Survival Analysis in Amputees Based on Physical Independence Grade Achievement

Backgound: Survival implications of achieving different grades of physical independence after lower extremity amputation are unknown. Objectives: To identify thresholds of physical independence achievement associated with improved 6-month survival and to identify and compare other risk factors after removing the influence of the grade achieved. Design: Data were combined from 8 administrative databases. Grade was measured on the basis of 13 individual self-care and mobility activities measured at inpatient rehabilitation discharge. Setting: Ninety-nine US Department of Veterans Affairs Medical Centers. Patients: Retrospective longitudinal cohort study of 2616 veterans who underwent lower extremity amputation and subsequent inpatient rehabilitation between October 1, 2002, and September 30, 2004. Main Outcome Measure: Cumulative 6-month survival after rehabilitation discharge. Results: The 6-month survival rate (95% confidence interval [CI]) for those at grade 1 (total assistance) was 73.5% (70.5%-76.2%). The achievement of grade 2 (maximal assistance) led to the largest incremental improvement in prognosis with survival increasing to 91.1% (95% CI, 85.6%-94.5%). In amputees who remained at grade 1, the 30-day hazards ratio for survival compared with grade 6 (independent) was 43.9 (95% CI, 10.8-278.2), sharply decreasing with time. Whereas metastatic cancer and hemodialysis remained significantly associated with reduced survival (both P <= .001), anatomical amputation level was not significant when rehabilitation discharge grade and other diagnostic conditions were considered. Conclusions: Even a small improvement to grade 2 in the most severely impaired amputees resulted in better 6-month survival. Health care systems must plan appropriate interdisciplinary treatment strategies for both medical and functional issues after amputation.