Effects of disturbance on the diversity of hard-bottom macrobenthic communities on the coast of Chile

The intermediate disturbance hypothesis (IDH) predicts maximal diversity at intermediate levels of disturbance, but the validity of this hypothesis is controversially discussed. In this study, results of a field experiment, which was conducted on the northern-central Chilean coast, are presented. Fouling communities on artificial settlement substrata were studied. A total of 7 disturbance frequencies were applied to previously established communities, and a single disturbance event resulted in a removal of ~20% of the biomass. Species cover was estimated at the end of the experimental period, and it was found that diversity was strongly affected by disturbance frequency. With high disturbance frequencies the composition of the community was changed, with a decrease in the solitary ascidian Pyura chilensis (Molina 1782). The decrease of P. chilensis resulted in an increase of the colonial ascidian Diplosoma sp. A unimodal relationship between disturbance frequency and species richness was found, supporting the IDH. The results suggest that disturbance sustains diversity by reducing the abundance of the dominant species (e.g. P. chilensis), preventing competitive exclusion of the subordinate species, thus allowing subordinate species to re-emerge when competition is alleviated by disturbance. The results also suggest that these species show a trade-off between competitive and colonizing abilities, pointing to the existence of a competitive hierarchy. Therefore, the presence of competitive exclusion and disturbance-induced suppression of the dominant species remains a crucial mechanism, permitting species coexistence in the context of the IDH in the system studied

5 practical actions for national health literacy development

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eHealth literacy among hospital health care providers: a systematic review

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Is global quality of life reduced before fracture in patients with low-energy wrist or hip fracture? A comparison with matched controls

<p>Abstract</p> <p>Background</p> <p>The aims of the study were (i) to examine global quality of life (GQOL) before fracture in patients with low-energy wrist or hip fracture compared with an age- and sex-matched control group, and (ii) to identify relationships between demographic variables, clinical fracture variables, and health- and global-focused quality of life (QOL) prior to fracture.</p> <p>Methods</p> <p>Patients with a low-energy fracture of the wrist (n = 181) or hip (n = 97) aged ≥ 50 years at a regional hospital in Norway and matched controls (n = 226) were included. The participants answered retrospectively, within two weeks after the fracture, a questionnaire on their GQOL before the fracture occurred using the Quality of Life Scale (QOLS), and health-focused QOL using the Short Form-36, physical component summary, and mental component summary scales. A broad range of clinical data including bone density was also collected. ANOVA and multiple linear regression analysis were used to analyse the data.</p> <p>Results</p> <p>Osteoporosis was identified in 59% of the hip fracture patients, 33% of the wrist fracture patients, and 16% of the controls. After adjusting GQOL scores and the three sub-dimensions for known covariates (sociodemographics, clinical fracture characteristics, and health-focused QOL), the hip patients reported significantly lower scores compared with the controls, except for the sub-dimension of personal, social, and community commitment (p = 0.096). Unadjusted and adjusted GQOL scores did not differ between the wrist fracture patients and controls. Sociodemographics (age, sex, education, marital status), clinical fracture variables (osteoporosis, falls, fracture group) and health-focused QOL explained 51.4% of the variance in the QOLS, 35.2% of the variance in relationship and marital well-being, 59.3% of the variance in health and functioning, and 24.9% of the variance of personal, social, and community commitment.</p> <p>Conclusion</p> <p>The hip fracture patients had lower GQOL before the fracture occurred than did controls, even after adjusting for known factors such as sociodemographics, clinical variables and health-focused QOL. The findings suggest that by identifying patients with low GQOL, in addition to other known risk factors for hip fracture, may raise the probability to target preventive health care activities.</p

Associations between disease severity, coping and dimensions of health-related quality of life in patients admitted for elective coronary angiography – a cross sectional study

<p>Abstract</p> <p>Background</p> <p>In patients with suspected coronary artery disease (CAD), the overall aim was to analyse the relationships between disease severity and both mental and physical dimensions of health related quality of life (HRQOL) using a modified version of the Wilson and Cleary model.</p> <p>Methods</p> <p>Using a cross-sectional design, 753 patients (74% men), mean age 62 years, referred for elective cardiac catheterisation were included. The measures included 1) physiological factors 2) symptoms (disease severity, self-reported symptoms, anxiety and depression 3) self-reported functional status, 4) coping, 5) perceived disease burden, 6) general health perception and 7) overall quality of life. To analyse relationships, we performed linear and ordinal logistic regressions.</p> <p>Results</p> <p>CAD and left ventricular ejection fraction (LVEF) were significantly associated with symptoms of angina pectoris and dyspnea. CAD was not related to symptoms of anxiety and depression, but less depression was found in patients with low LVEF. Angina pectoris and dyspnea were both associated with impaired physical function, and dyspnea was also negatively related to social function. Overall, less perceived burden and better overall QOL were observed in patients using more confronting coping strategy.</p> <p>Conclusion</p> <p>The present study demonstrated that data from cardiac patients to a large extent support the suggested model by Wilson and Cleary.</p

Erratum to: Assessment of predictive performance in incomplete data by combining internal validation and multiple imputation

Abstract Background Missing values are a frequent issue in human studies. In many situations, multiple imputation (MI) is an appropriate missing data handling strategy, whereby missing values are imputed multiple times, the analysis is performed in every imputed data set, and the obtained estimates are pooled. If the aim is to estimate (added) predictive performance measures, such as (change in) the area under the receiver-operating characteristic curve (AUC), internal validation strategies become desirable in order to correct for optimism. It is not fully understood how internal validation should be combined with multiple imputation. Methods In a comprehensive simulation study and in a real data set based on blood markers as predictors for mortality, we compare three combination strategies: Val-MI, internal validation followed by MI on the training and test parts separately, MI-Val, MI on the full data set followed by internal validation, and MI(-y)-Val, MI on the full data set omitting the outcome followed by internal validation. Different validation strategies, including bootstrap und cross-validation, different (added) performance measures, and various data characteristics are considered, and the strategies are evaluated with regard to bias and mean squared error of the obtained performance estimates. In addition, we elaborate on the number of resamples and imputations to be used, and adopt a strategy for confidence interval construction to incomplete data. Results Internal validation is essential in order to avoid optimism, with the bootstrap 0.632+ estimate representing a reliable method to correct for optimism. While estimates obtained by MI-Val are optimistically biased, those obtained by MI(-y)-Val tend to be pessimistic in the presence of a true underlying effect. Val-MI provides largely unbiased estimates, with a slight pessimistic bias with increasing true effect size, number of covariates and decreasing sample size. In Val-MI, accuracy of the estimate is more strongly improved by increasing the number of bootstrap draws rather than the number of imputations. With a simple integrated approach, valid confidence intervals for performance estimates can be obtained. Conclusions When prognostic models are developed on incomplete data, Val-MI represents a valid strategy to obtain estimates of predictive performance measures

The complexity of the relationship between chronic pain and quality of life: a study of the general Norwegian population

The aims of this paper were to evaluate the relationship between chronic pain and global quality of life (GQOL) and to explore the effect of possible confounders, mediators, and moderators such as selected demographic variables, chronic illnesses, stress-related symptoms, fatigue, and subjective health of the relationship between chronic pain and GQOL. We used a cross-sectional design, including 1,893 respondents from a population of 4,000 of Norwegian citizens, aged 19–81 years, who were randomly drawn from the National Register by Statistics Norway in November 2000 (48.5%). Pain duration of more than 3 months was categorized as having chronic pain. The Quality of Life Scale, the Fatigue Severity Scale, and the Posttraumatic Stress Scale were used as our main dependent and independent variables, respectively. A series of multiple regression analyses (GLM in SPSS) were applied using GQOL as the dependent variable, entering subsets of independent variables in a theoretically predefined sequence. In the total model, there was no significant relationship between chronic pain and GQOL. The model explained 39% of the variance in GQOL. For direct effect sizes, stress-related symptoms were related most strongly to GQOL, followed by subjective health, fatigue, chronic illnesses, and selected demographic variables. These findings support the assumption of a complex and indirect relationship between chronic pain and GQOL

What determines subjective health status in patients with chronic obstructive pulmonary disease: importance of symptoms in subjective health status of COPD patients

<p>Abstract</p> <p>Background</p> <p>Subjective health status is the result of an interaction between physiological and psychosocial factors in patients with chronic obstructive pulmonary disease (COPD). However, there is little understanding of multivariate explanations of subjective health status in COPD. The purpose of this study was to explore what determines subjective health status in COPD by evaluating the relationships between background variables such as age and sex, predicted FEV₁%, oxygen saturation, breathlessness, anxiety and depression, exercise capacity, and physical and mental health.</p> <p>Methods</p> <p>This study had a cross-sectional design, and included 100 COPD patients (51% men, mean age 66.1 years). Lung function was assessed by predicted FEV₁%, oxygen saturation by transcutaneous pulse oximeter, symptoms with the St George Respiratory Questionnaire and the Hospital Anxiety and Depression Scale, physical function with the Incremental Shuttle Walking Test, and subjective health status with the SF-36 health survey. Linear regression analysis was used.</p> <p>Results</p> <p>Older patients reported less breathlessness and women reported more anxiety (p < 0.050). Women, older patients, those with lower predicted FEV₁%, and those with greater depression had lower physical function (p < 0.050). Patients with higher predicted FEV₁%, those with more breathlessness, and those with more anxiety or depression reported lower subjective health status (p < 0.050). Symptoms explained the greatest variance in subjective health status (35%–51%).</p> <p>Conclusion</p> <p>Symptoms are more important for the subjective health status of patients with COPD than demographics, physiological variables, or physical function. These findings should be considered in the treatment and care of these patients.</p

Changes in Health Literacy during the first year following a kidney transplantation: Using the Health Literacy Questionnaire

Objectives The study aimed to identify changes in health literacy (HL) and associated variables during the first year following a kidney transplantation. Methods A total of 196 transplant recipients were included in a prospective follow-up study. The patients answered the Health Literacy Questionnaire (HLQ) at 5 days, 8 weeks, 6 and 12 months following the kidney transplantation. Mixed linear models were used to analyze changes in HL and backward elimination was used to identify variables associated with HL. Results Two main patterns of change were identified: a) HL increased during the first 8 weeks of close follow-up and b) in several domains, the positive increase from 5 days to 8 weeks flattened out from 5 days to 6 and 12 months. Self-efficacy, transplant-related knowledge, and general health were core variables associated with HL. Conclusions Overall, HL increased during the 8 weeks of close follow-up following the kidney transplantation, while 6 months seem to be a more vulnerable phase. Furthermore, low self-efficacy, less knowledge, and low self-perceived health may represent vulnerable characteristics in patients. Practical implications Future kidney transplant care should take into account patients’ access to and appraisal of health information and social support, and draw attention to potentially vulnerable groups.publishedVersio