‘Multimorbidity’ More Likely in Axial Spondyloarthropathy, Linked to Worse Outcomes, Irish Study Finds

People with axial spondyloarthropathy are more prone to develop additional disorders — called “multimorbidity” — which is associated with worse disease outcomes, according to a recent Irish study.

The study, “Multimorbidity is Common in Axial Spondyloarthropathy and is Associated with Worse Disease Outcomes: Results from the ASRI cohort,” was published in The Journal of Rheumatology.

Axial spondyloarthropathy (axSpA) is a musculoskeletal disease in which chronic inflammation affects the spine, causing pain and stiffness. Ankylosing spondylitis is a type of axSpA.

Evidence shows that people diagnosed with axSpA have an increase mortality rate compared with age- and sex-matched control individuals.

Multimorbidity is the term used to describe the presence of two or more chronic diseases in the same patient. It is distinct from comorbidity, researchers say, because there is no primary condition. Estimates point that multimorbidity ranges from 13 to 95%, with its prevalence increasing with age. These individuals experience worse disability and reduced quality of life, and rely more on healthcare services.

Researchers at St. James’s Hospital, in Dublin, assessed the prevalence of multimorbidity in a group of 734 axSpA patients enrolled at 12 centers in Ireland as part of the Ankylosing Spondylitis Registry of Ireland (ASRI). The goal of this registry is to evaluate the burden of axSpA, and to find prognostic factors.

The majority (77%) of those in the ASRI cohort were male, with a mean age of 45 years, and median disease duration of 16 years.

The team observed that 55% of the ASRI patients were multimorbid, meaning they had at least one other chronic disease. About 25% had one additional chronic disease, while 16% had two.  The assessment showed 8% had three additional chronic conditions, and 7% had four.

Obesity was the most frequent additional chronic condition, affecting 27% of people with axSpA. Hypertension affected 21%, followed by hyperlipidemia, or elevated fat levels in the blood, which was found in 16% of those registered. Depression was seen in 10% of patients.

Researchers found that 30% of people with axSpA had a cardiovascular condition, to include ischemic heart disease, hypertension, cerebrovascular disease, and high blood-cholesterol levels. In addition, 5.3% already had been diagnosed with osteoporosis prior to an axSpA diagnosis.

People with multimorbidy were, in general, older and had longer disease duration. The diagnosis of axSpA in the multimorbid was delayed when compared with patients without additional diseases.

Multimorbidity also was associated with a worst disease severity. Patients with a higher burden of multimorbidity had worse Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores. BASDAI measures disease severity — the higher the score, the more severe the disease.

In this study, multimorbid patients had a higher BASDAI score of 0.7 compared to patients with axSpA only.

Similarly, patients with additional diseases also had higher BASDAI scores, worse physical function and increased disability.

“[W]e have demonstrated that multimorbidity is prevalent in axSpA patients and that the presence of multimorbidity is associated with worse disease outcomes,” the researchers concluded.