Patient characteristics (n=119)
| Patient characteristic* | n (%) or mean (SD) |
|---|---|
| Female | 100 (77.5%) |
| Race | |
| Asian | 45 (37.8%) |
| Caucasian | 67 (56.3%) |
| Other | 2 (1.7%) |
| Unknown | 5 (4.2%) |
| Age (years) | 42.2 (14.8) |
| Age at SLE diagnosis (years) | 33.3 (14.4) |
| Disease duration (years) | 8.7 (7.1) |
| Vitamin D level (nmol/L) | |
| Mean (SD) | 56.3 (25.9) |
| Median (IQR) | 55 (36–74) |
| Vitamin D <40 nmol/L | 33 (27.7%) |
| SLEDAI-2K† | |
| Mean (SD) | 5.6 (5.7) |
| Median (IQR) | 4 (2–8) |
| Minimum–Maximum | 0–24 |
| Elevated anti-dsDNA antibody | 58 (48.7%) |
| C3 (g/L) | 0.9 (0.4) |
| C4 (g/L) | 0.2 (0.1) |
| SLICC-DI‡ | (1.3) |
| ESR (mm/h) | 24.6 (24.5) |
| CRP (mg/L) | 6.2 (13.6) |
| Serum creatinine (μmol/L) | 70.6 (29.1) |
| eGFR <50 (mL/min/1.73 m2) | 6 (5.0%) |
| Femoral neck T score§ | −0.6 (1.0) |
| Lumbar spine T score§ | −0.6 (1.5) |
| Vitamin D supplementation | 53 (44.5%) |
| Glucocorticoid use | 70 (58.8%) |
| Prednisolone dose | 9.8 (14.2) |
| Immunosuppressive use¶ | 40 (33.6%) |
| Antimalarial use | 119 (100%) |
| Change in vitamin D level over 12 months (nmol/L) | 29.3 (39.5) |
| Change in SLEDAI-2K score over 12 months** | −2.2 (5.3) |
| Vitamin D supplementation at 12 months** | 16 (13.4%) |
| Glucocorticoid use at 12 months | 14 (11.8%) |
| Immunosuppressive use at 12 months | 47 (39.5%) |
*Characteristics of patients, recorded at baseline (first vitamin D measurement) or as indicated.
†Scores range from 0 to 105, with higher scores indicating more active disease.
‡Scores range from 0 to 46, with higher scores indicating greater disease-related damage.
§Bone densitometry performed in 68 patients.
¶Immunosuppressives include methotrexate, azathioprine, mycophenolate mofetil, cyclosporine and cyclophosphamide.
**Refers to the first 12 months of follow-up; negative value means decline in level.
CRP, C-reactive protein; eGFR, estimated glomerular filtration rate; dsDNA, double-stranded DNA; ESR, erythrocyte sedimentation rate; SLE, systemic lupus erythematosus; SLEDAI-2K, Systemic Lupus Erythematosus Disease Activity Index 2000; SLICC-DI, Systemic Lupus International Collaborating Clinics—Disease Index.