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Biomedical subjects

David L Streiner

Publications and source records attributed to David L Streiner.

At least 19 recordsLinked to original sources
PubMed2005

A comparison of Canadian medical students from rural and non-rural backgrounds.

CONTEXT: Very little is known about medical students from rural areas currently enrolled in Canadian medical schools. PURPOSE: We aimed to compare rural and non-rural students in terms of demographics, socioeconomic status, financial status and career choices. METHODS: As part of a larger Internet survey of all students at Canadian medical schools outside Quebec, conducted in January and February 2001, we conducted post-hoc analyses to compare students from rural and non-rural areas. Canada Post's classification system was used to determine rural status. To compare differences between rural and non-rural students, we used logistical regression models for categorical variables and factorial analysis of variance for continuous variables. RESULTS: We received responses from 2994 (68.5%) of 4368 medical students. Eleven percent of Canadian medical students come from rural backgrounds. Rural students tend to be older and originate from families of lower socioeconomic status. Students from rural areas report higher levels of debt, increased rates of paid part-time and summer employment, and greater stress from their finances. Nevertheless, rural students are not more likely to state that financial considerations will affect their choice of specialty or practice location. CONCLUSIONS: Canadian medical students who come from rural backgrounds are different from their non-rural counterparts. Students from rural areas face numerous financial barriers in obtaining a medical education and report greater levels of financial stress. Medical schools should examine and address barriers to admission of rural students and they should consider directing more financial resources toward this financially vulnerable group.

Canada↗
PubMed2004

Relation between randomized controlled trials published in leading general medical journals and the global burden of disease.

BACKGROUND: More than two-thirds of the world's population live in low-income countries, where health priorities are different from those of people living in more affluent parts of the world. We evaluated the relation between the global burden of disease and conditions or diseases studied in randomized controlled trials (RCTs) published in general medical journals. METHODS: A MEDLINE search identified 373 RCTs that had been published in 6 international peer-reviewed general medical journals in 1999. Manual review excluded non-RCTs, brief reports and trials in which the unit of randomization was not the patient; 286 RCTs remained eligible for analysis. We identified the RCTs that studied any of the 40 leading causes of the global burden of disease. Five of these conditions were considered unsuitable for study with an RCT design and were excluded from subsequent analysis. To provide a practical perspective, we asked 12 experts working with international health organizations to rate the relevance to global health of the articles that studied any of the top 10 causes of the global burden of disease, as measured by disability-adjusted life years (DALYs) and mortality, using a 5-point Likert scale. RESULTS: Among the 286 RCTs in our sample, 124 (43.4%) addressed 1 of the 35 leading causes of the global burden of disease. Of these, ischemic heart disease, HIV/AIDS and cerebrovascular disease were the most commonly studied conditions. Ninety articles (31.5%) studied 1 of the top 10 causes of the global burden of disease. The mean rating (and standard deviation) for international health relevance assigned by experts was 2.6 (1.5) out of 5. Only 14 (16%) of the 90 trials received a rating of 4 or greater, indicating high relevance to international health. Almost half of the 40 leading causes of the global burden of disease were not studied by any trial. INTERPRETATION: Many conditions or diseases common internationally are underrepresented in RCTs published in leading general medical journals. Trials published in these journals that studied one of these high-priority conditions were generally rated as being of little relevance to international health.

Bibliometrics↗
PubMed2004

Sex differences in first-year students at Canadian medical schools.

OBJECTIVES: To compare male and female medical students by age, level of education before admission to medical school, race/ethnicity, parental education level, socioeconomic status, and attitudes toward public health care. METHODS: In 2001, we conducted an Internet-based survey of all students enrolled in the 16 medical schools across Canada. Based on the high response rate, first-year medical students at Canadian medical schools outside of Quebec were included in this analysis. The interactions between sex and age, years of premedical education, race/ethnicity, parental occupation, education and household income, impact of finances on choice of medical school, future specialty and practice location, attitudes toward private funding in the Canadian health care system were examined using descriptive statistics and chi2 tests. RESULTS: There were no significant differences between male and female medical students in age, level of education before admission, and race/ethnicity. Female students' fathers (p=.046) and mothers (p=.061) were more likely to hold positions of higher occupational status than were those of male students. There was no significant difference between the parental household incomes of male and female students. Male students were more likely than female students to state that financial considerations would affect their choice of specialty (p=.002) and practice location (p=.002). Male students were more likely to express a positive attitude toward private funding in the health care system, both with respect to increasing the amount of private funding (p=.007) and the addition of private paying patients (p=.002). CONCLUSION: Although women have almost reached equity with men in undergraduate medical education, female students are more likely than male students to have highly educated parents, suggesting that some barriers to access may still exist. The differences in attitudes of female and male medical students to finances and the public health care system become increasingly important as more women practice medicine. These sex differences need to be investigated further, as they could have implications for health policy.

Adult↗
PubMed2004

Program structure and continuity of mental health care.

Continuity has been a much discussed but under-researched objective of mental health care, in part due to measurement challenges. A small body of research has identified program features associated with continuity, based on measures of service use. A recent planning project provided an opportunity to examine the effects of these features on continuity using a new self-report continuity measure. Nine program features were measured and linear regression analyses were used to assess the relationship between these features and continuity, controlling for client characteristics. Client continuity was higher in programs that offered some night or weekend coverage and lower in programs that provided more care in the community. This latter finding was unexpected and may represent program efforts to engage individuals experiencing difficulties with service access. The association between each of the other 7 program features and continuity was not significant. Possible explanations for this finding are explored.

Community Mental Health Services↗
PubMed2003

Health-related quality of life in childhood epilepsy: moving beyond 'seizure control with minimal adverse effects'.

Childhood epilepsy is one of the most important and prevalent neurological conditions in the developing years. Persons with childhood onset epilepsy are at a high risk for poor psychosocial outcomes, even without experiencing co-morbidities. The goal of management of children with epilepsy should be to enable the child and the family to lead a life as free as possible from the medical and psychosocial complications of epilepsy. This comprehensive care needs to go beyond simply trying to control seizures with minimal adverse drug reactions. Seizure frequency and severity is only one important outcome variable. Other factors such as social, psychological, behavioural, educational, and cultural dimensions of their lives affect children with epilepsy, their families and their close social networks. A number of epilepsy-specific health-related quality of life (HRQL) scales for children have been developed with the aim to include and measure accurately the impact and burden of epilepsy. Their target populations, details of the origin of the items, and psychometric properties vary significantly. Their strengths and weaknesses will be identified more clearly through their continued use in the clinical setting and in research studies. Only a few studies to date have utilized these or generic HRQL measures to assess the HRQL of specific populations with epilepsy. Future research needs to develop theory driven models of HRQL and identify measurable factors that have important correlations with outcomes. Since biomedical variables like seizure frequency and severity have only moderate correlations with HRQL, other independent factors including the child's resilience, co-morbid conditions, parental well-being, family factors and societal/cultural variables may play a major role. We also need to learn what encompasses comprehensive patient care, define the goals of management and evaluate the impact of different interventions. Future studies need to include the children's own perspectives of their HRQL in addition to parental reports. Finally, clinicians need to familiarize themselves with outcome measures, be able to evaluate them, and use them routinely in their day-to-day practice.

Child↗
PubMed2003

Stability of maternal preferences for pediatric health states in the perinatal period and 1 year later.

BACKGROUND: We have previously shown that parents of premature children provided relatively high valuation of their children's health state in adolescence. However, stability of parental preferences for future pediatric health states is unknown during the antenatal and neonatal periods and infancy. OBJECTIVE: To determine whether preference-based, health-related quality-of-life scores obtained serially from 2 cohorts (women with high-risk pregnancies [antenatal cohort] and mothers of very low-birth-weight newborns [VLBW cohort]) are stable during the first year after birth. DESIGN AND METHODS: Longitudinal cohort study. Participants included 80 high-risk pregnant women recruited at 24 +/- 2 weeks of gestation, and 75 mothers of VLBW infants recruited within 1 week of delivery. We conducted 2 to 3 standardized interviews (antenatally, at 1 week after delivery, and at the 12-month corrected age visit) using the Standard Gamble technique to elicit preferences for 5 pediatric hypothetical health states with varying disabilities. RESULTS: Seventy-three mothers with high-risk pregnancies (91%) and 72 mothers of VLBW infants (96%) completed all scheduled interviews. As expected, preference scores were affected by the level of severity of the hypothetical health states (antenatal cohort, F(4,288) = 87.0 [P<.001]; VLBW cohort, F(4,284) = 64.2 [P<.001]). At each assessment, at least 38% of mothers rated 1 or more health states as worse than death. Repeated-measures analysis showed no change in preference scores over time (antenatal cohort, F(2,144) = 1.3 [P =.29]; VLBW cohort, F(1,71) = 0.7 [P =.42]). Maternal socioemotional factors, infant severity of illness at birth, and global health at 12 months did not affect preference scores. CONCLUSION: In our population, maternal preference scores for disabling health states appear to be stable during the first year of life and are unaffected by key maternal and infant variables.

Adult↗
PubMed2003

Clinimetrics vs. psychometrics: an unnecessary distinction.

The term "clinimetrics" was introduced by Feinstein to describe an approach to scale development that ostensibly is different from the more traditional "psychometrics." I argue that, for a number of reasons, it is time for this term to retire from the scene. I show that the clinimetric approach is neither new nor unique, but is rather a subset of psychometrics. Further, because the majority of new developments in scale construction (e.g., new variations of the intraclass correlation, item response theory, structural equation modeling, and cognitive theories) are reported in the psychometric literature, use of the term "clinimetric," especially among people not exposed to traditional test theory, cuts them off from a rich source of information.

Health Status↗
PubMed2003

Health-related quality of life in children with epilepsy: development and validation of self-report and parent proxy measures.

PURPOSE: To answer a need to include and measure accurately the impact and burden of epilepsy as outcomes of interventions with affected children, we developed and validated self-report and parent-proxy respondent health-related quality of life (HRQL) instruments for preadolescent children with epilepsy. METHODS: We combined qualitative and quantitative research methods. Items were extracted from focus group discussions involving children with epilepsy and their parents. We created scales formatted with alternative paired options of forced responses and used factor analysis to generate relevant subscales and reduce the number of items. We checked internal consistency, assessed test-retest reliability 10-14 days apart, and documented construct validity. RESULTS: A sample of 381 children with epilepsy, age 6-15 years, and their parents independently completed a 67-item questionnaire, from which we chose five items for each subscale. The measures share four subscales, but each measure has an additional distinct subscale. The children and parents could discern differences and report differentially between the various aspects of the HRQL. Internal consistency measured with Cronbach's alpha was acceptable for all subscales; construct validity has been demonstrated from the testing of several hypotheses. Test-retest reliability examined with the intraclass correlation coefficient was satisfactory for the parents and for children age 8 years and older. The correlations between the mothers' and children's responses was poor to moderate. CONCLUSIONS: The data demonstrate sound psychometric properties for both related measures, which are easy to administer for children with epilepsy who are 8 years and older and their parents. The subscales encompass HRQL dimensions judged most important by children with epilepsy for the self-report measure and by parents for the proxy response measure. The parent-proxy measure should be useful as a complement to the child self-report measure in evaluating the validity of parental assessment of the child's health status; in longitudinal outcome research; and in HRQL assessment of children who are unable to respond independently.

Adolescent↗
PubMed2003

Unicorns do exist: a tutorial on "proving" the null hypothesis.

Introductory statistics classes teach us that we can never prove the null hypothesis; all we can do is reject or fail to reject it. However, there are times when it is necessary to try to prove the nonexistence of a difference between groups. This most often happens within the context of comparing a new treatment against an established one and showing that the new intervention is not inferior to the standard. This article first outlines the logic of "noninferiority" testing by differentiating between the null hypothesis (that which we are trying to nullify) and the "nill" hypothesis (there is no difference), reversing the role of the null and alternate hypotheses, and defining an interval within which groups are said to be equivalent. We then work through an example and show how to calculate sample sizes for noninferiority studies.

Humans↗
PubMed2003

Starting at the beginning: an introduction to coefficient alpha and internal consistency.

Cronbach's a is the most widely used index of the reliability of a scale. However, its use and interpretation can be subject to a number of errors. This article discusses the historical development of a from other indexes of internal consistency (split-half reliability and Kuder-Richardson 20) and discusses four myths associated with a: (a) that it is a fixed property of the scale, (b) that it measures only the internal consistency of the scale, (c) that higher values are always preferred over lower ones, and (d) that it is restricted to the range of 0 to 1. It provides some recommendations for acceptable values of a in different situations.

Canada↗
PubMed2003

Being inconsistent about consistency: when coefficient alpha does and doesn't matter.

One of the central tenets of classical test theory is that scales should have a high degree of internal consistency, as evidenced by Cronbach's a, the mean interitem correlation, and a strong first component. However, there are many instances in which this rule does not apply. Following Bollen and Lennox (1991), I differentiate between questionnaires such as anxiety or depression inventories, which are composed of items that are manifestations of an underlying hypothetical construct (i.e., where the items are called effect indicators) and those such as Scale 6 of the Minnesota Multiphasic Personality Inventory (Hathaway & McKinley, 1943) and ones used to tap quality of life or activities of daily living in which the items or subscales themselves define the construct (these items are called causal indicators). Questionnaires of the first sort, which are referred to as scales in this article, meet the criteria of classical test theory, whereas the second type, which are called indexes here, do not. I discuss the implications of this difference for how items are selected, the relationship among the items, and the statistics that should and should not be used in establishing the reliability of the scale or index.

Activities of Daily Living↗
PubMed2003

Diagnosing tests: using and misusing diagnostic and screening tests.

Tests can be used either diagnostically (i.e., to confirm or rule out the presence of a condition in people suspected of having it) or as a screening instrument (determining who in a large group of people has the condition and often when those people are unaware of it or unwilling to admit to it). Tests that may be useful and accurate for diagnosis may actually do more harm than good when used as a screening instrument. The reason is that the proportion of false negatives may be high when the prevalence is high, and the proportion of false positives tends to be high when the prevalence of the condition is low (the usual situation with screening tests). My first aim of this article is to discuss the effects of the base rate, or prevalence, of a disorder on the accuracy of test results. My second aim is to review some of the many diagnostic efficiency statistics that can be derived from a 2 x 2 table, including the overall correct classification rate, kappa, phi, the odds ratio, positive and negative predictive power and some variants of them, and likelihood ratios. In the last part of this article, I review the recent Standards for Reporting of Diagnostic Accuracy guidelines (Bossuyt et al., 2003) for reporting the results of diagnostic tests and extend them to cover the types of tests used by psychologists.

Abstracting and Indexing↗
PubMed2003

School-age outcomes in children who were extremely low birth weight from four international population-based cohorts.

OBJECTIVE: The aim of this study was to determine whether learning and school problems in extremely low birth weight (ELBW) and reference children differ between cohorts in different countries. METHODS: Participants were 4 international population-based cohorts of ELBW survivors who were 500 to 1000 g birth weight from New Jersey, central-west Ontario, Bavaria, and Holland (n = 532) and were followed longitudinally from birth. Psychometric data were collected independently and prospectively and included at least 1 measure of cognitive status and 1 measure of achievement administered to the children between the ages of 8 and 11 years. Adjustments were made for comparison of all measures based on reference norms within each country. Information on special educational assistance and grade repetition was obtained from the parents. RESULTS: The overall follow-up rate was 84% (range: 74%-90%; n = 436). The proportion of children who performed within the normal range (> or =85) were as follows: IQ between 44% and 62%; reading between 46% and 81%; arithmetic between 31% and 76%; and spelling between 39% and 65%. Children from New Jersey had the lowest rates of cognitive and achievement deficits, and Bavarian children did less well in achievement scores relative to their peers and other cohorts. Despite these differences, more than half of all cohorts required special educational assistance and/or repeated a grade. CONCLUSIONS: School difficulties were found to be a serious sequelae of ELBW in all 4 countries, an observation that has social and economic implications.

Child↗
PubMed2003

Exploring the association between atypical neuroleptic agents and diabetes mellitus in older adults.

STUDY OBJECTIVE: To explore the suggested association between atypical neuroleptic use and the development of diabetes mellitus, with a focus on older adults. DESIGN: Retrospective cohort study. SUBJECTS: Eleven thousand one hundred four older (> 65 yrs) residents of long-term care institutions in Ontario, Canada, who received either atypical neuroleptic agents, typical neuroleptic agents, benzodiazepines, or corticosteroids. MEASUREMENTS AND MAIN RESULTS: Each subject was followed for the development of a diabetic event, defined as newly prescribed antidiabetic drug therapy. Our Cox regression model was adjusted for age, sex, socioeconomic status, comorbidity, and concomitant use of beta-blockers, thiazide diuretics, and antiepileptic agents. The adjusted hazard ratio for the development of diabetes in patients receiving atypical neuroleptics compared with those receiving benzodiazepines (control group) was 0.89 (95% confidence interval [CI] 0.66-1.21). The adjusted hazard ratio for typical neuroleptic users compared with the benzodiazepine group was 1.27 (95% CI 0.91-1.77). As expected, patients receiving corticosteroid therapy were almost twice as likely to develop diabetes as those receiving benzodiazepines (adjusted hazard ratio 2.2, 95% CI 1.41-3.12). For patients receiving atypical neuroleptic agents, no statistically significant difference in the percentage of diabetic events was found among individual agents (2.1% olanzapine, 1% quetiapine, 2.1% risperidone). CONCLUSION: Drug therapy with atypical neuroleptic agents in older adults did not increase their risk of developing diabetes mellitus.

Aged↗
PubMed2002

Comparison of review articles published in peer-reviewed and throwaway journals.

CONTEXT: To compare the quality, presentation, readability, and clinical relevance of review articles published in peer-reviewed and "throwaway" journals. METHODS: We reviewed articles that focused on the diagnosis or treatment of a medical condition published between January 1 and December 31, 1998, in the 5 leading peer-reviewed general medical journals and high-circulation throwaway journals. Reviewers independently assessed the methodologic and reporting quality, and evaluated each article's presentation and readability. Clinical relevance was evaluated independently by 6 physicians. RESULTS: Of the 394 articles in our sample, 16 (4.1%) were peer-reviewed systematic reviews, 135 (34.3%) were peer-reviewed nonsystematic reviews, and 243 (61.7%) were nonsystematic reviews published in throwaway journals. The mean (SD) quality scores were highest for peer-reviewed articles (0.94 [0.09] for systematic reviews and 0.30 [0.19] for nonsystematic reviews) compared with throwaway journal articles (0.23 [0.03], F(2,391) = 280.8, P<.001). Throwaway journal articles used more tables (P =.02), figures (P =.01), photographs (P<.001), color (P<.001), and larger font sizes (P<.001) compared with peer-reviewed articles. Readability scores were more often in the college or higher range for peer-reviewed journals compared with the throwaway journal articles (104 [77.0%] vs 156 [64.2%]; P =.01). Peer-reviewed article titles were judged less relevant to clinical practice than throwaway journal article titles (P<.001). CONCLUSIONS: Although lower in methodologic and reporting quality, review articles published in throwaway journals have characteristics that appeal to physician readers.

Consumer Behavior↗