Demographic and Disease Features
A total of 31 patients with childhood-onset SLE participate in our study. Among the 31 patients, 26 (84%) were female, 17 (55%) were Caucasian, 13 were Black (42%), 1 (3%) was Asian, and 1 (3%) was Hispanic. The average disease duration was 5 years (SD 3.5). Median SLEDAI for all patients was 2.0 (IQR 0.0-4.0), suggesting on average patients had mild disease activity. Mean IgG level at the time of diagnosis, prior to any therapeutic intervention, was 1570.0 (SD 734.5) mg/dL. The majority of patients, 21 of 31, (68%) were anti-dsDNA positive. Anti-RNP was also positive in a majority, 22 of 31 (71%) patients. Anti-Smith antibody was seen in 16 (52%) patients. Anti-Ro antibody was present in 15 (48%) patients and anti-La antibody in 5 (16%) patients (Table 1).
Medication Use
Medication use in the last month was recorded at the time of each study visit. Almost every patient was on hydroxychloroquine, 30 of 31 (97%). A majority of patients were also on mycophenolate, 22 (71%). There was one patient (3%) receiving treatment with azathioprine and one patient (3%) receiving treatment with cyclophosphamide. 13 (42%) patients were receiving steroids, with a mean prednisone dose of 13.8 mg (Table 2).
Patient-Reported Measures
Each patient was asked to complete symptom questionnaires on a scale of 0-10. The median dryness score was 2.0 (IQR 0.0-4.0). The median fatigue score was 2.0 (IQR 1.0-5.0). Median pain score was 1.0 (IQR 0.0-3.0). When asked if water was needed to help swallow food 7 (23%) patients said yes. Additionally, 4 (13%) patients reported a history of episodic glandular swelling (Table 2).
Ultrasound Examination
The average time to complete the ultrasound examination was 5 minutes. The average time to score all of the ultrasound images was 2 minutes (Table 2). There were no instances of clinic delays secondary to ultrasound examination. Patients found the examination protocol acceptable, with 100% reporting the exam was quick and painless. Others stated they enjoyed being able to see the structures we were examining and better understood the purpose of the research study. There were only three patients that chose not to participate in the study and they declined because of research burden and prior to learning about ultrasound examination.
SGUS Imaging and Disease Associations
Pathologic SGUS findings were observed in 11 of 31 (35%) patients (Table 3). Patients with positive SGUS findings (SGUS+) were slightly older than those with negative SGUS findings (SGUS-), 19.6 years vs. 18.0 years, however this was not statistically significant (p=0.11). Additionally, there was no significant difference in disease duration between the groups. The proportion of females in the SGUS+ and SGUS- groups were similar. There were a higher proportion of Black patients with SGUS+ compared to those with SGUS-, 7 out of 11 (64%) vs. 6 out of 20 (30%), but this was not significant (p=0.13). Patients had mildly active disease on average based on SLEDAI scores and there were no differences between SGUS+ and SGUS- patients, 4.0 vs. 2.0 (p=0.90)(Table 3).
SGUS+ patients reported higher median dryness scores than SGUS- patients, 3.0 vs. 0.5, although these results were not statistically significant (p=0.08). There were no differences in median fatigue score or pain scores reported on the patient questionnaire between SGUS+ and SGUS- patients (Table 3). Additionally, no associations were seen between the number of patients reporting needing water to swallow and ultrasound abnormalities.. Rates of reported episodic glandular swelling were comparable with 1 of 11 (9%) in SGUS+ vs. 3 of 20 (15%) of SGUS- patients (p=1.00).
There was an association between SGUS+ patients and the presence of anti-Ro antibody. 9 of 11 (82%) of SGUS+ patients had anti-Ro antibody positivity vs. 6 of 20 (30%) of patients in the SGUS- group (p=0.01). A similar association was seen for anti-La antibody. Additionally, mean IgG at the time of disease diagnosis was higher in SGUS+ patients vs. SGUS- patients, 2017.3 mg/dL vs. 1323.4 mg/dL (p=0.01)(Table 3).
There were no significant differences between rates of anti-RNP, anti-Smith, or anti-dsDNA between the two groups (Table 3). Most patients in both groups were on some form of systemic treatment with a majority being on hydroxychloroquine and/or mycophenolate. There were no differences in medication regimen between SGUS+ and SGUS- patients, including the presence or mean dose of steroids.