Impact of Glucose Control and Regimen on Limb Salvage in Patients Undergoing Vascular Intervention
Johnston L Moore, Zdenek Novak, Mark Patterson, Marc Passman, Emily Spangler, Adam W Beck, Benjamin J Pearce
UAB School of Medicine, Birmingham, AL
Background:
Studies have demonstrated correlation between levels of glycosylated hemoglobin (HbA1c) in diabetic patients and the incidence of both peripheral artery disease (PAD) and lower extremity amputation (AMP). However, the impact of glucose control on outcomes in patients undergoing open or endovascular PAD treatment has not been examined. The purpose of this study is to assess the effect of HbA1c and medication regimen on amputation-free survival (AFS) in patients undergoing treatment for limb salvage.
Methods:
Limb salvage patients with a baseline HbA1c within one month of treatment were identified from a prospectively maintained vascular registry queried from 2010-17. The hospital EMR was cross-referenced to identify patients with HbA1c measured within 3 months of the index procedure. Patient records were examined and instances of AMP, type of treatment (ENDO v OPEN), demographics, co-morbidities, and diabetic glycemic control modalities were analyzed. Diagnosis of diabetes was determined by a combination of HbA1c, physician diagnosis, and usage of diabetic medications.
Results:
Our query found 306 eligible limbs for analysis. AFS was associated with diabetes (82.6%, p=0.002), non-white race (56.5%, p=0.006), insulin-only diabetic control (52.2%, p<0.001), post-operative creatinine >1.3mg/dL (38.0%, p<0.001), and dialysis (26.1%, p<0.001). [Table 1] HbA1c was not significantly associated with AFS. Survival analysis (Kaplan-Meier plots) revealed a diagnosis of diabetes was significantly associated with worse AFS in the entire cohort (Log rank=0.011) [Graph 1] as well as in the critical limb ischemia subgroup (Log rank=0.049) (Rutherford >3) (not pictured). Logistic regression demonstrated an association with age (p=0.040, AOR=1.027), post-operative creatinine level (p=0.003, AOR=1.247), non-white race (p=0.048, AOR=0.567), and insulin-only diabetic control (p=0.002, AOR=2.535) with worse AFS across all limbs surveyed.
Conclusions:
Diabetes with insulin only regimen has significantly worse AFS than non-diabetic patients or those on an insulin sensitizing regimen. This may represent a surrogate for disease severity, but the type of medications may present a modifiable risk factor to improve limb salvage.
| Table 1. Baseline characteristics of all limbs surveyed | ||||||||||
| Amputation Free Survival (AFS) | Total | |||||||||
| Yes (n=214) | No (n=92) | (n=306) | p-value | |||||||
| Male (vs Female) | 111 | 51.9% | 61 | 66.3% | 172 | 56.2% | 0.239 | |||
| Non-white | 73 | 34.1% | 52 | 56.5% | 125 | 40.8% | 0.006 | |||
| Cardiovascular Events | 100 | 46.7% | 53 | 57.6% | 153 | 50.0% | 0.465 | |||
| Post-operative MI | 10 | 4.7% | 10 | 10.9% | 20 | 6.5% | 0.088 | |||
| Smoking History | 160 | 74.8% | 71 | 77.2% | 231 | 75.5% | 0.203 | |||
| Dialysis | 13 | 6.1% | 24 | 26.1% | 37 | 12.1% | <0.001 | |||
| GFR <60ml/min | 9 | 4.2% | 7 | 7.6% | 16 | 5.2% | 0.425 | |||
| Creatinine >1.3mg/dL | 36 | 16.8% | 35 | 38.0% | 71 | 23.2% | <0.001 | |||
| COPD | 33 | 15.4% | 19 | 20.7% | 52 | 17.0% | 0.515 | |||
| Hyperlipidemia | 112 | 52.3% | 57 | 62.0% | 169 | 55.2% | 0.664 | |||
| Hypertension | 168 | 78.5% | 85 | 92.4% | 253 | 82.7% | 0.455 | |||
| Stroke | 40 | 18.7% | 17 | 18.5% | 57 | 18.6% | 0.610 | |||
| Obesity (BMI>30) | 106 | 49.5% | 41 | 44.6% | 147 | 48.0% | 0.086 | |||
| Transplant | 4 | 1.9% | 4 | 4.3% | 8 | 2.6% | 0.445 | |||
| Endo VI (vs Open) | 65 | 30.4% | 30 | 32.6% | 95 | 31.0% | 0.783 | |||
| Reinterventions | 50 | 23.4% | 31 | 33.7% | 81 | 26.5% | 0.211 | |||
| HbA1C >7.0% | 75 | 35.0% | 40 | 43.5% | 115 | 37.6% | 0.543 | |||
| Rutherford >3 (CLI) | 159 | 74.3% | 80 | 87.0% | 239 | 78.1% | 0.576 | |||
| Diabetes Diagnosed | 120 | 56.1% | 76 | 82.6% | 196 | 64.1% | 0.002 | |||
| Diet Only Diabetic Control | 12 | 5.6% | 8 | 8.7% | 20 | 6.5% | 0.470 | |||
| Insulin Only Diabetic Control | 41 | 19.2% | 48 | 52.2% | 89 | 29.1% | <0.001 | |||
| Diabetes Medications | 40 | 18.7% | 13 | 14.1% | 53 | 17.3% | 0.164 | |||
| Insulin + Diabetes Meds | 22 | 10.3% | 7 | 7.6% | 29 | 9.5% | 0.303 | |||
| Age (Mean +/- SD) | 60.0 +/- 10.8 | 63.3 +/- 10.5 | 61.0 +/- 10.8 | 0.015 | ||||||
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