Evaluation and enhancement of standard equations for renal function estimation in individuals with components of metabolic disease.

BACKGROUND: The primary objective of this study aims to test patient factors, with a focus on cardiometabolic disease, influencing the performance of the Cockcroft-Gault equation in estimating glomerular filtration rate. METHODS: A cohort study was performed using data from adult patients with both a 24-h urine creatinine collection and a serum creatinine available. Creatinine clearance was calculated for each patient using the Cockcroft-Gault, Modified Diet in Renal Disease, and Chronic Kidney Disease Epidemiology Collaboration equations and estimates were compared to the measured 24-h urine creatinine clearance. In addition, new prediction equations were developed. RESULTS: In the overall study population (n = 484), 44.2% of patients were obese, 44.0% had diabetes, and 30.8% had dyslipidemia. A multivariable model which incorporating patient characteristics performed the best in terms of correlation to measured 24-h urine creatinine clearance, accuracy, and error. The modified Cockcroft-Gault equation using lean body weight performed best in the overall population, the obese subgroup, and the dyslipidemia subgroup in terms of strength of correlation, mean bias, and accuracy. CONCLUSIONS: Regardless of strategy used to calculate creatinine clearance, residual error was present suggesting novel methods for estimating glomerular filtration rate are urgently needed.

Staphylococcus lugdunensis Urinary Tract Infection With Associated Neutropenic Fever.

We present a 62-year-old woman with a history of uterine cancer status post-total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH-BSO) on paclitaxel, who presented to the emergency department febrile at 101.7 Fahrenheit and complaining of fatigue and urinary incontinence. Laboratory testing revealed neutropenia and urinalysis showed elevated bacteria with minimal white blood cells, and negative leukocyte and negative nitrites. Urine cultures ultimately showed Staphylococcus lugdunensis with negative blood cultures. S. lugdunensis is a less frequently speciated Staphylococcus and has been increasingly found due to advances in identification using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). S. lugdunensis are Gram-positive cocci, nonsporulating, nonmotile, facultatively anaerobic, catalase-positive, coagulase-negative, oxidase-negative, delta-hemolytic organism. Traditionally, it is seen in skin and soft-tissue infections, as well as vascular infections, however, has minimal occurrences in urinary tract infections. The risk of infection is increased in immunocompromised states and empiric treatment is warranted while waiting for definitive results. Our patient was started on cefepime, valacyclovir, fluconazole, and a single dose of vancomycin while in the emergency department. Worsening thrombocytopenia during her antibiotic course necessitated the re-evaluation of antibiotic agents which can cause thrombocytopenia. Subsequently, due to the patient's improved clinical status, and low risk of severe outcome, fluconazole and valacyclovir were discontinued, and cefepime was changed to ceftriaxone.