Chronic kidney disease and metabolic syndrome as risk factors for cardiovascular disease in a primary care program

INTRODUCTION

Cardiovascular disease (CVD) is especially prevalent in patients with chronic kidney disease (CKD).

OBJECTIVE

To evaluate the role of CKD and metabolic syndrome (MS), which is a cluster of risk factors for CVD, as predictors of CVD.

METHODS

Observational, cross-sectional study with a random sample aged 45 or more years extracted from the population assisted by the primary care program in Niterói city in the state of Rio de Janeiro, Brazil. CKD was diagnosed by the K/DOQI guidelines and MS, by the harmonized criteria. CVD was said to be present if the participant had one or more of the following findings: echocardiographic abnormalities, and history of myocardial infarction, stroke or heart failure. A logistic regression model was developed to analyze risk factors for CVD using CKD as the variable of primary interest.

RESULTS

Fifty hundred and eighty-one participants (38.2% male) with a mean age of 59.4 ± 10.2 years were analyzed. The prevalence rate of CKD was 27.9%. In participants without CKD, MS was associated with a slight but statistically significant increase in the risk for CVD (OR = 1.52, p = 0.037); in those with CKD but without MS the risk for CVD was also statistically significant and at a greater magnitude (OR = 2.42, p = 0.003); when both were present the risk for CVD was substantially higher (OR = 5.13, p < 0.001).

CONCLUSION

In this study involving a population assisted by a primary care program, CKD was confirmed as an independent risk factor for CVD. The presence of MS concurrent with CKD substantially amplified the risk for CVD.

Effects of in-center daily hemodialysis upon mineral metabolism and bone disease in end-stage renal disease patients

CONTEXT

Alternative hemodialysis schedules have been proposed to improve the quality of the dialysis. Nonetheless, their influence upon mineral and bone disorders is unknown.

OBJECTIVE

To report the impact of a daily hemodialysis schedule upon the lesions of renal osteodystrophy.

TYPE OF STUDY

Prospective non-controlled study.

SETTING

Public University Hospital.

PARTICIPANTS

Five patients treated by daily hemodialysis for at least 24 months.

INTERVENTION

Daily dialysis sessions were accomplished with non-proportional dialysis machines without an ultrafiltration control device, with blood flow of 300 ml/min, bicarbonate dialysate ([Ca]=3.5 mEq/L) at 500 ml/min, and low-flux membrane dialyzers. Sessions were started at 6:00 p.m. (except Sundays) and lasted 2 hours.

MAIN MEASUREMENTS

Serum levels of Ca and P from the last 6 months on conventional hemodialysis for the same patients were used for comparison with each semester of daily hemodialysis. Bone biopsies and PTH levels were obtained at the end of the conventional hemodialysis period and then again after 2 years of daily hemodialysis.

RESULTS

Mean serum calcium was significantly higher during the second and third semesters of daily dialysis [10.0 mg% (SD 0.6), and 10.0 mg% (SD 0.8), respectively] compared to standard dialysis [9.4 mg% (SD 0.8)], p < 0.05. Mean values for phosphorus were significantly lower during every semester of daily hemodialysis [6.3 mg% (SD 1.8), 5.8 mg% (SD 1.7), 6.0 mg% (SD 1.7), and 6.0 mg% (SD 1.8)] compared to standard dialysis [7.2 mg% (SD 2.7)], P < 0.05. Variations in mean Ca x P product followed the same pattern as for phosphorus [59.5 (SD 16.0), 57.1 (SD 16.3), 59.8 (SD 17.7), and 58.31 (SD 20.9) vs. 68.6 (SD 27.3), P < 0.05]. After 2 years on daily hemodialysis, 2 patients who had aplastic lesion were found to have mild bone disorder. In addition, one patient with mixed bone lesion and moderate bone aluminum accumulation had osteitis fibrosa with no aluminum. Intact PTH values at the beginning of study and after 2 years on daily hemodialysis did not differ [134 pg/ml (SD 66) vs. 109 pg/ml (SD 26), P = 0.60, respectively].

CONCLUSIONS

Patients treated using daily hemodialysis had better control of serum phosphorus and perhaps a lower risk of metastatic calcifications. Daily hemodialysis also seemed to be beneficial to low turnover bone disease and bone aluminum deposition.

Effects of dialyzer reuse on the permeability of low-flux membranes

Little attention has been given to the effects of reuse on the permeability of low-flux membranes, especially regarding middle molecules. We studied two different types of low-flux membranes at reuses 0, 6, and 12 in five patients undergoing hemodialysis with the following combinations of membrane and sterilant: cellulose diacetate membrane and formaldehyde, polysulfone membrane and formaldehyde, cellulose diacetate membrane and peracetic acid, and polysulfone and peracetic acid. The permeability of the membranes was assessed through the hydraulic ultrafiltration coefficient (K(UF)), sieving coefficient for beta(2)-microglobulin (B2M), and vitamin B(12) and albumin concentrations in ultrafiltrate. After 12 reuses, total cell volume (TCV) tended to be reduced in both cellulose diacetate and polysulfone dialyzers irrespective of the sterilant used, but significance was only found for the first set of dialyzers. Cellulose diacetate dialyzers reprocessed with either formaldehyde or peracetic acid showed an important reduction in K(UF) (31% [P < 0.05] and 23% [P < 0.05], respectively). A significant elevation in K(UF) was found in polysulfone membranes reprocessed with peracetic acid (41%; P < 0.05), but no alterations in K(UF) were found in polysulfone membranes reprocessed with formaldehyde. Cellulose diacetate membranes were intrinsically more permeable to B2M than polysulfone membranes (sieving coefficient, 6. 85 +/- 2.53 versus 0.04 +/- 0.02 x 10(-2); P < 0.001), which was not modified by any of the sterilants. Vitamin B(12) levels in ultrafiltrate decreased to an undetectable level in four of five samples collected after 12 reuses in polysulfone membranes reprocessed with peracetic acid (90 +/- 71 to 3 +/- 8 pg/mL; P < 0. 05 versus reuse 0). Albumin leakage occurred in two of five samples after the 12th reuse, but only in polysulfone membranes reprocessed with peracetic acid. Our findings suggest that reuse of low-flux polysulfone dialyzers reprocessed with peracetic acid is associated with structural damage of the membrane and a reduced permeability to middle molecules.