Dementia and cognitive impairment in ESRD: diagnostic and therapeutic strategies. Kidney Int. 2011;79:14-22. [PMID: 20861818 DOI: 10.1038/ki.2010.336]

Out of control: accelerated aging in uremia

Next to a high morbidity, patients with end-stage renal failure (ESRD) suffer from a complex spectrum of clinical manifestations. Both the phenotype of patients with ESRD as well as the pathophysiology of uremia show interesting parallels with the general aging process. Phenotypically, patients with ESRD have an increased susceptibility for both cardiovascular as well as infectious disease and show a reduction in functional capacity as well as muscular mass (sarcopenia), translating into a high prevalence of frailty also in younger patients. Pathophysiologically, the immune dysfunction, telomere attrition and the presence of low-grade inflammation in uremic patients also show parallels with the aging process. System models of aging, such as the homeodynamic model and reliability theory of Gavrilov may also have relevance for ESRD. The reduction in the redundancy of compensatory mechanisms and the multisystem impairment in ESRD explain the rapid loss of homeodynamic/homeostatic balance and the increased susceptibility to external stressors in these patients. System theories may also explain the relative lack of success of interventions focusing on single aspects of renal disease. The concept of accelerated aging, which also shares similarities with other organ diseases, may be of relevance both for a better understanding of the uremic process, as well as for the design of multidimensional interventions in ESRD patients, including an important role for early rehabilitation. Research into processes akin to both aging and uremia may result in novel therapeutic approaches.

Solid-organ transplantation in older adults: current status and future research

An increasing number of patients older than 65 years are referred for and have access to organ transplantation, and an increasing number of older adults are donating organs. Although short-term outcomes are similar in older versus younger transplant recipients, older donor or recipient age is associated with inferior long-term outcomes. However, age is often a proxy for other factors that might predict poor outcomes more strongly and better identify patients at risk for adverse events. Approaches to transplantation in older adults vary across programs, but despite recent gains in access and the increased use of marginal organs, older patients remain less likely than other groups to receive a transplant, and those who do are highly selected. Moreover, few studies have addressed geriatric issues in transplant patient selection or management, or the implications on health span and disability when patients age to late life with a transplanted organ. This paper summarizes a recent trans-disciplinary workshop held by ASP, in collaboration with NHLBI, NIA, NIAID, NIDDK and AGS, to address issues related to kidney, liver, lung, or heart transplantation in older adults and to propose a research agenda in these areas.

Nervous system autoantibodies and vitamin D receptor gene polymorphisms in hemodialysis patients

Cognitive deficits are prevalent in hemodialysis (HD) patients. Vitamin D deficiency and vitamin D receptor (VDR) gene single nucleotide polymorphism (SNPs) have been linked to both neurodegeneration (ND) and neuroprotection, respectively. Autoantibodies (Ab) to myelin basic protein (MBP), glial fibrillary acidic protein (GFAP), and neurofilament (NF) triplet proteins arise secondary to nervous system (NS) damage providing a means to assess neurological injury. Characterization of Ab biomarkers of NS damage in HD patients, their association with VDR SNPs, and nutritional vitamin D (NVD) therapy was performed. VDR genotypes, cytokines, and Ab biomarkers to NS proteins in HD subjects receiving ergocalciferol (n = 40) were compared with nonusers (n = 71). Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and immunoglobulin G (IgG) titers against NFs, GFAP, and MBP were measured by immunoassay. Subjects were genotyped for VDR SNPs BsmI (rs1544410) and FokI (rs2228570). Subjects (age 63.3 ± 16.1 years, 66% male) who were C allele carriers of BsmI had higher values of NF-68 antibody titers (p = 0.027). Ergocalciferol users (n = 40) compared with nonusers (n = 71) had lower Ab titers to NS proteins; however, only anti-NF-160 and anti-MBP titers were significantly (p < 0.05) higher. IgG against NS proteins in HD patients suggests neuronal and glial insult and a relationship with VDR alleles. NVD may provide some neuroprotection, indicated by anti-NF-160 and anti-MBP, which was markedly lowered in ergocalciferol patients. This preliminary study suggests that Ab detection may be useful in monitoring ND and the potential of NVD for neuroprotection in HD patients.

A simple prediction score for kidney disease in the Korean population

AIM

Screening algorithms for chronic kidney disease have been developed and validated in American populations. Given the worldwide burden of kidney disease, developing algorithms for populations outside the USA is needed.

METHODS

Using simple, non-invasive questions, we developed a prediction model for chronic kidney disease from national population samples in Korea. The Korean National Health and Nutrition Examination Survey (n = 6565) was used for model development while validation was performed in two independent population samples, internal (n = 2921) and external datasets (n = 8166). Chronic kidney disease was defined as glomerular filtration rate < 60 mL/min per 1.73 m(2).

RESULTS

Seven factors - age, female gender, anaemia, hypertension, diabetes mellitus, cardiovascular disease and proteinuria - were significantly associated with prevalent chronic kidney disease. Integer scores were assigned to variables based on the magnitude of associations: 2 for age 50-59 years, 3 for age 60-69 years and 4 for age 70 years or older, and 1 for female gender, anaemia, hypertension, diabetes, proteinuria and cardiovascular dis ase. Based on the Youden index, a value of 4 or greater defined a high risk population with sensitivity 89%, specificity 71%, and positive predictive value 19%, and negative predictive value 99%. The area under the curve was 0.83 for the development set, and 0.87 and 0.78 in the two validation datasets.

CONCLUSION

This prediction algorithm, weighted towards common non-invasive variables, had good performance characteristics in an Asian population, and provides new evidence of the similarity of the algorithms for Western and Eastern populations.

Advance care planning in CKD/ESRD: an evolving process

Advance care planning was historically considered to be simply the completion of a proxy (health care surrogate designation) or instruction (living will) directive that resulted from a conversation between a patient and his or her physician. We now know that advance care planning is a much more comprehensive and dynamic patient-centered process used by patients and families to strengthen relationships, achieve control over medical care, prepare for death, and clarify goals of care. Some advance directives, notably designated health care proxy documents, remain appropriate expressions of advance care planning. Moreover, although physician orders, such as do-not-resuscitate orders and Physician Orders for Life-Sustaining Treatment, may not be strictly defined as advance directives, their completion, when appropriate, is an integral component of advance care planning. The changing health circumstances and illness trajectory characteristic of ESRD mandate that advance care planning discussions adapt to a patient's situation and therefore must be readdressed at appropriate times and intervals. The options of withholding and withdrawing dialysis add ESRD-specific issues to advance care planning in this population and are events each nephrologist will at some time confront. Advance care planning is important throughout the spectrum of ESRD and is a part of nephrology practice that can be rewarding to nephrologists and beneficial to patients and their families.

The kidney disease quality of life cognitive function subscale and cognitive performance in maintenance hemodialysis patients

BACKGROUND

Cognitive impairment is common but often undiagnosed in patients with end-stage renal disease, in part reflecting limited validated and easily administered tools to assess cognitive function in dialysis patients. Accordingly, we assessed the utility of the Kidney Disease Quality of Life Cognitive Function (KDQOL-CF) scale in comparison to an extensive neuropsychological battery, building on a prior assessment of this potential cognitive screen.

STUDY DESIGN

Cross-sectional cohort.

SETTING & PARTICIPANTS

Maintenance hemodialysis patients at 6 Boston area dialysis units were administered an extensive neurocognitive battery and the KDQOL-CF at the beginning of a hemodialysis session.

PREDICTORS

KDQOL-CF score, depression symptom burden, and demographic and clinical characteristics.

OUTCOMES

Neurocognitive performance classified into executive function and memory domains, determined using principal components analysis.

MEASUREMENTS

Univariate and multivariable linear regression models adjusting for age, sex, race, and end-stage renal disease cause were used to evaluate the association between KDQOL-CF score and cognitive performance, and test metrics were determined for a KDQOL-CF cutoff score of 60 or less from a maximum score of 100.

RESULTS

For 168 prevalent hemodialysis patients, KDQOL-CF score was 76 ± 19 and 40 (24%) had scores of 60 or less, consistent with self-identified worse cognitive performance. There was no significant correlation between KDQOL-CF score and either memory (P = 0.2 and P = 0.3) or executive function (P = 0.1 and P = 0.4) in univariate and multivariable models, respectively. There was a strong correlation between higher KDQOL-CF score and fewer depression symptoms (P < 0.001). Sensitivity of the KDQOL-CF was poor (range, 0.28-0.36), with modest specificity (range, 0.77-0.81) for identifying worse executive function and memory.

LIMITATIONS

Cross-sectional study, modest population size, and abbreviated gold-standard cognitive battery.

CONCLUSIONS

The KDQOL-CF is a poor determinant of neurocognitive performance in hemodialysis patients, with limited sensitivity. To assess cognitive impairment in hemodialysis patients, better screening tests are essential.

[Benefits and risks of current pharmacotherapy in the treatment of type 2 diabetes]

The development of new drugs for the treatment of type 2 diabetes (T2DM) and metabolic disorders is currently one of the most innovative areas of drug development. However, a considerable number of newly developed drugs have either not reached the market and were stopped late in development or have been withdrawn after initial approval soon after market authorization due to serious safety concerns. How can drug safety problems be anticipated and, even more important, how can adverse events definitely caused by a drug be differentiated from incidences of naturally occurring diseases? This review article will provide an update about the state of the art treatment of type 2 diabetes and reflect on the newest available study evidence on glitazones, incretin mimetics (GLP-1 agonists and DPP-4 inhibitors), SGLT-2 inhibitors (gliflocines) and pan-PPAR agonists (glitazars). Furthermore, new and still experimental approaches for the treatment of T2DM, such as bardoxolone, salsalate and anakinra will be briefly reviewed.

Managing older adults with CKD: individualized versus disease-based approaches

The last decade has seen the evolution and ongoing refinement of a disease-oriented approach to chronic kidney disease (CKD). Disease-oriented models of care assume a direct causal association between observed signs and symptoms and underlying disease pathophysiologic processes. Treatment plans target underlying disease mechanisms with the goal of improving disease-related outcomes. Because average glomerular filtrate rates tend to decrease with age, CKD becomes increasingly prevalent with advancing age and those who meet criteria for CKD are disproportionately elderly. However, several features of geriatric populations may limit the utility of disease-oriented models of care. In older adults, complex comorbid conditions and geriatric syndromes are common; signs and symptoms often do not reflect a single underlying pathophysiologic process; there can be substantial heterogeneity in life expectancy, functional status, and health priorities; and information about the safety and efficacy of recommended interventions often is lacking. For all these reasons, geriatricians have tended to favor an individualized patient-centered model of care over more traditional disease-based approaches. An individualized approach prioritizes patient preferences and embraces the notion that observed signs and symptoms often do not reflect a single unifying disease process and instead reflect the complex interplay between many different factors. This approach emphasizes modifiable outcomes that matter to the patient. Prognostic information related to these and other outcomes generally is used to shape rather than dictate treatment decisions. We argue that an individualized patient-centered approach to care may have more to offer than a traditional disease-based approach to CKD in many older adults.

Albuminuria, kidney function, and the incidence of cognitive impairment among adults in the United States

BACKGROUND

Albuminuria and estimated glomerular filtration rate (eGFR) are each associated with increased risk of cognitive impairment, but their joint association is unknown.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

A US national sample of 19,399 adults without cognitive impairment at baseline participating in the REGARDS (Reasons for Geographic and Racial Disparities in Stroke) Study.

PREDICTORS

Albuminuria was assessed using urine albumin-creatinine ratio (UACR) and GFR was estimated using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation.

OUTCOMES

Incident cognitive impairment was defined as score ≤4 on the 6-Item Screener at the last follow-up visit.

RESULTS

During a mean follow-up of 3.8 ± 1.5 years, UACRs of 30-299 and ≥300 mg/g were associated independently with 31% and 57% higher risk of cognitive impairment, respectively, relative to individuals with UACR <10 mg/g. This finding was strongest for those with high eGFRs and attenuated at lower levels (P = 0.04 for trend). Relative to eGFR ≥60 mL/min/1.73 m(2), eGFR <60 mL/min/1.73 m(2) was not associated independently with cognitive impairment. However, after stratifying by UACR, eGFR <60 mL/min/1.73 m(2) was associated with a 30% higher risk of cognitive impairment in participants with UACR <10 mg/g, but not higher UACRs (P = 0.04 for trend).

LIMITATIONS

Single measures of albuminuria and eGFR, screening test of cognition.

CONCLUSIONS

When eGFR was preserved, albuminuria was associated independently with incident cognitive impairment. When albuminuria was <10 mg/g, low eGFR was associated independently with cognitive impairment. Albuminuria and low eGFR are complementary, but not additive, risk factors for incident cognitive impairment.