Related Experiment Videos
Prediction of creatinine clearance by several methods in patients with severe infections
S Cronberg1, L Nordström, H Ringberg
1Department of Infectious Diseases, University of Lund, Malmö General Hospital, Sweden.
Abstract:
Since almost all urinary creatinine is derived from the muscle mass, the amount of creatinine in the urine will be proportional to muscle mass, and it will show an almost constant decrease with age. A simple equation for estimating creatinine clearance has been derived. For women the creatinine clearance (ml.min-1) was [150-(years)].body weight (kg)/serum creatinine (mumol.l-1). For men less than 70 years it was [170-age (years)].body weight (kg)/serum creatinine (mumol/l) and for men greater than or equal to 70 years it was [160-age (years)].body weight (kg)/serum creatinine (mumol/l). The prediction was quite simple when laboratory results were given in SI units. A simple nomogram was devised for easy estimation of the creatinine clearance in individual patients according to the age, sex and weight. Predicted values according to our equations were compared with those derived from other formulae in 54 patients with severe infections treated with aminoglycosides. No major differences were found, but the new method seemed more convenient.
Insights
This study introduces simple equations and a nomogram to estimate creatinine clearance, a key indicator of kidney function, based on age, weight, and serum creatinine levels.
Area of Science:
- Nephrology
- Clinical Chemistry
- Geriatrics
Background:
- Urinary creatinine levels correlate with muscle mass and decline with age.
- Accurate estimation of creatinine clearance is crucial for drug dosing and assessing kidney function.
Purpose of the Study:
- To develop and validate simple equations and a nomogram for estimating creatinine clearance.
- To provide a convenient method for calculating creatinine clearance using readily available patient data.
Main Methods:
- Derived equations for creatinine clearance based on age, body weight, and serum creatinine in SI units.
- Developed a nomogram for simplified estimation.
- Compared predicted values with existing formulas in patients with severe infections.
Main Results:
- Established distinct equations for women and men (stratified by age <70 and >=70 years).
- The developed nomogram allows for easy estimation of creatinine clearance.
- New method showed no major differences compared to existing formulas but offered greater convenience.
Conclusions:
- The proposed equations and nomogram offer a simple and convenient method for estimating creatinine clearance.
- This approach is particularly useful in clinical settings, especially when dealing with age-related changes in kidney function.
- The method is validated for use in patients with severe infections treated with aminoglycosides.