What are the complications of Ankylosing Spondylitis (AS)?

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Last updated: February 25, 2025View editorial policy

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From the Guidelines

Ankylosing Spondylitis (AS) can lead to several serious complications, including spinal fusion, postural abnormalities, osteoporosis, and extra-articular complications such as anterior uveitis, cardiovascular issues, and pulmonary fibrosis, which can significantly impact morbidity, mortality, and quality of life. The most common complications include spinal fusion (ankylosis), which causes permanent stiffness and limited mobility of the spine, and postural abnormalities such as kyphosis (forward curvature of the spine) that can lead to a stooped posture known as "question mark posture" 1. Patients may develop osteoporosis, making bones more susceptible to fractures, particularly vertebral fractures which can cause spinal cord injury. Extra-articular complications include anterior uveitis (eye inflammation) in up to 40% of patients, cardiovascular issues such as aortitis and aortic valve disease, pulmonary fibrosis with decreased lung capacity, and neurological complications from spinal stenosis or atlantoaxial subluxation.

Some key complications to consider include:

  • Spinal fusion and postural abnormalities, which can lead to permanent disability and decreased quality of life
  • Osteoporosis and increased risk of fractures, particularly vertebral fractures
  • Anterior uveitis and other eye complications
  • Cardiovascular issues, such as aortitis and aortic valve disease
  • Pulmonary fibrosis and decreased lung capacity
  • Neurological complications, such as spinal stenosis or atlantoaxial subluxation

Early diagnosis and aggressive treatment with NSAIDs, DMARDs, and biologics such as TNF inhibitors or IL-17 inhibitors can help prevent or minimize these complications, as recommended by the American College of Rheumatology/Spondylitis Association of America/Spondyloarthritis Research and Treatment Network 2015 recommendations for the treatment of ankylosing spondylitis and nonradiographic axial spondyloarthritis 1. Regular monitoring with imaging and clinical assessments is essential to detect complications early and adjust treatment accordingly. The use of tumor necrosis factor inhibitors (TNFi) is strongly recommended for patients with active AS who do not respond to NSAID treatment, and hip arthroplasty is recommended for patients with advanced hip arthritis 1.

From the FDA Drug Label

The safety and efficacy of HUMIRA 40 mg every other week was assessed in 315 adult patients in a randomized, 24 week double-blind, placebo-controlled study in patients with active ankylosing spondylitis (AS) who had an inadequate response to glucocorticoids, NSAIDs, analgesics, methotrexate or sulfasalazine Active AS was defined as patients who fulfilled at least two of the following three criteria: (1) a Bath AS disease activity index (BASDAI) score ≥4 cm, (2) a visual analog score (VAS) for total back pain ≥ 40 mm, and (3) morning stiffness ≥ 1 hour

The complications of Ankylosing Spondylitis (AS) are not directly stated in the provided drug labels. However, the labels do describe the disease activity criteria used to define active AS, which include:

  • Bath AS disease activity index (BASDAI) score: measures the severity of symptoms such as back pain, morning stiffness, and fatigue
  • Visual analog score (VAS) for total back pain: measures the severity of back pain
  • Morning stiffness: measures the duration of morning stiffness These criteria suggest that AS can cause significant back pain, stiffness, and fatigue, which can impact a patient's quality of life. However, the labels do not provide a comprehensive list of complications associated with AS. 2 3

From the Research

Complications of Ankylosing Spondylitis (AS)

  • The disease can cause pain and stiffness in the spine and sacroiliac and peripheral joints, and may also affect the eyes, heart, and lungs 4
  • Characteristic features include ankylosis of the spine with a progressive loss of spinal mobility 4
  • Extra-articular manifestations can occur, including uveitis, bowel disease, heart, lung, skin, bone, and kidney involvement 5
  • Joint stiffness, pain, and a progressive loss of spinal mobility can lead to severe functional limitations with a subsequent negative impact on patients' quality of life 6
  • The disease can interfere with physical health, social life, and psychological wellbeing 6

Extra-Articular Manifestations

  • The most common extra-articular manifestations are represented by uveitis, bowel disease, heart, lung, skin, bone, and kidney involvement 5
  • Acute anterior uveitis (AAU) is the most common extra-articular manifestation of AS and may lead to severe visual impairment 7
  • TNF inhibitors have demonstrated effectiveness in the treatment of AS symptoms, but their efficacy varies in the presence of extra-articular manifestations 5

Impact on Quality of Life and Economic Issues

  • AS has a socio-economic impact on patients, society, and the healthcare system 6
  • The disease can lead to severe functional limitations, negative impact on quality of life, and increased healthcare costs 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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