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Charting the phenotypic landscape of mitochondrial diseases through a systematic evaluation of pathogenic mitochondrial DNA and nuclear gene variants.

PURPOSE: Primary mitochondrial diseases (PMD) arise from variants in the mitochondrial or nuclear genomes. Phenotype-based recognition of specific PMD genotypes remains difficult, prolonging the diagnostic odyssey. We expanded the MitoPhen database to characterize phenotypic variation across PMD more systematically. METHODS: Individual-level data on mitochondrial DNA disorders, nuclear-encoded mitochondrial diseases, and single large-scale mitochondrial DNA deletions were manually curated with Human Phenotype Ontology (HPO) terms to produce MitoPhen v2. Principal-component analysis summarized system-level abnormalities; HPO-level enrichment and mean phenotype-similarity scores were then used to distinguish common PMD genotypes. RESULTS: MitoPhen v2 adds 3940 individuals to the original release, now encompassing 1597 publications, 10,626 individuals, and 117 genotypes. Among 7586 affected cases, 72,861 HPO terms were recorded. Principal-component analysis revealed 6 phenotype dimensions capturing most system-level variance. At the HPO level, we observed genotype-specific enrichments and identified 111 gene-phenotype links absent from the current HPO database. Using MT-TL1, single large-scale mitochondrial DNA deletions, and POLG as exemplars, phenotype-similarity scores reliably separated individuals with these genotypes from those without. CONCLUSION: MitoPhen v2 enabled systematic, genotype-aware analysis of heterogeneous PMD phenotypes and highlighted the diagnostic value of structured, individual-level data. Phenotype-similarity metrics from such data sets can refine variant interpretation in large rare-disease cohorts and provide a transferable framework for other phenotypically complex genetic disorders.

Humans↗

Self-reported eating behaviors of extremely obese persons seeking bariatric surgery: a factor analytic approach.

OBJECTIVE: To summarize the self-reported eating behaviors of persons seeking bariatric surgery and to provide reliability data for a clinical instrument that assesses those eating behaviors. RESEARCH METHODS AND PROCEDURES: Adults (552) with extreme obesity (mean +/- standard deviation BMI = 52.4 +/- 10.1 kg/m2) completed the Weight and Lifestyle Inventory (WALI) before undergoing bariatric surgery. The WALI is a self-report instrument that includes 24 items that assess the eating behaviors to which respondents attribute their excess weight. These items were entered into a principal components analysis with promax rotation. Relationships of factor scores to demographic and psychosocial variables were examined. Test-retest reliability data were obtained from a smaller sample (n = 58) of less obese participants (BMI = 34.4 +/- 4.0 kg/m2) who completed the WALI twice within 2 weeks, before beginning a non-surgical weight loss program. RESULTS: The principal components analysis yielded five factors with acceptable internal consistency and test-retest reliability. These included: eating in response to negative affect, eating in response to positive affect and social cues, general overeating and impaired appetite regulation, overeating at early meals, and snacking. Each factor was related to symptoms of binge eating disorder, and every factor except the second one was associated with depressive symptoms. Factor scores were unrelated or weakly associated with demographic characteristics. DISCUSSION: The eating behaviors of persons seeking bariatric surgery can be assessed reliably and parsimoniously with the WALI. The predictive utility of the factors obtained in this study remains to be examined.

Adult↗

Clinical phenotype and gene expression profile in Crohn's disease.

The clinical course varies significantly among patients with Crohn's disease (CD). This study investigated whether gene expression profiles generated by DNA microarray technology might predict disease progression. Biopsies from the descending colon were obtained colonoscopically from 40 CD patients. Gene profiling analyses were performed using a Human Genome U133 Plus 2.0 GeneChip Array, and summarization into a single expression measure for each probe set was performed using the robust multiple array procedure. Principal component analysis demonstrated that three components explain two-thirds of the total variation. The most important parameters for the determination of the colonic gene expression patterns were the presence of disease (CD) and presence of inflammation. Superimposition of clinical phenotype data revealed a grouping of the samples from patients with stenosis toward negative values on the axis of the second principal component. The functional annotation analysis suggested that the expression of genes involved in intracellular transport and cytoskeletal organization might influence the development of stenosis. In conclusion, even though most variation in the colonic gene expression patterns is due to presence or absence of CD and inflammation status, the development of stenosis is a parameter that affects colonic gene expression to some extent.

Adolescent↗

Mercury distribution in fish organs and food regimes: Significant relationships from twelve species collected in French Guiana (Amazonian basin).

Within a multidisciplinary research programme set up in French Guiana (Amazonian basin), twelve fish species from six food regimes were collected from the upper part of the Maroni River in order to analyze mercury (Hg) distribution in six organs (gills, liver, kidneys, skeletal muscle, stomach, and intestine) and to look for a relationship between Hg organotropism and food regimes. As many studies have shown, mercury biomagnification leads to extremely marked differences in muscle accumulation levels: the average ratio between extreme concentrations measured in piscivorous and herbivorous species was almost 500. A first principal component analysis on primary Hg concentration variables showed that biomagnification had a marked effect, masking differences between Hg distribution in the organs according to fish species and their food regimes. In order to avoid this, we determined ratios between Hg concentrations measured in the different organs and in the skeletal muscle, considered as the reference tissue for biomagnification effects. A new principal component analysis using these normalized values, in conjunction with a Ward's hierarchical clustering method, revealed that there is a link between Hg organotropism and the food regimes, with comparatively high [Hg]gills/[Hg]muscle ratios for the herbivorous species; high [Hg]intestine-liver-kidneys/[Hg]muscle ratios for the benthivorous and periphytophagous species, and, in contrast, ratios of less than 1 in the different organs for the piscivorous and omnivorous species. Our determinations of methylmercury (MMHg) percentages in the food consumed by the fish (aquatic macrophytes, terrestrial material from the river banks, biofilms, benthic invertebrates, fish muscle tissues), according to the different food regimes (herbivorous, periphytophagous, benthivorous, omnivorous, carnivorous, piscivorous), showed that this criterion can account for the differences in Hg distribution in the fish organs. For instance, the periphytophagous and benthivorous fish species ingest biofilms and small benthic invertebrates with quite low MMHg burdens (18% and 35 to 52% of Hgtotal, respectively). The highest [Hg]organs/[Hg]muscle ratios were observed for the liver and kidneys, the two principal target organs for inorganic Hg in fish. On the other hand, the piscivorous species ingest a large amount of fish of varying size, with high MMHg percentages in their muscle tissue (nearly 80%); Hg organotropism is characterized by high MMHg concentrations in the skeletal muscle and comparatively low [Hg]organs/[Hg]muscle ratios.

Animals↗

Comparative proteomic analysis of planktonic and immobilized Pseudomonas aeruginosa cells: a multivariate statistical approach.

The protein maps of Pseudomonas aeruginosa cells from two natural (attached) and one artificial (gel-entrapped) immobilized-cell (IC) systems, together with their free (suspended) counterparts, were compared after incubation for 18 or 48 h in a minimal salt medium. Principal component analysis (PCA) was used to interpret the variations in protein spot densities that were observed on electropherogram obtained by two-dimensional electrophoresis (2-DE). PCA of the 2-DE data, a matrix of 933 rows (observations, i.e., spot density values) and 12 columns (variables, i.e., incubation conditions), in which observations were standardized horizontally, extracted four principal components (PCs) accounting for 78.75% of the variability in the protein expression profiles. PC1 opposed the two modes of growth (planktonic and immobilized) while PC2 discriminated between the incubation times of free cell cultures. The incubation conditions of ICs, including the immobilization procedure (entrapment vs attachment) and the nature of the biofilm substratum, were fairly separated in PC3xPC4. The dependence of the protein patterns on the cell immobilization process was further illustrated by the identification of a number of peptides whose amount remained unchanged or was altered in ICs compared to free bacteria. These results reinforce the topical assertion that bacteria in the immobilized state display a specific physiological behavior but also question the existence of a unique IC phenotype.

Bacterial Proteins↗

Relationships of human disturbance, bird communities, and plant communities along the land-water interface of a large reservoir.

We examined the relationships of human activity, bird communities, and plant communities along the land-water interface of Lake Texoma, a large human-made reservoir on the Texas-Oklahoma border. Measurements of human activity, plant surveys, and bird surveys were performed at 40 paired transects, one with human disturbance, the other undisturbed. Both principal components and correspondence analyses of bird-survey data separated disturbed sites from paired undisturbed sites, and typical disturbance-tolerant species from those less tolerant of human activity. Compared to undisturbed sites, disturbed sites tended to have more individual birds per survey, pavement, and mowed lawns, and less canopy, vegetation volume, and vegetation vertical diversity. A principal components analysis of quantitative disturbance measurements revealed that most bird and plant measures were highly correlated with the first disturbance component. However, the correlation between birds and human activity was much stronger than that between birds and plants, or between plants and disturbance. Our data suggest that bird-species composition is regulated more by human activity than by plant-community composition. Also, in this system, bird communities are a better choice than plant communities to index the effect of human disturbance. To maintain regional diversity of both birds and plants, undisturbed areas should be maintained around reservoirs.

Animals↗

Self-reported eating behaviors of extremely obese persons seeking bariatric surgery: a factor analytic approach.

OBJECTIVE: To summarize the self-reported eating behaviors of persons seeking bariatric surgery and to provide reliability data for a clinical instrument that assesses those eating behaviors. RESEARCH METHODS AND PROCEDURES: Adults (552) with extreme obesity (mean +/- standard deviation BMI = 52.4 +/- 10.1 kg/m(2)) completed the Weight and Lifestyle Inventory (WALI) before undergoing bariatric surgery. The WALI is a self-report instrument that includes 24 items that assess the eating behaviors to which respondents attribute their excess weight. These items were entered into a principal components analysis with promax rotation. Relationships of factor scores to demographic and psychosocial variables were examined. Test-retest reliability data were obtained from a smaller sample (n = 58) of less obese participants (BMI = 34.4 +/- 4.0 kg/m(2)) who completed the WALI twice within 2 weeks, before beginning a non-surgical weight loss program. RESULTS: The principal components analysis yielded five factors with acceptable internal consistency and test-retest reliability. These included: eating in response to negative affect, eating in response to positive affect and social cues, general overeating and impaired appetite regulation, overeating at early meals, and snacking. Each factor was related to symptoms of binge eating disorder, and every factor except the second one was associated with depressive symptoms. Factor scores were unrelated or weakly associated with demographic characteristics. DISCUSSION: The eating behaviors of persons seeking bariatric surgery can be assessed reliably and parsimoniously with the WALI. The predictive utility of the factors obtained in this study remains to be examined.

Adult↗

Analysis of serum and whole blood values in relation to helminth and ectoparasite infections of feral pigs in Texas.

In the summers of 1996 and 1997, 60 wild pigs (Sus scrofa) were necropsied from three sites in south Texas (USA) to test the hypothesis that serum and whole blood parameters vary significantly (P < or = 0.05) with the prevalence and intensity of parasites infecting wild pigs. We found ten parasite species: five nematodes (Metastrongylus salmi, Metastrongylus pudentotectus, Stephanurus dentatus, Oesophagostomum dentatum, and Physocephalus sexalatus); four ixodid ticks (Amblyomma cajennense, Amblyomma maculatum, Amblyomma americanum, and Dermacentor variabilis); and one trematode (Fascioloides magna). Among juvenile pigs, the intensity of the four species of ticks, collectively, was negatively correlated (P < or = 0.05) with whole blood principal component number one (PC-1); this factor was positively associated with lymphocytes and eosinophils. Lungworm intensity (Metastrongylus spp.) among adult pigs was negatively correlated (P < or = 0.05) with whole blood PC-2; this factor was negatively associated with segmented neutrophils and monocytes. There were no significant correlations found between parasite prevalences and either serum or whole blood principal component factors. The correlations observed between parasite intensities and serum and whole blood parameters generally were weak. Thus, we found no strong evidence that serum and whole blood parameters provided good predictive information on parasite infections in wild pigs for most practical management decisions.

Age Factors↗

Precision of composite measures of osteoarthritis efficacy in comparison to that of individual endpoints.

OBJECTIVE: Osteoarthritis (OA) clinical studies generally employ various endpoints to evaluate a spectrum of disease manifestations. Compared with individual endpoints, a composite measure might (1) provide a uniform outcome measure of OA efficacy with greater face validity, (2) address multiplicity, and (3) enhance precision. Combinations of endpoints were analyzed to investigate precision of composite measures of OA efficacy. METHODS: We reanalyzed three 6 week, placebo controlled, double blind, parallel group studies (2 by the same protocol) of the cyclooxygenase-2 (COX-2) specific inhibitor rofecoxib. The average change from baseline at study weeks 2, 4, and 6 was assessed for 10 individual response variables, including patient and investigator global assessments, WOMAC 3.0V OA Index pain, stiffness and physical function subscales, graded study joint tenderness, and rescue analgesic use. Relationships among variables were evaluated using pairwise correlations and principal components analysis. The precision of variables to differentiate rofecoxib from placebo was evaluated using effect size (i.e., mean difference between rofecoxib versus placebo divided by pooled SD). RESULTS: Correlations among all pairs of response variables ranged from 0.5 to 0.9, except those with tenderness (0.4 to 0.6) and those with analgesic use (0.2 to 0.4). The first principal component explained about 70% of the total variability, with weights generally similar (0.17 for rescue analgesic use, 0.25 for tenderness, and 0.30 to 0.37 for the others). These results indicate that nearly all measures are closely related. Based on these results, various linear combinations of the 9 endpoints were formed and their precision to discriminate active treatment from placebo was compared to that of the individual endpoints. Effect sizes of the individual endpoints ranged from 0.6 to 1.1; those of the composites from 0.7 to 0.9. The results were very consistent between study protocols. CONCLUSION: In comparison to individual endpoints, composite analyses of OA clinical endpoints do not increase precision to discriminate active treatment from placebo.

Analgesics↗

Reliability of high and low anxiety-related behaviour: influence of laboratory environment and multifactorial analysis.

The reliability of behavioural data constitutes a major concern in the neuroscience field. Indeed, discrepancies in the behavioural patterns of mice or rats in the same anxiety tests performed in different laboratories have been reported recently. The question raised by such data addressed, in particular, the selection and breeding of two lines of rats on the basis of their high (HAB) and low (LAB) anxiety-related behaviour in the elevated plus-maze test at the Max Planck Institute of Psychiatry in Munich (Germany). As the majority of the behavioural data in these animals has been derived from research carried out in this institute, the aims of the present study were: (1) to test the reliability of the differences in anxiety-related behaviour of these rats in two other laboratories (Villeneuve d'Ascq, France and Innsbruck, Austria); and (2) to determine how the different behavioural traits were associated in both HAB and LAB rats by a principal component analysis. Results were in agreement with the studies performed in Munich, as the divergence in anxiety-related behaviour of the two lines was highly consistent in all tests performed in Villeneuve d'Ascq and Innsbruck. Moreover, the most important parameters to discriminate the two lines were similar to those found in a previous study. Finally, the principal component analysis again confirmed that the selection of HAB and LAB rats is based on anxiety-related behaviour rather than locomotor activity.

Animals↗

Development of a disease specific quality of life questionnaire for patients with Graves' ophthalmopathy: the GO-QOL.

AIM: To develop a reliable and valid disease specific quality of life questionnaire (the GO-QOL) for patients with Graves' ophthalmopathy (GO), that can be used to describe the health related quality of life and changes in health related quality of life over time as a consequence of disease and treatment. METHODS: 70 consecutive GO patients (age > 18 years) who were referred for the first time to the combined outpatient clinic of the orbital centre and the department of endocrinology completed the 16 questions of the GO-QOL. Additional information on general quality of life and disease characteristics was obtained. Construct validity and internal consistency of the disease specific questionnaire was determined, based on principal component analysis, Cronbach alphas and correlations with MOS-24, three subscales of the SIP, demographic, and clinical measures. RESULTS: The a priori expected subdivision of the questionnaire in two subscales, one measuring the consequences of double vision and decreased visual acuity on visual functioning, and one measuring the psychosocial consequences of a changed appearance, was confirmed in the principal component analysis. Both scales had a good reliability and high face validity. Correlations with other measures supported construct validity. Mean scores (range 0-100) were 54.7 (SD 22.8) for visual functioning and 60.1 (24.8) for appearance (higher score = better health). CONCLUSION: The GO-QOL is a promising tool to measure disease specific aspects of quality of life in patients with GO and provides additional information to traditional physiological or biological measures of health status.

Activities of Daily Living↗

Need for enforcement of ethicolegal education - an analysis of the survey of postgraduate clinical trainees.

BACKGROUND: The number of medical lawsuits in Japan was between 14 and 21 each year before 1998, but increased to 24 to 35 per year after 1999. There were 210 lawsuits during this 10-year period. There is a need for skills and knowledge related to ethics, which is as fundamental to the practice of medicine as basic sciences or clinical skills. In Japan education in ethics is relatively rare and its importance is not yet recognized. Establishing ethics education using legal precedents, which has already been achieved in Western countries, will be a very important issue in Japan. In the present study, a questionnaire survey was conducted among graduate intern doctors, in order to investigate whether ethics education using precedents might have a positive effect in Japan. METHODS: In 2002, a questionnaire survey entitled Physicians' Clinical Ethics was carried out in a compulsory orientation lecture given to trainees before they started clinical practice in our hospital. The attendees at this lecture were trainees who came from colleges in various districts of Japan. During the lecture, 102 questionnaires were distributed, completed by attendees and collected. The recovery rate was 100%. The questionnaire consisted of 22 questions (in three categories), of which 20 were answered by multiple choices, and the other two were answered by description. The time required to complete the questionnaire was about 10 minutes. RESULTS: The recovered questionnaires were analyzed using statistical analysis software (SPSS for Windows, Release 10.07J-1/June/2000), in addition to simple statistical analysis. answers using multiple choices for the 20 questions in the questionnaire were input into SPSS. The principal component analysis was performed for each question. As a result, the item that came to the fore was "legal precedent". Since many intern doctors were interested in understanding laws and precedents, learning about ethical considerations through education using precedents might better meet with their needs and interests. CONCLUSION: We applied a new method in which the results of principal component analysis and frequencies of answers to other questions were combined. From this we deduced that the precedent education used in Western countries was useful to help doctors acquire ethical sensitivity and was not against their will. A relationship was found between reading precedents and the influence of lawsuits, and it was thought that student participation-type precedent education would be useful for doctors in order to acquire ethical sensitivity.

Curriculum↗

Multivariate relationships between groundwater chemistry and toxicity in an urban aquifer.

Multivariate statistical methods were used to investigate the causes of toxicity and controls on groundwater chemistry from 274 boreholes in an urban area (London) of the United Kingdom. The groundwater was alkaline to neutral, and chemistry was dominated by calcium, sodium, and sulfate. Contaminants included fuels, solvents, and organic compounds derived from landfill material. The presence of organic material in the aquifer caused decreases in dissolved oxygen, sulfate and nitrate concentrations, and increases in ferrous iron and ammoniacal nitrogen concentrations. Pearson correlations between toxicity results and the concentration of individual analytes indicated that concentrations of ammoniacal nitrogen, dissolved oxygen, ferrous iron, and hydrocarbons were important where present. However, principal component and regression analysis suggested no significant correlation between toxicity and chemistry over the whole area. Multidimensional scaling was used to investigate differences in sites caused by historical use, landfill gas status, or position within the sample area. Significant differences were observed between sites with different historical land use and those with different gas status. Examination of the principal component matrix revealed that these differences are related to changes in the importance of reduced chemical species.

Animals↗

Computational methods for gene expression-based tumor classification.

Gene expression profiles may offer more or additional information than classic morphologic- and histologic-based tumor classification systems. Because the number of tissue samples examined is usually much smaller than the number of genes examined, efficient data reduction and analysis methods are critical. In this report, we propose a principal component and discriminant analysis method of tumor classification using gene expression profile data. Expression of 2000 genes in 40 tumor and 22 normal colon tissue samples is used to examine the feasibility of gene expression-based tumor classification systems. Using this method, the percentage of correctly classified normal and tumor tissue was 87.0%. The combined approach using principal components and discriminant analysis provided superior sensitivity and specificity compared to an approach using simple differences in the expression levels of individual genes.

Analysis of Variance↗

Measuring diabetes self-care: a psychometric analysis of the Self-Care Inventory-Revised with adults.

OBJECTIVE: To examine psychometric properties of the Self-Care Inventory-revised (SCI-R), a self-report measure of perceived adherence to diabetes self-care recommendations, among adults with diabetes. RESEARCH DESIGN AND METHODS: We used three data sets of adult type 1 and type 2 diabetic patients to examine psychometric properties of the SCI-R. Principal component and factor analyses examined whether a general factor or common factors were present. Associations with measures of theoretically related concepts were examined to assess SCI-R concurrent and convergent validity. Internal reliability coefficients were calculated. Responsiveness was assessed using paired t tests, effect size, and Guyatt's statistic for type 1 patients who completed psychoeducation. RESULTS: Principal component and factor analyses identified a general factor but no consistent common factors. Internal consistency of the SCI-R was alpha = 0.87. Correlation with a measure of frequency of diabetes self-care behaviors was r = 0.63, providing evidence for SCI-R concurrent validity. The SCI-R correlated with diabetes-related distress (r = -0.36), self-esteem (r = 0.25), self-efficacy (r = 0.47), depression (r = -0.22), anxiety (r = -0.24), and HbA(1c) (r = -0.37), supporting construct validity. Responsiveness analyses showed SCI-R scores improved with diabetes psychoeducation with a medium effect size of 0.62 and a Guyatt's statistic of 0.85. CONCLUSIONS: The SCI-R is a brief, psychometrically sound measure of perceptions of adherence to recommended diabetes self-care behaviors of adults with type 1 or type 2 diabetes.

Adult↗

Relationships among tempo of maturation, midparent height, and growth in height of adolescent boys and girls.

The influence of rate of skeletal maturation and midparent height on growth in height during adolescence was analyzed on longitudinal data for 184 boys and 166 girls from the Wrocław Growth Study. Seven biological parameters describing the shape of the growth curve in stature were derived from the Preece-Baines model 1 applied to individual serial data. Rate of skeletal maturation inferred from the difference between chronological and skeletal ages at 12 years in girls and 14 in boys. Principal components analysis of the biological parameters extracted three factors for boys and four for girls. The factors explained 90% and 97% of the total variance in boys and girls, respectively. The factors reflected attained size and the timing and intensity of the adolescent spurt in height. Multiple regression showed a high relationship between skeletal maturation rate, midparent height, and principal component scores. Three aspects of adolescent growth: size, timing, and intensity show an apparent sex difference. The timing and intensity of the spurt are highly affected by tempo of maturation in girls, but less so than in boys. It might suggest in girls a less efficient compensatory effect for reduced length of overall growth period in early maturers that increases height gain. Midparent height influences the size component during the spurt, thus adjusting the height parameters. The dependency between attained stature (height at take-off, PHV, and adult stature), timing, and initial intensity of the growth spurt of daughters and midparent height is greater than in sons.

Adolescent↗

A cohort study found good respiratory, sensory and motor functions decreased mortality risk in older people.

BACKGROUND AND OBJECTIVE: The main aims of this study were to evaluate the separate and joint effects of respiratory, sensory, and psychomotor function, muscle strength, and mobility in predicting mortality in older men and women, and to find a way to control multicollinearity in a multivariate Cox regression model. METHODS: Mortality was followed for 10 years (1990-2000) in an entire cohort of 75-year-old residents of the city of Jyvaskyla, Finland (born in 1914; N=388). Cox regression models and principal component estimation were employed to study the association between the covariates and mortality. RESULTS: The study indicated that, after adjustment for fatal diseases and cognitive capacity, vital capacity, tapping rate, muscle strength, and walking speed predict mortality in elderly men and women to a similar extent. The hazard ratio for mortality for those in the lowest tertile of the principal component representing all the significant physiological functions was from three to four times higher than for those in the highest tertile. CONCLUSION: Our results suggest that a poor level in any of the measured functions has a similar impact on the risk for mortality, which is further increased by combining the different results. No single, dominant predictor of mortality emerged.

Aged↗

Adaptation and psychometric evaluation of the Swedish version of the Good Nursing Care Scale for Patients.

The aim of this study was to adapt the instrument 'Good Nursing Care Scale for Patients' to Swedish conditions as a measure of patients' satisfaction, as well as estimating its reliability and validity. Following a pilot test, discussions in the author group, testing for readability among patients and judgement of content validity by a panel of experts, the final version was reduced to 72 items focusing on good caring. The refined instrument was assessed for internal consistency in 447 surgical in-patients, for 2 week test-retest reliability in 100 patients and subjected to orthogonal principal components factor analysis with varimax rotation, followed by second-order factor analysis. The internal consistency item-item correlation coefficient ranged from 0.15 to 0.91, correlation between each item and the total scale was >or=0.30 for 70 items, Cronbach's alpha coefficient for the final scale was 0.79 and test-retest reliability was 0.75. An orthogonal principal components factor analysis with varimax rotation was conducted on the final 71 items and the 15 first-order factors with eigenvalues >or=1 explained 66% of the total variance. A second-order factor analysis of these 15 factors as items resulted in a seven-factor solution. The total variance explained by the seven factors was 79%. Cronbach's alpha coefficient for the seven factors ranged between 0.32 and 0.95. The instrument seems reliable and valid to assess the patients' satisfaction with what happened during their hospital stay. To confirm the factor structure and improve factor consistency additional development and testing is suggested.

Adolescent↗

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