Incidence and predictors of morphometric vertebral fractures in patients with ankylosing spondylitis

Table 2 Comparison of characteristics of patients with and without new vertebral fractures

Variables	Patients without new VFs	Patients with new VFs	P-value
Mean ± SD or number (%)	(n = 272)	(n = 26)
Male	215 (79)	22 (85)	0.617
Age, years	33.8 ± 10.9	35.2 ± 12.2	0.526
Age at diagnosis, years	30.0 ± 10.6	31.6 ± 11.9	0.459
Disease duration, years	3.8 ± 5.1	3.6 ± 5.2	0.847
Family history of AS	24 (9)	3 (12)	0.717
HLA-B27-positive¹	226 (93)	18 (82)	0.083
Back pain	267 (98.5)	26 (100)	1.000
History of peripheral arthritis	176 (65)	14 (54)	0.290
History of enthesitis	62 (23)	9 (35)	0.226
History of uveitis	85 (32)	2 (8)	0.012
Presence of baseline VF	22 (8)	9 (35)	<0.001
Baseline BASDAI score	5.5 ± 1.8	5.2 ± 1.7	0.726
Baseline mean sacroiliitis grade	3.1 ± 0.7	3.1 ± 0.9	0.945
Baseline SASSS score	15.8 ± 1.0	13.1 ± 17.8	0.138
Significant SASSS progression²	47 (18)	9 (39)	0.026
Baseline ESR, mm/h	26.2 ± 1.6	24.4 ± 20.6	0.397
Baseline CRP, mg/L	1.8 ± 3.2	1.0 ± 1.3	0.251
Increase in ESR at 2 years	153 (56)	12 (46)	0.542
Increase in CRP at 2 years	50 (22)	9 (47)	0.020
Patients on NSAIDs	223 (82)	22 (85)	1.000
Patients on sulfasalazine	124 (46)	12 (46)	1.000
Patients on MTX	82 (30)	4 (15)	0.119
Patients on TNF inhibitors	112 (41)	6 (23)	0.093
Patients on calcium	31 (12)	2 (8)	0.751
Patients on bisphosphonate	8 (3)	0 (0)	0.475

¹Confirmed in 265 patients; ²change ≥2 SASSS units over the first 2 years post-baseline. VF, vertebral fracture; AS, ankylosing spondylitis; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein; BASDAI, Bath AS disease activity index; SASSS, Stokes ankylosing spondylitis spine score; NSAIDs, Non-steroidal anti-inflammatory drugs; MTX, Methotrexate; TNF, tumor necrosis factor.

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