Common blood laboratory values are associated with cognition among older inpatients referred for neuropsychological testing

Dysnatremia in Relation to Frailty and Age in Community-dwelling Adults in the National Health and Nutrition Examination Survey

Background

Frailty represents an age-related state of increased risk of adverse health outcomes, reflecting some combination of increased damage and compromised repair processes. Our objectives were to establish whether frailty is associated with dysnatremia (a deviation of serum sodium from normal values), to determine whether frailty explains the previously established association between age and dysnatremia and to assay the impact of each on mortality.

Methods

The relationship between age, frailty, and dysnatremia was investigated across the adult life course in 8,911 respondents from the 2003-2004 and 2005-2006 cross-sectional National Health and Nutrition Examination Survey, on whom both laboratory and mortality data were available. A frailty index (FI) was calculated for each respondent and related to dysnatremia (serum sodium values outside a 136-144 mmol/L reference range).

Results

Dysnatremia was significantly related to both age and frailty; as the degree of frailty increased, so did the proportion with dysnatremia, for example, from 4.1% in those with FI less than 0.10, to 12.4% in those with FI 0.40 or more; p less than .001. Adjusted for frailty, the relationship between age and dysnatremia was no longer significant. In the age- and sex-adjusted Cox models, both frailty (hazard ratio [HR]: 1.05; 95% confidence interval [CI]: 1.04-1.05 for every 0.01 increase in FI) and dysnatremia (HR: 1.85; 95% CI: 1.51-2.26) were significant predictors of mortality; when hyponatremia was separated from hypernatremia in the Cox models, hypernatremia wasn't significant, but only 41 participants were identified as hypernatremic.

Conclusion

Increasing frailty is associated with dysnatremia and confounds the association between age and dysnatremia.

Nutrition and Cognition in Older Adults With Heart Failure: A Systematic Review

Cognitive impairment is commonly observed in older adults with heart failure; nutrition is a possible contributing factor. The purpose of the current systematic review is to examine the relationship between nutrition and cognition in older adults with heart failure. A literature review was performed through August 2015 that examined published, peer-reviewed studies from PubMed, PsycINFO, CINAHL, and Web of Science. Four articles were selected for inclusion. Findings revealed that poorer nutritional habits were associated with poorer attention, executive functioning, and memory in older adults with heart failure. Nutritional biomarkers, including anemia, hyponatremia, hypokalemia, hyperglycemia, and hypoalbuminemia, were also associated with cognitive impairment. More research is needed to explore the relationship between nutrition and cognition in this population. Descriptive studies will inform scientists as they design and test nutritional interventions to optimize cognitive function in older adults with heart failure.

Severity of Type 2 Diabetes, Cognitive Function, and Self-Care

Type 2 diabetes mellitus (T2DM) is associated with poorer performance on certain measures of cognitive function. However, little is known about the associations among working memory (WM), executive function (EF), and self-care in those with severe T2DM. This investigation explored these relationships among 67 middle-aged and older individuals with T2DM (mean age of 62.9 years). Severity of T2DM was measured with a health status composite (HSC) score from the Diabetes Care Profile, the number of prescribed medications, and the number of comorbid conditions. Cognitive assessments included the Working Memory Index and the Executive Interview 25 (EXIT 25). Self-care was measured using the Self-Care Inventory-Revised (SCI-R) and hemoglobin A1c (HgbA1c). WM was significantly correlated with all measures of severity of T2DM (HSC, r = .542, p < . 01; number of comorbidities, r = -.476, p < .01; and number of prescription medications, r = -.344, p < .01). EF was significantly correlated with all measures of severity of T2DM (HSC, r = -.504, p < .01; number of comorbidities, r = .492, p < .01; and number of prescription medications, r = .326, p < .01). The self-care measure HgbA1c was significantly correlated with WM (r = -.352, p < .01) and EF (r = .510, p < .01). The EXIT 25 score fully mediated the relationship between severity of T2DM and self-care as measured by HgbA1c (β = .431, p < .001). These findings provide preliminary evidence for the associations among severity of T2DM, WM, EF, and self-care.

Contingent negative variation is associated with cognitive dysfunction and secondary progressive disease course in multiple sclerosis

BACKGROUND AND PURPOSE

The relationship between contingent negative variation (CNV), which is an event-related potential, and cognition in multiple sclerosis (MS) has not been examined previously. The primary objective of the present study was thus to determine the association between CNV and cognition in a sample of MS patients.

METHODS

The subjects of this study comprised 66 MS patients [50 with relapsing-remitting MS (RRMS) and 16 with secondary progressive MS (SPMS)] and 40 matched healthy volunteers. A neuropsychological battery was administered to all of the subjects; CNV recordings were made from the Cz, Fz, and Pz electrodes, and the amplitude and area under the curve (AUC) were measured at each electrode.

RESULTS

RRMS patients exhibited CNVs with lower amplitudes and smaller AUCs than the controls at Pz. SPMS patients exhibited CNVs with lower amplitudes and smaller AUCs than the controls, and CNVs with a smaller amplitude than the RRMS patients at both Cz and Pz. After correcting for multiple comparisons, a lower CNV amplitude at Pz was significantly associated with worse performance on measures of speed of information processing, verbal fluency, verbal learning, and verbal recall.

CONCLUSIONS

CNV may serve as a marker for disease progression and cognitive dysfunction in MS. Further studies with larger samples and wider electrode coverage are required to fully assess the value of CNV in these areas.

Interpreting routine biochemistry in those aged over 65 years: a time for change

In clinical practice, routine biochemistry tests are often performed for diagnostic or screening purposes. We reviewed papers that have reported reference values for people older than 65 years with or without overt health problems. Wider intervals have generally been reported for sodium, potassium, calcium and C-reactive protein (CRP) in the elderly. Higher levels of creatinine and lower levels of total cholesterol (TC) and serum albumin (SA) are observed with ageing. Elderly people have been found to be at greater risk for overt abnormalities in sodium, potassium, creatinine, TC, SA and CRP. The consequences of these abnormalities could be severe. For instance, even mild hyponatremia was associated with increased risk of mortality, disability and myocardial infarction. Mild hypernatremia was associated with severe disability. Mild increases in CRP levels were associated with an increased risk of sarcopenia, disability, cardiovascular disease and cognitive decline. Mild decreases in TC levels were associated with an increased risk of disability or mortality, and mild decreases in SA were associated with an increased risk of mortality, disability, sarcopenia and frailty. Nutritional factors could not wholly explain these effects. Modified biochemical reference values are required for elderly patients, as biochemical results can serve as markers of vulnerability to age-related diseases, linked to metabolism. Careful diagnosis and corrective interventions are needed for patients in this age group.