Ankylosing Spondylitis Patients Have Lower Health-Related Quality of Life, Study Shows

People with ankylosing spondylitis have diminished health-related quality of life (HRQoL) compared to the general population, a Swedish study shows.

The study, “Factors related to health-related quality of life in ankylosing spondylitis, overall and stratified by sex,” was published in the journal Arthritis Research & Therapy.

Studies on ankylosing spondylitis are often focused on investigating functional disabilities and measures of disease activity. However, information regarding patients’ quality of life and how it is related to the disease’s characteristics remains scarce.

HRQoL is a multi-dimensional concept that includes a person’s physical well-being, mental health and physical ability, both as an individual and as a participating member of the community.

Swedish researchers investigated the HRQoL of patients with ankylosing spondylitis using the Medical Outcome Survey Short Form-36 (SF-36) — a set of generic and easily administered quality-of-life measures that rely upon patient self-reporting and are used for routine monitoring and assessment of care outcomes in adult patients.

The study (NCT00858819) enrolled 210 patients (121 men and 89 women) with ankylosing spondylitis, with a median age of 49 years and median symptom duration of 24 years.

Researchers compared patients’ clinical manifestations to the clinical records of 1,055 age- and sex-matched individuals randomly drawn from the Swedish normative population database.

Forty-three (20.5%) patients were treated with a TNF inhibitor. Of these, 32 (15.2%) used it in combination with a conventional disease-modifying anti-rheumatic drug (DMARD). In total, 73 (34.8%) patients were on a TNFi and/or a DMARD.

Patients with ankylosing spondylitis had significantly lower health-related quality of life compared to the general Swedish population. This pattern was also observed for physical and mental health domains. The SF-36 physical component summary was approximately 7.8 points lower (score of 42.4) in ankylosing spondylitis patients, while the SF-36 mental component summary was 5.9 points lower (score of 52.4).

“The SF-36 is grouped into eight domains reflecting physical and mental health and two summary scores, a physical component summary (PCS) and a mental component summary (MCS) score,” researchers said. “The items within each domain contribute to an overall domain score between 0 and 100, with 0 representing worst and 100 excellent health.”

Physical component scores were more affected compared to mental component scores, which was noted in the whole group but also in men and in women analyzed individually. Women affected by the disease had significantly lower physical function, vitality, and mental health scores than men.

“This indicates a general phenomenon that women report worse HRQoL compared to men,” researchers said.

Also, the SF-36 physical component summary score was significantly lower in patients 61 or older compared to patients 40 or younger. No difference in mental health status was noted among different patient age groups.

Patients who lived alone had 2.38 times the risk of having worse physical scores. Longer symptom duration, higher BASFI (Bath Ankylosing Spondylitis Functional Index), and higher disease activity as determined by CRP levels were also associated with a worse physical health status.

To live alone, to have high fatigue scores and disease activity were linked to 3.04, 6.36, and 2.97 times the risk of poorer mental health status in ankylosing spondylitis patients.

“We have identified variables associated with worse HRQoL, which are modifiable,” researchers wrote. “By modifying factors such as [disease activity] and fatigue, HRQoL may potentially be improved.”

Additional studies are still warranted to help identify predictors related to the course of HRQoL in this population over time.

“We intend to investigate factors related to the change in HRQoL over a 5-year period in this same cohort of patients with [ankylosing spondylitis] in a future study,” researchers concluded.