Measuring Nutritional Status, Hydration and Body Composition Changes in Acute Stroke

Background: Dysphagia and cognitive problems, both common after stoke, may affect dietary intake increasing the risk of malnutrition. Malnutrition has adverse effects on body composition especially in conditions that escalate the stress response in the body and may be associated with immobility such as stroke. Study objective: The objective of my study was to understand the prognosis of malnutrition on post cardiovascular disease (CV) outcomes, understand body composition changes after stroke assessed using multi-frequency bioelectrical impedance analysis (MF-BIA) methods, examine the utility of MF-BIA in diagnosing dehydration in stroke patients, and validate MF-BIA selected body composition estimates against the reference method Dual X-ray absorptiometry (DEXA). Methodology: To understand the prognosis of malnutrition on post CVD outcomes I carried out a systematic review and meta-analysis examining the association between selected markers of malnutrition on outcomes. The systematic review is presented in Chapter 2 of this thesis. Chapter 3 presents an observational longitudinal study that describes body composition changes after ischaemic stroke and their prognosis on outcomes. Ischaemic stroke patients admitted to an acute unit were prospectively recruited between January-July 2011. Body composition variables (BioScan 920-2, Maltron International Ltd, Essex, United Kingdom) were measured on admission and discharge. Results were descriptively presented stratified by type of feeding regimen, type of stroke and stroke severity. Validated follow up questionnaire were sent to participants by post to understand body composition changes association with their health and quality of life. In chapter 4 the diagnostic accuracy of MF-BIA BioScan 920-2 in diagnosing dehydration after stroke was examined for several diagnostic cut offs of current and impending dehydration. In chapter 5 external validation of MF-BIA BioScan 920-2 fat free mass and fat mass estimates against reference method DEXA was examined using ten participants data. Bland and Altman analysis for understanding the agreement between two methods of clinical measurement was carried out. Results: Undernutrition (assessed using nutrition assessment tools) were associated with mortality post cardiovascular event. Other findings are presented in Chapter 2. Fat free mass loss, and fat mass gain, protein mass loss, muscle mass loss, and body cell mass loss were observed in patients on modified diet (soft/mashed diet, pureed diet, nilby- mouth feeding regimen). Sample size was small to generalize a conclusion on the association between body composition changes in acute stay and outcomes. MF-BIA BioScan 920-2 did not show diagnostic accuracy in diagnosing dehydration in stroke patients. MF-BIA BioScan 920-2 fat free mass and fat mass estimates were in agreement with their corresponding estimate from the reference methods DEXA. Conclusion: My study was novel as it provided new information with regard to body composition changes in acute stroke while utilizing new validated equipment in estimating body composition component of fat free mass and fat mass. My study also aimed to investigate new non-invasive methods to diagnose dehydration in stroke patients. It contributed new knowledge that can be useful in future research, sample size calculation, and can help researchers in the field to determine minimally clinically significant differences for similar research and targeted intervention clinical trials

Body Mass Index and Mortality, Recurrence and Readmission after Myocardial Infarction : Systematic Review and Meta-analysis

Acknowledgments: The authors thank the contribution of Lee Hooper, University of East Anglia, who has provided supervision of Kafri’s work which contributed to this paper. Funding: This research received no external funding.Peer reviewedPublisher PD

Bioelectrical Impedance Versus Biochemical Analysis of Hydration Status: Predictive Value for Prolonged Hospitalisation and Poor Discharge Destination for Older Patients

Dehydration is prevalent in hospitalised patients and is associated with increased morbidity and mortality, particularly among the elderly (≥65 years). We aimed at comparing the performance of intracellular water to extracellular water ratio (ICW/ECW), calculated through a bioelectrical impedance analysis (BIA) of blood urea nitrogen, with the creatinine ratio (BUN/Cr) to predict poor outcomes in a cohort of prospectively identified patients. Data were combined from a cohort of elderly patients (≥65 years) admitted to hospital with fragility fracture (n = 125) and older adults aged ≥50 years admitted to hospital with stroke (n = 40). The association between hydration status and study outcomes (unfavourable discharge destination (rehabilitation, another ward, or death) and prolonged hospitalisation (>10 days)) was examined using logistic regression. The overall diagnostic accuracy of each hydration status measurement was assessed using the area under the receiver operating characteristic (ROC) curve. In 165 participants (mean age (SD) of 76.7 (9.2) years), an ICW/ECW ratio below the 25th percentile was associated with increased odds of poor discharge destination (OR (95% CI) = 4.25 (1.59–11.34)). Neither the relationship between the BUN/Cr ratio and prolonged stay nor discharge destination was significant. A BIA could be used utilised in conjunction with biochemical measurements to inform patient prognosis

The relationship between nutritional status at the time of stroke on adverse outcomes: a systematic review and meta-analysis of prospective cohort studies

Context and Objective: The impact of existing malnutrition on stroke outcomes is poorly recognised and treated. Evidence was systematically reviewed and quantified by meta-analysis. Methods: MEDLINE, EMBASE and Web of Science were searched from inception to 11 January 2021 and updated in July. Prospective cohort studies, in English, evaluating anthropometric and biomarkers of nutrition on stroke outcomes were included. Risk of bias was assessed using the Scottish Intercollegiate Guidelines Network checklist. Results: Twenty-six studies (n = 156 249) were eligible (follow-up: One month-14 years). Underweight patients had increased risk of long-term mortality (adjusted hazard ratio = 1.65,1.41-1.95), whilst overweight (0.80,0.74-0.86) and obese patients (0.80,0.75-0.85) had decreased risk compared to normal weight. Odds of mortality decreased in those with high serum albumin (odds ratio = 0.29,0.18-0.48) and increased with low serum albumin (odds ratio = 3.46,1.78-6.74) compared to normal serum albumin (30-35 g/L). Being malnourished compared to well-nourished, as assessed by the Subjective Global Assessment (SGA) or by a combination of anthropometric and biochemical markers increased all-cause mortality (odds ratio = 2.38,1.85-3.06) and poor functional status (adjusted odds ratio = 2.21,1.40-3.49). Conclusion: Nutritional status at the time of stroke predicts adverse stroke outcomes

Clinical symptoms, signs and tests for identification of impending and current water-loss dehydration in older people (Review)

BackgroundThere is evidence that water-loss dehydration is common in older people and associated with many causes of morbidity and mortality.However, it is unclear what clinical symptoms, signs and tests may be used to identify early dehydration in older people, so that support can be mobilised to improve hydration before health and well-being are compromised.ObjectivesTo determine the diagnostic accuracy of state (one time), minimally invasive clinical symptoms, signs and tests to be used as screeningtests for detecting water-loss dehydration in older people by systematically reviewing studies that have measured a reference standard and at least one index test in people aged 65 years and over. Water-loss dehydration was defined primarily as including everyone with either impending or current water-loss dehydration (including all those with serum osmolality ≥ 295 mOsm/kg as being dehydrated).Search methodsStructured search strategies were developed for MEDLINE (OvidSP), EMBASE (OvidSP), CINAHL, LILACS, DARE and HTAdatabases (The Cochrane Library), and the International Clinical Trials Registry Platform (ICTRP). Reference lists of included studiesand identified relevant reviews were checked. Authors of included studies were contacted for details of further studies.Selection criteriaTitles and abstracts were scanned and all potentially relevant studies obtained in full text. Inclusion of full text studies was assessed independently in duplicate, and disagreements resolved by a third author. We wrote to authors of all studies that appeared to have collected data on at least one reference standard and at least one index test, and in at least 10 people aged ≥ 65 years, even where no comparative analysis has been published, requesting original dataset so we could create 2 x 2 tables.Data collection and analysis.Diagnostic accuracy of each test was assessed against the best available reference standard for water-loss dehydration (serum or plasma osmolality cut-off≥295mOsm/kg, serumosmolarity or weight change) within each study. For each index test study data were presented in forest plots of sensitivity and specificity. The primary target condition was water-loss dehydration (including either impending or current water-loss dehydration). Secondary target conditions were intended as current (> 300 mOsm/kg) and impending (295 to 300 mOsm/kg) water-loss dehydration, but restricted to current dehydration in the final review.We conducted bivariate random-effects meta-analyses (Stata/IC, StataCorp) for index tests where there were at least four studies and study datasets could be pooled to construct sensitivity and specificity summary estimates. We assigned the same approach for index tests with continuous outcome data for each of three pre-specified cut-off points investigated.Pre-set minimum sensitivity of a useful test was 60%, minimum specificity 75%. As pre-specifying three cut-offs for each continuoustest may have led to missing a cut-off with useful sensitivity and specificity, we conducted post-hoc exploratory analyses to createreceiver operating characteristic (ROC) curves where there appeared some possibility of a useful cut-off missed by the original three.These analyses enabled assessment of which tests may be worth assessing in further research. A further exploratory analysis assessed the value of combining the best two index tests where each had some individual predictive ability.Main resultsThere were few published studies of the diagnostic accuracy of state (one time), minimally invasive clinical symptoms, signs or tests tobe used as screening tests for detecting water-loss dehydration in older people. Therefore, to complete this review we sought, analysed and included raw datasets that included a reference standard and an index test in people aged ≥ 65 years.We included three studies with published diagnostic accuracy data and a further 21 studies provided datasets that we analysed. Weassessed 67 tests (at three cut-offs for each continuous outcome) for diagnostic accuracy of water-loss dehydration (primary targetcondition) and of current dehydration (secondary target condition).Only three tests showed any ability to diagnose water-loss dehydration (including both impending and current water-loss dehydration) as stand-alone tests: expressing fatigue (sensitivity 0.71 (95% CI 0.29 to 0.96), specificity 0.75 (95% CI 0.63 to 0.85), in one study with 71 participants, but two additional studies had lower sensitivity); missing drinks between meals (sensitivity 1.00 (95% CI 0.59 to 1.00), specificity 0.77 (95% CI 0.64 to 0.86), in one study with 71 participants) and BIA resistance at 50 kHz (sensitivities 1.00 (95% CI 0.48 to 1.00) and 0.71 (95% CI 0.44 to 0.90) and specificities of 1.00 (95% CI 0.69 to 1.00) and 0.80 (95% CI 0.28 to 0.99) in 15 and 22 people respectively for two studies, but with sensitivities of 0.54 (95% CI 0.25 to 0.81) and 0.69 (95% CI 0.56 to 0.79) and specificities of 0.50 (95% CI 0.16 to 0.84) and 0.19 (95% CI 0.17 to 0.21) in 21 and 1947 people respectively in two other studies). In post-hoc ROC plots drinks intake, urine osmolality and axillial moisture also showed limited diagnostic accuracy. No test was consistently useful in more than one study.Combining two tests so that an individual both missed some drinks between meals and expressed fatigue was sensitive at 0.71 (95%CI 0.29 to 0.96) and specific at 0.92 (95% CI 0.83 to 0.97).There was sufficient evidence to suggest that several stand-alone tests often used to assess dehydration in older people (including fluid intake, urine specific gravity, urine colour, urine volume, heart rate, dry mouth, feeling thirsty and BIA assessment of intracellular water or extracellular water) are not useful, and should not be relied on individually as ways of assessing presence or absence of dehydration in older people.No tests were found consistently useful in diagnosing current water-loss dehydration.Authors’ conclusionsThere is limited evidence of the diagnostic utility of any individual clinical symptom, sign or test or combination of tests to indicatewater-loss dehydration in older people. Individual tests should not be used in this population to indicate dehydration; they miss a highproportion of people with dehydration, and wrongly label those who are adequately hydrated.Promising tests identified by this review need to be further assessed, as do new methods in development. Combining several tests may improve diagnostic accuracy

Clinical and physical signs for identification of impending and current water-loss dehydration in older people

This is the protocol for a review and there is no abstract. The objectives are as follows:.To determine the diagnostic accuracy of state, minimally invasive clinical and physical signs (or sets of signs) to be used as screening tests for detecting impending or current water-loss dehydration, or both, in older people by systematically reviewing studies that have measured a reference standard and at least one index test in people aged 65 years and over..To assess the effect of different cut offs of index test results assessed using continuous data on sensitivity and specificity in diagnosis of impending or current water-loss dehydration..To identify clinical and physical signs that may be used in screening for impending or current water-loss dehydration in older people..To identify clinical and physical signs that are not useful in screening for impending or current water-loss dehydration in older people..To directly compare promising index tests (sensitivity ? 0.60 and specificity ? 0.75) where two or more are measured in a single study (direct comparison)..To carry out an exploratory analysis to assess the value of combining the best three index tests where the three tests each have some predictive ability of their own, and individual studies include participants who had all three tests.We will explore sources of heterogeneity of diagnostic accuracy of individual clinical and physical signs that show some evidence of discrimination by the reference standard used, cut off value for tests providing continuous data, type of participants (community-dwelling older people, those in residential care, and those in hospital), sex, and baseline prevalence of dehydration.5. To carry out an exploratory analysis to assess the value of combining the best three index tests where the three tests each have some predictive ability of their own, and individual studies include participants who had all three tests.We will explore sources of heterogeneity of diagnostic accuracy of individual clinical and physical signs that show some evidence ofdiscrimination by the reference standard used, cut off value for tests providing continuous data, type of participants (communitydwellingolder people, those in residential care, and those in hospital), sex, and baseline prevalence of dehydration