Occurrence and relative risks for non-vertebral fractures in patients with ankylosing spondylitis compared with the general population: a register-based study from Sweden

• ObjectivesTo estimate the incidence of non-vertebral fractures in ankylosing spondylitis (AS) compared with the general population.MethodsNationwide register-based cohort study including patients with AS (n=11 611, 65% men, mean age 48 years), and matched general population controls (n=58 050). Five prespecified fracture outcomes: (1) non-vertebral; (2) fracture of the proximal humerus, distal forearm or hip; (3) proximal humerus; (4) distal forearm and (5) hip) were identified through register linkages with follow-up 2007-2016. We used Poisson regression to calculate incidence rates (IRs), number of fractures per 1000 person-years at risk and IR ratios (IRRs), overall and by sex and age. IRRs were adjusted for history of any prior fracture.ResultsIRs (men/women) for non-vertebral fracture in AS were 11.9 (95% CI 11.0 to 12.9)/14.5 (95% CI 13.1 to 16.1) and in controls 10.0 (95% CI 9.7 to 10.4)/11.8 (95% CI 11.1 to 12.4), IRR (men/women) 1.2 (95% CI 1.1 to 1.3)/1.2 (95% CI 1.1 to 1.4). IRs (men/women) for fractures of the humerus, forearm or hip in AS were 4.0 (95% CI 3.5 to 4.6)/6.3 (95% CI 5.4 to 7.3) and in controls 2.7 (95% CI 2.5 to 2.9)/5.5 (95% CI 5.1 to 6.0), IRR (men/women) 1.5 (95% CI 1.3 to 1.7)/1.1 (95% CI 0.9 to 1.3). IRRs were statistically significantly elevated in men with AS versus controls for forearm fracture (1.4 (95% CI 1.1 to 1.7)) and hip fracture (1.8 (95% CI 1.4 to 2.3)), whereas not in women with AS where the IRRs were 1.1 (95% CI 0.9 to 1.4) and 1.0 (95% CI 0.6 to 1.4). For humerus fracture, IRRs were 1.4 (95% CI 0.99 to 1.9) in men with AS versus controls and 1.1 (95% CI 0.8 to 1.6) in women.ConclusionsBoth men and women with AS have a slightly higher risk of non-vertebral fractures than the general population. A statistically significantly higher risk of fractures of the proximal humerus, distal forearm or hip was found in men with AS in comparison to general population, where the relative risk was especially pronounced for hip fracture.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Reumatologi och inflammation (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Rheumatology and Autoimmunity (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Ortopedi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Orthopaedics (hsv//eng)

Keyword

spondylitis

ankylosing

epidemiology

osteoporosis

bone-mineral density

prevalence

osteoporosis

spondyloarthritis

epidemiology

Rheumatology

spondylitis, ankylosing

Publication and Content Type

ref (subject category)

art (subject category)