Trabecular Bone Score Improves Fracture Risk Discrimination in Postmenopausal Rheumatoid Arthritis Patients Receiving Glucocorticoids

Figures & data

Table 1 Baseline Characteristics, BMD, and TBS of Postmenopausal Rheumatoid Arthritis Patients Receiving Glucocorticoids with and without Osteoporotic Fracture

Factors	Fracture (n=14)	Non-Fracture (n=50)	p value
Age (years)	62.4 ± 9.1	61.5 ± 9.5	0.77
Body weight (kg)	50.2 ± 6.6	53.2 ± 9.6	0.28
Height (cm)	153.1 ± 4.9	153.7 ± 6.0	0.75
BMI (kg/m^2)	21.4 ± 2.6	22.5 ± 3.7	0.31
Alcohol consumption, n (%)	0 (0)	3 (6)	0.35
Current smoking, n (%)	0 (0)	1 (2)	1.00
Duration of RA (years)	6.9 ± 5.6	7.7 ± 5.5	0.77
Dosage of glucocorticoid use			0.77
- Prednisolone 5 mg/day, n (%)	5 (35.7)	18 (36)
- Prednisolone 10 mg/day, n (%)	9 (64.3)	27 (54)
- Prednisolone > 10 mg/day, n (%)	0 (0)	5 (10)
Osteoporosis using BMD criteria	11 (78.6)	19 (38.0)	0.001*
Lumbar spine BMD (g/cm^2)	0.807 ± 0.134	0.930 ± 0.187	0.03*
T-score of lumbar spine BMD	−2.471 ± 1.087	−1.550 ± 1.530	0.04*
Femoral neck BMD (g/cm^2)	0.586 ± 0.097	0.725 ± 0.124	< 0.001*
T-score of femoral neck BMD	−2.614 ± 0.815	−1.496 ± 1.010	< 0.01*
Total hip BMD (g/cm^2)	0.726 ± 0.154	0.803 ± 0.144	< 0.01*
T-score of total hip BMD	−2.714 ± 0.680	−1.450 ± 1.274	< 0.01*
TBS	1.217 ± 0.080	1.316 ± 0.103	< 0.01*
T-score of TBS	−3.850 ± 1.171	−2.370 ± 1.517	< 0.01*

Notes: Data were presented as mean ± standard deviation and proportions for continuous and categorical variables, respectively. *Statistically significant (p value < 0.05).

Abbreviations: BMI, body mass index; RA, rheumatoid arthritis; BMD, bone mineral density; TBS, trabecular bone score.

Table 2 Logistic Regression Analysis of BMD and TBS Reduction and the Prevalent Osteoporotic Fracture

Parameter^#	Odds Ratio (95% CI)	p value	Adjusted OR† (95% CI)	p value
L-spine TBS	2.78 (1.45–6.15)	0.004*	3.12 (1.48–7.90)	0.01*
Lumbar spine BMD	1.72 (1.13–2.89)	0.02*	1.78 (1.10–3.31)	0.04*
Femoral neck BMD	3.51 (1.75–8.82)	0.002*	4.11 (1.90–11.32)	0.002*
Total hip BMD	2.62 (1.48–5.40)	0.003*	2.83 (1.53–6.27)	0.003*

Notes: ^#Every 0.1 unit decrease of each parameter. ^†Adjusted with age, and BMI. *Statistically significant (p value < 0.05).

Abbreviations: BMD, bone mineral density; TBS, trabecular bone score; OR, odds ratio.

Figure 1 Receiver operating characteristic (ROC) curve in predicting osteoporotic fracture when using TBS (red line), lumbar spine BMD (blue dashed line), femoral neck BMD (green dotted line), and total Hip BMD (purple dashed line). There was no statistically significant difference between each parameter.

Table 3 The Accuracy of Using a BMD T-Score ≤ −2.5 Alone, BMD T-Score ≤ −2.5 or TBS < 1.24, and BMD T-Score ≤ −2.5 Combined with TBS Threshold <1.24 in Osteoporosis Fracture Discrimination

Parameter	Osteoporotic Fracture Discrimination
	Sensitivity (95% CI)	Specificity (95% CI)	Accuracy (95% CI)
BMD T-score ≤ −2.5 at any sites	0.79 (0.49–0.95)	0.62 (0.47–0.74)	0.66 (0.53–0.77)
BMD T-score ≤ −2.5 at any sites OR TBS < 1.24	0.86 (0.57–0.98)	0.56 (0.41–0.70)	0.63 (0.50–0.74)
BMD T-score ≤ −2.5 at any sites AND TBS < 1.24	0.71 (0.42–0.92)	0.90 (0.78–0.97)	0.86 (0.75–0.93)

Abbreviations: BMD, bone mineral density; TBS, trabecular bone score.

Figure 2 Receiver operating characteristic (ROC) curve in discriminating osteoporotic fracture between using BMD T-score threshold ≤ −2.5 alone (grey dotted line), BMD T-score threshold ≤ −2.5 alone or the proposed TBS of < 1.24 (blue dashed line), and combining BMD T-score threshold of ≤ −2.5 and the proposed TBS of < 1.24 (red line). The area under ROC of combining the BMD threshold and the proposed TBS threshold is significantly better than the BMD threshold alone (p value = 0.003).