Disease severity accounts for minimal variance of quality of life in people with dementia and their carers: analyses of cross-sectional data from the MODEM study

Background Due to the progressive nature of dementia, it is important to understand links between disease severity and health-related outcomes. The aim of this study is to explore the relationship between disease severity and the quality of life (QoL) of people with dementia and their family carers using a number of disease-specific and generic measures. Methods In the MODEM cohort study, three-hundred and seven people with clinically diagnosed dementia and their carers were recruited on a quota basis to provide equal numbers of people with mild (standardised Mini-Mental State Examination (sMMSE), n = 110), moderate (sMMSE 10–19, n = 100), and severe (sMMSE 0–9, n = 97) cognitive impairment. A series of multiple regression models were created to understand the associations between dementia severity and the QoL of people with dementia and the QoL of their carers. QoL was measured using self- (DEMQOL, EQ-5D, CASP-19) and proxy-reports (DEMQOL-Proxy, EQ-5D) of disease-specific and generic QoL of the person with dementia. Carer generic QoL was measured by self-report (EQ-5D, SF-12). Results Disease severity, as measured by the sMMSE, was not significantly associated with the QoL of the person with dementia or the carer (p > 0.05), even after controlling for potential confounding variables for self-reported instruments. Proxy measures (rated by the carer) differed systematically in that there were small, but statistically significant proportions of the variance of QoL was explained by severity of cognitive impairment in multiple adjusted models. We also found little in the way of statistically significant relationships between the QoL of people with dementia and that of their carers except between DEMQOL-Proxy scores and the carer EQ-5D scores and carer SF-12 mental sub-scores. Conclusions The data generated supports the somewhat counterintuitive argument that severity of cognitive impairment (and therefore severity of dementia) is not associated with lower QoL for the person with dementia when self-report measures are used. However, in absolute terms, as judged by the variance in the multivariate models, it is clear that the contribution of dementia severity to the QoL of people with dementia is minimal whatever the measurement used, be it self- or proxy-rated, or disease-specific or generic

Factors associated with change over time in quality of life of people with dementia: longitudinal analyses from the MODEM cohort study

Background: Research to date offers mixed evidence about the relationship between quality of life and severity of cognitive impairment in people with dementia. We aimed to investigate longitudinal changes in patient- and proxy-rated health-related quality of life (HRQL) by severity of dementia and explore factors associated with changes in HRQL over a one-year period. We used data from the MODEM longitudinal cohort study which recruited dyads of persons with clinically diagnosed dementia and their principal carer and interviewed them face-to-face at baseline and again 1 year later. Methods: Quota sampling was used to generate balanced numbers (target n = 100 for each severity level) of people with mild cognitive impairment (20+ on the standardised Mini-Mental State Examination (sMMSE)), moderate cognitive impairment (score 10 to 19), and severe cognitive impairment (score 0 to 9). Persons with dementia without an identifiable family carer or other informant (e.g., a formal/professional/paid carer) were excluded from the study. Participants answered a series of questions measuring their HRQL: DEMQOL, DEMQOL-proxy, EQ-5D-3 L, EQ-5D-3L proxy. Multiple regression models were built to understand the effects of baseline demographics and dementia symptoms (cognitive impairment, neuropsychiatric symptoms) on change in HRQL over 1 year. Results: Two hundred and forty-three dyads of people with clinically diagnosed dementia and carers completed baseline and follow-up interviews. Most measures of HRQL remaining relatively stable between time-points, but one index of HRQL, EQ-5D proxy, significantly declined. Depending on the HRQL measure, different factors were associated with change in HRQL. The only factor consistently associated with decline in HRQL (when compared to improvement) was having a diagnosis of a non-Alzheimer’s dementia. Conclusions: Deterioration in HRQL is not an inevitable part of the dementia journey. However, people with non-Alzheimer’s dementias may be more susceptible to HRQL decline. This may indicate that those with non-Alzheimer’s dementia may benefit from specific support focussed on maintaining their quality of life

Swimming performance of hatchling green turtles is affected by incubation temperature

In an experiment repeated for two separate years, incubation temperature was found to affect the body size and swimming performance of hatchling green turtles (Chelonia mydas). In the first year, hatchlings from eggs incubated at 26 degrees C were larger in size than hatchlings from 28 and 30 degrees C, whilst in the second year hatchlings from 25.5 degrees C were similar in size to hatchings from 30 degrees C. Clutch of origin influenced the size of hatchlings at all incubation temperatures even when differences in egg size were taken into account. In laboratory measurements of swimming performance, in seawater at 28 degrees C, hatchlings from eggs incubated at 25.5 and 26 degrees C had a lower stroke rate frequency and lower force output than hatchlings from 28 and 30 degrees C. These differences appeared to be caused by the muscles of hatchlings from cooler temperatures fatiguing at a faster rate. Clutch of origin did not influence swimming performance. This finding that hatchling males incubated at lower temperature had reduced swimming ability may affect their survival whilst running the gauntlet of predators in shallow near-shore waters, prior to reaching the relative safety of the open sea