Role of peritoneal loss of albumin in the hypoalbuminemia of continuous ambulatory peritoneal dialysis patients: relationship to peritoneal transport of solutes

The effects of peritoneal albumin loss and the consequences of heterogeneous peritoneal solute transport on serum albumin levels were investigated in 25 adult patients on standard continuous ambulatory peritoneal dialysis (0-58 months). The patients were divided into three groups according to their albumin concentrations (g/l/l.73 m2) in 8-hour overnight effluents: group 1 ( < 0.6, n = 5), group 2 (0.6-1.1; n = 14), and group 3 ( > 1.1;n= 6). Significant differences (mean +/- SD) were observed in serum albumin levels (4.4 +/- 0.2, 3.7 +/- 0.3, and 3.1 +/- 0.5 g/dl, respectively) and in net ultrafiltration (0.37 +/- 0.13, 0.19 +/- 0.21, and -0.06 +/- 0.20 liters/8 h/1.73m2, respectively). The serum albumin levels were strongly correlated with 8-hour peritoneal mass transfer, clearance of albumin, 8-hour effluent concentrations of protein and glucose, and ultrafiltration rate. Moreover, the serum albumin levels showed significant negative correlations with dialysate-to-serum ratios of small solutes (urea, creatinine, and uric acid) and macromolecules (IgG, IgA, and IgM) estimated from 8-, 4-, and 1-hour dwell times. In addition, an overnight dialysate glucose-to-protein ratio < 1.0 was highly predictive of low serum albumin levels ( < or = 3.5 g/dl) and poor ultrafiltration. From the results of this study we conclude that peritoneal loss of albumin as well as peritoneal transport of other solutes of wide size ('permeability') contribute to the low serum albumin levels during continuous ambulatory peritoneal dialysis, especially in patients with a high peritoneal permeability.

Trends in stroke incidence and mortality in Hawaiian Japanese men

BACKGROUND AND PURPOSE

Vital statistics show a sharp decline in stroke mortality since the late 1960s. It is not clear whether this has been associated with a decline in stroke incidence.

METHODS

Since 1966 the Honolulu Heart Program has monitored the incidence and mortality of coronary heart disease and stroke in a target population of 11,136 men of Japanese ancestry living on Oahu. Trends were analyzed from January 1, 1969, through December 31, 1988.

RESULTS

Of 7893 men aged 45 to 68 years and free of stroke at entry examination, 530 developed first episodes of stroke in the period 1969 to 1988 (389 cases of thromboembolic stroke, 124 cases of hemorrhagic stroke, and 17 cases of stroke of unknown type). Age-adjusted annual stroke incidence declined from 5.1 per 1000 person-years in 1969 to 1972 to 2.4 in 1985 to 1988. The incidences of thromboembolic stroke, hemorrhagic stroke, and total stroke decreased 3.5%, 4.2%, and 4.4% per year, respectively. The 1-month case-fatality rates for thromboembolic stroke decreased moderately; those for hemorrhagic stroke fell dramatically.

CONCLUSIONS

These findings suggest that the decline in stroke mortality in the past two or three decades results from a decline in both incidence rates and early case-fatality rates in thromboembolic and hemorrhagic stroke and stroke of unknown type. The decreases may be related to changes in risk factors, such as the decline in blood pressure and the decrease in cigarette smoking, as well as improvements in diagnosis and treatment.

Elevated serum cholesterol is a risk factor for both coronary heart disease and thromboembolic stroke in Hawaiian Japanese men. Implications of shared risk

BACKGROUND AND PURPOSE

The relation between total serum cholesterol level and thromboembolic or nonhemorrhagic stroke is controversial. The Honolulu Heart Program cohort of Japanese-American men provides data which show that elevated serum cholesterol is an independent predictor of thromboembolic stroke as well as coronary heart disease (CHD). The data are presented to suggest that the association of elevated cholesterol with stroke is sometimes underestimated or underreported partly because of competing or shared risk with CHD, the other major atherosclerotic end point.

METHODS

The data are based on 6352 men (aged 51 to 74 years) at baseline examination (1971 to 1974) who were free of clinical CHD and stroke and were followed an average of 15 years for new cases of both end points. Relative risks of serum cholesterol for CHD and thromboembolic stroke were calculated, controlling for other major cardiovascular covariates.

RESULTS

There was a continuous and progressive increase in both CHD and thromboembolic stroke rates with increasing levels of serum cholesterol. The relative risk between the highest and lowest quartiles of serum cholesterol was 1.7 (95% confidence interval, 1.4 to 2.0) for CHD and 1.4 (95% confidence interval, 1.1 to 1.9) for thromboembolic stroke. There was a decline in the difference in relative risks between CHD and thromboembolic stroke in older men (aged 60 years and older) compared with younger men (aged younger than 60 years).

CONCLUSIONS

These data provide additional evidence that elevated serum cholesterol should be considered a primary risk factor for thromboembolic stroke, presumably through its effect on both coronary and cerebrovascular atherosclerosis. It is suggested that this association is sometimes underestimated or underreported partly because of shared or competing risk with CHD, the clinical manifestation of atherosclerosis that generally occurs earlier in life and with greater frequency than thromboembolic stroke.

Heterogeneity in peritoneal transport during continuous ambulatory peritoneal dialysis and its impact on ultrafiltration, loss of macromolecules and plasma level of proteins, lipids and lipoproteins

We investigated the effect of heterogeneity in the peritoneal transport of plasma proteins on dialysis efficiency and plasma levels of proteins, lipids and lipoproteins in 32 patients undergoing long-term continuous ambulatory peritoneal dialysis (CAPD; 9 females and 23 males, 18-76 years old). Eleven patients were studied on several occasions (at 0-42 months) and the remainder at 6-60 months on CAPD (n = 49). We have divided our patients arbitrarily into two equal groups according to their protein concentration in the peritoneal effluent at the end of an 8-hour cycle. Patients with a high peritoneal protein concentration (> or = 2 g/l/1.73 m2) have lower ultrafiltration capacity, higher glucose absorption rate and increased loss of most plasma proteins [including albumin, immunoglobulins (Ig), complement components and high-density lipoproteins (HDL)] compared to patients with a low peritoneal protein concentration (< 2 g/l/1.73 m2). Consequently, plasma levels of albumin, IgM and HDL were lower in patients with a high peritoneal protein concentration. The latter had also increased levels of plasma triglycerides and very-low-density lipoproteins. The difference observed in peritoneal transport between the groups could be ascribed only in part to the duration of CAPD treatment, and hence to the number of peritonitis episodes but not to medications. Therefore, we suggest that inherent constitutional factors may be responsible for some of the observed heterogeneity in the peritoneal transport of these patients which is already evident at the start of CAPD treatment. Patients with high peritoneal transport are exposed to an augmented atherogenic plasma lipid profile in addition to a reduction in dialysis efficiency (ultrafiltration failure). These patients may become prone also to nutritional and immunological disturbances. Therefore, we suggest taking these effects into consideration before choosing the appropriate dialysis modality in patients with increased peritoneal transport for plasma proteins.

Serum cholesterol and mortality among Japanese-American men. The Honolulu (Hawaii) Heart Program

Hawaiian men of Japanese ancestry followed up for 18 or more years after a baseline examination showed a quadratic distribution of death rates at different levels of serum cholesterol. Mortality from cancer progressively decreased and mortality from coronary heart disease progressively increased with rising levels of serum cholesterol. There was a positive association between baseline serum cholesterol levels and deaths from coronary heart disease at 0 to 6 years, 7 to 12 years, and 13 years and longer after examination. The inverse relationship between cancer and serum cholesterol levels was stronger in the first 6 years than in the next 6 years and, although still inverse, lost statistical significance after 13 years. Cancers of the colon and lung showed the strongest association with low baseline serum cholesterol levels, while gastric or rectal cancer failed to show this association. Organ specificity and persistence of the inverse association beyond 6 years suggest that the nutritional demands of cancers may not entirely explain the inverse association with some cancers. The quadratic distribution of deaths in this cohort remained after coronary heart disease, stroke, and cancer were removed from the analysis. For the entire period of observation, the lowest mortalities were found in men with serum cholesterol levels between 4.65 and 6.18 mmol/L (between 180 and 239 mg/dL). Manipulation of serum cholesterol levels below this level would not be desirable if this were to result in increased risk of death from cancer or other disease. This study does not rule out this possibility.

Kinetics of peritoneal protein loss during CAPD: I. Different characteristics for low and high molecular weight proteins

We studied the peritoneal protein loss in 13 patients during CAPD using 2 liters of 1.5% dextrose dialysis solutions. We compared the kinetic characteristics of the peritoneal mass transfer and clearance of proteins over a wide range of molecular size, to those of small molecular weight solutes. The peritoneal clearance of all studied proteins and solutes correlated strongly and negatively with their molecular mass. No changes were observed in these clearances during 58 months of dialysis. Unlike the peritoneal mass transfer and clearance of small molecular weight solutes (less than 200) which revealed a remarkable progressive drop after the first hour of an eight-hour dialysis cycle, the mass transfer and clearance of proteins of large molecular weight (greater than 68,000) was continuous throughout the eight hours. The clearance of proteins of small molecular weight (less than 15,000) showed similar kinetics to small solutes (less than 200). These results indicate that long dwell times (6 or 8 hr) of peritoneal dialysis are detrimental for the loss of large molecular weight proteins (such as albumin and immunoglobulins) in view of the negligible dialysance of both small solutes (creatinine and potassium) and "intermediate molecules" (represented by the small molecular weight proteins) during the latter hours of long dwell cycles. Thus we suggest that substituting CAPD (3 x 8 hr or 4 x 6 hr) with CCPD (6 x 1 hr) may limit protein loss in these patients.

Kinetics of peritoneal protein loss during CAPD: II. Lipoprotein leakage and its impact on plasma lipid levels

We quantified the plasma levels and peritoneal loss of lipids and lipoproteins, and studied the composition of plasma and effluent lipoproteins in 16 patients on CAPD (5 females and 11 males, 18 to 76 years old). Five patients were studied prospectively (at 0, 1, 3 and 6 months) and 11 patients at 6 to 58 months on CAPD (N = 30). Elevated levels of plasma VLDL and reduced levels of plasma HDL were maintained in these patients throughout 58 months of CAPD, whereas the initially increased LDL levels showed a tendency towards normalization. All plasma lipoproteins (VLDL, IDL, LDL and HDL) were present in the peritoneal effluent. The lipoproteins isolated from plasma and peritoneal fluid shared a similar lipid and apolipoprotein composition. The peritoneal transport characteristics of plasma lipoproteins were similar to other plasma macromolecules. Their clearance correlated with their molecular mass, plasma concentration and dwell time, but was not affected by duration of CAPD treatment. The plasma lipid and lipoprotein levels were unaffected by the rate of glucose absorption. The peritoneal protein clearance correlated positively with plasma levels of triglyceride and LDL, and negatively with plasma HDL. An inverse correlation was observed also between plasma levels of HDL and its peritoneal clearance (r = -0.393, P less than 0.025, N = 30). The continuous peritoneal loss of HDL and the hypertriglyceridemia were found to contribute most to the persistent low plasma levels of HDL in CAPD patients, and thus may lead to the accelerated atherosclerosis observed in these patients.

Response bias in the Honolulu Heart Program

The 14-year incidence rates (1969-1982) for coronary heart disease, cerebrovascular disease (stroke), total mortality, and cause-specific mortality were compared between 8,006 examined and 3,130 nonexamined men of the Honolulu Heart Program using identical surveillance procedures. There was a significant decrease in examination participation with increasing age. Examined men smoked less, weighed more, had a higher level of education, and had a lower percentage of never-married status than did nonexamined men. Total mortality rates, cancer mortality rates, and coronary heart disease incidence rates were higher in nonexamined men, while there were no differences in stroke rates. The average annual response error for total mortality and coronary heart disease rates was underestimated at 8.7% and 5.4%, respectively. The differences in rates were greatest during the first half of the follow-up period and converged during the second half. By the end of 10 years, there were no differences between nonexamined and examined men for any of the endpoints studied. The pattern of convergence of rates suggests a diminishing healthy participant advantage over time. In conclusion, a response bias did occur in this study, but the effect was small and did not alter any of the earlier findings concerning the relative incidence of cardiovascular disease. Because the degree of response bias can vary widely depending on when during follow-up a particular analysis is undertaken, it is recommended that prospective studies monitor, insofar as possible, a sample of nonparticipants in order to ensure valid results.

Predictors of sudden cardiac death among Hawaiian-Japanese men

A cohort of 7,591 middle-aged Hawaiian-Japanese men free at initial examination of evidence of coronary heart disease or stroke were followed starting in 1965. Between 1965 and 1983, 1,342 of these men died; 229 deaths occurred less than 24 hours after the onset of the terminal episode, of which 98 deaths occurred in less than one hour. In the category of deaths occurring less than one hour after onset, the risk characteristics of those whose deaths were attributed to coronary heart disease and those whose deaths were attributed to an unknown cause were similar. It is appropriate to combine them as "sudden cardiac death." In the category of deaths occurring one to 24 hours after onset, the risk characteristics of those whose deaths were attributed to coronary heart disease and those whose deaths were attributed to an unknown cause differed. It is not appropriate to assume coronary heart disease as the underlying cause of death in this unknown cause group. The predictors of sudden cardiac death were blood pressure, serum cholesterol, serum glucose, cigarette smoking, history of parental heart attack, and electrocardiographic evidence of left ventricular hypertrophy or strain. Inversely related to risk were alcohol intake and the number of years spent in Japan. No factor distinguished those at risk for sudden cardiac death from those at risk for other manifestations of coronary heart disease.

A comparison of the 12-year mortality and predictive factors of coronary heart disease among Japanese men in Japan and Hawaii

The mortality and predictive factors of coronary heart disease among men of Japanese ancestry in Japan and Hawaii were compared on the basis of 12 years follow-up data using comparable methods of case ascertainment and risk factor measurements. Among 1,687 men (Japan) and 7,536 men (Hawaii) who were free of coronary heart disease and aged 45-69 at baseline examination in 1965-1968, 20 (Japan) and 123 (Hawaii) cases of fatal coronary heart disease were identified. The age-adjusted mortality rate was 40% higher in Hawaii than in Japan. The difference was not statistically significant, but consistent with earlier studies. More than half of this difference in mortality rate was attributed to different levels of known risk factors in the two cohorts. In multivariate analysis using the combined population, age, blood pressure, serum cholesterol, serum glucose, cigarette smoking, and alcohol intake (inversely) remained as significant predictors of coronary heart disease mortality. Although the associations of risk factors with coronary heart disease tended to be stronger in Hawaii than in Japan, there was no statistically significant difference in regression coefficient for any of the risk factors studied. These findings cannot be claimed to be definitive because of the small number of cases, especially in Japan.

Postmortem findings in sudden and non-sudden deaths among Japanese-American men in Hawaii

Analyses were made of the cause of death and major pathologic findings among 1,085 autopsied Japanese-American men in Hawaii to determine the differences between the 167 men who experienced sudden death within 24 hours of being well and the 918 men with non-sudden death. Sudden deaths were further divided into three subgroups according to the interval from the onset of symptoms to death: (less than one hour; one to six hours; more than six hours). Nearly 90 percent of sudden deaths and 25 percent of non-sudden deaths were attributed to cardiovascular disease. The proportion of deaths due to coronary heart disease was highest in sudden deaths less than one hour (72 percent) and lowest in sudden deaths more than six hours (49 percent), whereas the proportion of stroke deaths was highest in sudden deaths more than six hours (37 percent) and lowest in sudden deaths less than one hour (9 percent). The prevalence of myocardial infarction and the grade of coronary atherosclerosis were also significantly greater for sudden deaths (especially sudden deaths less than one hour) than for non-sudden deaths.

Lipids and lipoproteins as predictors of coronary heart disease, stroke, and cancer in the Honolulu Heart Program

A group of 2,122 healthy men in the Honolulu Heart Program who participated in the Cooperative Lipoprotein Phenotyping Study, 1970 to 1972, were followed for 10 years by repeated examinations and surveillance of hospital discharge and mortality records in order to diagnose new cases of coronary heart disease, stroke, cancer, and other deaths. Total cholesterol and low-density lipoprotein cholesterol were significantly associated with all clinical types of coronary heart disease in multivariate analyses, whereas high-density lipoprotein cholesterol was inversely associated with nonfatal myocardial infarction and total coronary heart disease, but not with fatal coronary heart disease nor angina. Triglyceride and very-low-density lipoprotein cholesterol were associated with total coronary heart disease by univariate but not multivariate analysis. None of the other specific chronic diseases were significantly associated with any lipid or lipoprotein, although there were trends of inverse associations of all noncardiovascular disease with total cholesterol and low-density lipoprotein cholesterol. Thus, for total disease (coronary heart disease, stroke, cancer, and other deaths), the optimal range for lowest disease incidence was about 200 to 220 mg/dl for total cholesterol and 120 to 140 mg/dl for low-density lipoprotein cholesterol. A strong inverse pattern of total disease with high-density lipoprotein cholesterol indicated that the highest levels were the optimal levels.

The development of a functional rating scale to measure the treatment outcome of chronic spinal patients

A Functional Rating Scale (FRS) was developed to quantify behavioral changes in chronic pain patients relative to six subcategories. The aim was to demonstrate its validity, test the instrument's reliability, and determine its value in measuring treatment outcome. Five sample populations were examined: a test group of 58 pain clinic patients; a medical control group comprising 29 outpatients with arthritis; and a three-part, healthy control group of 98 subjects. The validation and reliability of the scale were affirmed by clearly differentiating healthy from infirm subjects and through a test-retest check of the four control groups. The difference between means of the test group, before and after treatment, was of high statistical significance, which indicates the practical value of the FRS in measuring relative changes.