Systemic lupus erythematosus patients with mild or inactive disease should receive checkups every 3-4 months based on evidence of how frequently they may experience disease features they would not otherwise recognize on their own, a study has shown.
About a quarter of the patients in the study who were seen at a single center during a follow-up period of at least 18 months had 1 feature from a group of up to 10 different variables associated with systemic lupus erythematosus (SLE) that "triggered either further investigation or a change in therapy, or suggested more frequent follow-up," the investigators found.
Dr. Dafna D. Gladman and her associates at the University of Toronto lupus clinic at Toronto Western Hospital aimed to establish the "optimal frequency of follow-up visits" in SLE patients with low disease activity, given that the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) have different recommendations.
The authors noted that ACR recommendations – follow-up every 3-6 months for those with very mild stable disease – rely on "the nature of the protean clinical and laboratory features of SLE and the variety of treatments required to control these features." Meanwhile, EULAR recommends asymptomatic patients be clinically assessed every 6-12 months based on expert opinion on quality indicators, including disease activity, damage accumulation, quality of life, drug toxicity, and comorbidities.
With an Oxford Center for Evidence Based Medicine category 2b level of evidence and a B grade of recommendation, Dr. Gladman and her colleagues suggested that "ACR and EULAR recommendations be amended to reflect" the evidence-based finding that 3- to 4-month follow-up intervals are most appropriate for patients with mild or inactive disease.
The researchers tracked 515 SLE patients (89%, female; 61%, white; mean age, 42.2) from Jan. 1, 2009, to Dec. 31, 2010, if they had at least three visits and at least 18 months of follow-up. The patients had a mean disease duration of 14.2 years and a mean SLE Disease Activity Index 2000 (SLEDAI-2K) score of 4.1 at study baseline (J. Rheumatol. 2013 March 1 [doi:10.3899/jrheum.121094]).
Outcomes of interest were the following "solitary silent new features" of disease activity, recorded as such in the study if they were new to the patient:
• Proteinuria (greater than 500 mg per 24 hours).
• Hematuria (greater than five red blood cells per high power field).
• Pyuria (greater than five white blood cells per high power field).
• Both hematuria and pyuria in the absence of infection, menses, or stones.
• Heme granular or red blood cell casts.
• Low hemoglobin level (less than 100 g/L).
• Leukopenia (less than 3,000/mm3).
• Thrombocytopenia (less than 100,000/mm3).
• Elevated serum creatinine (greater than 120 mg/dL).
• Positive anti-DNA antibodies (greater than 7 U by Farr).
• Low complement (less than 0.10 g/L for C4 and less than 0.9 g/L for C3).
The 515 patients in the study made 3,126 visits during the 2-year period. Overall, 126 (25%) had at least one solitary silent new feature found at 175 (5.6%) of the clinic visits. During the study, patients averaged 6.1 visits with a mean follow-up of 1.8 years and an average 3.8 months between clinic visits.
The most frequent features were low complement (45 patients), pyuria (35 patients), positive anti-DNA antibodies (32 patients), casts (16 patients), and proteinuria (15 patients). These and the less frequently occurring features – low hemoglobin, elevated serum creatinine, leukopenia, thrombocytopenia, and hematuria – led to a variety of different treatment or management changes.
"In the majority of cases, concern was expressed and further laboratory tests were undertaken," the authors wrote. "In 18 patients, steroids, antimalarials, and/or immunosuppressives were added or doses increased within the 12 months following the identification of a silent solitary new feature." Patients with anemia, leukopenia, or thrombocytopenia received second lab tests, which sometimes led to discontinuation of their cytotoxic drugs.
At the start of the study, the SLEDAI-2K score for those with no solitary silent new features during the study was 4.8, compared with 2.1 for those who had solitary silent new features (P less than .0001). The Systemic Lupus International Collaborating Clinics Damage Index for the 389 patients without the features during the study was 1.41, compared with 1.83 in those who had the features (P = .05).
The study was funded by the Lupus Flare Foundation, the Toronto General and Toronto Western Hospital Foundation, and the Arthritis and Autoimmune Research Centre Foundation. Disclosures were not noted in the study.