Table 3.

Multivariate logistic regression analysis of the association between marrow fibrosis and JAK2- or MPL-mutant allele burden in patients with ET or post-ET myelofibrosis belonging to the Pavia cohort (see Table 1)

Risk factors for the presence of fibrosis (covariates)	Odds ratio	P	95% CI
Model 1 (including JAK2-mutated, MPL-mutated, and JAK2/MPL-unmutated patients)
Age at diagnosis (y)	1.01	.225	0.99-1.03
MPL exon 10 mutation vs JAK2 (V617F)	3.22	.017	1.24-8.40
MPL exon 10 mutation vs JAK2/MPL-unmutated patients	1.64	.323	0.62-4.37
Model 2 (including JAK2-mutated and MPL-mutated patients exclusively)
Age at diagnosis (y)	1.01	.396	0.99-1.04
MPL exon 10 mutation vs JAK2 (V617F)	2.42	.116	0.80-7.29
Mutation burden, %	1.05	<.001	1.03-1.07
Model 3 (including JAK2-mutated and MPL-mutated patients exclusively)
Age at diagnosis (y)	1.01	.227	0.99-1.04
MPL exon 10 mutation vs JAK2 (V617F)	2.67	.066	0.94-7.57
Mutation burden, >50% vs ≤50%	15.45	<.001	3.89-61.38