Novel methods of predicting ionized calcium status from routine data in critical care: External validation in MIMIC-III.

Background: Low ionized calcium (I) is prevalent and prognostic in critical care, but poorly detected by either total calcium (T) or albumin-corrected T (cT). We recently derived models of I (Pred-I) and low I (Prob) in critical care that adjust T for binding to albumin and small anions-represented by the anion gap's components. On internal validation, they outperformed cT in diagnosing low I.

Predicting ionized hypocalcemia: External validation of an ionized calcium prediction model in patients with COVID-19 and renal failure.

Background: Ionized hypocalcemia is common in critically ill patients with COVID-19 and is associated with adverse outcomes. We previously developed a linear model that estimates ionized calcium (I) by adjusting total calcium (T) for the three components of the anion gap and albumin. On internal validation, it outperformed the popular method that corrects T for albumin alone (cT) in diagnosing low I.

Predicting Ionized Hypocalcemia in Critical Care: An Improved Method Based on the Anion Gap.

Background: Low ionized calcium (ICa) is prevalent in critical care patients. It is poorly detected by the popular indirect method, which corrects serum total calcium (TCa) for change in albumin. That correction (cTCa) ignores any concomitant change in the anion-complexed fraction of TCa.

Graded interference with the direct potentiometric measurement of sodium by hemoglobin.

Objectives: Sodium concentration is measured by either indirect (I) or direct potentiometry (D), on chemistry and gas panels, respectively. A spurious difference between these methods (ΔNa=I-D) can be confusing to the clinician. For example, variation in serum total protein (TP) is well known to selectively interfere with I.

Pseudohypernatremia and pseudohyponatremia: a linear correction.

Background: Serum sodium is commonly measured by direct potentiometry (DNa), in blood gas panels, or indirect potentiometry (INa), in metabolic panels run on chemistry analyzers. Abnormal values of the serum non-water fraction interfere with INa, with low values causing pseudohypernatremia (INa > DNa) and high values causing pseudohyponatremia (INa < DNa). Previous attempts to derive a linear correction for the difference between INa and DNa (ΔNa) arising from non-water bias--using serum total protein (TP) or albumin (ALB) to represent the non-water fraction--have yielded inconsistent results, possibly owing to differences in sample inclusion criteria, analytic platforms and statistical approach.

Pseudohypobicarbonatemia caused by an endogenous assay interferent: a new entity.

Serum total carbon dioxide, measured using a chemistry analyzer, and gas panel-derived plasma bicarbonate, calculated from the pH and partial pressure of carbon dioxide, often are used interchangeably for clinical purposes. When they disagree, there is a tendency to accept total carbon dioxide and discredit gas panel-derived plasma bicarbonate values. We report a patient who, during a 5-month hospitalization, had persistently low total carbon dioxide levels (12.

Effect of dialysis modality on plasma fibrinogen concentration: a meta-analysis.

Background: Concentrations of plasma fibrinogen, a vascular risk factor, tend to be greater in patients on peritoneal dialysis (PD) than hemodialysis (HD) therapy, like concentrations of serum cholesterol, lipoprotein(a), and transthyretin, despite the substantial loss of protein during PD. Worse vascular outcome has been noted in PD patients compared with HD patients in several studies.

Methods: In this study, the mean difference in plasma fibrinogen levels (PD-HD) was quantified by means of meta-analysis of mean differences found in 12 cohorts with both PD and HD patients (set 1; N = 630) by using a fixed-effects model and meta-analysis of mean fibrinogen values reported in 30 cohorts of patients on a single dialysis modality (set 2; 8 PD cohorts, 22 HD cohorts; N = 2,096) by using a mixed model.

Serum albumin is a powerful predictor of survival among HIV-1-infected women.

Background: We previously reported that single measurements of albumin strongly predict survival in HIV-1-infected women independent of disease-specific markers. We now extend this to the use of serial measurements and single albumin values prior to initiation of highly active antiretroviral therapy.

Design: Prospective cohort study of 1941 women enrolled at six sites in the Women's Interagency HIV Study.

C-reactive protein is an independent predictor of mortality in women with HIV-1 infection.

The relationship of C-reactive protein (CRP) to mortality was assessed in 209 HIV-1-infected women after adjusting for age, body mass index (BMI), serum albumin, CD4 cell lymphocyte count, and HIV-1 RNA. During the follow-up period of up to 5 years (median = 45 months) there were 49 deaths. CRP at study enrollment was measured using a low sensitivity assay.

Serum prealbumin is higher in peritoneal dialysis than in hemodialysis: a meta-analysis.

Background: Although not widely appreciated, the reported concentration of serum prealbumin, like that of serum cholesterol, tends to be higher in patients on peritoneal dialysis (PD) than on hemodialysis (HD), despite the substantial loss of protein during PD.

Methods: The mean difference in serum prealbumin was quantified by meta-analysis of the mean differences found in six cohorts with both PD and HD patients (set 1; N = 639) using a fixed-effects model, and meta-analysis of the mean prealbumin values reported in 23 cohorts of unselected dialysis patients on a single modality (set 2; 9 PD cohorts, 14 HD cohorts; N = 12,256) using a mixed model. For comparison, the mean difference in serum albumin concentration between PD and HD also was estimated in sets 1 and 2 using the same methods.

Rise in serum albumin and creatinine in the first half year on hemodialysis.

Unlabelled: Rise in serum albumin and creatinine in the first half year on hemodialysis.

Background: Serum albumin and creatinine have been reported to rise in new hemodialysis patients; however, these trends have not been quantitated in a stable cohort, and their determinants and prognostic value are unknown.

Methods: This study examined the changes in monthly values of serum albumin and creatinine over the first half year of hemodialysis in 115 patients who survived to the start of the sixth month.

Race and creatinine excretion in chronic renal insufficiency.

Black race and the absence of diabetes are associated with higher levels of serum creatinine in patients with end-stage renal disease. We examined whether these factors have a similar influence on creatinine excretion in men with chronic renal insufficiency. The hypotheses were tested in one sample (group A, n = 35) and the findings replicated in a second, independent sample (group B, n = 66).

Association of serum albumin and mortality risk.

Reduced levels of serum albumin concentration, a routine blood test, within the "normal" range have been reported to be associated with mortality risk. The literature is reviewed, with a focus on cohort studies meeting specified criteria, and findings are summarized. In studies of many populations, comprising healthy subjects and patients with acute or chronic illness, serum albumin concentration is inversely related to mortality risk in a graded manner over its entire range; the estimated increase in the odds of death ranges from 24% to 56% for each 2.

Correlates of vascular access occlusion in hemodialysis.

Vascular access occlusion results in significant morbidity in hemodialysis patients. Age, diabetes, and synthetic grafts (polytetrafluoroethylene [PTFE]) have been associated with vascular access occlusion in univariate analysis. However, the independent risk associated with each of these factors has not been assessed adjusting for confounding among the factors or by other variables, such as blood pressure (BP) or hematocrit.

Predictors of survival in continuous ambulatory peritoneal dialysis patients: the importance of prealbumin and other nutritional and metabolic markers.

Serum markers of visceral and somatic protein status are directly correlated with the survival of hemodialysis patients. We prospectively examined the relationship of single baseline levels of serum albumin, cholesterol, creatinine, and urea to prognosis in 80 continuous ambulatory peritoneal dialysis patients monitored for up to 33 months. Other variables tested included age, race, gender, diabetes, cause of end-stage renal disease, and number of months on dialysis.

Serum ferritin, hematocrit and mean corpuscular volume in hemodialysis.

Prior to beginning to administration erythropoietin (EPO) in 1989, we examined the relationships of hematocrit (HCT), mean corpuscular volume (MCV), and serum ferritin (FER) in one group of hemodialysis patients (group A, n = 117) and replicated the findings in a second group (group B, n = 73). The groups had similar mean (+/- SD) HCT (A: 25.7 +/- 5.

Prealbumin and lipoprotein(a) in hemodialysis: relationships with patient and vascular access survival.

The high morbidity and mortality of hemodialysis patients has led to a search for early markers of risk. Because cardiovascular and nutritional risk are prevalent in this population, we examined the prognostic value of the serum levels of two markers of risk in the general population: (1) lipoprotein(a) [Lp(a)], a low-density lipoprotein-like particle linked to myocardial infarction and coronary bypass stenosis, and (2) prealbumin, a marker of visceral protein status, with a shorter half-life than that of serum albumin. Baseline demographics, clinical information, dialysis prescription, and serum biochemistry measurements of 125 hemodialysis patients followed for up to 14 months were recorded on enrollment.

Predictors of mortality in hemodialysis patients.

Serum biochemical measures suggestive of undernutrition have been reported to correlate with 1-yr mortality risk in prevalent groups of hemodialysis patients. The predictive power of these variables has not been reported in newly diagnosed patients or in patients whose dialysis prescription is guided by urea kinetics. The relationship of these predictors to mortality over periods of longer than 1 yr is also unreported.

The uremic dyslipidemia: a cross-sectional and longitudinal study.

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.