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PubMed2003

Reliability and validity of the multiple sclerosis quality of life inventory in older individuals.

PURPOSE: Despite the increasing number of older individuals with multiple sclerosis (MS), there is a paucity of research on this subpopulation. Health-related quality of life (HRQOL) has received extensive attention in MS; however samples tend to be young. The present study assesses the internal consistency reliability and construct validity of the MS Quality of Life Inventory (MSQLI), a widely employed measure of HRQOL, in older individuals. METHOD: Select subscales of the MSQLI and other measures of mental health and physical functioning were administered by telephone to 30 randomly selected older ( >or= 60) individuals and a gender-matched sample of younger ( < 60) individuals. Reliability estimates were calculated separately for each group. Construct (convergent) validity was assessed by examining the pattern of correlations between MSQLI subscales and measures of related constructs in the two groups. RESULTS: Reliability estimates were similar in the two groups. With few exceptions, the correlations measuring convergent validity were in the expected direction, and of considerable magnitude, in both groups. CONCLUSIONS: Results provide preliminary evidence that the MSQLI is a reliable and valid instrument for use with older individuals. The slightly different pattern of results observed in the validity analysis might be explained by an adjustment hypothesis. Future research on HRQOL in this subpopulation is encouraged.

Activities of Daily Living↗

PubMedDate not supplied

Computer validation in toxicology: historical review for FDA and EPA good laboratory practice.

The application of computer validation principles to Good Laboratory Practice is a fairly recent phenomenon. As automated data collection systems have become more common in toxicology facilities, the U.S. Food and Drug Administration and the U.S. Environmental Protection Agency have begun to focus inspections in this area. This historical review documents the development of regulatory guidance on computer validation in toxicology over the past several decades. An overview of the components of a computer life cycle is presented, including the development of systems descriptions, validation plans, validation testing, system maintenance, SOPs, change control, security considerations, and system retirement. Examples are provided for implementation of computer validation principles on laboratory computer systems in a toxicology facility.

Clinical Laboratory Information Systems↗

PubMed2007

Concurrent validity and clinical usefulness of several individually administered tests of children's social-emotional cognition.

In this study, the validity of 5 tests of children's social-emotional cognition, defined as their encoding, memory, and interpretation of social information, was tested. Participants were 126 clinic-referred children between the ages of 5 and 17. All 5 tests were evaluated in terms of their (a) concurrent validity, (b) incremental validity, and (c) clinical usefulness in predicting social functioning. Tests included measures of nonverbal sensitivity, social language, and social problem solving. Criterion measures included parent and teacher report of social functioning. Analyses support the concurrent validity of all measures, and the incremental validity and clinical usefulness of tests of pragmatic language and problem solving.

Adolescent↗

PubMed2005

Predicting outcome after traumatic brain injury: development and validation of a prognostic score based on admission characteristics.

The early prediction of outcome after traumatic brain injury (TBI) is important for several purposes, but no prognostic models have yet been developed with proven generalizability across different settings. The objective of this study was to develop and validate prognostic models that use information available at admission to estimate 6-month outcome after severe or moderate TBI. To this end, this study evaluated mortality and unfavorable outcome, that is, death, and vegetative or severe disability on the Glasgow Outcome Scale (GOS), at 6 months post-injury. Prospectively collected data on 2269 patients from two multi-center clinical trials were used to develop prognostic models for each outcome with logistic regression analysis. We included seven predictive characteristics-age, motor score, pupillary reactivity, hypoxia, hypotension, computed tomography classification, and traumatic subarachnoid hemorrhage. The models were validated internally with bootstrapping techniques. External validity was determined in prospectively collected data from two relatively unselected surveys in Europe (n = 796) and in North America (n = 746). We evaluated the discriminative ability, that is, the ability to distinguish patients with different outcomes, with the area under the receiver operating characteristic curve (AUC). Further, we determined calibration, that is, agreement between predicted and observed outcome, with the Hosmer-Lemeshow goodness-of-fit test. The models discriminated well in the development population (AUC 0.78-0.80). External validity was even better (AUC 0.83-0.89). Calibration was less satisfactory, with poor external validity in the North American survey (p < 0.001). Especially, observed risks were higher than predicted for poor prognosis patients. A score chart was derived from the regression models to facilitate clinical application. Relatively simple prognostic models using baseline characteristics can accurately predict 6-month outcome in patients with severe or moderate TBI. The high discriminative ability indicates the potential of this model for classifying patients according to prognostic risk.

Adolescent↗

PubMed2003

Comparisons and validation of statistical clustering techniques for microarray gene expression data.

MOTIVATION: With the advent of microarray chip technology, large data sets are emerging containing the simultaneous expression levels of thousands of genes at various time points during a biological process. Biologists are attempting to group genes based on the temporal pattern of their expression levels. While the use of hierarchical clustering (UPGMA) with correlation 'distance' has been the most common in the microarray studies, there are many more choices of clustering algorithms in pattern recognition and statistics literature. At the moment there do not seem to be any clear-cut guidelines regarding the choice of a clustering algorithm to be used for grouping genes based on their expression profiles. RESULTS: In this paper, we consider six clustering algorithms (of various flavors!) and evaluate their performances on a well-known publicly available microarray data set on sporulation of budding yeast and on two simulated data sets. Among other things, we formulate three reasonable validation strategies that can be used with any clustering algorithm when temporal observations or replications are present. We evaluate each of these six clustering methods with these validation measures. While the 'best' method is dependent on the exact validation strategy and the number of clusters to be used, overall Diana appears to be a solid performer. Interestingly, the performance of correlation-based hierarchical clustering and model-based clustering (another method that has been advocated by a number of researchers) appear to be on opposite extremes, depending on what validation measure one employs. Next it is shown that the group means produced by Diana are the closest and those produced by UPGMA are the farthest from a model profile based on a set of hand-picked genes. AVAILABILITY: S+ codes for the partial least squares based clustering are available from the authors upon request. All other clustering methods considered have S+ implementation in the library MASS. S+ codes for calculating the validation measures are available from the authors upon request. The sporulation data set is publicly available at http://cmgm.stanford.edu/pbrown/sporulation

Algorithms↗

PubMed2005

Validation of a model to predict adverse outcomes in patients with pulmonary embolism.

AIMS: To validate a model for quantifying the prognosis of patients with pulmonary embolism (PE). The model was previously derived from 10 534 US patients. METHODS AND RESULTS: We validated the model in 367 patients prospectively diagnosed with PE at 117 European emergency departments. We used baseline data for the model's 11 prognostic variables to stratify patients into five risk classes (I-V). We compared 90-day mortality within each risk class and the area under the receiver operating characteristic curve between the validation and the original derivation samples. We also assessed the rate of recurrent venous thrombo-embolism and major bleeding within each risk class. Mortality was 0% in Risk Class I, 1.0% in Class II, 3.1% in Class III, 10.4% in Class IV, and 24.4% in Class V and did not differ between the validation and the original derivation samples. The area under the curve was larger in the validation sample (0.87 vs. 0.78, P=0.01). No patients in Classes I and II developed recurrent thrombo-embolism or major bleeding. CONCLUSION: The model accurately stratifies patients with PE into categories of increasing risk of mortality and other relevant complications. Patients in Risk Classes I and II are at low risk of adverse outcomes and are potential candidates for outpatient treatment.

Aged↗

PubMed2003

Development and validation of a short food list to assess the intake of total fat, saturated, mono-unsaturated, polyunsaturated fatty acids and cholesterol.

BACKGROUND: The aim of this study was the development and validation of a short list of food items to assess the intake of total fat, saturated, mono-unsaturated, polyunsaturated fatty acids, and cholesterol. The short list should be able to correctly classify persons according to their intake. METHODS: A short list of 20 food items was selected out of 1009 seven-day food records by means of the variance-based method Max_r. This list was validated using data from a further 479 persons who completed seven-day food records (validation sample 1, VS1) as well as a food frequency questionnaire (validation sample 2, VS2). The intake of total fat, different fatty acids, and cholesterol from the complete VS1 (VS1(complete)) and from the complete VS2 (VS2(complete)), respectively, was computed. Further, the intake in VS1 (VS1(short)) as well as in VS2 (VS2(short)) using only the 20 food items on the short list were calculated. RESULTS: Pearson correlation coefficients between the intake calculated from the items on the short list and the nutrient intake calculated from the full instrument in VS1 and VS2, respectively, were r = 0.81-0.91. In a quartile's cross-classification 53.4-64.1% of the participants were assigned to the same quartile. When comparing VS1(complete) with VS2(short), neither correlation coefficients nor the cross-classification differ much from the comparison of VS1(complete) with VS2(complete). CONCLUSIONS: The short list shows good results in both validation samples. Thus, the short list can assess the variability of fat intake and classify persons according to their intake.

Adult↗

PubMed2004

A pilot study to validate modification of the Duke University Severity of Illness scale to measure a family's burden of illness.

BACKGROUND: Measurement of burden of illness is rarely undertaken in general practice, although a specific tool [Duke University Severity of Illness DUSOI scale] has been incorporated in the International Classification in Primary Care. This measures the burden of illness in an individual at a point in time. There has not been any measure of the burden of illness in families. Such an instrument would allow measurement of the impact of events on the health of families. OBJECTIVE: This pilot study aimed to modify the DUSOI to measure a family's burden of illness and to validate any changes. METHODS: The DUSOI was modified to measure the mean burden of illness in a family over a 1 year period. The changes were then subject to a validation process using convenient samples of patients from the author's multidoctor practice in Australia. Reliability was examined by the test-re-test method. Inter-rater reliability could not be assessed. Responsiveness was measured by measuring changes in score in the years before and after four events: counselling for a minor mental health problem; referral to a psychiatrist; diagnosis and treatment of breast cancer; and the occurrence of an acute myocardial infarction. RESULTS: The modifications made to the DUSOI have not altered the face or content validity of the original instrument. Construct validity and test-re-test reliability were satisfactory. Inter-rater reliability was not tested, but the original single patient score showed levels lower than are desirable. Responsiveness varied significantly. Families where a member was referred to a psychiatrist showed a decrease in burden after referral, while families where a member suffered an infarct showed a large increase. The other family groups did not show any change. CONCLUSION: A Family DUSOI will be of value in research when validated for individual conditions.

Australia↗

PubMed2006

Physical and cognitive domains of the Instrumental Activities of Daily Living: validation in a multiethnic population of Asian older adults.

BACKGROUND: We sought to assess the validity of the physical and cognitive domains of Lawton and Brody's Instrumental Activities of Daily Living (IADL) scale and its cross-cultural applicability across ethnic groups in an Asian population of community-living older adults. METHODS: Using data from a random population sample of noninstitutionalized Chinese, Malay, and Indian older adults 60 years old and older in Singapore (N = 1072), we modeled the dimensional structure of the 8-item IADL Scale using exploratory and confirmatory factor analyses, and assessed its convergent and divergent validity using known group differences and strengths of association. RESULTS: Factor analyses yielded two strong and reliable factors representing underlying physical and cognitive dimensions of IADL. The validity of the model was supported by the pattern of associations of the IADL with age, gender, education, self-reported health status, hospitalization, physical comorbidities, dementia and depression, and Mini-Mental State Examination (MMSE) scores. Notably, cognitive IADL showed a greater total effect on MMSE cognitive performance score than did physical IADL, with the effect of physical IADL on MMSE score mostly explained by cognitive IADL. Reasonably good cross-cultural validity was demonstrated among Chinese, Malays, and Indians, with strongest validity for Indians. CONCLUSION: The eight-item IADL Scale has physical and cognitive domains and is cross-culturally applicable. The cognitive IADL domain taps a set of activities directly related to cognitive functioning.

Activities of Daily Living↗

PubMed2001

Quality of paediatric care: application and validation of an instrument for measuring parent satisfaction with hospital care.

OBJECTIVE: To apply and validate an adapted version of an existing adult patient questionnaire in a study of parental satisfaction with paediatric care in a university hospital. DESIGN: A cross-sectional, anonymous questionnaire study. A total of 912 questionnaires were distributed to parents by hospital staff during a 2-week period. SETTING: A university children's hospital in Stockholm, Sweden. STUDY PARTICIPANTS: Six hundred and twenty-four parents whose children were receiving care at the hospital during a 2-week period in April of 1999. MAIN OUTCOME MEASURES: The 63-item questionnaire uses eight main measurement indices and an overall quality rating to define parental satisfaction with paediatric care. Measures of the instrument's reliability and validity were established by comparison with results of a pilot study conducted 1 year earlier on the paediatric departments of two regional Swedish hospitals. All measures were compared to reliability and validity estimates in the original patient questionnaire. RESULTS: A total of 624 questionnaires were returned, a response rate of 68%. The instrument demonstrated good reliability and validity. Reliability estimates for all eight indices were greater than 0.70 and consistent over time. Inter-index correlations were generally lower than 0.60, indicating index independence. Of the nine parameters measured, parents were most satisfied with staff attitudes, care processes and medical treatment. Parents' ratings were lowest for accessibility and staff work environment. CONCLUSION: This study presents a valid and reliable questionnaire instrument for measuring parental views of paediatric hospital care. The instrument measures the quality of paediatric care from a broader perspective than previously existing parent questionnaires.

Adolescent↗

PubMed2004

Validation of the Functional Assessment of Cancer Therapy-General (FACT-G) scale for measuring the health-related quality of life in Korean women with breast cancer.

BACKGROUND: The Functional Assessment of Cancer Therapy-General (FACT-G) scale, which was developed and validated in the USA, is widely used to measure the health-related quality of life in cancer patients. The purpose of the present study was to empirically validate the FACT-G scale with Korean breast cancer patients. METHODS: A convenience sample of 193 women with breast cancer was recruited from a university hospital. The subjects were asked to complete the Korean version of the FACT-G scale. The data were analyzed using exploratory factor analysis with varimax rotation to determine factor construct validity. The loading criterion was set at 0.40 and above, inter-subscale correlations were computed using Pearson correlation, and the reliability of the internal consistency for the total scale and its subscales were assessed by Cronbach's alpha. RESULTS: The factor structure of the Korean version of the FACT-G scale paralleled that of the English version: the physical, social/family, emotional, and functional well-being subscales were constructively valid in Korean breast cancer patients. However, there is the possibility of culture-specific differences in the social/family well-being subscale, and some problematic translations were revealed. Cronbach's alpha for the total scale was 0.89 and that for the subscales ranged from 0.78 to 0.90. CONCLUSION: The Korean version of the FACT-G scale was demonstrated as reliable and valid. Therefore, the scale can be used in research and clinical settings to assess the quality of life of Korean breast cancer patients.

Adult↗

PubMed2004

Reproducibility and validity of major dietary patterns among Swedish women assessed with a food-frequency questionnaire.

Defining dietary patterns by factor analysis is an alternative approach to dietary assessment that has been used recently to examine diet-disease relations. However, only 1 study evaluated the reproducibility and validity of this method. Our aim was to assess both the validity and reproducibility of major dietary patterns based on data from a 60-item FFQ. We chose 2 independent random samples among over 60,000 women aged 40-74 y participating in the Swedish Mammography Cohort (SMC). In the validation study, the FFQ was compared with 4 7-d dietary records (DRs) among 129 women. For the reproducibility study, the FFQ was administered twice, 1 y apart in 212 women. By conducting factor analysis, 3 major dietary patterns were identified: healthy (high in vegetables, fruits, fish, poultry, tomato, cereal, and low-fat dairy products), Western (processed meat, meat, refined grains, sweets, and fried potatoes), and drinker (beer, wine and liquor, snacks) pattern. These 3 patterns explained 29-34% of the total variance in these 2 studies. The Spearman correlation coefficients between FFQ1 and FFQ2 (reproducibility) for healthy, Western, and drinker pattern were 0.63, 0.68, and 0.73, respectively (all P < 0.0001). Correlation coefficients between the FFQ and DRs (validity) for these patterns were 0.59, 0.50, and 0.85, respectively (all P < 0.0001). Our results indicate that identification of dietary patterns through factor analysis is a reproducible and valid method. The dietary patterns approach might be used in nutritional epidemiology as an alternative method of dietary assessment.

Adult↗

PubMed2006

Reliability and validity of the Asthma Trigger Inventory applied to a pediatric population.

OBJECTIVE: To test the reliability and validity of the Asthma Trigger Inventory (ATI) applied to a pediatric population. METHOD: Children with asthma (N = 272, 56% male, age 7-17) and their primary caregivers answered together an asthma trigger inventory, ATI (Ritz, Steptoe, Bobb, Harris, & Edwards, 2006) developed for adults. Cronbach's alpha, principal component analysis (PCA), hierarchical regression, and correlations of the ATI subscales with skin prick tests, psychological questionnaires, and disease severity were used to assess the psychometric properties of the ATI. RESULTS: The ATI subscales demonstrated excellent reliability regardless of gender, race, socioeconomic status (SES), or age. PCA confirmed and replicated the theoretical structure of the ATI. Hierarchical multiple regressions illuminated the association of ATI subscales with demographics and asthma history. Evidence in support of construct validity was found in associations between ratings of triggering and disease severity and asthma-related quality of life (PAQLQ). Criterion validity for allergy triggering was partially supported by correlations between ATI animal allergens subscale and the cat dander skin prick test, and construct validity for emotional triggering by associations between the emotional trigger subscale score and the anxiety (STAIC) and depression (CDI, CDI-P, CDRS-R, and CBCL-I) scores. CONCLUSION: The ATI holds promise as a reliable, valid, and useful clinical and research tool to assess the type and degree of asthma triggering in a pediatric population (age 7-17) of varied gender, race, and SES.

Asthma↗

PubMed2005

Race/ethnicity differences in the validity of self-reported drug use: results from a household survey.

Data were analyzed from a multistage probability household survey of over 600 adults, ages 18-40 from the city of Chicago conducted during 2001-2002. The survey employed audio computer-assisted self-interviews to obtain information about drug use. To investigate race/ethnicity differences in reporting validity, drug test results were compared with self-reports of past month drug use for cocaine, marijuana, and a combined indicator of both substances. The main indicators of validity were self-report sensitivity and concordance. Possible theoretical models accounting for potential cultural differences in reporting validity were discussed. Survey variables reflecting these potential explanations were examined as potential mediators of race/ethnicity differences in validity and as direct correlates of validity. Socioeconomic status was identified as one potential mediator. With this exception, race/ethnicity differences suggesting lower levels of marijuana and cocaine concordance for African Americans as compared with Whites were sustained after controlling for potential mediators. Methodological implications for epidemiological and health disparities research are discussed.

Adolescent↗

PubMed2005

Validity and reliability of an Italian version of the revised Leeds disability questionnaire for patients with ankylosing spondylitis.

OBJECTIVE: The purpose of the present study was to produce an Italian version of the Revised Leeds Disability Questionnaire (LDQ) in a group of patients with ankylosing spondylitis, and to examine the psychometric properties of this version, evaluating its internal consistency, external validity and reliability. METHODS: The LDQ was administered to 60 Caucasian patients affected by ankylosing spondylitis (50 males, 10 females, mean age 46.1 +/- 14.2 yr, range 22-74, median disease duration 4.5 yr, range 1-24) together with the Italian version of the Stanford Health Assessment Questionnaire (HAQ), and anthropometric measurements. Thirty patients completed the questionnaire after a 10-day interval. Internal consistency was evaluated with Cronbach's alpha coefficient of reliability. Construct validity of the LDQ was evaluated using the correlation between the HAQ and anthropometric measurements. Test-retest reliability was assessed with the intraclass correlation coefficient. RESULTS: All patients completed the validation study. The questionnaire was internally consistent (alpha=0.90). A significant correlation was recorded between the LDQ and the HAQ score (rho=0.841, P<0.01) and the anthropometric measurements. Test-retest reliability showed a good correlation coefficient (intraclass correlation=0.97). CONCLUSION: The Italian LDQ is a valid and reliable instrument for detecting and measuring functional disability in patients with ankylosing spondylitis. Our results confirm the utility of this questionnaire as a valid and feasible functional measure for patients with ankylosing spondylitis.

Adult↗

PubMed2006

Validation of a Dutch translation of the fibromyalgia impact questionnaire.

OBJECTIVES: To validate a Dutch translation of the fibromyalgia impact questionnaire (FIQ). MATERIALS AND METHODS: Data were taken from two randomized clinical trials on Spa treatment and venlafaxine in fibromyalgia (FM). Participants completed the Dutch FIQ and a set of validated questionnaires for general health (RAND-36), depression (Beck depression inventory, BDI), pain (McGill pain questionnaire, MPQ) and fatigue (checklist individual strength, CIS). Internal consistency within the FIQ item 'physical functioning' was studied using Cronbach's alpha. Test-retest reliability was studied with intra-class-correlation (ICC) in a subsample of 76 control subjects over a 3 month period without specific intervention. Construct validity was evaluated by correlating the FIQ to other questionnaires. Sensitivity to change was studied using standardized response means (SRM). RESULTS: The study sample consisted of 213 women and 11 men (mean age 47 yrs, mean disease duration 11 yrs). Cronbach's alpha for the item 'physical functioning' was 0.91, indicating high internal consistency. Test-retest reliability was acceptable, with ICC ranging from 0.45 for 'morning tiredness' to 0.71 for 'physical function'. FIQ correlated significantly with the RAND-36, with Spearman's rho ranging from -0.60 to -0.70 for items measuring the same concept. Similar patterns of correlation were seen with MPQ, BDI and CIS. Sensitivity to change was sufficient, with SRM after Spa treatment ranging from 0.3 for 'work days missed' to 0.9 for 'days felt good'. Similar SRM were found in the venlafaxine trial for patients reporting general improvement. CONCLUSION: The Dutch FIQ is a valid instrument for measuring health status in FM, showing sufficient reliability, construct validity and responsiveness.

Activities of Daily Living↗

PubMedDate not supplied

Whose quality of life is it anyway? The validity and reliability of the Quality of Life-Alzheimer's Disease (QoL-AD) scale.

Quality of life (QoL) is becoming an increasingly used outcome measure in both clinical practice and research. There are now more than 1000 scales available to measure QoL, and it is important that they are assessed for reliability and validity. This study aims to assess the reliability and validity of the Quality of Life-Alzheimer's Disease (QoL-AD) scale, which is dementia specific and brief and uses the patient's own responses. Two separate samples of people with dementia (sample 1, n = 60; sample 2, n = 201) were assessed. Five focus groups were conducted involving both people with dementia and their caregivers; the focus groups showed that people with dementia had higher hopes for their QoL than their caregivers did for them. Questionnaires about the scale were completed by 71 health care professionals working with people with dementia. The scale was found to have good content validity with no additional items required and all items necessary. It also correlated well with the Dementia Quality of Life scale (0.69) and with the Euroqol-5D scale (0.54), indicating good criterion concurrent validity. Construct validity was also good with the principal components analysis showing all 13 items of the QoL-AD loaded on component 1. Interrater reliability was excellent with all Cohen's kappa values >0.70. Internal consistency was excellent with a Cronbach's alpha coefficient of 0.82. Some people with severe dementia and a Mini-Mental State Examination score as low as 3 were able to satisfactorily complete the QoL-AD. The QoL-AD has very good psychometric properties and can be completed with people with a wide range of severity of dementia.

Aged↗

PubMed2001

Validation of the SADL questionnaire.

OBJECTIVE: To cross-validate the psychometric characteristics of the Satisfaction with Amplification in Daily Life (SADL) questionnaire (Cox & Alexander, 1999), and to explore the SADL's construct validity. DESIGN: Thirteen private practice Audiology clinics each distributed SADL questionnaires, by mail, to 20 adults who had recently obtained hearing aids. The completed questionnaires were returned to a central site and subject anonymity was assured. There were 196 usable responses. RESULTS: Psychometric characteristics of the items were found to be very similar to those reported previously. Thus, the internal validity of the instrument was strongly supported. The assumption that the SADL quantifies satisfaction by assessing its components was evaluated by examining the relationship between SADL scores and scores on a traditional single-item satisfaction measure. A logical and statistically significant relationship was seen between the two measures, thereby supporting the construct validity of both types of data. For private-pay clients, satisfaction scores were very similar to the interim norms published by Cox and Alexander (1999). However, clients whose hearing aids were partly or fully purchased by insurance or benefits programs tended to be more satisfied than interim norms for third-party pay clients derived 5 yr ago. For most types of clients, there was a tendency toward more satisfaction in the Negative Features subscale than observed in our previous research. CONCLUSIONS: Both construct and internal validity of the SADL questionnaire were supported by this research. The previously published interim norms appear to be mostly appropriate for private-pay clients, but might require adjustment in the Negative Features subscale. Further research is needed to explore the relationship between satisfaction and device purchase issues (third-party versus private pay).

Adult↗