Potential predictors of spinal damage progression in people with spondyloarthritis

The presence of syndesmophytes (bony growths in the spine), acute phase reactants (proteins that are released into the blood in response to inflammation), and smoking status can all serve as predictors for the progression of structural damage in the spine in people with spondyloarthritis, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in Chicago.

Spondyloarthritis is the overall name for a family of inflammatory rheumatic diseases that can affect the spine, joints, ligaments and tendons. These diseases can cause pain and stiffness in the back and neck as well as pain and swelling of the joints and inflammation of the eyes, skin, lungs, and heart valves. While there is no way to prevent these diseases, early treatment by a rheumatologist can reduce pain, stiffness and loss of functionality.

Within the spondyloarthritis family is axial spondyloarthritis - a disease that affects the axial skeleton, the spine and/or sacroiliac joints (joints between the pelvis and the spine). In its more severe form, known as ankylosing spondylitis, radiographic changes may be identified in the spine and sacroiliac joints. Less severe, or earlier, axial spondyloarthritis may present with symptoms but no radiographic damage (non-radiographic axial spondyloarthritis).

While there have been some studies on risk factors of progression of structural damage (such as the development of syndesmophytes) in people with longstanding ankylosing spondylitis, there is very little data on people who have early spondylarthritis, and researchers recently investigated predictors of progression of structural damage in a group of people with ankylosing spondylitis and a group with non-radiographic axial spondyloarthritis.

Led by Denis Poddubnyy, MD, PhD; Martin Rudwaleit, MD, PhD; and Joachim Sieper, MD, PhD, researchers studied 210 people with early spondylarthritis. Of these, 115 had ankylosing spondylitis with less than 10 years of symptoms and 95 had non-radiographic axial spondyloarthritis with less than five years of symptoms. All patients had X-rays taken of the lumbar and cervical spine at the beginning of the study and again two years later. These X-rays were read by two trained readers who — without knowledge of when the X-rays were taken or the health history of the patients — scored each one for structural changes such as erosions, sclerosis, vertebral squaring (caused by formation of new bone at the corners of spinal vertebrae) and syndesmophytes.

The researchers were looking for significant worsening in the resulting score, which would indicate progression of the structural damage in the spine. Among the entire study group, researchers noted significant progression of structural damage in the spine in just over 14 percent of the patients. When broken down, those with ankylosing spondylitis who already had radiographic changes at the beginning of the study showed a higher rate (20 percent) of progression than those with non-radiographic axial spondyloarthritis (just over seven percent).

After noting the percentages of patients who showed progression of structural damage, the researchers began to look into the potential predictors of damage progression. Among others, the following predictor candidates were studied: presence of syndesmophytes at the beginning of the study, sex, presence of a specific genetic marker called HLA-B27, acute phase reactants reflecting activity of inflammation, and smoking status. And, among these, only the presence of syndesmophytes at the beginning of the study, elevated acute phase reactants, and cigarette smoking were able to independently predict progression of the structural damage in the spine after two years.

"Although syndesmophytes, once occurred, cannot regress, two other factors related to structural damage in the spine - active inflammation and cigarette smoking - were identified, which could be potentially modified," says Dr. Poddubnyy of the findings. "This indicates that effective anti-inflammatory treatment and smoking cessation — especially done at the early stage — might interfere with the course of the disease, retard development of structural damage in the spine, and improve outcome in patients with axial spondyloarthritis."