Patterns of autosomal dominant polycystic kidney diseases in black Africans

Autosomal dominant polycystic kidney disease (ADPKD) is not well described in black Africans while some data suggesting the disease is exceptional in this race. A retrospective study of patients with ADPKD followed in nephrology department of a teaching hospital in Dakar (January 1, 1995 to December 31, 2005) was therefore undertaken. Prevalence of ADPKD was one in 250. Mean age was 47 + or - 5 years with a predominance of male (57%). High blood pressure (HBP) was present in 68% of patients. Other renal manifestations were flank pain, hematuria and proteinuria. Majority of patients had impaired renal function at time of diagnosis. Extra-renal cysts were essentially found in liver (45.5%), pancreas and seminal vesicles. Main complications: ESRD (51%) occurred within a 6 year mean period, urinary tract infection (13%) and cerebral haemorrhage (2%). HBP control, in general needed 2 or more antihypertensive drugs. Fourteen patients died, ten patients had been on haemodialysis and four others died from uremic complications. In conclusion, ADPKD in black African adults is not rare and probably underdiagnosed. Early HBP and ESRD are likely more frequent than in other races. Earlier ultrasound detection and strategies to preserve renal function should be offered to at-risk individuals to improve outcomes.

Prognostic predictors of technique and patient survival in elderly Southeast Asian patients undergoing continuous ambulatory peritoneal dialysis

The population of elderly patients entering chronic dialysis programmes is increasing. Elderly patients are susceptible to malnutrition and have multiple complicating disorders in addition to uraemia. Selecting appropriate dialysis modality is particularly critical in elderly patients. Continuous ambulatory peritoneal dialysis (CAPD) has many advantages to elderly patients; however, the clinical outcome varies for elderly CAPD patients. In comparison with Westerners, Southeast Asians have a small body mass index and may be more suited to CAPD therapy. To identify the prognostic predictors in elderly Southeast Asian patients, this historical cohort study analysed 144 patients aged > or = 65 years at initiation of CAPD. A group of haemodialysis (HD) patients aged > or = 65 years was utilised as the control group. Survival curves for patient and technique were derived from Kaplan-Meier analysis and were further analysed by Cox-Mantel log-rank test. To elucidate the impact of individual factors on patient survival, various significant univariables were further subjected to multivariate analysis. No significant increase existed for relative risk of technique failure in elderly patients compared with younger patients. This analytical data indicates that CAPD was as good as HD for elderly uraemic patients regarding to the patient survival. Diabetes, dependent patients, low albumin levels and previous HD history were significant poor prognostic factors for survival of elderly CAPD patients. In conclusion, CAPD is an effective modality of renal replacement therapy for Southeast Asian elderly patients. The technique survival was not affected by patient age.

Serum paraoxonase activities in hemodialyzed uremic patients: cohort study

AIM

To determine whether paraoxonase activity, paraoxonase phenotypes, and lipid status are altered in uremic patients on long-term hemodialysis treatment as compared to healthy population.

METHODS

Patients (n = 69) and control subjects (n = 145) were from the area of Slavonski Brod, Croatia. Paraoxon was used as a substrate for measuring basal or sodium chloride-stimulated (NaCl-stimulated) paraoxonase activity, and phenylacetate for measuring arylesterase activity. The double substrate method was used to assign phenotypes. Cholesterol, triglycerides, and high-density lipoprotein cholesterol (HDL-cholesterol) were determined by methods routinely used in medical-biochemical laboratories. Enzyme activities are expressed as international units per liter of serum or per mmol of HDL-cholesterol (HDL-standardized activities).

RESULTS

Basal and NaCl-stimulated paraoxonase activity, as well as arylesterase activity expressed per serum volume, were significantly lower in the hemodialyzed uremic patients compared to the controls; 69% (p < 0.001), 73% (p < 0.001) and 49%, (p < 0.001), respectively. However, basal and NaCl-stimulated paraoxonase activity standardized for HDL-cholesterol concentrations were not significantly reduced in the hemodialyzed uremic patients as compared to controls (86%, p = 0.614 and 87%, p = 0.720, respectively), contrary to arylesterase activity, which remained significantly lower (72%, p < 0.001). The distribution of paraoxonase phenotypes in hemodialyzed uremic patients and controls was as follows: AA 45% and 39%, AB 37% and 48%, BB 18%, and 13%, respectively.

CONCLUSION

Patients on long-term hemodialysis have decreased paraoxonase/arylesterase activity, which might indicate a greater risk of premature atherogenesis.

Atherosclerotic cardiovascular disease risks in chronic hemodialysis patients

BACKGROUND

Cardiovascular diseases are the most common causes of death among chronic hemodialysis patients, yet the risk factors for these events have not been well established.

METHODS

In this cross-sectional study, we examined the relationship between several traditional cardiovascular disease risk factors and the presence or history of cardiovascular events in 936 hemodialysis patients enrolled in the baseline phase of the Hemodialysis Study sponsored by the U.S. National Institutes of Health. The adjusted odds ratios for each of the selected risk factors were estimated using a multivariable logistic regression model, controlling for the remaining risk factors, clinical center, and years on dialysis.

RESULTS

Forty percent of the patients had coronary heart disease. Nineteen percent had cerebrovascular disease, and 23% had peripheral vascular disease. As expected, diabetes and smoking were strongly associated with cardiovascular diseases. Increasing age was also an important contributor, especially in the group less than 55 years and in nondiabetic patients. Black race was associated with a lower risk of cardiovascular diseases than non-blacks. Interestingly, neither serum total cholesterol nor predialysis systolic blood pressure was associated with coronary heart disease, cerebrovascular disease, or peripheral vascular disease. Further estimation of the coronary risks in our cohort using the Framingham coronary point score suggests that traditional risk factors are inadequate predictors of coronary heart disease in hemodialysis patients.

CONCLUSIONS

Some of the traditional coronary risk factors in the general population appear to be also applicable to the hemodialysis population, while other factors did not correlate with atherosclerotic cardiovascular diseases in this cross-sectional study. Nontraditional risk factors, including the uremic milieu and perhaps the hemodialysis procedure itself, are likely to be contributory. Further studies are necessary to define the cardiovascular risk factors in order to devise preventive and interventional strategies for the chronic hemodialysis population.

Race is a major determinant of secondary hyperparathyroidism in uremic patients

In the general population, blacks have higher parathyroid gland mass and circulating parathyroid hormone (PTH) levels than whites. This may predispose black patients to more severe parathyroid disease when renal failure develops. Therefore, racial differences in the severity of uremic hyperparathyroidism were examined in a population of patients with end-stage renal disease (ESRD). Among ESRD patients receiving hemodialysis or peritoneal dialysis, two or more values of intact PTH (immunoradiometric assay, pg/ml) obtained at least 90 d apart were available in 1270 prevalent cases (61.1% blacks, 51% males, and 31.1% diabetic), including 466 incident cases with onset of ESRD after 1993. Maximum PTH levels were analyzed as a function of race, gender, age, diabetic status, and levels of serum calcium, phosphorus, alkaline phosphatase, and aluminum. Using a stepwise multiple regression model, the determinants of maximum PTH in the order of their importance were black race, serum phosphorus, absence of diabetes, younger age, serum calcium, and female gender. The maximum PTH levels averaged 641.7 in blacks and 346.0 in whites after adjusting for age, gender, diabetic status, serum calcium, and phosphorus (P < 0.0001). In blacks compared with whites, the odds ratio (95% confidence interval) for adynamic bone disease (maximum PTH <150 pg/ml) was 0.26 (0.17 to 0.41), whereas the odds ratio for hyperparathyroid bone disease (mean PTH >500 pg/ml) was 4.4 (2.10 to 9.25). Race is a major independent determinant of uremic secondary hyperparathyroidism. Among ESRD patients, blacks may be at an increased risk for hyperparathyroid bone disease and whites for adynamic bone disease.