Validity and reliability of the Spanish version of the DN4 (Douleur Neuropathique 4 questions) questionnaire for differential diagnosis of pain syndromes associated to a neuropathic or somatic component

Table 3 Internal consistency, inter-rater agreement, and test-retest reliability of the Spanish version of the DN4 questionnaire.

	Inter-rater agreement
	Rater A	Rater B	ICC (95% CI)	Kappa^§ (95% CI)
Total sample (n = 158)	4.1 (2.3)^†	4.2 (2.5)	0.926 (0.899–0.946) ^‡	0.79 (0.69–0.89)
NP (n = 99)	5.0 (2.2) ^†	5.1 (2.4)	0.925 (0.888–0.949) ^‡	0.68 (0.49–0.86)
NNP (n = 59)	2.6 (1.8)^†	2.7 (2.0)	0.840 (0.730–0.905) ^‡	0.72 (0.50–0.93)
	Internal consistency (Cronbach's α¹)
	0.65	0.71
	Test-retest reliability
	Test	Re-test	ICC (95% CI)	Kappa^§ (95% CI)
Retest sample (n = 67)	3.7 (2.5)^†	3.6 (2.6)	0.949 (0.916–0.969) ^‡	0.79 (0.64–0.94)
NP (n = 37)	4.7 (2.4) ^†	4.4 (2.5)	0.952 (0.904–0.976) ^‡	0.75 (0.53–0.98)
NNP (n = 30)	2.5 (2.0)^†	2.7 (2.4)	0.923 (0.840–0.963) ^‡	0.78 (0.56–1.00)

NP = Neuropathic Pain, NNP = Non-Neuropathic Pain (somatic), ICC = Intra-class Correlation Coefficient, 95% CI = 95% confidence interval, ¹Coefficients for the entire questionnaire (10 items) ^†p > 0.05 between raters (Friedman's paired test), ^‡ p < 0.001 (p value for intra-class correlation coefficient), ^§Kappa using a cut-off value > 4 pts.

ISSN: 1477-7525