Table 3

Symptom attributes for neurogenic intermittent claudication

Attribute*Measure (95% CI)
SensitivitySpecificityPLRNLR
Single symptom attributes
Trigger
 Standing (1)0.97 (0.81–1.0)0.70 (0.47–0.86)3.2 (1.7–5.9)0.04 (0.0067–0.34)
 Walking (2)0.90 (0.72–0.97)0.04 (0.0023–0.24)0.94 (0.81–1.1)2.30 (0.12–43)
Alleviator
 Sitting (3a)0.83 (0.65–0.94)0.78 (0.56–0.92)3.80 (1.7–8.5)0.21 (0.083–0.44)
Posture
 Shopping cart sign (4)0.80 (0.61–0.92)0.52 (0.31–0.73)1.70 (1.1–2.7)0.38 (0.17–0.85)
 Walking uphill (7)0.23 (0.11–0.43)0.78 (0.55–0.92)1.07 (0.39–2.9)0.98 (0.79–1.2)
Nature
 Numbness (8)0.75 (0.55–0.89)0.41 (0.21–0.63)1.30 (0.84–1.9)0.61 (0.28–1.3)
 Cramping (9)0.53 (0.35–0.71)0.35 (0.17–0.57)0.82 (0.52–1.3)1.30 (0.78–2.3)
 Burning pain (10)0.62 (0.42–0.79)0.52 (0.31–0.73)1.30 (0.78–2.2)0.73 (0.42–1.3)
 Weakness (11)0.43 (0.25–0.63)0.59 (0.37–0.79)1.00 (0.54–2.0)0.97 (0.66–1.4)
Location
 Above the knees (5)0.80 (0.61–0.92)0.65 (0.43–0.83)2.30 (1.3–4.1)0.31 (0.14–0.66)
Time for relief
 > 10 min0.30 (0.15–0.50)0.78 (0.56–0.92)1.40 (0.53–3.6)0.89 (0.69–1.1)
Constellation of symptom attributes
Triggered with standing (1), alleviated with sitting (3a)0.80 (0.61–0.92)0.87 (0.65–0.97)6.10 (2.1–18)0.23 (0.11–0.48)
Triggered with standing (1), alleviated with sitting (3a), located above the knees (5)0.67 (0.47–0.82)0.91 (0.70–0.98)7.70 (2.0–30)0.37 (0.22–0.61)
Triggered with standing (1), alleviated with sitting (3a), located above the knees (5), positive shopping cart sign (4)0.57 (0.38–0.74)0.96 (0.76–1.0)13.00 (1.9–91)0.45 (0.30–0.68)
  • CI = confidence interval; NLR = negative likelihood ratio; PLR = positive likelihood ratio.

  • * Numbers in brackets represent the corresponding question number in the questionnaire (see the Appendix, available at cma.ca/cjs).

  • Numbers whose values represent clinical significance.