Measurement of clinical activity of systemic lupus erythematosus and laboratory abnormalities: a 12-month prospective study.

OBJECTIVE

To assess flares in outpatients with systemic lupus erythematosus (SLE) using SLAM (systemic lupus activity measure) and to determine laboratory abnormalities as predictors of disease activity.

METHODS

Fifty-three Mexican patients were assessed using SLAM scale. They were evaluated monthly for a total of at least 572 months. The SLAM scale was applied at each visit. Samples were drawn for complete blood cell count, erythrocyte sedimentation rate, urinalysis, 24-h protein and creatinine clearance, anti-DNA, C3 and C4. An SLE flare was defined as the occurrence of new clinical manifestations or worsening compared to the previous month that usually required restarting or increasing prednisone or immunosuppressive drugs.

RESULTS

Thirty-three patients had flares, mainly in minor organs. The incidence of flares was 0.69/patient/year of followup. Active nephritis and extrarenal manifestations correlated with high levels of dsDNA and low complement levels. We found an odds ratio (OR) = 3 (CI = 1.7-5.7) for flare in asymptomatic patients with high dsDNA and OR = 2 (CI = 1.3-4.5) for low C3 levels.

CONCLUSION

Flares are frequent in patients with SLE and they occur independent of disease duration and the time the disease has been under control. Flares are apparently predictable and are related to serologic abnormalities.