Ankylosing spondylitis (AS) is a chronic inflammatory disease that most often affects the sacroiliac (SI) joints and axial skeleton (see figure above). However, it is also a multisystemic disorder that can cause enthesitis (insertion site of tendons and ligaments into bone), peripheral arthritis, and multi-organ involvement. Although AS has been called rheumatoid spondylitis, it's not related to rheumatoid arthritis (RA) or other rheumatic disorders; it also has a better prognosis than RA. Chronic inflammation causes changes including ossification of the annulus fibrosus (the tough exterior of the intervertebral disc) and fusion of the spine resulting in immobility and reduced physical function. AS first presents with dull pain and stiffness in the lower back in approximately 75% of patients and is accompanied by severe fatigue in 65%.
Most studies of AS have analyzed measures of disease activity and functional disabilities, but few are designed to assess the quality of life of AS patients related to their disease characteristics. The objectives of the study performed by Law et al. were: the utilization of the Medical Outcome Survey Short Form-36 (SF-36) to measure the health-related quality of life (HRQoL) of AS patients compared to controls, and the measurement of the HRQoL based on age, the correlations between spinal x-rays and SF-36 scores, mobility, physical function, demographic data, and disease activity. They defined the concept of HRQoL as "not only a person’s physical well-being, but also a person’s mental health and physical ability, both as an individual and as a participating member of the community."
Other questionnaires used were the BASDAI (estimates disease activity) and BASFI (estimates functional limitations). The Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP), which calculates the disease activity, and the visual analog scale for global fatigue were also administered.
Participants in this study were recruited from three sites in Western Sweden. Inclusion criteria were a diagnosis of AS by the New York criteria and adults over the age of 18. Patients were excluded if they did not understand the Swedish language or if dementia or pregnancy were present. They invited 361 participants to take part in the study, and a total of 210 patients were included.
Analysis of the data showed that patients with AS had lower scores for HRQoL than the controls and the physical components of the disease were more limiting than the mental components in both sexes. The authors stated that, for the first time, this study "identified determinants of worse HRQoL separately in men and women with AS and we found that the factors associated with HRQoL differed in part between the sexes." They also found that the mental component scores were stable for all age groups, but the physical components score was significantly worse in patients over 61 years of age compared to those less than 40 years of age. Reducing factors involved in the ASDAS-CRP and fatigue may help to improve these patients' HRQoL.
The researchers plan to monitor this cohort of patients for five years in a future study.