Evaluating a Risk Score for Lower Extremity Amputation in Patients with Diabetic Foot Infections PC14-PC19
Dr. Deepak Phalgune,
18/27, Bharat Kunj-1, Erandawane, Pune-411004, Maharashtra, India.
Introduction: Factors associated with Diabetes Mellitus (DM) patients developing a foot ulcer are well defined, but risk factors for amputation are less clear. There are substantial morbidity and mortality associated with Lower Extremity Amputation (LEA) in patients with DM. The ability to identify which patients hospitalised for diabetic foot are at highest risk of LEA, could help clinicians to direct patients for special preventive efforts.
Aim: To develop a scoring system to predict the risk of LEA in patients with a diabetic foot ulcer.
Materials and Methods: One hundred and fifty patients with infected diabetic foot ulcer were included for this prospective, observational study. Score was allotted to following variables: age, sensory neuropathy, motor neuropathy, deformity, Infectious Diseases Society of America (IDSA) infection grade, past H/O amputation, ulcer depth grade, duration of DM, HbA1c, Rutherford grading and ankle brachial index. Total score of each subject was calculated after adding scores of risk factors. Statistical significance of categorical variables was tested using chi-square test or Fisher’s-Exact test. Threshold cut-off of total risk score for predicting incidence of amputation was determined using Receiver Operating Characteristics (ROC) curve analysis. Measures of diagnostic efficacy indices such as sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated.
Results: Patients with score of >16.5 were at increased risk of LEA and risk of amputation increased as the score increased. Percentage of patients who required amputation was significantly high in >65 years of age, duration of DM >20 years, sensory neuropathy Grade 2, presence of motor neuropathy, presence of deformity, IDSA infection Grade IV, past H/O amputation, ulcer depth Grade IV, HbA1c =12.5% (113.5 mmol/mol), ankle brachial index =0.9 or =1.30, and Rutherford Grading IV. Multivariate analysis revealed that duration of DM, HbA1c, Rutherford grading and ankle brachial index were significantly associated with LEA.
Conclusion: The score will help clinicians to identify patients at high risk of LEA on examination.