Severity More Important than SLE Label in Lupus

April 12, 2016

Excluding patients with SCLE from clinical trials because they don't meet SLE criteria may not make much sense, researchers report.

Excluding patients with subacute cutaneous lupus erythematosus (SCLE) from clinical trials because they don't meet criteria for systemic lupus erythematosus (SLE) may not make much sense.

New research suggests that most SCLE patients who fulfill the criteria for systemic disease do so based on laboratory results and their skin and mucosal symptoms, and don't have major internal organ involvement. This is true whether patients are diagnosed using the 1997 American College of Rheumatology (ACR) criteria for systemic lupus or the newer Systemic Lupus International Collaborating Clinics (SLICC) criteria published in 2012.

"It's an arbitrary decision to say somebody is SLE versus non-SLE," said Victoria Werth, M.D., a professor of dermatology at the Hospital of the University of Pennsylvania and the Veteran's Administration Medical Center. "And in some ways, it's more important to know which organs are involved and the severity of the disease than whether patients get called SLE."

Limiting clinical studies to SLE patients only on this basis might therefore exclude some patients who could benefit, Dr. Werth said.

Dr. Werth and her colleagues are the authors of a new study that compared the ACR and SLICC criteria for classifying patients with SCLE as having systemic disease. The ACR criteria were originally developed in 1982 and updated in 1997, though those updates weren't validated. In 2012, the SLICC criteria were released. This classification expanded the number of criteria for a diagnosis from 11 to 17, of which four are required, one immunological and one clinical. (Alternatively, patients can be classified as having SLE if they have lupus nephritis proven by biopsy with positive-ANA or positive anti-DNA.)

Comparison of the two classification systems has found that the SLICC criteria are more sensitive than the ACR criteria. One major reason was that the SLICC clinical criteria include acute cutaneous lupus, which is defined as lupus malar rash (not malar discoid), bullous lupus, toxic epidermal necrolysis SLE, maculopapular lupus rash or photosensitive lupus rash without dermatomyositis. This expands the criteria beyond the ACR's photosensitive malar rash item. "Chronic cutaneous lupus" replaces the old discoid rash item. This criteria includes discoid rash as well as hypertrophic lupus, lupus panniculitis, mucosal lupus, lupus erythematosus tumidus, chilblains lupus and discoid lupus/lichen planus overlap. [[{"type":"media","view_mode":"media_crop","fid":"47643","attributes":{"alt":"©Artemida-psy/Shutterstock.com","class":"media-image media-image-right","id":"media_crop_7718867109254","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"5627","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"font-size: 13.008px; line-height: 1.538em; float: right;","title":"©Artemida-psy/Shutterstock.com","typeof":"foaf:Image"}}]]

But no one had compared the two classification systems with regard to the diagnosis of SLE in patients with SCLE, said Werth, who was part of the original SLICC working group. She and her colleagues analyzed a database of patients with cutaneous or systemic lupus erythematosus at the University of Pennsylvania outpatient autoimmune skin diseases clinic between 2007 and 2014. A total of 85 patients were assessed under both the 1997 ACR and the 2012 SLICC criteria.

Using the ACR criteria, four patients were categorized more as having SCLE/SLE than the SLICC criteria, while using the SLICC criteria, eight patients were categorized more as having SCLE/SLE than the ACR criteria, for a net total of four additional patients under SLICC - not a significant difference (P = .6350), the researchers reported in the Journal of the American Academy of Dermatology

The four patients who met the ACR criteria, but not the SLICC criteria for SLE, did not qualify because of the move away from photosensitivity as a stand-alone criterion. This was appropriate, the researchers wrote, because none of these patients showed signs of systemic disease. On the other hand, the eight who met criteria under SLICC, but not ACR, largely failed to meet ACR criteria because SCLE is not a criterion in that classification. Under SLICC, either acute cutaneous lupus or subacute cutaneous lupus can count as one clinical criterion needed to diagnose systemic lupus erythematosus. Many patients also qualified for a diagnosis under SLICC, but not ACR, because of the newer diagnostic scheme's expanded hematologic criteria. 

Regardless of the diagnostic criteria used, SCLE patients who qualified for SLE were not any more likely than patients with only SCLE to have renal disease, central nervous system disease or other major systemic damage, consistent with previous research.

"Those who meet or don't meet SLE are clinically often similar," Dr. Werth said. Currently, lupus studies typically require patients to meet SLE criteria under either the 1997 ACR or 2012 SLICC rubric, she said, which can needlessly exclude patients who don't meet those criteria but who are no more or less severely affected by disease than those who do.

"It's a huge issue for these patients," Dr. Werth said, adding, "'SLE, yes or no' becomes somewhat arbitrary, and perhaps almost an unimportant designation, in terms of it being more important to define the level of severity of their skin disease."

 

References:

Tiao J, Feng R, Carr K, Okawa J, Werth VP. “Using the American College of Rheumatology (ACR) and Systemic Lupus International Collaborating Clinics (SLICC) criteria to determine the diagnosis of systemic lupus erythematosus (SLE) in patients with subacute cutaneous lupus erythematosus (SCLE).” Journal of the American Academy of Dermatology 2016. doi: 10.1016/j.jaad.2015.12.029.

Petri, M., et al. “Derivation and validation of the Systemic Lupus International Collaborating Clinics classification criteria for systemic lupus erythematosus.” Arthritis Rheum. 2012 Aug;64(8):2677-86. doi: 10.1002/art.34473.

Inês L, Silva C, Galindo M, et al., "Classification of Systemic lupus erythematosus: Systemic Lupus International Collaborating Clinics versus American College of Rheumatology criteria.” Arthritis Care & Research. 2015; Accepted MS. Online Jan 7-15. soi: 10.1002/acr.22539.