Evaluation of functional measures and laboratory parameters to portend limitations of spinal mobility in patients with radiographic axial spondyloarthritis

Aim of the work

To specify clinical and laboratory parameters related to limited spinal mobility in radiographic axial spondyloarthritis (r-axSpA) patients.

Patients and methods

The study included 202 adult r-axSpA patients. Clinical characteristics, medications, investigations including serum C-reactive protein (CRP) and human leukocytic antigen-B27 positivity were noted. Lateral lumbar flexion (LLF), chest expansion (CE) and tragus-to-wall distance (TWD) were measured. Values <2.5 percentile in LLF, CE and TWD were noted as reduced mobility of lumbar, thoracic and cervical spine, respectively.

Results

The median age of patients was 43 years, male:female was 3.7:1. The time to diagnosis was 7.5 (3–40) years and were followed-up for 7.2 (4–22) years. Disease duration and high baseline CRP (>10 mg/L) were critical risk factors for reduced spinal mobility (p = 0.001 and p < 0.01). The duration to impaired LLF was significantly shorter in smokers (n = 105) (10.3;0–30.5 years) vs non-smokers (15.2;4.5–35 years) (p = 0.001) and in those with positive family history (n = 50) (9.7;0–20 years) compared to those without (12.9;4–35 years) (p = 0.09). LLF, CE and TWD were impaired in 40 % vs 75 %, 10 % vs 55 % and 12 % vs 60 % of patients with symptom duration of 10 vs 30 years respectively. Those with delayed introduction of biologics had significantly more impaired LLF, CE and TWD: 10.1(2–25) vs 14(3–33) years; 10.4(3–26) vs 17.5(8–33) years; 10.7(3–27) vs 16.7(5–33) years; p = 0.001 for all, respectively).

Conclusions

The most prominent factors affecting spinal mobility were the duration of symptoms and high serum CRP levels. The decreased spinal mobility was markedly less in patients with the early introduction of biologic therapy.