Diagnosis of conditions on the AxSpA spectrum can be difficult, and research is being done to improve both diagnosis and management of these conditions. A diagnosis of a condition on the AxSpA spectrum can take up to 5 to 10 years; diagnosis is often delayed.1 This has other effects on a person, as well as the condition itself. Research to shorten the time to diagnosis is underway, as well as research on other factors in diagnosis and treatment.
Diagnostic criteria at earlier stages
In 2009, new diagnostic criteria were created by the Assessment in Spondyloarthritis International Society (ASAS).2 These criteria made it possible for AxSpA to be diagnosed in people even if they didn’t have visible structural changes on X-ray.2 However, the criteria for presence of a positive HLA-B27 blood test along with two other clinical markers may still exclude some people who have an AxSpA spectrum condition but don’t have a positive blood test.
It has also been pointed out that using X-rays to assess the sacroiliac (SI) joints is not always reliable and can be challenging.2 Researchers have noted that using classification criteria as a strict guide for diagnosis is inappropriate and misses patients who have an AxSpA spectrum condition.2 These should be used as general guidelines and not strict diagnostic guides.
More research needs to be done on earlier stages of AxSpA spectrum conditions, educating primary care providers and rheumatologists about AxSpA spectrum conditions, their symptoms, and how they may present. This can help reduce the time to diagnosis, resulting in better treatment and quality of life for people living with these conditions.
Gender differences in presentation
Women with AxSpA spectrum conditions often present differently than men in the clinical setting, which may result in further delays of diagnosis for them. This may be due to different immunological, hormonal, and genetic responses.3 Women are also less likely to be studied in clinical research and men are more represented in this research.3
Estrogen may have an anti-inflammatory effect on some manifestations of AxSpA spectrum conditions, which may account for men having more damage on imaging tests.3 Women tend to present with psoriasis, enthesitis, and inflammatory bowel disease; men tend to present more often with uveitis.3 Women also have a higher disease burden than men, resulting in higher reported levels of back pain, fatigue, and longer morning stiffness.3
Being aware of these differences and potential underlying causes of these differences can help providers be more cognizant of possible symptoms when people come to them for potential AxSpA spectrum conditions. Knowing the differences in disease presentation between men and women may help reduce delays in diagnosis and treatment.
AxSpA spectrum conditions have a genetic component to them. The risk of these conditions is increased if you have a first-degree relative with an AxSpA spectrum condition.4 The HLA-B27 gene also increases your risk of developing the condition.4 Having a first-degree relative with an AxSpA condition or having the gene doesn’t necessarily mean you definitely will develop an AxSpA spectrum condition, though – so genetics is not always a clear indicator of disease presence.
The HLA-B27 presence only accounts for approximately 25 percent of heredity in AxSpA spectrum conditions.5 There are other genetic components that aren’t well understood.5 More research is being done on other genetic variants that are associated with AxSpA spectrum conditions.
Prediction of progression to radiographic disease
Conditions under the AxSpA umbrella are on a spectrum. There can be a wide range of variability among these conditions. These conditions are progressive, but the rate of progression can also vary widely. Sometimes progression can occur quickly even with no risk factors, and sometimes certain risk factors like smoking, can worsen the condition and possibly increase the rate of progression.6
A positive HLA-B27 blood test and inflammation in the SI joints on MRI were also positive predictors of progression to radiographic disease, when compared to people who did not have either one of these predictors.6 More research needs to be done to identify other predictors of disease progression.
If you have been diagnosed with non-radiographic AxSpA (nr-AxSpA), talk with your doctor about any risk factors you may have that might increase the rate of disease progression. Keep in mind that research is constantly being done to study progression, and even modifying any risk factors you might have may not slow down disease progression.