Article Figures & Data
Figures
- Figure 1.
The Calin questionnaire and the 6-item questionnaire with [associated domains].
Tables
- Table 1.
Background characteristics of the patients with mechanical and inflammatory back pain. Data are mean ± SD (95% CI).
Characteristic IBP, n = 220 MBP, n = 66 Age, yrs 39.7 ± 12.6 (38.0–41.4) 48.7 ± 15.6 (44.9–52.6) Symptom duration, yrs 15.3 ± 11.2 (13.8–16.8) 12.7 ± 14.4 (9.2–16.3) Pain numerical rating scale (0–10) 5.8 ± 2.5 (5.3–6.2) 6.2 ± 2.3 (5.4–7.0) Sex, male:female 170:50 25:41 -
IBP: inflammatory back pain; MBP: mechanical back pain.
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- Table 2.
Classification utility of response to IBP domain questions in patients with inflammatory back pain (IBP) (n = 220) or mechanical back pain (MBP) (n = 66).
Domain Criteria No. IBP (%) No. MBP (%) OR (95% CI) p Sensitivty, % Specificity, % LR + (95% CI) LR − (95% CI) Morning stiffness Calin 199 (90) 45 (68) 4.42 (2.23–8.78) 0.0001 90 32 1.33 (1.12–1.57) 0.30 (0.18–0.51) 6-item 95 (48)* 16 (25)* 2.80 (1.49–5.25) 0.001 48 75 1.94 (1.24–3.04) 0.69 (0.57–0.84) Response to exercise Calin 136 (67) 21 (38) 3.43 (1.86–6.36) 0.0001 67 63 1.80 (1.26–2.55) 0.52 (0.39–0.69) 6-item 116 (53)* 20 (30)* 2.62 (1.45–4.71) 0.001 53 70 1.76 (1.19–2.58) 0.67 (0.54–0.83) Diurnal variation 6-item 99 (49)* 5 (8) 10.66 (4.10–27.71) 0.0001 49 92 5.95 (2.54–13.94) 0.56 (0.48–0.65) Response to rest 6-item 131 (60) 28 (42) 2.07 (1.18–3.61) 0.010 60 58 1.42 (0.69–1.05) 0.69 (0.53–0.9) Nocturnal pain 6-item 97 (51)* 22 (38)* 1.71 (0.93–3.12) 0.080 51 62 1.35 (0.94–1.92) 0.79 (0.62–1.01) Age of onset (< 40 yrs) Calin 203 (93) 45 (70)* 5.71 (2.70–27.71) 0.0001 93 30 1.32 (1.12–1.56) 0.23 (0.13–0.43) Insidious onset Calin 170 (80) 48 (76) 1.24 (0.63–2.41) 0.534 80 24 1.05 (0.90–1.22) 0.85 (0.51–1.42) -
↵* Denominator is not 220 for IBP or 66 for MBP due to missing responses. LR: likelihood ratio positive/negative.
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- Table 3.
Multivariate logistic regression analysis of inflammatory back pain (IBP) items significant by univariate analysis to determine independent association with IBP.
Criteria Domain OR (95% CI) p Calin Morning stiffness 3.59 (1.57–8.22) 0.002 Age of onset < 40 yrs 3.07 (1.17–8.10) 0.023 Response to exercise 3.26 (1.70–6.26) 0.0001 6-item questionnaire Morning stiffness 0.61 (0.26–1.40) 0.243 Diurnal variation 11.18 (3.66–34.16) 0.0001 Response to exercise 2.38 (1.21–4.70) 0.012 Response to rest 1.99 (1.02–3.87) 0.043 6-item questionnaire Morning stiffness 0.80 (0.35–1.82) 0.589 Diurnal variation 9.37 (3.11–28.29) 0.0001 Combination “response to rest” + “response to exercise” 4.71 (1.57–14.17) 0.006 - Table 4.
Classification utility of candidate tools for inflammatory back pain (IBP): (1) additive score, (2) weighted score, (3) “diurnal variation” single item, (4) Calin criteria, and (5) ASAS IBP according to expert criteria.
Score Sensitivity, % Specificity, % LR+ (95% CI) LR− (95% CI) AUC Additive score* ≥ 2 54 90 5.52 (2.55–11.92) 0.51 (0.43–0.60) 0.75 Weighted** ≥ 0.4 60 89 5.51 (2.57–10.56) 0.45 (0.37–0.55) 0.77 Diurnal variation single item 49 92 5.95 (2.54–13.94) 0.56 (0.48–0.65) 0.70 Calin criteria 83 42 1.42 (1.14–1.78) 0.41 (0.27–0.62) 0.62 ASAS IBP criteria 59 66 1.72 (1.19–2.47) 0.62 (0.48–0.79) 0.62 -
↵* Additive tool domains are “diurnal variation,” “response to rest,” “response to exercise” from the 6-item questionnaire.
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↵** Weighted score = (0.6 × diurnal variation + 0.24 × response to exercise + 0.16 × response to rest) from the 6-item questionnaire. ASAS: Assessment of Spondyloarthritis International Society; LR: likelihood ratio positive/negative; AUC: area under the curve analysis.
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- Table 5.
Classification utility of candidate tools for inflammatory back pain stratified by sex and symptom duration.
Factor Scoring Tool Sensitivity, % Specificity, % LR+ (95% CI) LR− (95% CI) Sex Male Additive ≥ 2 55 79 2.64 (1.19–5.82) 0.57 (0.49–0.75) Female Additive ≥ 2 52 97 19.30 (2.74–136.00) 0.49 (0.36–0.67) Male Weighted ≥ 0.4 59 75 2.38 (1.18–4.82) 0.54 (0.40–0.73) Female Weighted ≥ 0.4 61 97 22.52 (3.21–157.85) 0.40 (0.28–0.58) Male Diurnal variation 47 79 2.26 (1.02–5.02) 0.67 (0.52–0.86) Female Diurnal variation 54 100 —* 0.46 (0.34–0.62) Symptom duration, yrs ≥ 6 Additive ≥ 2 54 86 3.89 (1.70–8.89) 0.53 (0.43–0.66) < 6 Additive ≥ 2 55 96 13.78 (1.99–95.57) 0.47 (0.34–0.64) ≥ 6 Weighted ≥ 0.4 59 83 3.52 (1.67–7.40) 0.50 (0.39–0.63) < 6 Weighted ≥ 0.4 63 96 15.82 (2.29–109.21) 0.38 (0.26–0.56) ≥ 6 Diurnal variation 58 89 5.48 (1.46–20.61) 0.47 (0.35–0.64) < 6 Diurnal variation 48 96 12 (1.72–83.67) 0.54 (0.41–0.72) -
↵* Incalculable (100% specificity). LR: likelihood ratio positive/negative.
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