[Assessment of renal function in elderly after eighty years: Cockroft and Gault or Modification of diet in renal disease equation?]

Reduced estimated glomerular filtration rate is associated with depressive symptoms in elder Chinese: A population-based cross-sectional study

Depression has been associated with chronic kidney disease (CKD). However, few studies have examined whether such association exist in average older individuals with mild to moderate reduced kidney function. This study investigated the association between reduced estimated glomerular filtration rate (eGFR) and depressive symptoms in Chinese older population. Data was obtained from the Rugao Longevity and Ageing Study conducted in Jiangsu, China. Cockcroft-Gault (CG) equation was used to calculate eGFR. Depressive symptoms were defined by using Chinese version of 15-item Geriatric Depression Scale (GDS-15). The prevalence of depressive symptoms was 9.9% among 1749 elderly participants aged 70-84 years. Many elderly had a mild to moderate reduced renal function (84.3%, 57.1% in stage2 CKD and 27.2% in stage3 CKD, respectively). The overall GDS-15 score showed an upward trend with decreasing of eGFR (p < 0.05). Furthermore, a moderate decline of eGFR (in stage3 CKD) was significantly associated with increased risk of depressive symptoms even after adjusting for confounders (OR = 1.71, 95%CI 1.05-2.77, P = 0.03). Elder had no depressive symptoms if their eGFR was normal or mildly reduced. Our results suggest that a moderate decrease of eGFR (stage3 CKD) was independently associated with depressive symptoms in general Chinese elderly.

Implications of using the MDRD or CKD-EPI equation instead of the Cockcroft-Gault equation for estimating renal function and drug dosage adjustment in elderly patients

The objectives of this study were to compare the estimations of renal function obtained with six equations, including the Cockcroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations and to evaluate the implication of using other equations for drug dosing in elderly patients in place of CG. An observational prospective study was conducted over 6 months in two geriatric hospitals with inclusions of all hospitalized inpatients. A list of 36 drugs for which recommendations of dosage adjustment for renal function were mentioned in the manufacturer dosing guidelines was used to compare the implications of using the various equations for drug dosing. A total of 249 patients with a mean age of 83.6 years were included. Mean estimates of renal function from the CG, MDRD, and CKD-EPI equations were 51.3 ± 23.5 mL/min, 72.2 ± 35.2, and 64.3 ± 22.5 mL/min/1.73 m² , respectively (P < 0.001). Twenty percent of patients had at least one drug for which the dose was not appropriately adjusted to renal function. The use of the MDRD and CKD-EPI equations in place of the CG equation was associated with dosage discrepancy in 20-25% of patients and 15% of drug orders, resulting in potential overdosage in 95% of cases. Use of MDRD or CKD-EPI equations results in higher estimates of renal function and may have important implications for drug dosing decision and drug safety in elderly patients. The best way is to directly measure the drug effect or its concentration when it is possible to do so.

Antibiothérapie du sujet âgé : On peut toujours mieux faire

Antimicrobials are among the most prescribed drugs and their prescription increases with age, due to frailty and accrued risk factors for acquiring infections. Antimicrobial prescription in elderly patients must not only account for the risk of toxicity due to drug overexposure, but also of treatment failure or promotion of antimicrobial resistance due to under-dosage. This paper reviews the main antimicrobial, pharmacokinetic and pharmacodynamic variations induced by aging, comorbidities and polypharmacy, and how to take them into account to optimize antimicrobial prescription in elders.

Glomerular filtration rate equations overestimate creatinine clearance in older individuals enrolled in the Baltimore Longitudinal Study on Aging: impact on renal drug dosing

OBJECTIVES

To evaluate the performance of kidney function estimation equations and to determine the frequency of drug dose discordance in an older population.

DESIGN

Cross-sectional analysis of data from community-dwelling volunteers randomly selected from the Baltimore Longitudinal Study of Aging from January 1, 2005, to December 31, 2010.

SUBJECTS

A total of 269 men and women with a mean ± SD age of 81 ± 6 years, mean serum creatinine concentration (Scr ) of 1.1 ± 0.4 mg/dl, and mean 24-hour measured creatinine clearance (mClcr ) of 53 ± 13 ml/minute.

MEASUREMENTS AND MAIN RESULTS

Kidney function was estimated by using the following equations: Cockcroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). The performance of each equation was assessed by measuring bias and precision relative to mClcr . Dose calculation errors (discordance) were determined for 10 drugs requiring renal dosage adjustments to avoid toxicity when compared with the dosages approved by the Food and Drug Administration. The CG equation was the least biased estimate of mClcr . The MDRD and CKD-EPI equations were significantly positively biased compared with CG (mean ± SD 34 ± 20% and 22 ± 15%, respectively, p<0.001) and mClcr (29 ± 47% and 18 ± 40%, respectively, p<0.001). Rounding low Scr values (less than 1.0 mg/dl) up to an arbitrary value of 1.0 mg/dl resulted in CG values (44 ± 10 ml/minute) that were significantly lower than mClcr (56 ± 12 ml/minute, p<0.001) and CG (56 ± 15 ml/minute, p<0.001). The MDRD and CKD-EPI equations had median dose discordance rates of 28.6% and 22.9%, respectively.

CONCLUSION

The MDRD and CKD-EPI equations significantly overestimated creatinine clearance (mClcr and CG) in elderly individuals. This leads to dose calculation errors for many drugs, particularly in individuals with severe renal impairment. Thus equations estimating glomerular filtration rate should not be substituted in place of the CG equation in older adults for the purpose of renal dosage adjustments. In addition, the common practice of rounding or replacing low Scr values with an arbitrary value of 1.0 mg/dl for use in the CG equation should be avoided. Additional studies that evaluate alternative eGFR equations in the older populations that incorporate pharmacokinetic and pharmacodynamic outcomes measures are needed.

Incorporating glomerular filtration rate or creatinine clearance by the modification of diet in renal disease equation or the Cockcroft-Gault equations to improve the global accuracy of the Age, Creatinine, Ejection Fraction [ACEF] score in patients undergoing percutaneous coronary intervention

BACKGROUND

The aim of the present study was to appraise the comparative ability of different ACEF models incorporating glomerular filtration rate or creatinine clearance estimated by the Modification of Diet in Renal Disease [ACEFMDRD] or Cokcroft-Gault [ACEFCG] equations, respectively, over the original ACEF score (ACEFSrCr) in patients undergoing percutaneous coronary intervention (PCI).

METHODS

A total of 537 patients were analyzed by different measures of discrimination, calibration and net reclassification improvement (NRI).

RESULTS

A significant gradient in all-cause mortality was consistently seen with all the models at 30 days, 1 year and 5 years. The comparison of the three models showed that the best balance in terms of discrimination and calibration for all-cause mortality was offered by the ACEFCG at 30 days, the ACEFMDRD at 1 year and similarly by the ACEFCG and ACEFMDRD at 5 years. At 30 days, the NRI was +32.9% for ACEFMDRD over ACEFSrCr and +16% for ACEFCG over ACEFSrCr. At 1 year, the NRI was 13.8% for ACEFMDRD over ACEFSrCr and -7.8% for ACEFCG over ACEFSrCr. At 5 years, the NRI was +7.7% for both the ACEFMDRD and the ACEFCG over the ACEFSrCr.

CONCLUSIONS

In patients undergoing PCI, the ACEF score is associated with satisfactory early-, mid- and long-term discrimination regardless of the definition of renal function. However, incorporating glomerular filtration rate or creatinine clearance by the MDRD or CG formulas in the ACEF score yields superior calibration compared with the original SrCr-based equation, with the ACEFMDRD displaying superior reclassification ability over the ACEFCG and ACEFSrCr at 30 days and 1 year.

Circulating adiponectin is associated with renal function independent of age and serum lipids in west africans

Adiponectin, a protein secreted by adipose tissue, has been associated with renal dysfunction. However, these observations have not been adequately investigated in large epidemiological studies of healthy individuals in general and in African populations in particular. Hence, we designed this study to evaluate the relationship between adiponectin and renal function in a large group of nondiabetic West Africans. Total adiponectin was measured in 792 participants. MDRD and Cockroft-Gault (CG-) estimated GFR were used as indices of renal function. Linear and logistic regression models were used to determine the relationship between adiponectin and renal function. Adiponectin showed an inverse relationship with eGFR in univariate (Beta_MDRD = −0.18, Beta_CG = −0.26) and multivariate (Beta_MDRD = −0.10, Beta_CG = −0.09) regression analyses. The multivariate models that included age, sex, BMI, hypertension, smoking, HDL-C, LDL-C, triglycerides, and adiponectin explained 30% and 55.6% of the variance in GFR estimated by MDRD and CG methods, respectively. Adiponectin was also a strong predictor of moderate chronic kidney disease (defined as eGFR < 60 mL/min/1.73 m²). We demonstrate that adiponectin is associated with renal function in nondiabetic West Africans. The observed relationship is independent of age and serum lipids. Our findings suggest that adiponectin may have clinical utility as a biomarker of renal function.