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The uremic dyslipidemia: a cross-sectional and longitudinal study
M M Avram1, P Goldwasser, D E Burrell
1Division of Nephrology, Avram Center for Kidney Diseases, Long Island College Hospital, Brooklyn, NY 11201.
Insights
Patients undergoing continuous ambulatory peritoneal dialysis (CAPD) have more atherogenic lipid profiles than those on hemodialysis (HD). Nutritional status influences these lipid disturbances and cardiovascular risk in dialysis patients.
Area of Science:
- Nephrology
- Cardiovascular Medicine
- Clinical Biochemistry
Background:
- Patients on maintenance hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) exhibit lipid and apoprotein disturbances linked to high cardiovascular mortality.
- Previous studies suggest lipid levels are inversely related to dialysis duration, but the reasons (patient attrition vs. lipid decrease) remain unclear.
- The impact of dialysis modality on uremic lipoprotein disturbances, adjusted for confounding factors, requires further investigation.
Purpose of the Study:
- To investigate cross-sectional and longitudinal changes in lipids, apoproteins, and atherogenic risk ratios in HD and CAPD patients.
- To determine the influence of dialysis modality, clinical factors, and nutritional status on lipoprotein profiles.
- To examine the relationship between lipid profiles and mortality in dialysis patients.
Main Methods:
- Cross-sectional and longitudinal study of 196 HD and 77 CAPD patients enrolled in annual cohorts from 1987-1990, monitored until 1991.
- Measurement of total cholesterol (TC), HDL-C, apo A-I, and apo B at enrollment and annually in survivors.
- Multivariate analysis to assess relationships between lipids, apoproteins, risk ratios, clinical factors (race, gender, diabetes, PTH), nutritional status (albumin), and mortality.
Main Results:
- CAPD patients showed significantly higher TC, apo A-I, apo B, and lower apo A-I/apo B ratio compared to HD patients.
- Serum albumin correlated with lipid levels and atherogenic ratios; normal albumin was linked to higher TC/HDL-C in CAPD patients.
- Patients who died had lower TC and apo B, and higher apo A-I/apo B ratio compared to survivors throughout their course.
Conclusions:
- Continuous ambulatory peritoneal dialysis (CAPD) patients exhibit more atherogenic lipoprotein profiles than hemodialysis (HD) patients.
- Improved nutritional status (higher serum albumin) is associated with hyperlipidemia and worsened atherogenic risk ratios, particularly in CAPD.
- Lipid profiles, while stable longitudinally, showed differences between HD and CAPD patients and were associated with mortality risk.
Abstract:
Patients on maintenance hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) exhibit numerous disturbances of serum lipids and apoproteins that may contribute to their high cardiovascular mortality. Cross-sectional studies have found that lipid levels are inversely related to time on dialysis. However, it is not known whether this association is the result of the attrition of hyperlipidemic patients or a decrease in lipid levels over time in all patients. Additionally, few studies have investigated the effect of dialysis modality on the lipoprotein disturbances of uremia adjusting for the confounding influences of demographics, or nutritional and endocrine status. To address these issues, we undertook a cross-sectional and longitudinal study of lipids, apoproteins, and atherogenic risk ratios in patients maintained on HD and CAPD. Patients were enrolled in annual cohorts from 1987 to 1990 and monitored until 1991. A total of 196 HD and 77 CAPD patients were studied. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), apoprotein (apo) A-I, and apo B were measured on enrollment and remeasured annually in survivors through 1990. Using multivariate methods, we examined the relationship of the lipids, apoproteins, their respective ratios, and their changes over time, to a broad range of clinical factors and to mortality. Compared with HD patients, CAPD patients had significantly higher TC, apo A-I, and apo B, and a significantly lower apo A-I/apo B ratio. Serum albumin correlated directly with TC and apo B and inversely with apo A-I/apo B. For patients with normal serum albumin (> or = 3.5 g/dL [35 g/L]), CAPD patients had a significantly higher TC/HDL-C than HD patients; otherwise the ratios were similar for CAPD and HD. Independent influences on lipoprotein levels in HD and CAPD patients were also demonstrated for race, gender, and diabetes, but not for parathyroid hormone (PTH) levels. For both dialysis modalities, patients who died had significantly lower TC and apo B, and significantly higher apo A-I/apo B throughout their entire courses compared with survivors. In the subset of patients followed longitudinally for 2 or more years, apo B tended to decrease with time, but TC, HDL-C, and apo A-I were stable. The longitudinal changes in lipoproteins did not correlate with outcome or other factors. In conclusion, CAPD patients have more atherogenic lipoprotein profiles than HD patients. Improved visceral protein nutritional status, as defined by serum albumin level, is associated with hyperlipidemia and, especially vor CAPD, worsened atherogenic risk ratios.(ABSTRACT TRUNCATED AT 400 WORDS)