Bernard G. Jaar

Frailty and Cognitive Function in Incident Hemodialysis Patients

BACKGROUND AND OBJECTIVES Patients of all ages undergoing hemodialysis (HD) have a high prevalence of cognitive impairment and worse cognitive function than healthy controls, and those with dementia are at high risk of death. Frailty has been associated with poor cognitive function in older adults without kidney disease. We hypothesized that frailty might also be associated with poor cognitive function in adults of all ages undergoing HD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS At HD initiation, 324 adults enrolled (November 2008 to July 2012) in a longitudinal cohort study (Predictors of Arrhythmic and Cardiovascular Risk in ESRD) were classified into three groups (frail, intermediately frail, and nonfrail) based on the Fried frailty phenotype. Global cognitive function (3MS) and speed/attention (Trail Making Tests A and B [TMTA and TMTB, respectively]) were assessed at cohort entry and 1-year follow-up. Associations between frailty and cognitive function (at cohort entry and 1-year follow-up) were evaluated in adjusted (for sex, age, race, body mass index, education, depression and comorbidity at baseline) linear (3MS, TMTA) and Tobit (TMTB) regression models. RESULTS At cohort entry, the mean age was 54.8 years (SD 13.3), 56.5% were men, and 72.8% were black. The prevalence of frailty and intermediate frailty were 34.0% and 37.7%, respectively. The mean 3MS was 89.8 (SD 7.6), TMTA was 55.4 (SD 29), and TMTB was 161 (SD 83). Frailty was independently associated with lower cognitive function at cohort entry for all three measures (3MS: -2.4 points; 95% confidence interval [95% CI], -4.2 to -0.5; P=0.01; TMTA: 12.1 seconds; 95% CI, 4.7 to 19.4; P<0.001; and TMTB: 33.2 seconds; 95% CI, 9.9 to 56.4; P=0.01; all tests for trend, P<0.001) and with worse 3MS at 1-year follow-up (-2.8 points; 95% CI, -5.4 to -0.2; P=0.03). CONCLUSIONS In adult incident HD patients, frailty is associated with worse cognitive function, particularly global cognitive function (3MS).

Associations of low-level urine cadmium with kidney function in lead workers

Objectives Low-level cadmium exposure, resulting in, for example, urinary cadmium <2.0 μg/g creatinine, is widespread; recent data suggest nephrotoxicity even at these low levels. Few studies have examined the impact of low-level cadmium exposure in workers who are occupationally exposed to other nephrotoxicants such as lead. Methods We evaluated associations of urine cadmium, a measure of cumulative dose, with four glomerular filtration measures and N-acetyl-β-D-glucosaminidase (NAG) in lead workers. Recent and cumulative lead doses were assessed via blood and tibia lead, respectively. Results In 712 lead workers, mean (SD) blood and tibia lead values, urine cadmium values and estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease equation were 23.1 (14.1) μg/dl, 26.6 (28.9) μg Pb/g bone mineral, 1.15 (0.66) μg/g creatinine and 97.4 (19.2) ml/min/1.73 m2, respectively. After adjustment for age, sex, body mass index, urine creatinine, smoking, alcohol, education, annual income, diastolic blood pressure, current or former lead worker job status, new or returning study participant, and blood and tibia lead, higher ln-urine cadmium was associated with higher calculated creatinine clearance, eGFR (β=8.7 ml/min/1.73 m2; 95% CI 5.4 to 12.1) and ln-NAG but lower serum creatinine. Conclusions Potential explanations for these results include a normal physiological response in which urine cadmium levels reflect renal filtration, the impact of adjustment for urine dilution with creatinine in models of kidney outcomes, and cadmium-related hyperfiltration.

Clinical Testing Patterns and Cost Implications of Variation in the Evaluation of CKD Among US Physicians

BACKGROUND Clinical practice guidelines were established to improve the diagnosis and management of chronic kidney disease (CKD), but the extent, determinants, and cost implications of guideline adherence and variation in adherence have not been evaluated. STUDY DESIGN Cross-sectional survey. SETTINGS & PARTICIPANTS The questionnaire was sent (on paper or through the internet) to a nationally representative sample of 1,200 US primary care physicians and nephrologists. PREDICTOR Provider and patient characteristics. OUTCOMES & MEASUREMENTS Guideline adherence was assessed as present if physicians recommended at least 5 of 6 clinical tests prescribed by the National Kidney Foundations Kidney Disease Outcomes and Quality Initiative guidelines for a hypothetical patient with newly identified CKD. We also assessed patterns and costs of additional nonrecommended tests for the initial clinical evaluation of CKD. RESULTS Of the 301 (86 family medicine, 89 internal medicine, and 126 nephrology) eligible physicians who responded to the survey (response rate, 32%), most practiced longer than 10 years (54%), were in nonacademic practices (76%), spent greater than 80% of their time performing clinical duties (77%), and correctly estimated kidney function (73%). Overall, 35% of participants were guideline adherent. Compared with nephrologists, internal medicine and family physicians had lower odds of adherence for all recommended testing (odds ratio, 0.6; 95% confidence interval, 0.3 to 1.1; and odds ratio, 0.3; 95% confidence interval, 0.1 to 0.6, respectively). Participants practicing longer than 10 years had lower odds of ordering all recommended testing compared with participants practicing fewer than 10 years (odds ratio, 0.5; 95% confidence interval, 0.3 to 0.9). Eighty-five percent of participants recommended additional tests, which resulted in a 23% increased total per-patient cost of the clinical evaluation. LIMITATIONS Recommendations for a hypothetical case scenario may differ from those of actual patients. CONCLUSIONS Adherence to recommended clinical testing for the diagnosis and management of CKD was poor, and additional testing was associated with substantially increased cost of the clinical evaluation. Improved clarity, dissemination, and uptake of existing guidelines are needed to improve quality and decrease costs of care for patients with CKD.

Health-Related and Psychosocial Concerns about Transplantation among Patients Initiating Dialysis

BACKGROUND AND OBJECTIVES Disparities in kidney transplantation remain; one mechanism for disparities in access to transplantation (ATT) may be patient-perceived concerns about pursuing transplantation. This study sought to characterize prevalence of patient-perceived concerns, explore interrelationships between concerns, determine patient characteristics associated with concerns, and assess the effect of concerns on ATT. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Prevalences of 12 patient-perceived concerns about pursuing transplantation were determined among 348 adults who recently initiated dialysis, recruited from 26 free-standing dialysis centers around Baltimore, Maryland (January 2009-March 2012). Using variable reduction techniques, concerns were clustered into two categories (health-related and psychosocial) and quantified with scale scores. Associations between patient characteristics and concerns were estimated using modified Poisson regression. Associations between concerns and ATT were estimated using Cox models. RESULTS The most frequently cited patient-perceived concerns were that participants felt they were doing fine on dialysis (68.4%) and felt uncomfortable asking someone to donate a kidney (29.9%). Older age was independently associated with having high health-related (adjusted relative risk, 1.35 [95% confidence interval, 1.20 to 1.51], for every 5 years older for those ≥ 60 years) or psychosocial (1.15 [1.00 to 1.31], for every 5 years older for those aged ≥ 60 years) concerns, as was being a woman (1.72 [1.21 to 2.43] and 1.55 [1.09 to 2.20]), having less education (1.59 [1.08 to 2.35] and 1.77 [1.17 to 2.68], comparing postsecondary education to grade school or less), and having more comorbidities (1.18 [1.08 to 1.30] and 1.18 [1.07 to 1.29], per one comorbidity increase). Having never seen a nephrologist before dialysis initiation was associated with high psychosocial concerns (1.48 [1.01 to 2.18]). Those with high health-related (0.37 [0.16 to 0.87]) or psychosocial (0.47 [0.23 to 0.95]) concerns were less likely to achieve ATT (median follow-up time 2.2 years; interquartile range, 1.6-3.2). CONCLUSIONS Patient-perceived concerns about pursuing kidney transplantation are highly prevalent, particularly among older adults and women. Reducing these concerns may help decrease disparities in ATT.

Association of Clinic Vascular Access Monitoring Practices with Clinical Outcomes in Hemodialysis Patients

Background: Early identification of access dysfunctions may be associated with improved patient outcomes. We examined whether patient outcomes were associated with vascular access monitoring practices in an incident dialysis cohort. Methods: We conducted a national prospective cohort study and analyzed 363 hemodialysis patients who had a first permanent vascular access (arteriovenous fistula or graft) by 6 months after the start of dialysis. Multivariate methods were used to examine associations between monitoring practices and 6-month Kt/V (reaching Kt/V ≧1.2), access intervention, access failure, and 2-year septicemia and all-cause hospitalization and mortality. Results: Patients who received monitoring weekly or more often (49%) were more likely to have an access intervention (adjusted RH = 1.40, 95% CI, 1.07–1.84) than those who received monitoring less frequently. Additionally, patients treated at clinics that reported performing regular access monitoring (80% of patients) were less likely to be hospitalized for septicemia (IRR = 0.35, 95% CI, 0.21–0.61) or for any cause (IRR = 0.77, 95% CI, 0.60–0.99). There were no statistically significant differences between patients exposed to different vascular access monitoring practices in access failure, achievement of Kt/V, or survival. Conclusion: Frequent monitoring of dialysis access may initially increase the number of interventions but is beneficial to longer-term outcomes, including septicemia-related and all-cause hospitalization.

Racial differences in chronic kidney disease incidence and progression among individuals with HIV.

This Practice Point commentary discusses the findings of Lucas et al.s longitudinal cohort study of chronic kidney disease (CKD) in African American and white individuals with HIV. The study found that—compared with whites—African Americans had a slightly increased risk of incident CKD, but markedly increased rates of estimated glomerular filtration rate decline and progression to end-stage renal disease. This commentary details the clinical implications and limitations of these findings in the context of known racial differences in CKD prevalence and progression to end-stage renal disease in the general population and highlights the importance of screening high-risk HIV patients for kidney disease. CKD is common among HIV patients, and—as in the general population—has a more-aggressive course among African Americans than whites.