-
[show abstract]
[hide abstract]
ABSTRACT: The log transformation has been widely used in biomedical research to deal with the skewed data. However, in the medical publications, we have found many misuses and misinterpretations of analysis based on log-transformed data. In this paper, we list some common scenarios of misuse and misinterpretation of log transformation in biomedical applications. We also provide both theoretical and practical justifications to support our viewpoints. Copyright © 2012 John Wiley & Sons, Ltd.
Statistics in Medicine 07/2012; · 1.88 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper is aimed to develop and validate the hypertension scale of the system of Quality of Life Instruments for Chronic Diseases, QLICD-HY.
The QLICD-HY instrument was developed based on programmed decision procedures with multiple nominal and focus group discussions and pilot testing. A total of 157 inpatients with hypertension were used to provide the data measuring QOL three times before and after treatment. The psychometric properties of the scale were evaluated with respect to validity, reliability and responsiveness employing correlation and factor analyses, and t-tests.
Correlation and factor analyses confirmed good construct validity and criterion-related validity when using Short Form (36) Health Survey (SF-36) as a criterion. Test-retest reliability coefficients (Pearson r and intra-class correlation (ICC)) for the overall instrument score and all domains except for the hypertension-specific domain (SPD) (0.75) were higher than 0.80 with a range of 0.75-0.91; the internal consistency α for all domains except for the hypertension-specific domain (0.66) was higher than 0.70. The overall score and scores for most facets within each domain except for the social domain (SOD) had statistically significant changes (t-tests) after treatment with moderate effect sizes.
QLICD-HY has good validity, reliability, responsiveness and can be used as the quality-of-life instrument for patients with hypertension.
International journal of nursing studies 12/2011; 49(4):465-80. · 1.91 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The generalized linear mixed-effects model (GLMM) is a popular paradigm to extend models for cross-sectional data to a longitudinal setting. When applied to modeling binary responses, different software packages and even different procedures within a package may give quite different results. In this report, we describe the statistical approaches that underlie these different procedures and discuss their strengths and weaknesses when applied to fit correlated binary responses. We then illustrate these considerations by applying these procedures implemented in some popular software packages to simulated and real study data. Our simulation results indicate a lack of reliability for most of the procedures considered, which carries significant implications for applying such popular software packages in practice. Copyright © 2011 John Wiley & Sons, Ltd.
Statistics in Medicine 06/2011; · 1.88 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: There are few data on the role of drinking patterns in suicidal thoughts or behavior among alcohol-dependent individuals (ADIs) and meager data on variables that may influence the role of drinking in suicidal thoughts and behavior. This study tested a heuristic model that predicts that drinking promotes suicidal thoughts and behavior, the association is mediated (accounted for) by depressive symptoms, and that anger moderates (increases) the risk associated with intense drinking.
Data from Project MATCH, a multisite alcohol use disorders treatment trial, were analyzed using structural equation modeling. There were 1,726 participants including 24% women and a mean age of 40.2 ± 11.0 years. Subjects were assessed at baseline and at 3-, 9-, and 15-month follow-up. Two categorical measures (presence/absence) of suicidal ideation (SI) were used that were analyzed in separate models. Predictors of interest were continuous assessments of average drinking intensity (i.e., drinks per drinking day or DDD), drinking frequency (i.e., percent days abstinent or PDA), depression, and anger.
Both DDD and PDA were associated with SI at a statistically significant level, with PDA showing an inverse association. Depression scores served as a partial mediator or a full mediator of the drinking-SI relationship depending on the measure of SI used in the analysis. The models testing anger scores as a moderator fit the data poorly and did not support that anger serves as a moderator of the drinking-SI association.
Greater drinking intensity and drinking frequency predict SI among ADIs and depression serves as a mediator of these associations, but anger does not appear to serve as a moderator. Further research is required to clarify whether depression serves as a partial or full mediator and to see whether the results herein extend to suicidal behavior (i.e., suicide attempt, suicide).
Alcoholism Clinical and Experimental Research 10/2010; 35(1):60-8. · 3.34 Impact Factor
-
Paul R Duberstein,
Yan Ma,
Benjamin P Chapman,
Yeates Conwell,
Joanne McGriff,
James C Coyne,
Nathan Franus,
Marnin J Heisel,
Kimberly A Kaukeinen,
Silvia Sörensen, Xin M Tu,
Jeffrey M Lyness
[show abstract]
[hide abstract]
ABSTRACT: The capacity of friends and family member informants to make judgments about the presence of a mood disorder history in an older primary care patient has theoretical, clinical, and public health significance. This study examined the accuracy of informant-reported mood disorder diagnoses in a sample of primary care patients aged 65 years or older. We hypothesized that the accuracy (sensitivity and specificity) of informant reports would vary with the patient's personality.
Hypotheses were tested in 191 dyads consisting of patients and their friends or relatives (informants) recruited from primary care settings. Gold-standard mood disorder diagnoses were established at consensus conferences based on a review of medical charts and data collected in a structured interview with the patient. Patients completed an assessment battery that included the NEO-Five Factor Inventory.
Sensitivity and specificity of informant-derived mood disorder diagnoses were related to patient personality. Sensitivity of informant-derived lifetime mood disorder diagnoses was compromised by higher Extraversion and higher Agreeableness. Specificity of informant-derived lifetime mood disorder diagnoses was compromised by lower Agreeableness and higher Conscientiousness.
Patient personality has implications for the accuracy of mood disorder histories provided by friends and family members. Given that false negatives can have grave consequences, we recommend that practitioners be particularly vigilant when interpreting collateral information about their extraverted, agreeable patients.
International Psychogeriatrics 09/2010; 23(4):634-43. · 2.24 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We study the loss of power of the stratified log-rank test (SLRT) compared to the unstratified log-rank test (ULRT) in the case of a large number of strata with relatively a small number of stratum sizes in terms of the asymptotic distributions of test statistics under local alternatives. The SLRT tends to lose information due to overstratification. It is better to test the homogeneity among strata before using the stratified log-rank test.
International Journal of Quality, Statistics, and Reliability. 01/2010;
-
[show abstract]
[hide abstract]
ABSTRACT: This study examined the associations of pretreatment and posttreatment depressive symptoms with drinking outcomes in the year following treatment in Project MATCH (Matching Alcoholism Treatments to Client Heterogeneity), a multisite clinical trial of behavioral treatments for alcohol-use disorders.
Data from 1,726 participants were modeled using generalized estimating equations to examine drinking frequency and intensity, as reflected by percentage days abstinent (PDA) and average drinks per drinking day (DDD). We predicted that patients who reported more pretreatment and posttreatment depressive symptoms would report greater drinking frequency (PDA) and more intense drinking (DDD) across the 12-month follow-up period.
Pretreatment Beck Depression Inventory (BDI) scores predicted more frequent and intense drinking in the year following treatment, although not after accounting for posttreatment BDI scores, which were associated with the drinking outcomes as hypothesized. Patients who reported more depressive symptoms in the year following treatment reported less abstinence (PDA) and more intense drinking (DDD) than patients with fewer posttreatment depressive symptoms.
Our findings underscore the importance of obtaining repeated assessments of depression during the course of substance use treatment. Moreover, the data suggest the potential utility of augmenting standard chemical dependency care with depression-focused interventions for alcohol-dependent patients whose depressive symptoms do not subside during treatment.
Journal of studies on alcohol and drugs 01/2010; 71(1):71-7. · 2.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Conceptually, a moderator is a variable that modifies the effect of a predictor on a response. Analytically, a common approach as used in most moderation analyses is to add analytic interactions involving the predictor and moderator in the form of cross-variable products and test the significance of such terms. The narrow scope of such a procedure is inconsistent with the broader conceptual definition of moderation, leading to confusion in interpretation of study findings. In this paper, we develop a new approach to the analytic procedure that is consistent with the concept of moderation. The proposed framework defines moderation as a process that modifies an existing relationship between the predictor and the outcome, rather than simply a test of a predictor by moderator interaction. The approach is illustrated with data from a real study.
Journal of data science: JDS 07/2009; 7(3):313-329.
-
[show abstract]
[hide abstract]
ABSTRACT: We report preliminary findings of the first ever study testing a 16-week course of Interpersonal Psychotherapy (IPT) modified for older outpatients at elevated risk for suicide. Participants were referred from inpatient and outpatient medicine and mental health services. Psychotherapy sessions took place in a therapist's office in a teaching hospital. Twelve adults 60 years or older (M=70.5, SD=6.1) with current thoughts of suicide (suicide ideation) or a wish to die (death ideation) or with recent self-injurious behavior were recruited into weekly sessions of IPT; one was subsequently excluded due to severe cognitive impairment. Participants completed measures of suicide ideation, death ideation, and depressive symptom severity at pre-treatment, mid-treatment, post-treatment, and at 3-month follow-up periods, and measures of therapeutic process variables. Preliminary findings of this uncontrolled pre-post-treatment study support the feasibility of recruiting and retaining older adults at-risk for suicide into psychotherapy research and suggest that adapted IPT is tolerable and safe. Findings indicate a substantial reduction in participant suicide ideation, death ideation, and depressive symptoms; controlled trials are needed to further evaluate these findings. We discuss implications for clinical care with at-risk older adults.
Professional Psychology Research and Practice 01/2009; 40(2):156-164. · 1.34 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We describe the sexual risk behaviors, psychological distress, and substance use of 102 late adolescent girls and identify predictors of protected and unprotected vaginal sex. Participants completed questionnaires assessing hypothesized predictors and then daily behavioral diaries for 12 weeks. Protected intercourse was predicted by baseline sexual behavior, greater knowledge, positive condom attitudes, lower perceived condom-use difficulty, greater condom-use intentions, more drinking days, less binge drinking, less Ecstasy use, and lower psychological distress. Unprotected intercourse was predicted by baseline sexual behavior, binge drinking, Ecstasy and opiate use, fewer drinking days, and fewer daily drinks. These findings suggest that psychological distress, substance use, and sexual risk behavior are interconnected and should be considered collectively in interventions for adolescent females.
Research in Nursing & Health 09/2008; 31(4):329-40. · 1.71 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Analysis of instrument reliability and rater agreement is used in a wide range of behavioral, medical, psychosocial, and health-care-related research to assess psychometric properties of instruments, consensus in disease diagnoses, fidelity of psychosocial intervention, and accuracy of proxy outcomes. For categorical outcomes, Cohen's kappa is the most widely used index of agreement and reliability. In many modern-day applications, data are often clustered, making inference difficult to perform using existing methods. In addition, as longitudinal study designs become increasingly popular, missing data have become a serious issue, and the lack of methods to systematically address this problem has hampered the progress of research in the aforementioned fields. In this article, we develop a novel approach based on a new class of kappa estimates to tackle the complexities involved in addressing missing data and other related issues arising from a general multirater and longitudinal data setting. The approach is illustrated with real data in sexual health research.
Biometrics 12/2007; 64(3):781-9. · 1.83 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A Simplified Chinese version of the EORTC QLQ-BR53 was evaluated using responses from 233 patients with breast cancer in China by assessing the construct and criterion-related validity, internal consistency and test-retest reliability, and responsiveness as measured by score changes of the scales. Internal consistency reliability measured by Cronbach's coefficient alpha is greater than 0.75 for most multi-item scales except cognitive functioning (0.41) and breast symptoms (0.71). Test-retest reliability coefficients for all domains are greater than 0.80 with the exception of physical functioning (0.65), social functioning (0.75), appetite loss (0.75), diarrhea (0.72), and body image (0.72). Correlation and factor analysis among domains and items showed good construct validity for both QLQ-C30 and QLQ-BR23. Score changes over time were observed in most domains except emotional functioning, global health status/QOL, dyspnoea, constipation, diarrhea, financial difficulties, sexual functioning, sexual enjoyment, and breast symptoms. Therefore, the Simplified Chinese version of QLQ-BR53 shows reasonable validity, reliability, and responsiveness and can be used to measure QOL for Chinese patients with breast cancer.
Breast Cancer Research and Treatment 11/2007; 105(2):187-93. · 4.43 Impact Factor
