history of ischaemic heart disease or diabetes ranged from 1.7 to 2.2 in patients with PsA compared to RA.
“In addition to their long-term impact on cardiovascular morbidity and mortality, these cardiovascular risk factors may impact on disease progression in PsA,” the study said.
“The metabolic syndrome and insulin resistance have been associated with the severity of underlying PsA, and obesity has been associated with a low probability of achieving minimal disease activity.”
While the study did not collect data to calculate BMI, another ARAD sub-study has previously found 39.8% of PsA patients were obese.
Co-author Dr Premarani Sinnathurai, from the Institute of Bone and Joint Research at the Kolling Institute in Sydney, said the increased risk of cardiovascular disease with rheumatoid arthritis was well recognised but there had been less research in PsA.
“The important thing is for physicians and GPs looking after these patients to be aware of the increased risk, that they are screening their patients for it and making sure their risk factors for cardiovascular disease are well controlled so in the long term we hopefully reduce their risk of having cardiovascular events and mortality.”
She told the limbic GPs were better placed to be managing risk factors but needed to know to look early in rheumatology patients.
“Some of our patients are in a younger age category to that in which GPs would normally expect to see these conditions. While the median age was older in our cohort (50 years), a lot of patients get their arthritis when they are younger – for example in their 30s or 40s – and wouldn’t necessarily be thinking about seeing their GP for regular checks for blood pressure and cholesterol.”
The study found the odds ratio of having depression was 2.1 in patients with PsA compared to RA.
“Certainly it’s probably tied up with a combination of things such as pain from arthritis, for those who’ve got skin disease it can be socially stigmatisaed and have an impact on mood, but also there are some papers that suggest that uncontrolled inflammation can have a direct affect on brain processing,” Dr Sinnathurai said.
“We wouldn’t be the ideal people to be managing depression. It’s more important for us to be aware of it, so that when we pick up on those symptoms, the patients can be referred on appropriately.”
The study found a history of infection in the last six months was 2.1 times more likely in PsA than rheumatoid arthritis however there was no difference in cancer rates between the two patient groups.