Foot Care Education
Other studies have shown that education on footwear and foot care as a sole intervention is effective in reducing the risk of subsequent ulceration and amputation.21 In our study, education on foot care and footwear was recorded 1 or more times for 44% of the case patients and 32% of the control patients, but after controlling for foot risk conditions, foot care education was not significantly different between the groups. Education may have been provided more frequently, but if not recorded in the medical record it would not have been identified. Nonadherence to foot care recommendations, which is related to educational efforts, was associated with an amputation risk OR of 1.9 (95% CI, 0.9-4.3).
Limitations
Our attempt to identify the independent effect of foot examination on amputation risk was complicated by methodologic difficulties. Case patients had more foot risk conditions, foot ulcers, diabetes complications, and longer diabetes duration than control patients, all of which may have increased the opportunities for foot examinations. We attempted to control the potential for confounding by indication by adjusting for the differences in disease severity, and we carefully excluded all visits for ulcer care. Although our effect estimate was in the hypothesized direction, the results still lacked statistical significance. The lack of statistical significance most likely reflects the limited power of the study due to limited sample size and the high examination rate in both case and control patients (at least 1 preventive foot examination was recorded in 87% of case patients and 72% of the control patients). Other possibilities include inaccuracies in recording foot examinations. Omissions in recording foot examinations was probably decreased by the annual chart audit, but concern about the audit may have also led to the recording of care that was never performed. In addition, foot examination risk factors were available only on those who had had foot examinations, which limited our ability to control for this important confounder.
Conclusions
Current recommendations from the American Diabetes Association (ADA) suggest that a “comprehensive vascular, neurological, musculoskeletal, and skin and soft tissue evaluation should be done at least annually.”1 In addition, patients with identified foot risks should be examined quarterly or at each routine diabetes visit several times a year. These recommendations were developed from expert opinion without the benefit of rigorous evidence. Our findings do not either support or refute these recommendations. However, foot examinations are the logical first step in identifying the patients most likely to benefit from specific interventions and preventive care. Future research conducted in a prospective fashion should examine the optimum frequency and type of examination and should incorporate the linkage of risk identification (foot examinations) to management (patient education and footwear) to fully support the current care recommendations.
Acknowledgments
This project was supported in part by the Indian Health Service Diabetes Program (Dr Mayfield) and a grant from the Agency for Health Care Policy and Research (HS 07238). We would also like to thank Ann Etheridge, RN, for her careful chart abstraction, Wes Yamada, DPM, for sharing his podiatric expertise, and Virginia Thomas for her assistance with data entry. Most important, we would like to thank the Pima Indians who graciously allowed us to work with them.