Indexation du debit de filtration glomerulaire par la surface corporelle : mythe et realite

in Néphrologie & Thérapeutique (2009), 5(7), 614-22

Indexing glomerular filtration rate (GFR) for body surface area (BSA) is often realized without arising any questions. However, physiological basis for such an indexation are very poor. Indeed, indexing ... [more ▼]

Indexing glomerular filtration rate (GFR) for body surface area (BSA) is often realized without arising any questions. However, physiological basis for such an indexation are very poor. Indeed, indexing GFR for BSA to avoid variation due to differences in body size necessarily implies that GFR is a linear function of BSA and that the intercept of this linear function is zero. Moreover, when GFR is indexed for BSA, the relation indexed GFR-BSA must completely disappear. These physiological prerequisites are not found for BSA indexation. We will review the history of this indexation and will underline errors and defaults. Different equations to estimate BSA exist and will be discussed. The choice of "1.73m(2)" will be also criticized. Moreover, indexing GFR for BSA has little impact on GFR results in "normal" body size population. Nevertheless, this indexation will have strong consequences in very lean (such as anorexia) and in obese patients. We will discuss possible alternatives proposed to substitute for BSA indexation. [less ▲]

Prévalence de la maladie rénale chronique par l’estimation du DFG dans une population de plus de 50 ans selon la formule MDRD versus la nouvelle formule CKD-EPI.

in Néphrologie & Thérapeutique (2009), 5(5), 001

Vitamin D: current status and perspectives.

in Clinical Chemistry & Laboratory Medicine (2009), 47(2), 120-127

Abstract The role of vitamin D in maintaining bone health has been known for decades. Recently, however, the discovery that many tissues expressed the vitamin D receptor and were able to transform the 25 ... [more ▼]

Abstract The role of vitamin D in maintaining bone health has been known for decades. Recently, however, the discovery that many tissues expressed the vitamin D receptor and were able to transform the 25-OH vitamin D into its most active metabolite, 1,25-(OH)(2) vitamin D, has led to a very promising future for this "old" molecule. Indeed, observational studies, and more and more interventional studies, are raising the importance of a significant vitamin D supplementation for not-only skeletal benefits. Among them, 25-OH vitamin D has been found to play an important role in prevention of cancers, auto-immune diseases, cardiovascular diseases, diabetes, and infections. Vitamin D deficiency, defined as serum 25-OH vitamin D levels <30 ng/mL, is very common in our population. The cost/benefit ratio and some recently published studies are clearly now in favor of a controlled and efficient vitamin D supplementation in these patients presenting a 25-OH vitamin D level <30 ng/mL. More attention should also be focused on pregnant and lactating women, as well as children and adolescents. Clin Chem Lab Med 2009;47. [less ▲]

Etude analytique des trois trousses de cystatine C et impact sur les formules basées sur la cystatine pour l'estimation du DFG.

in Néphrologie & Thérapeutique (2008, November), 4(6), 399-400

Bioformation ACORATA: Exploration biologique des pathologies osseuses

Conference given outside the academic context (2008)

Analytical Validation of Diasorin Liaison and Roche Elecsys Methods for the Determination of Osteocalcin

in Journal of Bone and Mineral Research (2008, September), 23

Nouveautés sur la vitamine D

Conference given outside the academic context (2008)

Vitamin D: current status and perspectives

Conference (2008, May 15)

Déficit en vitamine D chez l'homme âgé vivant à domicile ou en institution en milieu urbain

in Presse Médicale (Paris, France : 1983) (2008), 37(2, Pt 1), 191-200

OBJECTIVES: Many studies report severe vitamin D deficiency in the elderly and its involvement in various health problems (not limited to bone metabolism disorders). Most papers concern elderly women ... [more ▼]

OBJECTIVES: Many studies report severe vitamin D deficiency in the elderly and its involvement in various health problems (not limited to bone metabolism disorders). Most papers concern elderly women, however, and little is known about this problem among elderly men. This study focused on vitamin D deficiency in elderly men living in urban areas, whether at home or in an institution. METHODS: Between December 2005 and June 2006, we randomly recruited from general practices 336 men aged 65 years or more, living either at home or in institutions for the elderly. The variables studied were: age, residence (home or institution), fall and fracture history, independence (Katz), mobility (TUG), balance, outdoor walking, blood 25-OH-D level, glomerular filtration rate (MDRD) and PINI index. RESULTS: Of the 336 men, 45 (13%) were excluded because they were already receiving vitamin D treatment. The study thus included 291 patients, 174 community-dwelling and 117 institutionalized. The latter were significantly older and had less independence. Their 25-OH-D levels were also significantly lower than for community-dwelling subjects. The prevalence of severe vitamin D deficiency (25-OH-D < 12 ng/mL) was 79% among men in institutions and 57% among those living in the community (p<0.0001), and for mild and moderate vitamin D deficiency (12-32 ng/mL), 21% and 42%, respectively. Overall, only 2 men, both living at home, had normal vitamin D levels (25-OH-D > or = 32 ng/mL). In institutions, factors predictive of severe deficiency were TUG > or = 30s, walking distance < or = 100 m and lack of outdoor walking. Among the men living at home, none of the variables studied was associated with severe vitamin D deficiency. DISCUSSION: Potential biases of the study are discussed. Seasonal variations of vitamin D levels were small and comparable in both groups. The study confirms the high prevalence of vitamin D deficiency in elderly men. These results could probably be extended to other European cities with similar characteristics. The problem of interpreting 25-OH-D results with respect to current laboratory norms for defining severe or moderate vitamin D deficiency (12 and 32 ng/mL, respectively) is also discussed. CONCLUSION: Vitamin D deficiency is widespread and severe in elderly men, especially those living in institutions. Moderate to severe deficiency is also frequent among men living at home. Vitamin D supplementation should be routinely prescribed in institutions for the elderly and probably also to any individual over 65 years. Laboratory norms should be harmonized and consistent with recent medical evidence. [less ▲]

Prévalence de la maladie rénale chronique par l’estimation du DFG avec une formule basée sur la créatinine versus la cystatine C

in Néphrologie & Thérapeutique (2008), 4(6), 004