Evolution of silent myocardial ischaemia prevalence and cardiovascular disease risk factor management in Type 2 diabetes over a 10-year period: an observational study.

AIMS: To assess the evolution of silent myocardial ischaemia prevalence and of cardiovascular disease risk factor management over 10 years in people with Type 2 diabetes. METHODS: This repeated cross-sectional study prospectively included 770 people with Type 2 diabetes who presented at our centre in the period 1999-2009. All had at least one additional cardiovascular disease risk factor, no history of coronary disease and were screened for silent myocardial ischaemia using myocardial perfusion imaging. The prevalence of silent myocardial ischaemia, clinical and biological variables and treatments were collected and compared among participants screened in three periods: 1999 to 2002; 2003 to 2005; and 2006 to 2009. We also identified predictive factors for silent myocardial ischaemia. RESULTS: Participants had a mean ± sd age of 62.3 ± 9.3 years, 57.4% were men and the mean time from diagnosis of diabetes was 13.4 ± 9.3 years. Overall, silent myocardial ischaemia screening was positive in 13.9% of participants. This prevalence decreased sharply over the 10-year study period (22.6% in 1999-2002, 13.7% in 2003-2005 and 5.9% in 2006-2009; P<0.0001). In parallel, diastolic and systolic blood pressure, HbA1c and LDL cholesterol significantly decreased and glitazone and statin use increased (all P<0.001). Male gender, peripheral artery disease, diastolic blood pressure >80 mmHg and LDL cholesterol >2.6 mmol/l were independently associated with silent myocardial ischaemia. Further adjustment showed the screening period had a significant effect, which erased the effects of diastolic blood pressure and LDL cholesterol. CONCLUSIONS: The prevalence of silent myocardial ischaemia decreased sharply over time, and control of the main cardiovascular disease risk factors improved. Although the causality link cannot be established, the present study supports current recommendations advocating glycaemic control and intensive management of cardiovascular factors instead of systematic screening.

Diffusion kinetics in blood during haemodialysis and in vivo clearance of inorganic phosphate.

Contradictory data are reported in the literature concerning the diffusion kinetics of inorganic phosphates (iPh) between red blood cells and plasma during haemodialysis. Accordingly, we performed mass balance and equilibration studies to analyze the diffusion kinetics of iPh in vivo and in vitro. Mass balance analysis shows that iPh is only cleared from the plasma volume and thus that it practically does not diffuse from red blood cells to plasma during the short time lapse of blood transit through the haemodialyzer. In vitro equilibration studies of blood drawn at the filter outlet show that at room temperature there is a slow, limited, and almost linear net efflux of iPh during the 4 h that follow blood drawing. Our results point out: (1) that the in vivo clearance of iPh should be exclusively determined as plasma clearance, and (2) that for accurate clearance determinations the iPh concentrations should be measured in blood samples centrifuged within at most 1 h after blood drawing. Whole-blood clearance determinations--as well as the in vitro dialyzer data--largely overestimate (>30%) the real in vivo dialyzer performance.

Water-soluble vitamin levels in patients undergoing high-flux hemodialysis and receiving long-term oral postdialysis vitamin supplementation.

The prescription of multivitamin supplements for dialysis patients is routine practice, but the doses prescribed differ greatly from one dialysis center to another. Few data are available concerning long-term vitamin supplementation and its effects on patients either on high-flux hemodialysis or receiving postdialysis supplementation. For several years, we have systematically prescribed to our patients an oral postdialysis multivitamin supplement containing thiamine hydrochloride 100 mg, riboflavin 20 mg, pyridoxine hydrochloride 50 mg, folic acid 6 mg, and ascorbic acid 500 mg. The aim of this study was to perform a cross-sectional long-term evaluation of the vitamin levels in patients who received this vitamin supplement for at least 12 months. We also were interested in investigating the plasma oxalic acid and total homocysteine levels associated with the long-term prescription of these vitamin supplements. Thirty-three patients on high-flux dialysis were studied. Vitamin levels and/or vitamin-dependent enzymatic activities were within the normal range (N) in all patients. The mean results (+/-SD) were plasma ascorbic acid 13.6 +/- 6.4 mg/L (N > 4), plasma folate 14.1 +/- 1.1 microg/L (N > 3), for vitamin B1, alpha-ETK 1.02 +/- 0.02 (N < 1.18) and ETKo 100 +/- 13 U/L (N > 70), for vitamin B2, alpha-EGR 1.00 +/- 0.07 (N < 1.52) and EGRo 1282 +/- 213 U/L (N > 672), and for vitamin B6, alpha-EGOT 1.34 +/- 0.10 (N < 1.8) and EGOTo 380 +/- 84 U/L (N > 228). Plasma oxalic acid was higher than normal in all patients (mean = 61 +/- 15 micromol/L, N < 33). However, all patients had oxalic acid levels within the range reported in the literature for patients not taking extra ascorbic acid. Mean total homocysteine was 24 +/- 8 micromol/L with only 4 patients (12%) having normal levels (N < 15). In conclusion, the postdialysis supplement given provides adequate vitamin levels in almost all patients in the long term. Postdialysis prescription allows an optimal compliance with the treatment, is well accepted by the patients, and is cost-effective.

Diffusion kinetics of urea, creatinine and uric acid in blood during hemodialysis. Clinical implications.

In order to elucidate some conflicting data reported in the literature the diffusion kinetics between red blood cells (RBC) and plasma during dialysis were studied for urea, creatinine and uric acid. Several complementary studies were performed. According to our results urea diffuses very rapidly from RBC to plasma and is almost at equilibrium at the dialyser outlet; thus the extraction of urea during dialysis is from both plasma and RBC. On the other hand creatinine and uric acid hardly diffuse at all from RBC to plasma during blood transit through the hemodialyser and these solutes are thus extracted mainly from plasma. As a consequence an important in-vitro equilibration process occurs for both solutes in blood drawn at the dialyser outlet; the equilibration rate is greatly temperature-dependent and to achieve complete equilibrium at room temperature, up to 6 to 12 hours were needed for creatinine and 2 to 3 hours for uric acid. Moreover, in the case of creatinine, but not for uric acid, a RBC/plasma disequilibrium was also found in blood drawn at the dialyser inlet; this finding is in contrast with previous reports and suggests that with high-efficiency dialysis modalities the interval between two successive RBC transits through the dialyser may be insufficient for complete equilibration of slowly equilibrating solutes. The clinical implications of these findings with respect to the in-vivo dialyser performance and clearance determinations are discussed.

The determination of thyroxine and thyroxine uptake with new homogeneous enzyme immunoassays using Boehringer Mannheim/Hitachi analysis systems.

New homogeneous enzyme immunoassays for the determination of thyroxine and thyroxine uptake have been developed. The CEDIA assays are based on the cloned enzyme donor immunoassay technology, which involves fragments of beta-galactosidase prepared by genetic engineering. The assays have been adapted for Boehringer Mannheim/Hitachi analysers. The CEDIA T4/T Uptake assays were evaluated in eleven clinical chemistry laboratories on various Boehringer Mannheim/Hitachi analysis systems, using a 2-point calibration. The analytical range of the T4 test was 10 to 258 nmol/l thyroxine. The T uptake test had a measuring range between 20-50%. Depending on the concentration of the analyte (samples from hypo-, eu- or hyperthyroid patients), mean coefficients of variation ranged from 1.8 to 4.8% within-run and from 4.1 to 6.5% between-run for the T4 assay. Even better coefficients of variation were obtained for the T uptake assay (1.4 to 2.3% within-run, 2.8 to 3.3% between run). The relative inaccuracy of the CEDIA assays with respect to values assigned by other tests was satisfactory in various control sera. The T4 assay was compared with one radioimmunoassay, one enzyme immunoassay and one fluorescence polarisation immunoassay. Slopes ranging from 0.9 to 1.1 and intercepts ranging from -10 to +10 nmol/l thyroxine were obtained with two exceptions. The results of the T uptake test correlated reasonably with those of other thyroxine-binding methods. No interference was observed with icteric and lipaemic sera. Haemoglobin up to 4 g/l had no significant influence. Results of the CEDIA T Uptake test are mainly used for calculation of the free thyroxine index, in which the thyroxine value is corrected for variations of thyroxine-binding protein concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)