Creatinine to Cystatin-C Ratio in Renal Cell Carcinoma: A Clinically Pragmatic Prognostic Factor and Sarcopenia Biomarker.

INTRODUCTION: Low creatinine to cystatin-C ratio (Cr/Cys-C) may be a biomarker for low-muscle mass. Furthermore, low Cr/Cys-C is associated with decreased overall survival (OS), but to date, has not been examined in patients with renal cell carcinoma (RCC). Our objective is to evaluate associations between low Cr/Cys-C ratio and OS and recurrence-free survival (RFS) in patients with RCC treated with nephrectomy. METHODS: We performed a retrospective review of patients with RCC treated with nephrectomy. Patients with end-stage renal disease and less than 1-year follow up were excluded. Cr/Cys-C was dichotomized at the median for the cohort (low vs. high). OS and RFS for patients with high versus low Cr/Cys-C were estimated with the Kaplan-Meier method, and associations with the outcomes of interest were modeled using Cox proportional Hazards models. Associations between Cr/Cys-C and skeletal muscle mass were assessed with correlations and logistic regression. RESULTS: A total of 255 patients were analyzed, with a median age of 64. Median (IQR) Cr/Cys-C was 1 (0.8-1.2). Low Cr/Cys-C was associated with age, female sex, Eastern Cooperative Oncology Group Performance Status ≥1, TNM stage, and tumor size. Kaplan-Meier and Cox regression analysis demonstrated an association between low Cr/Cys-C and decreased OS (HR = 2.97, 95%CI, 1.12-7.90, P =0.029) and RFS (HR = 3.31, 95%CI, 1.26-8.66, P = .015). Furthermore, a low Cr/Cys-C indicated a 2-3 increase in risk of radiographic sarcopenia. CONCLUSIONS: Lower Cr/Cys-C is associated with inferior oncologic outcomes in RCC and, pending validation, may have utility as a serum biomarker for the presence of sarcopenia in patients with RCC treated with nephrectomy.

Novel Trauma Composite Score is superior to Injury Severity Score in predicting mortality across all ages.

BACKGROUND: Injury Severity Score (ISS) is a widely used metric for trauma research and center verification; however, it does not account for age-related physiologic parameters. We hypothesized that a novel age-based injury severity metric would better predict mortality. METHODS: Adult patients (≥18 years) sustaining blunt trauma (BT) or penetrating trauma (PT) were abstracted from the 2010 to 2016 National Trauma Data Bank. Admission vitals, Glasgow Coma Scale, ISS, mechanism, and outcomes were analyzed. Patients with incomplete/non-physiologic vital signs were excluded. For each age: (1) a cut point analysis was used to determine the ISS with the highest specificity and sensitivity for predicting mortality and (2) a linear discriminant analysis was performed using ISS, ISS greater than 16, Trauma and Injury Severity Score, and Revised Trauma Scale to compare each scoring system's mortality prediction. A novel injury severity metric, the trauma component score (TCS), was developed for each age using significant (p < 0.05) variables selected from Abbreviated Injury Scale scores, Glasgow Coma Scale, vital signs, and gender. Receiver operator curves were developed and the areas under the curve were compared between the TCS and other systems. RESULTS: There 777,794 patients studied (BT, 91.1%; PT, 8.9%). Blunt trauma patients were older (53.6 ± 21.3 years vs. 34.4 ± 13.8 years), had higher ISS scores (11.1 ± 8.5 vs. 8.5 ± 8.9), and lower mortality (2.9% vs. 3.4%) than PT patients (p < 0.05). When assessing the entire PT and BT cohort the optimal ISS cut point was 16. The optimal ISS was between 20 and 25 for BT younger than 70 years. For those older than 70 years, the optimal BT ISS steadily declined as age increased PT's cut point was 16 or less for all ages assessed. When the injury metrics were compared by area under the curve, our novel TCS more accurately predicted mortality across all ages in both BT and PT (p < 0.001). CONCLUSION: Injury Severity Score is a poor mortality predictor in older patients and those sustaining penetrating trauma. The age-based TCS is a superior metric for mortality prediction across all ages. LEVEL OF EVIDENCE: Clinical outcomes, Level IV.

Novel Trauma Composite Score is a more reliable predictor of mortality than Injury Severity Score in pediatric trauma.

BACKGROUND: The equivalent Injury Severity Score (ISS) cutoffs for severe trauma vary between adult (ISS, >16) and pediatric (ISS, >25) trauma. We hypothesized that a novel injury severity prediction model incorporating age and mechanism of injury would outperform standard ISS cutoffs. METHODS: The 2010 to 2016 National Trauma Data Bank was queried for pediatric trauma patients. Cut point analysis was used to determine the optimal ISS for predicting mortality for age and mechanism of injury. Linear discriminant analysis was implemented to determine prediction accuracy, based on area under the curve (AUC), of ISS cutoff of 25 (ISS, 25), shock index pediatric adjusted (SIPA), an age-adjusted ISS/abbreviated Trauma Composite Score (aTCS), and our novel Trauma Composite Score (TCS) in blunt trauma. The TCS consisted of significant variables (Abbreviated Injury Scale, Glasgow Coma Scale, sex, and SIPA) selected a priori for each age. RESULTS: There were 109,459 blunt trauma and 9,292 penetrating trauma patients studied. There was a significant difference in ISS (blunt trauma, 9.3 ± 8.0 vs. penetrating trauma, 8.0 ± 8.6; p < 0.01) and mortality (blunt trauma, 0.7% vs. penetrating trauma, 2.7%; p < 0.01). Analysis of the entire cohort revealed an optimal ISS cut point of 25 (AUC, 0.95; sensitivity, 0.86; specificity, 0.95); however, the optimal ISS ranged from 18 to 25 when evaluated by age and mechanism. Linear discriminant analysis model AUCs varied significantly for each injury metric when assessed for blunt trauma and penetrating trauma (penetrating trauma-adjusted ISS, 0.94 ± 0.02 vs. ISS 25, 0.88 ± 0.02 vs. SIPA, 0.62 ± 0.03; p < 0.001; blunt trauma-adjusted ISS, 0.96 ± 0.01 vs. ISS 25, 0.89 ± 0.02 vs. SIPA, 0.70 ± 0.02; p < 0.001). When injury metrics were assessed across age groups in blunt trauma, TCS and aTCS performed the best. CONCLUSION: Current use of ISS in pediatric trauma may not accurately reflect injury severity. The TCS and aTCS incorporate both age and mechanism and outperform standard metrics in mortality prediction in blunt trauma. LEVEL OF EVIDENCE: Retrospective review, level IV.