Table 3.

Comparison between the ISI and non-ISI group in patients ≤ 65 years old.

	ISI (N = 26)	Non-ISI (N = 35)	P-value
Age, yrs	57.35 ± 6.65	57.06 ± 7.48	0.44
Sex
Men	11 (42.3%)	15 (42.9%)	0.97
Women	15 (57.7%)	20 (57.1%)
PM grade 3
Chondrocyte proliferation
C1	1 (25.0%)	5 (41.7%)	0.51
C2	1 (25.0%)	3 (25.0%)
C3	2 (50.0%)	4 (33.3%)
Granular matrix change
M1	2 (50.0%)	7 (58.3%)	1.00
M2	2 (50.0%)	5 (41.7%)
PM grade 4, 5
Chondrocyte proliferation
C1	3 (13.6%)	2 (8.7%)	0.74
C2	6 (27.3%)	7 (30.4%)
C3	13 (59.1%)	14 (60.9%)
Granular matrix change
M1	7 (31.8%)	10 (43.5%)	0.42
M2	15 (68.2%)	13 (56.5%)

Values are presented as number (%), or mean ± standard deviation unless otherwise indicated.

ISI, intradiscal steroid injection; PM, pfirrmann.

Continuous variables were analyzed using student's t-test.

Categorical variables were analyzed using the Cochran-Armitage trend test, Fisher's exact test, and chi-square test.