Early Lupus Features, Early Diagnosis

July 12, 2017

A risk prediction model might be used to identify persons at risk for systemic lupus erythematosus.

The rates of consults with general practitioners is higher in persons who have systemic lupus erythematosus than in those who do not, providing an important opportunity in primary care to reduce delayed diagnoses.

Researchers evaluated cases of systemic lupus erythematosus with practice-matched controls from the UK Clinical Practice Datalink. Odds ratios were calculated for age, sex, consultation rates, certain clinical features, and other diagnoses in the 5 years preceding the systemic lupus erythematosus diagnosis date in a study published online May 8 in Arthritis Care & Research.

Led by Frances Rees, BMBS, of the University of Nottingham in the United Kingdom, the investigators compared primary care consulting practices before a diagnosis between cases and controls and aimed to develop a risk prediction model to better assist providers with earlier identification and diagnosis of systemic lupus erythematosus.

Studies have shown that patients with systemic lupus erythematosus are often given an incorrect diagnosis, such as rheumatoid arthritis or fibromyalgia. Better methods are needed to identify patients with the disease, and earlier diagnoses would improve treatment opportunities and health outcomes.

The study

Data from the Clinical Practice Research Datalink, a longitudinal database of anonymized general practice records representative of the UK population, were used to create a case-control dataset of persons with systemic lupus erythematosus. Cases were adult men and women, aged 18 to 100 years, with incident cases of systemic lupus erythematosus.

The diagnosis of systemic lupus erythematosus was determined by 1 of 14 read codes for the disease or a subtype (excluding cutaneous-only lupus). All cases were newly diagnosed from January 1, 1999 to December 31, 2012. A cohort design was used for the risk prediction model validation portion of the study.

In total, there were 2635 incident cases of systemic lupus erythematosus from about 571 practices: 1739 cases in the development data set that were matched to 6956 controls and 896 cases that were included in the validation model.

Consultation rates with general practitioners were significantly higher for persons with systemic lupus erythematosus than for controls (median, 9.2 vs 3.8 per year) in the 5 years preceding diagnosis.

The following early clinical features occurred most often in systemic lupus erythematosus cases: arthritis or arthralgia, rash, fatigue, headache, and depression.

The best fitting risk prediction model included the following variables: age, sex, consultation rate, arthralgia or arthritis, rash, alopecia, sicca, Raynaud phenomenon, serositis, and fatigue. This model might be used in the future to help primary care providers identify patients who have systemic lupus erythematosus.

“Early clinical features may be mild and common, but presentation with 2 or more features should prompt clinical review and consideration of investigation such as with ANA,” wrote Rees and colleagues. “A risk prediction model has been developed and validated, which may assist this decision-making process in the future following further evaluation.”

Disclosures:

This research was supported by Lupus UK.

Professor Doherty has received advisory board honoraria from AstraZeneca, Nordic Biosciences, and Novartis (less than $10,000 each). Dr. Lanyon has received advisory board honoraria from Lilly and speaking fees from Pfizer (less than $10,000 each). Dr. Davenport has received advisory board honoraria from AstraZeneca and Consilient Health (less than $10,000 each).

References:

Rees, F., Doherty, M., Lanyon, P., et al. “Early Clinical Features in Systemic Lupus Erythematosus: Can They Be Used to Achieve Earlier Diagnosis? A Risk Prediction Model.” Arthritis Care & Research. Published online May 8, 2017. DOI: 10.1002/acr.23021