WASHINGTON, D.C.—Systemic lupus erythematosus (SLE) patients with renal failure often continue to experience flares, but most commonly these are serologic rather than clinical, according to study findings reported at the American College of Rheumatology annual meeting.
“A definition of a real lupus flare after renal failure is controversial,” said lead investigator Cristina Gonzalez Pulido, MD, a resident in internal medicine at University Hospital Virgen del Rocio in Seville, Spain. “We found that dialysis decreased lupus activity but careful assessment of patients for on-going activity is still important.”
Dr. Gonzalez Pulido and her colleagues followed a cohort of 182 patients with lupus nephritis (LN) for 34 years. During this study period, renal failure requiring dialysis developed in 32 patients (17.6%) and those were follow-up during 12 years.
The majority of published studies measuring activity in patients with LN have suggested the disease is relatively quiescent after renal failure. Dr. Gonzalez Pulido’s team retrospectively analyzed the activity index of 32 LN patients with end-renal stage disease (ESRD). They used the BILAG index, levels of complement C3 (0.9-1.8 g/L), and anti-DNA antibodies (0-50 IU/mL) to measure the lupus activity every six months at the start of dialysis or after renal transplantation finding 28 patients showed some kind of activity during the follow-up
The cohort was ethnically diverse (37.5% Afrocaribbean, 25% from the Indian subcontinent, 28% Caucasian, and 9.4% others). The researchers defined inactive disease as no BILAG A/B and both C3 and DNA level within the normal range and active disease when any alteration in BILAG and/or serological involvement was present. They defined moderate disease as at least 1 A/2 B in BILAG or serological alterations over 20% of the normal range (C3 levels below 0.73 g/L and/or DNA levels greater than 149 IU/mL). Patients were considered to have severely active disease when both BILAG and serological abnormalities were present. The researchers divided the cohort in two groups. Group 1 included 32 dialysis patients and Group 2 included 14 patients who started on dialysis but who went on to receive a renal transplant. In Group 1, 13% of the measurements showed completely inactive disease and 87% had at least mild-to-moderate activity at some time. Severe disease was present in just 18,7% of the measurements (12 patients). The BILAG involvement in Group 1 was hematologic (59,4%), mucocutaneous (25%), musculoskeletal (21,9%), constitutional (18,7%), cardiovascular (15,6%) and neurological. Eleven patients died.
In Group 2, 43.3% of the measurements showed inactive disease and 56.7% had at least one flare in this period but just in 16,3% of the measurements was severe (4 patients). The BILAG involvement in Group 2 was renal alteration (50%), hematologic (57,1%), mucocutaneous and musculoskeletal (35,7% each), constitutional and cardiovascular (21,4% each), neurological and vasculitis (7,1%). Three patients died.
“We found a higher prevalence of lupus activity after renal failure than expected in both groups,” Dr. Gonzalez Pulido said. “We tried to establish a higher cut-off to define a real lupus flare. When this was done we observed a decreased prevalence of lupus activity in our cohort—similar to recent published studies—and this drop in activity was more pronounced in the renal transplant group.”
Decreased activity after renal transplant could be due to the immunosuppressive therapy, the researchers speculated. Most clinical flares in the two groups were not life-threatening events and mainly consisted of mild-to-moderate hematologic alterations, they noted. The study demonstrated that lupus activity could be present even after more than 12 years on dialysis or after renal transplantation, suggesting that physicians should keep this in mind to avoid underdiagnosing and/or undertreating patients. Dr. Gonzalez Pulido said it makes sense to correlate serologic findings and then combine them with a validated lupus activity index to define a real lupus flare in this patient population.