Table 3

Univariate analysis of putative clinical and laboratory predictors of bone mineral density (BMD)

Low BMD (N=12)Normal BMD (N=68)OR (95% CI)
Baseline characteristics
 Mean BMI z score at diagnosis (SD)−0.99 (1.02)0.09 (0.95)0.35 (0.18 to 0.69)*
 Ethnicity: Asians (%)5 (42)24 (35)1.31 (0.38 to 4.57)
 Postpubertal patients (%)9 (75)52 (76)0.92 (0.22 to 3.83)
Disease characteristics
 Nephritis (%)5 (42)16 (24)2.32 (0.65 to 8.33)
 Central nervous system (%)2 (17)9 (13)1.31 (0.25 to 6.98)
Disease activity
 Median SLEDAI (range)13.5 (7–32)10.5 (2–43)2.46 (0.87 to 6.95)
 Median ECLAM (range)6.5 (4–10)5 (0–11)2.93 (0.75 to 11.46)
Treatment
 No corticosteroid (%)5 (42)17 (25)0.47 (0.13 to 1.67)
 Median cumulative steroid dose up to DEXA (mg/kg (range))8.2 (0–68.5)22.5 (0–115.5)1.21 (0.51 to 2.86)
 Hydroxychloroquine (%)4 (33)23 (34)0.98 (0.27 to 3.59)
 Any immunosuppressive agent (%)1 (8)18 (26)0.25 (0.03 to 2.10)
Laboratory tests
 Median C3 (g/l (range))0.62 (0.17–1.17)0.81 (0.15–1.98)0.69 (0.29 to 1.66)
 Median C4 (g/l (range))0.12 (0.04–0.18)0.12 (0.01–0.76)0.91 (0.43 to 1.91)
 Median ESR (mm/h (range))76 (1–135)45 (1–140)1.19 (0.73 to 1.93)
Laboratory assessment of bone health
 Median iPTH (ng/l (range))43 (21–64)29 (3–129)2.01 (0.45 to 9.00)
 Median calcium (mmol/l (range))2.36 (2.18–2.51)2.40 (2.01–2.73)0.14 (0.001 to 15.35)
 Median ionised calcium (mmol/l (range))1.22 (1.10–1.27)1.21 (0.86–1.32)1.69 (<0.001 to >999.99)
 Median phosphate (mmol/l (range))1.31 (0.74–1.67)1.33 (0.82–1.89)0.60 (0.02 to 17.09)
 Median 25 hydroxyvitamin D (nmol/l (range))37 (25–72)40 (10–134)1.13 (0.19 to 6.58)
 Median alkaline phosphatase (U/l (range))115 (81–169)77 (37–311)4.11 (0.72 to 23.52)
 Median alkaline phosphatase bone isozyme (U/l (range))69 (49–100)36 (15–299)2.44 (0.70 to 8.44)
 Median urine N-telopeptide (nmol BCE/mmol creatinine (range))104 (65–179)110 (38–553)0.76 (0.17 to 3.50)
  • * Significant p value was bolded (p=0.003 for BMI by univariate analysis).

  • BCE, bone collagen equivalent, BMI, body mass index; DEXA, dual energy x-ray absorptiometry; ESR, erythrocyte sedimentation rate; iPTH, intact parathyroid hormone; SLEDAI, Systemic Lupus Erythematosus Disease Activity Index.