Serum alkaline phosphatase and mortality in hemodialysis patients.

BACKGROUND: Alkaline phosphatase is typically considered as an innocent by-stander, but emerging data suggest that alkaline phosphatase might play a pathogenic role in vascular calcification and thus contribute to increased mortality in hemodialysis patients. STUDY DESIGN: Longitudinal analyses of the existing HEMO Study database. SETTING AND PARTICIPANTS: 1,827 HEMO Study participants. PREDICTOR: Serum alkaline phosphatase level. OUTCOME AND MEASUREMENTS: All-cause and cardiovascular mortality. RESULTS: Based on the median serum alkaline phosphatase of 97 IU/l, participants were divided into low (< 97 IU/l) and high (> or = 97 IU/l) serum alkaline phosphatase groups. The lower serum alkaline phosphatase group was associated with older age, male gender, non-black race and shorter dialysis years as well as higher serum calcium, higher serum calcium-phosphorus product and lower parathyroid hormone levels. Mean serum liver enzyme values were in the normal range in both groups, but the high alkaline phosphatase group had slightly higher values. In a multivariate time-dependent Cox model using baseline and follow-up values of serum alkaline phosphatase levels, adjusted for demographics, HEMO Study groups, comorbidity, bone metabolism parameters and liver enzymes, each doubling of serum alkaline phosphatase was significantly associated with increased hazard of all-cause (hazard ratio 1.44, 95% CI 1.30 - 1.59) and cardiovascular mortality (hazard ratio 1.35, 95% CI 1.16 - 1.57). LIMITATIONS: Nonstandardized measurements of alkaline phosphatase. CONCLUSIONS: Serum alkaline phosphatase is associated with increased mortality in hemodialysis patients, independent of bone metabolism parameters and liver enzymes. Alkaline phosphatase might be a potential therapeutic target in hemodialysis patients.

Metabolic syndrome and chronic kidney disease.

Chronic kidney disease is fast becoming a worldwide epidemic. In the US, the prevalence of chronic kidney disease is 11%. Its increase in the recent years has mirrored the rising trend of obesity, hypertension and diabetes, which are all components of the metabolic syndrome. Metabolic syndrome comprises of 5 components: impaired fasting glucose, abdominal obesity, hypertriglyceridemia, hypertension and low high density lipoprotein cholesterol. While it is a well known cardiovascular risk factor in the general population, its effects in chronic kidney disease and dialysis populations has not been fully elucidated. While the number of people requiring renal replacement therapy is increasing globally, many of those with chronic kidney disease also suffer from cardiovascular morbidity and mortality. This review discusses the interaction between chronic kidney disease and metabolic syndrome, and the impact of the two on the cardiovascular risk in patients with chronic kidney disease.

A simple comorbidity scale predicts clinical outcomes and costs in dialysis patients.

PURPOSE: In a university-based dialysis program, we found that 25% of the patients accounted for 50% of the costs and 42% of the deaths. We determined whether the Charlson Comorbidity Index, a simple measure of comorbid conditions, could predict clinical outcomes and costs in these patients. METHODS: Patients on hemodialysis or peritoneal dialysis from July 1996 to June 1998 at the University of Pittsburgh outpatient dialysis unit were studied. Comorbidity scores and outcomes were determined by reviewing the Medical Archival Retrieval System database and outpatient records. RESULTS: Two hundred sixty-eight patients were observed for 293 patient-years. The Comorbidity Index strongly predicted admission rate (relative risk per each unit increase = 1.20; 95% confidence interval [CI]: 1.16 to 1.23, P = 0.0001), hospital days and inpatient costs (both P <0.0001), and mortality (relative risk per unit increase = 1.24, 95% CI: 1.11 to 1.39, P = 0.0002.). Age and diabetes, used in the Health Care Financing Administration dialysis capitation model, correlated poorly with outcomes. CONCLUSIONS: The modified Charlson Comorbidity Index predicts outcomes and costs in dialysis patients. This index may be useful in determining appropriate payment for care of dialysis patients under capitated payment schemes and as a research tool to stratify dialysis patients in order to compare the outcomes of various interventions.