Quelle méthode d’évaluation de la fonction rénale utiliser chez le sujet âgé hospitalisé en unité de court séjour gériatrique ? Comparaison de quatre méthodes

Inflammatory Markers Change with Age, but do not Fall Beyond Reported Normal Ranges

We examined the serum levels of IL-6, IL-8, TNF, IL-6R, TNF-R1, and CRP and the dynamics of changes in these levels according to age. The study included healthy individuals of 20–90 years of age. Participants were divided into subgroups based on their decade of life, and into subgroups of ≥65 or <65 years. Serum cytokine levels were assayed by ELISA, and CRP using an immunoturbidimetric method. Serum CRP levels were within the normal range for all subgroups. The 60- to 70-year age group showed higher CRP than the 20- to 30- (p = 0.003), 30- to 40- (p = 0.009), and 40- to 50- (p = 0.030) year age groups. Serum cytokine levels were low. It was greater in the 60- to 70-year age group than in the 20- to 30- (p = 0.008) and 30- to 40- (p = 0.040) year groups, and was greater in the 70- to 90-year group than the 20- to 30-year group (p = 0.043). Serum TNF-R1 level in the 70- to 90-year group was greater than in all other age groups (p = 0.000 for all comparisons). Other measured parameters did not differ between groups. Serum levels of IL-6, CRP, and TNF-R1 were greater in participants ≥65 than <65 years of age. Healthy older people showed low serum levels of CRP and pro-inflammatory cytokines, but higher than in younger population. Therefore, the adjustment of normal ranges in the elderly should be considered. Serum levels of pro-inflammatory cytokines elevated beyond normal ranges indicate particular diseases.

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

Assessment of renal function is essential in the management of hospitalised patients, particularly in geriatric practice. Impairment of renal function is common in the elderly, aged of 80 years and over, and should be taken into account before prescribing drugs eliminated through the kidneys or performing investigations requiring iodine injection. Renal failure is also a predictor of mortality. In clinical practice, creatinine-based equations are recommended to assess kidney function. The most widely used equations are the Cockroft and Gault (CG) and the simplified Modification of diet in renal disease (MDRD) formulas. The former estimates the clearance of creatinine in millilitres per minute, the latter estimates the glomerular filtration rate in millilitres per minute per 1.73 m(2). In 2002, the French high authority for health recommended the use of the CG formula, but no recommendation was given for the elderly. In the literature, no study has compared CG and MDRD formulas with a reference method in this very old population. In the octogenarians, two studies have compared these formulas with the creatinine clearance calculated on the basis of a 24-hour urine collection and four studies have compared the formulas head to head. All these studies showed that the results obtained with the MDRD formula are higher from 10 to 30 mL/min/1.73 m(2) than the results obtained with the CG formula. Studies simulating drug prescription showed that the use of the MDRD formula would lead to a risk of drug over dosage in 20 to 36% of the elderly. Also, two studies have suggested that only creatinine clearance measured by the CG formula is a predictor of mortality in the very old population. In conclusion, in the octogenarian, none of these two formulas is ideal. However, based on the results of studies targeted to this elderly population, the best solution seems to be the use of the CG formula expecting new methods of evaluation of renal function.