Table 1.
Cohort Characteristics of the 3 Patient Groups*.
| DMD (n = 83) | OI (n = 90) | SLE (n = 194) | ANOVA P | |
|---|---|---|---|---|
| Cohort characteristics | ||||
| Age (years) | 10.3 (3.8) | 8.7 (4.8) | 15.6 (2.6) | <.001a |
| % Males | 100 | 50 | 22 | <.05b |
| Season of visit (% summer: fall: winter: spring) | 37:16:25:22 | 21:41:18:20 | 29:22:26:23 | NS |
| Ambulatory status (% independent: with assistance: wheelchair dependent) | 68: 16: 16 | 74: 13: 13 | 100: 0: 0 | <.05b |
| Height (Z score) | −1.7 (1.8) | −1.5 (2.0) | −0.4 (1.3) | <.001a |
| Weight (Z score) | −0.6 (1.5) | −0.5 (1.5) | 0.3 (1.3) | <.001a |
| BMI (Z score) | 0.4 (1.6) | 0.5 (1.4) | 0.7 (1.2) | NS |
| Glucocorticoid dose (mg/kg/day of prednisone equivalent) | 0.48 (0.27) | 0 | 0.13 (0.18) | <.001a,c |
| Serum biochemistry | ||||
| Total calcium (mmol/L) | 2.40 (0.1) | 2.51 (0.1) | 2.38 (0.1) | <.001c |
| Phosphate (mmol/L) | 1.53 (0.2) | 1.58 (0.2) | 1.36 (0.2) | <.001a |
| DXA values | ||||
| Lumbar spine BMD (Z score) | −2.6 (1.3) | −0.9 (1.4) | −0.8 (1.2) | <.001a,c |
| Height-adjusted lumbar spine BMD (Z score) | −1.6 (1.4) | −0.2 (1.5) | −0.5 (1.1) | <.001a,c |
| Total body BMD (Z score) | −4.3 (2.0) | −1.0 (1.4) | −0.4 (1.2) | <.001a,c |
| Height-adjusted total body BMD (Z score) | −2.8 (2.5) | −0.1 (1.5) | 0.0 (1.0) | <.001a,c |
| Body fat (% of total weight) | 39.1 (12.9) | 28.3 (10.8) | 33.4 (10.4) | <.05a,c |
| Body fat % (Z score) | 1.0 (1.3) | −0.5 (2.0) | 0.2 (1.5) | <.001a,c |
| Lean mass (% of total weight) | 59.3 (12.6) | 68.2 (10.1) | 62.8 (110.2) | <.001c |
| Lean mass/height2 (Z score) | −3.1 (2.1) | −0.6 (1.2) | −0.7 (1.1) | <.001a,c |
Abbreviations: DMD, Duchenne muscular dystrophy; OI, osteogenesis imperfecta; SLE, systemic lupus erythematosus; ANOVA, analysis of variance; NS, not significant; BMI, body mass index; DXA, dual-energy X-ray absorptiometry; BMD, bone mineral density.
*
Results are recorded as mean (SD).
Statistical significance across the 3 groups analyzed using ANOVA with Bonferroni post hoc analysis where aP < .05 when comparing DMD to SLE; bstatistical significance across the 3 groups analyzed groups using χ2 tests; cP < .05 when comparing DMD to OI.