Suma Prakash

Interaction of Aging and Chronic Kidney Disease

Our goals in this review are to describe what is known about the prevalence and clinical implications of non-dialysis-dependent chronic kidney disease in the elderly and to discuss some of the most common challenges to managing older patients with chronic kidney disease.

Central, peripheral, and other blood volume changes during hemodialysis.

Volume overload is a factor in development of hypertension in hemodialysis patients. Fluid removal by hemodialysis (HD), however, may cause intradialytic hypotension and associated symptoms. A better understanding of the relationships between blood pressure volume status and the pathophysiology of fluid removal during HD are, therefore, necessary to control blood pressure and to eliminate intradialytic hypotension. The objectives of the study were to determine the amount and direction of change of body fluid compartments after ultrafiltration (UF) and to determine whether any correlations exist between mean arterial pressure (MAP), change in circulating blood volume (&Dgr;BV), total body water (TBW), central blood volume (which constitutes the volume of blood in the lungs, heart, and great vessels [CBV]), and intracellular and extracellular fluid volumes (ICF, ECF). The study population included 20 patients on regular HD. Each individual had their CBV, cardiac output, and peripheral vascular resistance (PVR) measured by means of saline dilution technique and &Dgr;BV monitored by an online hematocrit sensor (Crit Line). MAP was calculated from measured blood pressure and ICF and ECF were measured using bioelectric impedance analysis techniques. Measurements were obtained before and after maximum UF measured by &Dgr;BV (reduction of 6–10% by Crit Line). Ten healthy controls also had ECF and ICF values measured by bioelectric impedance analysis. Before HD, MAP correlated with TBW (r = 0.473, p = 0.035) and CBV (r = 0.419, p = 0.066), suggesting that hypertension here may be due to volume overload. Patients were ECF expanded before HD with an ECF:ICF ratio of 0.96, which was significantly higher than the control ratio of 0.74 (p < 0.0001). During UF, fluid was removed from both ECF and ICF, but more from the ECF volume ratio 0.92 post UF, a significant reduction (p < 0.0001). After UF, MAP no longer correlated with TBW or CBV but correlated with peripheral vascular resistance (r = 0.4575, p = 0.043). After UF, &Dgr;BV correlated inversely with PVR (r = −0.50, p = 0.024). Despite the fall in &Dgr;BV (7.11 ± 2.49%) with UF, CBV was maintained. CBV were 0.899 L and 0.967 L pre and post UF, respectively. These data suggest that in hemodialysis patients, predialysis volume status influences predialysis blood pressure. UF causes BV to fall, but CBV is preferentially conserved by increasing PVR, which also maintains blood pressure. Failure of a PVR response likely leads to intradialytic hypotension.

Short daily versus long nocturnal hemodialysis

Interest in quotidian (daily) hemodialysis (HD) seems to be growing. A number of groups have advocated short, high efficiency daily HD, e.g., Buoncristiani and the group at Perugia, Italy,1,2 and a few have advocated long slow HD while the patient is asleep, so-called nocturnal HD. The leader in this area is the Toronto group that was headed by the late Dr. Uldall and now by Dr. A. Pierratos.3, 4 Several presentations have been made at major nephrologic meetings and there are a number of publications that purport improvement in the outcomes of HD patients who are treated with these methods.5 Unfortunately, there are as yet, no randomized prospective studies comparing outcomes in patients who are dialyzing with conventional three times per week HD and either the short daily or long slow nocturnal HD methods. This is the first daily/nocturnal HD study to obtain comparative data in this field. This study commenced in November of 1998 and will be complete by the end of 2001. This article gives, for the first time, preliminary results from the study.

Racial Composition of Residential Areas Associates with Access to Pre-ESRD Nephrology Care

Referral to a nephrologist before initiation of chronic dialysis occurs less frequently for blacks than whites, but the reasons for this disparity are incompletely understood. Here, we examined the contribution of racial composition by zip code on access and quality of nephrology care before initiation of renal replacement therapy (RRT). We retrospectively studied a cohort study of 92,000 white and black adults who initiated RRT in the United States between June 1, 2005, and October 5, 2006. The percentage of patients without pre-ESRD nephrology care ranged from 30% among those who lived in zip codes with <5% black residents to 41% among those who lived in areas with >50% black residents. In adjusted analyses, as the percentage of blacks in residential areas increased, the likelihood of not receiving pre-ESRD nephrology care increased. Among patients who received nephrology care, the quality of care (timing of care and proportion of patients who received a pre-emptive renal transplant, who initiated therapy with peritoneal dialysis, or who had a permanent hemodialysis access) did not differ by the racial composition of their residential area. In conclusion, racial composition of residential areas associates with access to nephrology care but not with quality of the nephrology care received.

Lactic acidosis in asthma: Report of two cases and review of the literature

Lactic acidosis is commonly associated with states of hypoxia and decreased tissue perfusion. Elevated lactic acid levels have also been observed in individuals who are not septic and who are normotensive, but who have received systemic adrenergic agonist therapy. This report presents two patients with acute asthma treated with very large doses of aerosolized and systemic salbutamol, who developed lactic acidosis despite normal systemic hemodynamics and adequate oxygenation. Lactic acidosis was clinically important because it contributed to respiratory failure in one patient, and complicated the assessment and management of acute, severe asthma in the other patient.

Hemodynamic and Volume Changes during Hemodialysis

Background: Volume overload is a factor in the hypertension of hemodialysis (HD) patients. Fluid removal is therefore integral to the hemodialysis treatment. Fluid removal by hemodialysis ultrafiltration (UF) may cause intradialytic hypotension and leg cramps. Understanding blood pressure (BP) and volume changes during UF may eliminate intradialytic hypotension and cramps. Studies (S1, S2, and S3) were carried out to determine the amount and direction of changes in body fluid compartments following UF and to determine the relationships between BP, changes in blood volume (ΔBV), central blood volume (CBV), cardiac output (CO), peripheral vascular resistance (PVR) plus total body water (TBW), and intra‐ and extracellular fluid volumes (ICF, ECF) in both the whole body and body segments (arms, legs, trunk).

Neighborhood Socioeconomic Status and Barriers to Peritoneal Dialysis: A Mixed Methods Study

BACKGROUND AND OBJECTIVES The objective of this study was to evaluate the association between neighborhood socioeconomic status and barriers to peritoneal dialysis eligibility and choice. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study was a mixed methods parallel design study using quantitative and qualitative data from a prospective clinical database of ESRD patients. The eligibility and choice cohorts were assembled from consecutive incident chronic dialysis patients entering one of five renal programs in the province of Ontario, Canada, between January 1, 2004 and December 31, 2010. Socioeconomic status was measured as median household income and percentage of residents with at least a high school education using Statistics Canada dissemination area-level data. Multivariable models described the relationship between socioeconomic status and likelihood of peritoneal dialysis eligibility and choice. Barriers to peritoneal dialysis eligibility and choice were classified into qualitative categories using the thematic constant comparative approach. RESULTS The peritoneal dialysis eligibility and choice cohorts had 1314 and 857 patients, respectively; 65% of patients were deemed eligible for peritoneal dialysis, and 46% of eligible patients chose peritoneal dialysis. Socioeconomic status was not a significant predictor of peritoneal dialysis eligibility or choice in this study. Qualitative analyses identified 16 barriers to peritoneal dialysis choice. Patients in lower- versus higher-income Statistics Canada dissemination areas cited built environment or space barriers to peritoneal dialysis (4.6% versus 2.7%) and family or social support barriers (8.3% versus 3.5%) more frequently. CONCLUSIONS Peritoneal dialysis eligibility and choice were not associated with socioeconomic status. However, socioeconomic status may influence specific barriers to peritoneal dialysis choice. Additional studies to determine the effect of targeting interventions to specific barriers to peritoneal dialysis choice in low socioeconomic status patients on peritoneal dialysis use are needed.

Continental variations in IgA nephropathy among Asians

BACKGROUND/AIMS Local variations in patient demographics and medical practice can contribute to differences in renal outcomes in patients with IgA nephropathy. We report the experiences of two groups of Asians with IgA nephropathy across continents. MATERIALS AND METHODS We retrospectively examined two cohorts of Asian patients with IgA nephropathy from The King Chulalongkorn Memorial Hospital registry, Thailand (1994 - 2005), and The Metropolitan Toronto Glomerulonephritis registry, Canada (1975 - 2006), and compared their baseline characteristics. Slope of estimated glomerular filtration rate (eGFR) in each group was approximated using separate repeated measures regression models for each country. RESULTS There were 152 Canadian and 76 Thai patients. At the time of first presentation, Thai patients were more likely to be female (63.2 vs. 44.1%, p = 0.01), have less baseline proteinuria (1.2 vs. 1.7 g/d, p = 0.08) and more likely to receive angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin receptor blockers (ARB) (64.0 vs. 15.2%, p < 0.01), or prednisone (41.3 vs. 4.6%, p < 0.01). The annual change in estimated glomerular filtration rate (eGFR) for the Thai and Canadian groups were -0.82 ml/min/1.73 m2/year and -3.35 ml/min/1.73 m2/year, respectively, after adjustment for age, sex, mean arterial pressure (MAP), proteinuria, body mass index, Haas histological grade, chronicity scores and baseline medications. CONCLUSIONS Although disease severity was similar among IgA nephropathy patients in Canada and Thailand, more Thai patients were on ACE-I/ARB or prednisone therapy at baseline. Further prospective research is needed to explore international differences in demographic and environmental factors, health resources, and disease management to determine how they may impact long-term outcomes in Asians with IgA nephropathy.

Lead poisoning from an Ayurvedic herbal medicine in a patient with chronic kidney disease

Background. A 60-year-old man with a history of diabetes and hypertension was referred to a nephrology clinic for investigation of his elevated serum creatinine level.Investigations. Physical examination; laboratory investigations, including measurement of whole-blood lead level, body lead burden and urine albumin:creatinine ratio; history of lead exposure and use of herbal medical products; and renal ultrasonography.Diagnosis. Stage 3 chronic kidney disease that was probably worsened by consumption of lead in the form of an Ayurvedic herbal remedy.Management. Cessation of the herbal product, followed by lead-chelation therapy with calcium disodium ethylenediaminetetraacetic acid. The patients whole-body lead burden and blood lead level decreased to acceptable levels and his serum creatinine value was within the normal range at final follow-up.

Travel distance and home dialysis rates in the United States

♦ Introduction: Rural residence is associated with increased peritoneal dialysis (PD) utilization. The influence of travel distance on rates of home dialysis utilization has not been examined in the United States. The purpose of this study was to determine whether travel distances to the closest home and in-center hemodialysis (IHD) facilities are a barrier to home dialysis. ♦ Methods: This was a retrospective cohort study of patients aged ≥ 18 years initiating dialysis between 2005 and 2011. Unadjusted PD and home hemodialysis (HHD) rates were compared by travel distances to both the closest home dialysis and closest IHD facilities. Adjusted PD and HHD utilization rates were examined using multivariable logistic regression models. ♦ Results: There were 98,608 patients in the adjusted analyses. 55.5% of the dialysis facilities offered home dialysis. IHD, PD and HHD patients traveled median distances of 5.4, 3.5 and 6.6 miles respectively to their initial dialysis facilities. Unadjusted analyses showed an increase in PD rates and decrease in HHD rates with increased travel distances. Adjusted odds of PD and HHD were 1.6 and 1.2 respectively for a ten mile increase in distance to the closest home dialysis facility, while for distances to the closest IHD facility the odds ratios for both PD and HHD were 0.7 (all p < 0.01). ♦ Conclusions: In metropolitan areas, PD and HHD generally increased with increased travel distance to the closest home dialysis facility and decreased with greater distance to an IHD facility. Examination of travel distances to PD and HHD facilities separately may provide further insight on specific barriers to these modalities which can serve as targets for future studies examining expansion of home dialysis utilization.