Table 3. Cox Proportional Hazards Regression Models for Limb Amputation by ABI Group.

Adjustment	Other ABI Values, Reference	Severe PAD		PCA
		HR (95% CI)	P Value	HR (95% CI)	P Value
Univariate	1 [Reference]	1.61 (1.00-2.53)	.04	4.47 (3.16-6.39)	<.001
Age and sex	1 [Reference]	1.74 (1.08-2.74)	.02	4.70 (3.31-6.72)	<.001
Age, sex, and year of PAD diagnosis	1 [Reference]	1.64 (1.03-2.60)	.04	4.80 (3.37-6.84)	<.001
Age, sex, and risk factorsa	1 [Reference]	1.68 (1.04-2.64)	.03	2.62 (1.81-3.81)	<.001
Age, sex, and comorbiditiesb	1 [Reference]	1.61 (1.00-2.53)	.04	3.89 (2.71-5.64)	<.001
Age, sex, and medicationsc	1 [Reference]	1.65 (1.04-2.62)	.04	4.43 (3.09-6.35)	<.001
Age, sex, and CLI	1 [Reference]	1.30 (0.82-2.07)	.27	3.12 (2.16-4.50)	<.001
Age, sex, CKD, diabetes, and CLI	1 [Reference]	1.33 (0.83-2.12)	.23	1.95 (1.33-2.86)	<.001

Abbreviations: ABI, ankle-brachial index; CKD, chronic kidney disease; CLI, critical limb ischemia; HR, hazard ratio; PAD, peripheral artery disease; PCA, poorly compressible arteries.

^aRisk factors were current smoking, hypertension, hyperlipidemia, and diabetes.

^bComorbidities were CKD, prior myocardial infarction, heart failure, and cerebrovascular disease;

^cMedications were antiplatelet agents, statins, angiotensin-converting enzyme inhibitors, and angiotensin-receptor blockers.