Table 2.

Univariable and multivariable analyses with pathological and histological features as covariates to determine the influence on DCIS grade (1 or 2 or 3).

Variable	Model‐based weighted kappa (κ ma)	95% CI	P value for kappa comparison with the outcome only
DCIS grade 1, 2, or 3	0.50	0.44–0.56
Univariable analysis – adjusted for features of the pathologists
Experience	0.50	0.44–0.57	0.95
Country of pathologist	0.51	0.44–0.57	0.91
Heterogeneous DCIS; highest versus most prominent versus other	0.53	0.48–0.57	0.54
Guideline used	0.53	0.48–0.57	0.52
Split according to guideline used
1 Consensus Conference	Only used by one pathologist, not possible
2 UK Royal College of Pathologists	0.58	0.56–0.61	0.02*
3 College of American Pathologists	Only used by two pathologists, not possible
4 WHO	0.48	0.36–0.61	0.80
Univariable analysis – histological features
Necrosis; absent versus present	0.45	0.39–0.52	0.31
Calcification; absent versus present	0.50	0.44–0.57	0.97
Lymphocytic infiltrate; absent versus subtle versus prominent	0.46	0.41–0.52	0.37
Periductal fibrosis; absent versus subtle versus prominent	0.48	0.43–0.54	0.72
Mitoses; sparse versus many	0.46	0.40–0.52	0.40
Architectural pattern; solid and comedo versus. cribriform, flat, and (micro)papillary	0.45	0.39–0.52	0.33
Multivariable analysis – adjusted for features of the pathologists
Guidelines + experience + solution to heterogeneity of DCIS	0.57	0.54–0.59	0.06
Country + experience + solution to heterogeneity DCIS	0.53	0.49–0.58	0.41
Multivariable analysis –adjusted for histological features
Necrosis + calcification + lymphoid infiltrate + periductal fibrosis + mitosis + architectural pattern	0.31	0.26–0.36	<0.01*

DCIS grade 1 denotes low grade, 2 intermediate grade, and 3 high grade.

^* P value showing a significant effect, i.e. p < 0.05.