Table 2. Statistical analysis as to stages.

Stage	Normal	Stage 1	Stage 2	Stage 3	Stage 4
1	<0.001
2	<0.001	0.5<
3	<0.001	0.039	0.5<
4	<0.001	<0.001	<0.001	0.5<
4S	0.003	0.001	0.067	0.5<	0.5<
The difference in serum MK level between the six groups was statistically significant (P<0.0001, by the Kruskal–Wallis test). P-values in this table for differences between the two groups were derived from the Mann–Whitney U-test with Bonferroni's correction.