Good agreement between questionnaire and administrative databases for health care use and costs in patients with osteoarthritis

Table 4 Agreement between the OCC-Q and the databases for the reported quantity of health care used

	OCC-Q Mean ± SD	Databases Mean ± SD	ρ _c*	Mean difference (95% CI)†	95% limits of agreement
GP contacts	1.3 ± 1.0	1.4 ± 1.2	0.41	0.06 (-0.3, 0.4)	-2.34 to 2.46
Total number of medications	1.8 ± 1.2	1.6 ± 1.2	0.63	-0.22 (-0.50, 0.07)	-2.25 to 1.8

*ρ _c = Lin's concordance correlation coefficient
†95% CI assumes a normal distribution
Abbreviations: OCC-Q, Osteoarthritis Cost and Consequences Questionnaire; GP, general practitioner; SD, standard deviation; CI, confidence interval

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