Table 1.

Characteristics of sample participants from the Veterans Integrated Pain Evaluation Research (VIPER) study.

	Control (N=40)	Case (N=36)	p-value
	Mean (SD)	Mean (SD)
Age	25.2 (4.8)	27.7 (9.1)	0.153
Body Mass Index	25.7 (2.8)	26.8 (3.6)	0.143
Time since amputation (months)	7.6 (3.5)	8.9 (5.9)	0.224
Smoking (ppd)	0.6 (0.5)	0.6 (0.54)	0.817
Average Pain Severity (0–10)	1.2 (0.73)	5.6 (1.38)	0.000
Pain Catastrophizing Scale	2.6 (4.53)	11.8 (11.1)	0.000
	N (%)	N(%)
Male	40 (100)	35(97)	0.958
Smokers	25 (63)	21 (58)	0.892
Opioid use	3 (8)	19 (53)	0.000
Ethnicity:	N (%)	N(%)
American Indian/Alaska Native	0 (0)	0 (0)	1.000
Asian	2 (5)	1 (3)	1.000
Native Hawaiian or Other Pacific       Islander	0 (0)	0 (0)	1.000
Black or African American	3 (7)	3 (8)	1.000
White	37 (93)	32 (89)	0.884
Amputation site:	N (%)	N(%)
Leg	37 (92)	32 (89)	0.587
Arm	3 (8)	4 (11)	0.587
Multiple	0 (0)	0 (0)	1.000
Proximal amputation	12 (30)	16 (44)	0.192

Note: Continuous variables were analyzed using t-tests whereas categorical values were examined using a chi-squared test.