Objectives: We compared patients assessments of systemic lupus erythematosus (SLE) disease activity by a Swedish version of the Systemic Lupus Activity Questionnaire (SLAQ) with physicians assessments by the Systemic Lupus Activity Measure (SLAM) and Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K). We also explored the performance of the SLAQ in patients with short (amp;lt;1year) versus long (1year) disease duration.Method: Patients filled out the SLAQ before physicians assessments. Correlations between SLAQ total, subscales (Symptom score, Flares, Patients global) and SLAM and SLEDAI-2K, as well as between the corresponding items in SLAQ and SLAM, were evaluated using Spearmans. Comparisons between patients with different disease durations were performed with Mann-Whitney U or chi-squared tests.Results: We included 203 patients (79% women), with a median age of 45years [interquartile range (IQR) 33-57 years] and disease duration of 5 years (IQR 0-14 years). Correlations between physicians SLAM without laboratory items (SLAM-nolab) and patients assessments were: SLAQ total, =0.685, Symptom score, =0.651, Flares, =0.547, and Patients global, =0.600. Of the symptom items, fatigue (=0.640), seizures (=0.635), and headache (=0.604) correlated most closely. Neurology/stroke syndrome, skin, and lymphadenopathy correlated less well (amp;lt;0.24). Patients and physicians assessments were notably more discordant for patients with short disease durations.Conclusion: We confirm that the SLAQ can be used to monitor disease activity. However, the discrepancy between patients and physicians assessments was greater for patients with short versus long disease duration. We encourage further use of the SLAQ, but would like to develop a shorter version which would be valuable in modern, partly web-based, clinical care.