Effects of Traumatic Amputation on β-Trace Protein and β2-Microglobulin Concentrations in Male Soldiers

Abstract

Background: Serum creatinine (SCr) levels are decreased following traumatic amputation, leading to the overestimation of glomerular filtration rate (GFR). β-Trace protein (BTP) and β₂-microglobulin (B2M) strongly correlate with measured GFR and have not been studied following amputation. We hypothesized that BTP and B2M would be unaffected by traumatic amputation. Methods: We used the Department of Defense Serum Repository to compare pre- and post-traumatic amputation serum BTP and B2M levels in 33 male soldiers, via the N Latex BTP and B2M nephelometric assays (Siemens Diagnostics, Tarrytown, N.Y., USA). Osterkamp estimation using DEXA scan measurements was used to establish percent estimated body weight loss (%EBWL). Results were analyzed for small (3-5.9% EBWL), medium (6-13.5%), and large (>13.5%) amputation subgroups; and for a control group matched 1:1 to the 12 large amputation subjects. Paired Student's t test was used for comparisons. Results: Mean serum BTP levels were unchanged in controls, all amputees, and the small and medium amputation subgroups. BTP appeared to decrease following large %EBWL amputation (p = 0.05). Mean serum B2M levels were unchanged in controls, all amputees, and the small and medium amputation subgroups. B2M appeared to increase following large %EBWL amputation (p = 0.05). Conclusions: BTP and B2M levels are less affected than SCr by amputation, and should be considered for future study of GFR estimation. BTP and B2M changes following large %EBWL amputation require validation and may offer insight into non-GFR BTP and B2M determinants as well as increased cardiovascular disease and mortality following amputation. This is a work of the US Government and is not subject to copyright protection in the USA. Foreign copyrights may apply. Published by S. Karger AG, Basel

Estimated glomerular filtration rate based on creatinine, cystatin C, β‐trace protein and β2 microglobulin in patients undergoing nontraumatic lower extremity amputation

“…In the same cohort, Little et al . observed no significant changes in BTP or B2M concentration following traumatic amputation, 27 similar to our findings for nontraumatic amputation. The authors hypothesize that an eGFR equation combining cystatin C, BTP and B2M (excluding creatinine) would be most accurate for patients with traumatic amputation because these markers are less influenced by muscle mass.…”

Non-GFR Determinants of Low-Molecular-Weight Serum Protein Filtration Markers in the Elderly: AGES-Kidney and MESA-Kidney

“…1, 2, 12 These findings suggest that eGFR B2M and eGFR BTP , similar to eGFR cys , may be more accurate than eGFR cr in patients with alterations in muscle mass, such as limb amputations, eating disorders, neuromuscular disorders or malnutrition. 13, 14 On the other hand, significant residual associations of cystatin C and B2M but not creatinine with BMI suggests that eGFR cys and eGFR B2M may be less accurate than eGFR cr in obesity.…”

Polypharmacy, Dosing Trends, and Drug-Drug Interaction Patterns After High-Level Limb Amputation Surgery

“…One found that agents such as propofol (with hepatic first-pass clearance) likely need to be dosed based on theoretical able-bodied weight (i.e., preamputation) rather than postamputation weight (as the full hepatic enzymatic complement is still operational and likely to act on the same fraction of an administered dose). 6 Another study calls attention to the deliberate therapeutic drug level monitoring for a chemotherapeutic agent, 7 as estimated glomerular filtration rates based on serum creatinine clearance postamputation typically overestimate renal function, [8][9][10] influencing dosing. 8 The purpose of this study was to perform a retrospective investigation into the practices surrounding postamputation transition of care medication prescribing patterns at an academic hospital.…”