Table 4.

Kappa agreements for self-reported type 1 and type 2 diabetes diagnoses.

Diabetes type	Test study	Retest study	Consistency (%)a	Kappa (95% CI)
	Cases in 1991 (n)	Cases in 1998 (n)
Type 1 diabetesb	111	103	83/111 (74.7)	0.83 (0.76–0.89)
Type 2 diabetesc	37	48	29/37 (78.4)	0.67 (0.55–0.79)
	Cases in 1991 (n)	Cases in 2005 (n)
Type 1 diabetesb	111	88	64/111 (57.6)	0.76 (0.68–0.84)
Type 2 diabetesc	37	42	21/37 (56.6)	0.57 (0.43–0.71)
	Cases in 1998 (n)	Cases in 2005 (n)
Type 1 diabetesb	111	97	70/111 (63.1)	0.73 (0.66–0.81)
Type 2 diabetesc	204	185	125/204 (61.3)	0.66 (0.59–0.72)

CI: confidence interval.

^a$\mathrm{Consistency}(\%)=\frac{\mathrm{Number\; of\; diabetes\; diagnosisi\; n\; both\; test\; and\; retest\; study}}{\mathrm{Number\; of\; diabetes\; diagnosis\; in\; test\; study}}\times 100$.

^bType 1 diabetes were classified as those reporting age at diagnosis <40 years.

^cType 2 diabetes were classified as those reporting age at diagnosis >39 years.