Table III.
Adjusted Cox regression models for 3-year major amputation after infrainguinal bypass. Race/ethnicity was included in all models, with non-Hispanic White as the reference group. For prosthetic conduit, vein conduit was used as the reference group. The second column shows the unadjusted hazard ratio (uHR) for each variable with respect to amputation. Subsequent columns present the adjusted HRs (aHR) for covariates included in each model. 95% confidence intervals are reported after HRs.
| Covariates | uHR | Model 1 aHR | Model 2 aHR | Model 3 aHR | Model 4 aHR | Model 5 aHR | Model 6 aHR | Model 7 aHR |
|---|---|---|---|---|---|---|---|---|
|
Race/ethnicity Black Hispanic Asian |
1.9 (1.7–2.2) 1.6 (1.3–2.0) 0.93 (0.44–2.0) |
1.7 (1.5–2.0) 1.5 (1.2–1.9) 0.96 (0.5–2.0) |
1.5 (1.3–1.7) 1.2 (1.0–1.5) 0.70 (0.33–1.5) |
1.9 (1.7–2.2) 1.6 (1.3–2.0) 0.93 (0.45–2.0) |
1.9 (1.7–2.2) 1.6 (1.3–1.9) 0.96 (0.46–2.0) |
1.9 (1.7–2.2) 1.5 (1.2–1.9) 0.83 (0.40–1.8) |
1.8 (1.6–2.1) 1.6 (1.3–2.0) 0.91 (0.41–2.0) |
1.4 (1.2–1.6) 1.2 (0.96–1.5) 0.69 (0.33–1.5) |
|
Demographic factors Female sex Age (years) |
0.91 (0.81–1.0) 0.98 (0.97–0.98) |
0.91 (0.8–1.0) 0.98 (0.98–0.99) |
– |
– |
– |
– |
– |
0.95 (0.83–1.1) 0.98 (0.98–0.99) |
|
Comorbidities Current smoker Diabetes Diabetes, insulin dependent CKD Preoperative dialysis |
0.96 (0.86–1.1) 1.7 (1.5–1.9) 1.8 (1.6–2.0) 2.3 (2.1–2.6) 2.7 (2.4–3.1) |
– |
1.1 (0.97–1.2) 1.3 (1.1–1.5) 1.4 (1.2–1.6) 1.3 (1.04–1.6) 1.7 (1.3–2.2) |
– | – | – | – |
1.0 (0.87–1.2) 1.2 (1.04–1.5) 1.2 (1.02–1.4) 1.3 (0.95–1.8) 1.4 (1.0–2.1) |
|
Optimal medical therapy Aspirin and statin |
0.92 (0.83–1.0) |
– |
– |
0.90 (0.81–1.01) |
– |
– |
– |
0.87 (0.78–0.98) |
|
Environmental factorsa Center volume Low center volume Medium center volume High center volume Surgeon volume Low surgeon volume Medium surgeon volume High surgeon volume |
Ref 1.1 (0.90–1.3) 1.1 (0.86–1.4) Ref 0.98 (0.86–1.1) 0.99 (0.86–1.1) |
– | – | – |
Ref 1.1 (0.92–1.3) 1.2 (0.97–1.4) Ref 0.95 (0.83–1.1) 0.97 (0.81–1.2) |
– | – |
Ref 1.0 (0.85–1.2) 1.0 (0.82–1.3) Ref 0.98 (0.85–1.2) 0.99 (0.82–1.3) |
|
Disease severity Rest pain Tissue loss Urgency status Elective Urgent Emergent |
Ref 1.7 (1.5–2.0) Ref 1.4 (1.3–1.6) 2.1 (1.4–3.1) |
– | – | – | – |
Ref 1.7 (1.5–1.9) Ref 1.4 (1.2–1.5) 2.0 (1.4–3.0) |
– |
Ref 1.4 (1.2–1.6) Ref 1.3 (1.1–1.5) 2.2 (1.6–3.2) |
|
Operative factors Infrapopliteal bypass Prosthetic conduit |
1.6 (1.4–1.7) 1.0 (0.92–1.2) |
– | – | – | – | – |
1.6 (1.4–1.8) 1.2 (1.04–1.4) |
1.4 (1.3–1.6) 1.3 (1.1–1.5) |