It’s Time for a Risk Prediction Model for Lupus

It can take as long as five years for patients presenting symptoms of systemic lupus erythematosus (SLE) to get a definitive diagnosis. 

In fact, the patients see their general practitioner almost 10 times a year as compared to healthy controls who saw their doctor four times per year. A delay in diagnosis can be life threatening, so a group of researchers has designed a risk prediction model that could help resolve the diagnostic delay in primary care.

Reported in a recent study published in the Sept. 2 issue of Arthritis Care & Research, Frances Rees of the University of Nottingham, U.K., and colleagues, documented the primary care consulting behavior of 1,739 SLE cases and compared them to 6,956 controls.

In systemic lupus erythematosus, which is extremely rare, the initial symptoms can be non-specific or be mistaken for other medical conditions. In the U.K., one analysis found an average delay from first patient-reported symptoms to diagnosis of 7.7 years. It is often mistaken for rheumatoid arthritis, undifferentiated connective tissue disease, renal disease or fibromyalgia.

One study showed that arthralgia was the most common presenting symptom in 60% of cases and patients with the malar rash, only 12%, were more quickly diagnosed.

Experts differ on where exactly the delay is occurring. Some say it is more frequent in primary care while others it is with secondary care. Newer studies are beginning to show that a delay in treatment can make it more difficult to control flares in the long-term and be associated with long-term poor outcomes.

“To consider a multi-system disease such as SLE in a 10-minute consultation (the usual duration of a consultation in the UK) a GP needs to assimilate the current symptoms and consider the significance of previous presentations which may seem unconnected. This could contribute to diagnostic delay. The lack of rheumatology experience in GP training makes educational initiatives - such as the “Think LUPUS and Refer" campaign -essential to increase GPs' awareness of SLE’s protean manifestations. In addition, with pressure on primary care, consultations are occurring with allied health professionals who may have limited training in SLE. Predictive models have gained increasing popularity in medical practice, particularly for estimating cardiovascular risk, osteoporosis risk and earlier diagnosis of malignancy,” the authors wrote.

The model the researchers tested considers several variables - age, gender, consultation rate, arthralgia or arthritis, rash, alopecia, sicca, Raynaud’s, serositis and fatigue. “The prediction model could be incorporated into primary care software so that it flags at-risk patients. It could prompt review of significant clinical features, to provide a threshold for ANA testing and if positive, for onward rheumatology referral,” the authors wrote.

The researchers caution that the model is not a diagnostic tool for SLE, but it provides a risk stratification to identify high-risk patients. The researchers recommend further clinical and economic evaluation of the tool.

Significance and Innovation

-  People diagnosed with SLE consult their GP more than twice as frequently as controls on average in the 5 years prior to diagnosis

-  People diagnosed with SLE consult their GP with clinical features attributable to SLE in the five years preceding diagnosis

-  This suggests that there are potential opportunities to reduce diagnostic delay for people with SLE in primary care.

-  A risk prediction model has been developed and validated which may be used to identify people at risk of SLE in future clinical practice.

Source:  Arthritis Care & Research

References:

Frances Rees, Michael Doherty, et. al.

"Early clinical features in Systemic Lupus Erythematosus: can they be used to 

achieve earlier diagnosis? A risk prediction model."

Sept. 2, 2016.

Arthritis Care & Research

 DOI 10.1002/acr.23021