154081 Foot surveillance was associated with reduce risk of lower extremity amputation among patients with diabetes

Tuesday, November 6, 2007: 3:15 PM

Chin-Lin Tseng, DrPH , Center for Healthcare Knowledge Management, Department of Veterans Affairs, NJ Health Care System, East Orange, NJ
Drew Helmer, MD, MS , Center for Healthcare Knowledge Management, Department of Veterans Affairs, NJ Health Care System, East Orange, NJ
Mangala Rajan, MBA , Center for Healthcare Knowledge Management, Department of Veterans Affairs, NJ Health Care System, East Orange, NJ
Anjali Tiwari, MSc , Center for Healthcare Knowledge Management, Department of Veterans Affairs, NJ Health Care System, East Orange, NJ
James Wrobel, DPM, MS , Center of Lower Extremity Ambulatory Research (CLEAR), Dr. William M. Scholl College of Podiatric Medicine at Rosalind Franklin University of Medicine and Science, North Chicago, IL
Leonard Pogach, MD, PhD , Center for Healthcare Knowledge Management, Department of Veterans Affairs, NJ Health Care System, East Orange, NJ
Usha Sambamoorthi, PhD , Department of Psychiatry, University of Massachusetts Medical School, Englishtown, NJ
Objective: To evaluate the provision of foot surveillance among patients with diabetes and its association with risk of major amputations. Methods: This was a retrospective study of 399,603 veterans with diabetes and without prior major amputations during fiscal year (FY)1997-1998 using Veteran Health Administrative and Medicare claims data. The follow-up period was FY 1999-2000. We defined foot surveillance to include primary/preventive foot care services in the podiatric and vascular surgery clinics during the baseline 12 months (FY1998). We coded presence/absence of foot surveillance for each quarter in the baseline year and summed these quarterly visit variables into a variable of consistence of care (range: 0-4). We categorized individuals into four risk classification groups according to the consensus of the International Working Group on the Diabetic Foot (Group 0: not defined foot risk condition; Group 1:only microvascular complication including neuropathy, retinopathy or chronic kidney disease; Group 2: microvascular complication and presence of either foot deformity or peripheral vascular diseases; Group 3: foot ulceration or minor lower-extremity amputations. We used Cox proportional regressions to assess the association between foot surveillance and major amputations adjusting for age, sex, race and medical comorbidities for each risk group. Results: There were 3780 incurred major amputations during FY1999-2000; individuals in the more severe foot-risk group had higher major amputation rates (range: 4.3 to 30.3 per 1000). On average, 23.8% had annual foot surveillance. The percentages of having foot surveillance increased with increasing risk classification group severity: 12.9% (Group 0), 24.7% (Group 1), 44.5% (Group 2), and 60.8 % (Group 3). Our multivariate Cox regression models showed that having foot surveillance reduced the risk of major amputation, but only for patients in Groups 2 and 3. For example, patients in Group 3 who received foot surveillance consistently for 3 calendar quarters were 32% less likely to have major amputations than patients who did not have foot surveillance: (adjusted hazard ratio(AHR)= 0.68; 95% CI: 0.58-0.79); in the same Group 3, those who received 4 quarters of surveillance were 42% less likely to have major amputations (AHR=0.58, 95% CI=0.50-0.68). Conclusion: The consistency of foot surveillance was independently associated in a graded fashion with lower risk of major amputations among individuals with diabetes at high risk for foot complications. A low proportion of veteran patients with diabetes had annual foot surveillance. Policy Implications: Foot surveillance may need to be improved and prioritized, and this may results in fewer major amputations.

Learning Objectives:
1. Create foot surveillance variables using claims data. 2. Identify foot risk classification categories and create them using claims data. 3. Recognize the importance of foot surveillance on risk of major amputations among patients with diabetes.

Keywords: Diabetes, Outcomes Research

Presenting author's disclosure statement:

Any relevant financial relationships? No
Any institutionally-contracted trials related to this submission?

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.