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1.
BMC Med Res Methodol ; 23(1): 128, 2023 05 25.
Article in English | MEDLINE | ID: mdl-37231360

ABSTRACT

Although superficially similar to data from clinical research, data extracted from electronic health records may require fundamentally different approaches for model building and analysis. Because electronic health record data is designed for clinical, rather than scientific use, researchers must first provide clear definitions of outcome and predictor variables. Yet an iterative process of defining outcomes and predictors, assessing association, and then repeating the process may increase Type I error rates, and thus decrease the chance of replicability, defined by the National Academy of Sciences as the chance of "obtaining consistent results across studies aimed at answering the same scientific question, each of which has obtained its own data."[1] In addition, failure to account for subgroups may mask heterogeneous associations between predictor and outcome by subgroups, and decrease the generalizability of the findings. To increase chances of replicability and generalizability, we recommend using a stratified split sample approach for studies using electronic health records. A split sample approach divides the data randomly into an exploratory set for iterative variable definition, iterative analyses of association, and consideration of subgroups. The confirmatory set is used only to replicate results found in the first set. The addition of the word 'stratified' indicates that rare subgroups are oversampled randomly by including them in the exploratory sample at higher rates than appear in the population. The stratified sampling provides a sufficient sample size for assessing heterogeneity of association by testing for effect modification by group membership. An electronic health record study of the associations between socio-demographic factors and uptake of hepatic cancer screening, and potential heterogeneity of association in subgroups defined by gender, self-identified race and ethnicity, census-tract level poverty and insurance type illustrates the recommended approach.


Subject(s)
Electronic Health Records , Research Design , Humans , Ethnicity , Poverty , Sample Size
2.
Commun Stat Theory Methods ; 52(1): 46-64, 2023.
Article in English | MEDLINE | ID: mdl-36743328

ABSTRACT

When designing repeated measures studies, both the amount and the pattern of missing outcome data can affect power. The chance that an observation is missing may vary across measurements, and missingness may be correlated across measurements. For example, in a physiotherapy study of patients with Parkinson's disease, increasing intermittent dropout over time yielded missing measurements of physical function. In this example, we assume data are missing completely at random, since the chance that a data point was missing appears to be unrelated to either outcomes or covariates. For data missing completely at random, we propose noncentral F power approximations for the Wald test for balanced linear mixed models with Gaussian responses. The power approximations are based on moments of missing data summary statistics. The moments were derived assuming a conditional linear missingness process. The approach provides approximate power for both complete-case analyses, which include independent sampling units where all measurements are present, and observed-case analyses, which include all independent sampling units with at least one measurement. Monte Carlo simulations demonstrate the accuracy of the method in small samples. We illustrate the utility of the method by computing power for proposed replications of the Parkinson's study.

3.
BMC Med Res Methodol ; 23(1): 12, 2023 01 12.
Article in English | MEDLINE | ID: mdl-36635621

ABSTRACT

BACKGROUND: When evaluating the impact of environmental exposures on human health, study designs often include a series of repeated measurements. The goal is to determine whether populations have different trajectories of the environmental exposure over time. Power analyses for longitudinal mixed models require multiple inputs, including clinically significant differences, standard deviations, and correlations of measurements. Further, methods for power analyses of longitudinal mixed models are complex and often challenging for the non-statistician. We discuss methods for extracting clinically relevant inputs from literature, and explain how to conduct a power analysis that appropriately accounts for longitudinal repeated measures. Finally, we provide careful recommendations for describing complex power analyses in a concise and clear manner. METHODS: For longitudinal studies of health outcomes from environmental exposures, we show how to [1] conduct a power analysis that aligns with the planned mixed model data analysis, [2] gather the inputs required for the power analysis, and [3] conduct repeated measures power analysis with a highly-cited, validated, free, point-and-click, web-based, open source software platform which was developed specifically for scientists. RESULTS: As an example, we describe the power analysis for a proposed study of repeated measures of per- and polyfluoroalkyl substances (PFAS) in human blood. We show how to align data analysis and power analysis plan to account for within-participant correlation across repeated measures. We illustrate how to perform a literature review to find inputs for the power analysis. We emphasize the need to examine the sensitivity of the power values by considering standard deviations and differences in means that are smaller and larger than the speculated, literature-based values. Finally, we provide an example power calculation and a summary checklist for describing power and sample size analysis. CONCLUSIONS: This paper provides a detailed roadmap for conducting and describing power analyses for longitudinal studies of environmental exposures. It provides a template and checklist for those seeking to write power analyses for grant applications.


Subject(s)
Environmental Exposure , Research Design , Humans , Sample Size , Environmental Exposure/adverse effects , Software , Longitudinal Studies
4.
Acad Pediatr ; 22(3S): S100-S107, 2022 04.
Article in English | MEDLINE | ID: mdl-35339236

ABSTRACT

BACKGROUND AND OBJECTIVE: First-line, nonpharmacological therapy is recommended for many pediatric mental health (MH) conditions prior to initiating antipsychotic prescription therapies. Many children do not receive these recommended services, despite the known association between antipsychotic medications and metabolic dysfunction. The main objective of this study was to quantify the association among children's MH diagnosis categories, sociodemographic characteristics and receipt of first-line psychosocial care among children in Florida Medicaid METHODS: Florida Medicaid enrollment, healthcare and pharmacy claims were used for this multivariate analysis. Children were assigned to condition clusters wherein related diagnoses were grouped into clinically relevant categories. A total of 7704 children were included in the final analysis. RESULTS: Twenty-four percent of children in Florida Medicaid do not receive first-line, nonpharmacological psychosocial care. Age was significantly associated with not receiving psychosocial services, with older children less likely to receive. Non-Hispanic White children as well as those living in rural areas had lower odds of receiving behavioral intervention prior to initiating antipsychotics. Children with mood-disorders, behavior problems, anxiety and stress related disorders were more likely to receive first-line psychosocial care. CONCLUSIONS: This study provides an important understanding of the variability in receipt of first-line psychosocial care before antipsychotic medication initiation among children in Medicaid based on sociodemographic and MH health characteristics. These analyses can be used to develop quality improvement initiatives targeted toward children that are most vulnerable for not receiving recommended care.


Subject(s)
Antipsychotic Agents , Psychiatric Rehabilitation , Adolescent , Antipsychotic Agents/therapeutic use , Child , Florida , Humans , Medicaid , Mood Disorders/drug therapy , United States
5.
Acad Pediatr ; 22(3S): S140-S149, 2022 04.
Article in English | MEDLINE | ID: mdl-35339240

ABSTRACT

OBJECTIVE: We sought to examine the extent to which body mass index (BMI) was available in electronic health records for Florida Medicaid recipients aged 5 to 18 years taking Second-Generation Antipsychotics (SGAP). We also sought to illustrate how clinical data can be used to identify children most at-risk for SGAP-induced weight gain, which cannot be done using process-focused measures. METHODS: Electronic health record (EHR) data and Medicaid claims were linked from 2013 to 2019. We quantified sociodemographic differences between children with and without pre- and post-BMI values. We developed a linear regression model of post-BMI to examine pre-post changes in BMI among 4 groups: 1) BH/SGAP+ children had behavioral health conditions and were taking SGAP; 2) BH/SGAP- children had behavioral health conditions without taking SGAP; 3) children with asthma; and 4) healthy children. RESULTS: Of 363,360 EHR-Medicaid linked children, 18,726 were BH/SGAP+. Roughly 4% of linked children and 8% of BH/SGAP+ children had both pre and post values of BMI required to assess quality of SGAP monitoring. The percentage varied with gender and race-ethnicity. The R2 for the regression model with all predictors was 0.865. Pre-post change in BMI differed significantly (P < .0001) among the groups, with more BMI gain among those taking SGAP, particularly those with higher baseline BMI. CONCLUSION: Meeting the 2030 Centers for Medicare and Medicaid Services goal of digital monitoring of quality of care will require continuing expansion of clinical encounter data capture to provide the data needed for digital quality monitoring. Using linked EHR and claims data allows identifying children at higher risk for SGAP-induced weight gain.


Subject(s)
Antipsychotic Agents , Adolescent , Aged , Antipsychotic Agents/adverse effects , Body Mass Index , Child , Child, Preschool , Humans , Medicaid , Medicare , United States , Weight Gain
7.
Medicine (Baltimore) ; 100(50): e28316, 2021 Dec 17.
Article in English | MEDLINE | ID: mdl-34918711

ABSTRACT

ABSTRACT: Hepatitis C virus (HCV) infection is a leading risk factor for hepatocellular carcinoma.We employed a retrospective cohort study design and analyzed 2012-2018 Medicaid claims linked with electronic health records data from the OneFlorida Data Trust, a statewide data repository containing electronic health records data for 15.07 million Floridians from 11 health care systems. Only adult patients at high-risk for HCV (n = 30,113), defined by diagnosis of: HIV/AIDS (20%), substance use disorder (64%), or sexually transmitted infections (22%) were included. Logistic regression examined factors associated with meeting the recommended sequence of HCV testing.Overall, 44.1% received an HCV test. The odds of receiving an initial test were significantly higher for pregnant females (odds ratio [OR]1.99; 95% confidence interval [CI] 1.86-2.12; P < .001) and increased with age (OR 1.01; 95% CI 1.00-1.01; P < .001).Among patients with low Charlson comorbidity index (CCI = 1), non-Hispanic (NH) black patients (OR 0.86; 95% CI 0.81-0.9; P < .001) had lower odds of getting an HCV test; however, NH black patients with CCI = 10 had higher odds (OR 1.41; 95% CI 1.21-1.66; P < .001) of receiving a test. Of those who tested negative during initial testing, 17% received a second recommended test after 6 to 24 months. Medicaid-Medicare dual eligible patients, those with high CCI (OR 1.14; 95% CI 1.11-1.17; P < .001), NH blacks (OR 1.93; 95% CI 1.61-2.32; P < .001), and Hispanics (OR 1.49; 95% CI 1.08-2.06; P = .02) were significantly more likely to have received a second HCV test, while pregnant females (OR 0.71; 95% CI 0.57-0.89; P = .003), had lower odds of receiving it. The majority of patients who tested positive during the initial test (97%) received subsequent testing.We observed suboptimal adherence to the recommended HCV testing among high-risk patients underscoring the need for tailored interventions aimed at successfully navigating high-risk individuals through the HCV screening process. Future interventional studies targeting multilevel factors, including patients, clinicians and health systems are needed to increase HCV screening rates for high-risk populations.


Subject(s)
Guideline Adherence/statistics & numerical data , Hepacivirus , Hepatitis C/diagnosis , Mass Screening , Medicaid/statistics & numerical data , Aged , Female , HIV Infections/diagnosis , HIV Infections/epidemiology , Hepatitis C/epidemiology , Humans , Medicare , Middle Aged , Pregnancy , Retrospective Studies , United States/epidemiology
8.
PLoS One ; 16(7): e0254811, 2021.
Article in English | MEDLINE | ID: mdl-34288958

ABSTRACT

We derive a noncentral [Formula: see text] power approximation for the Kenward and Roger test. We use a method of moments approach to form an approximate distribution for the Kenward and Roger scaled Wald statistic, under the alternative. The result depends on the approximate moments of the unscaled Wald statistic. Via Monte Carlo simulation, we demonstrate that the new power approximation is accurate for cluster randomized trials and longitudinal study designs. The method retains accuracy for small sample sizes, even in the presence of missing data. We illustrate the method with a power calculation for an unbalanced group-randomized trial in oral cancer prevention.


Subject(s)
Computer Simulation , Models, Biological , Neoplasms/therapy , Humans , Linear Models , Monte Carlo Method , Randomized Controlled Trials as Topic , Sample Size
9.
Value Health ; 24(3): 361-368, 2021 03.
Article in English | MEDLINE | ID: mdl-33641770

ABSTRACT

OBJECTIVES: Promoting patient involvement in managing co-occurring physical and mental health conditions is increasingly recognized as critical to improving outcomes and controlling costs in this growing chronically ill population. The main objective of this study was to conduct an economic evaluation of the Wellness Incentives and Navigation (WIN) intervention as part of a longitudinal randomized pragmatic clinical trial for chronically ill Texas Medicaid enrollees with co-occurring physical and mental health conditions. METHODS: The WIN intervention used a personal navigator, motivational interviewing, and a flexible wellness expense account to increase patient activation, that is, the patient's knowledge, skills, and confidence in managing their self-care and co-occurring physical and mental health conditions. Regression models were fit to both participant-level quality-adjusted life years (QALYs) and total costs of care (including the intervention) controlling for demographics, health status, poverty, Medicaid managed care plan, intervention group, and baseline health utility and costs. Incremental costs and QALYs were calculated based on the difference in predicted costs and QALYs under intervention versus usual care and were used to calculate the incremental cost-effectiveness ratios (ICERs). Confidence intervals were calculated using Fieller's method, and sensitivity analyses were performed. RESULTS: The mean ICER for the intervention compared with usual care was $12 511 (95% CI $8971-$16 842), with a sizable majority of participants (70%) having ICERs below $40 000. The WIN intervention also produced higher QALY increases for participants who were sicker at baseline compared to those who were healthier at baseline. CONCLUSION: The WIN intervention shows considerable promise as a cost-effective intervention in this challenging chronically ill population.


Subject(s)
Health Knowledge, Attitudes, Practice , Health Promotion/organization & administration , Medicaid/statistics & numerical data , Multiple Chronic Conditions/epidemiology , Adult , Cost-Benefit Analysis , Female , Health Promotion/economics , Health Status , Humans , Longitudinal Studies , Male , Medicaid/economics , Motivational Interviewing/organization & administration , Patient Navigation/organization & administration , Quality-Adjusted Life Years , Self Care , Self Concept , Socioeconomic Factors , Texas/epidemiology , United States , Young Adult
10.
Health Serv Res ; 54(6): 1156-1165, 2019 12.
Article in English | MEDLINE | ID: mdl-31642066

ABSTRACT

OBJECTIVE: To examine whether the Wellness Incentive and Navigation (WIN) intervention can improve health-related quality of life (HRQOL) among Medicaid enrollees with co-occurring physical and behavioral health conditions. DATA SOURCES: Annual telephone survey data from 2013 to 2016, linked with claims data. STUDY DESIGN: We recruited 1259 participants from the Texas STAR + PLUS managed care program and randomized them into an intervention group that received flexible wellness accounts and navigator services or a control group that received standard care. We conducted 4 waves of telephone surveys to collect data on HRQOL, patient activation, and other participant demographic and clinical characteristics. DATA COLLECTION/EXTRACTION METHODS: The 3M Clinical Risk Grouping Software was used to extract variables from claims data and group participants based on disease severity. PRINCIPAL FINDINGS: Our results showed that the WIN intervention was effective in increasing patient activation and HRQOL among Medicaid enrollees with co-occurring physical and behavioral health conditions. Furthermore, we found that this intervention effect on HRQOL was partially mediated by patient activation. CONCLUSIONS: Providing navigator support with wellness account is effective in improving HRQOL among Medicaid enrollees. The pragmatic nature of the trial maximizes the chance of successfully implementing it in state Medicaid programs.


Subject(s)
Health Behavior , Health Promotion/methods , Medicaid/statistics & numerical data , Motivation , Patient Navigation/methods , Patient Participation/psychology , Quality of Life/psychology , Adult , Female , Humans , Male , Middle Aged , Patient Participation/statistics & numerical data , Surveys and Questionnaires , Texas , United States
11.
Med Care Res Rev ; 76(4): 444-461, 2019 08.
Article in English | MEDLINE | ID: mdl-29148345

ABSTRACT

Patient activation, the perceived capacity to manage one's health, is positively associated with better health outcomes and lower costs. Underlying characteristics influencing patient activation are not completely understood leading to gaps in intervention strategies designed to improve patient activation. We suggest that variability in executive functioning influences patient activation and ultimately has an impact on health outcomes. To examine this hypothesis, 440 chronically ill Medicaid enrollees completed measures of executive functioning, patient activation, and health-related quality of life. Mediation analyses revealed that executive functioning: (a) directly affected patient activation and mental health-related quality of life, (b) indirectly affected mental health-related quality of life through patient activation, and (c) was unrelated to physical health-related quality of life. These data indicate that further study of the relationships among neurocognitive processes, patient activation, and health-related quality of life is needed and reinforces previous work demonstrating the association between patient activation and self-reported outcomes.


Subject(s)
Chronic Disease/psychology , Comorbidity , Executive Function/physiology , Quality of Life/psychology , Self Care , Adult , Female , Health Promotion , Humans , Longitudinal Studies , Male , Medicaid , Motivation , United States
12.
Am Stat ; 73(4): 350-359, 2019.
Article in English | MEDLINE | ID: mdl-32042203

ABSTRACT

Despite the popularity of the general linear mixed model for data analysis, power and sample size methods and software are not generally available for commonly used test statistics and reference distributions. Statisticians resort to simulations with homegrown and uncertified programs or rough approximations which are misaligned with the data analysis. For a wide range of designs with longitudinal and clustering features, we provide accurate power and sample size approximations for inference about fixed effects in linear models we call reversible. We show that under widely applicable conditions, the general linear mixed-model Wald test has non-central distributions equivalent to well-studied multivariate tests. In turn, exact and approximate power and sample size results for the multivariate Hotelling-Lawley test provide exact and approximate power and sample size results for the mixed-model Wald test. The calculations are easily computed with a free, open-source product that requires only a web browser to use. Commercial software can be used for a smaller range of reversible models. Simple approximations allow accounting for modest amounts of missing data. A real-world example illustrates the methods. Sample size results are presented for a multicenter study on pregnancy. The proposed study, an extension of a funded project, has clustering within clinic. Exchangeability among participants allows averaging across them to remove the clustering structure. The resulting simplified design is a single level longitudinal study. Multivariate methods for power provide an approximate sample size. All proofs and inputs for the example are in the Supplementary Materials (available online).

13.
J Form Des Learn ; 3(2): 97-110, 2019 Dec.
Article in English | MEDLINE | ID: mdl-33134804

ABSTRACT

The purpose of this design and development case is to share our experiences in the transformation of a face-to-face workshop into a Massive Open Online Course (MOOC) for a prominent MOOC platform. The goal of the workshop and MOOC is to teach learners how to conduct appropriate power and sample size analysis for multilevel and longitudinal studies in social and behavioral health research. Learners include people from across the biomedical research spectrum, from students to full professors. We first describe the design and development frameworks and processes used to create the three-day, face-to-face workshop. Then, we detail the design and development approach to transform this face-to-face workshop into a MOOC. At a macro-design level, we employed backward design (Wiggins & McTighe, 1998) as an instructional design framework. At a micro-design level, we used a combination of the first principles of instruction, the cognitive theory of multimedia learning, the nine events of instruction, and design recommendations for MOOCs found in the literature. We report the results of a formative evaluation of the MOOC. Finally, we provide closing remarks, lessons learned, and the next steps for the instructional program.

14.
JAMA Dermatol ; 154(11): 1272-1280, 2018 11 01.
Article in English | MEDLINE | ID: mdl-30208471

ABSTRACT

Importance: Nevi are a risk factor for melanoma and other forms of skin cancer, and many of the same factors confer risk for both. Understanding childhood nevus development may provide clues to possible causes and prevention of melanoma. Objectives: To describe nevus acquisition from the ages of 3 to 16 years among white youths and evaluate variation by sex, Hispanic ethnicity, and body sites that are chronically vs intermittently exposed to the sun. Design, Setting, and Participants: This annual longitudinal observational cohort study of nevus development was conducted between June 1, 2001, and October 31, 2014, among 1085 Colorado youths. Data analysis was conducted between February 1, 2015, and August 31, 2017. Main Outcomes and Measures: Total nevus counts on all body sites and on sites chronically and intermittently exposed to the sun separately. Results: A total of 557 girls and 528 boys (150 [13.8%] Hispanic participants) born in 1998 were included in this study. Median total body nevus counts increased linearly among non-Hispanic white boys and girls between the age of 3 years (boys, 6.31; 95% CI, 5.66-7.03; and girls, 6.61; 95% CI, 5.96-7.33) and the age of 16 years (boys, 81.30; 95% CI, 75.95-87.03; and girls, 77.58; 95% CI, 72.68-82.81). Median total body nevus counts were lower among Hispanic white children (boys aged 16 years, 51.45; 95% CI, 44.01-60.15; and girls aged 16 years, 53.75; 95% CI, 45.40-63.62) compared with non-Hispanic white children, but they followed a largely linear trend that varied by sex. Nevus counts on body sites chronically exposed to the sun increased over time but leveled off by the age of 16 years. Nevus counts on sites intermittently exposed to the sun followed a strong linear pattern through the age of 16 years. Hispanic white boys and girls had similar nevus counts on sites intermittently exposed to the sun through the age of 10 years, but increases thereafter were steeper for girls, with nevus counts surpassing those of boys aged 11 to 16 years. Conclusions and Relevance: Youths are at risk for nevus development beginning in early childhood and continuing through midadolescence. Patterns of nevus acquisition differ between boys and girls, Hispanic and non-Hispanic white youths, and body sites that are chronically exposed to the sun and body sites that are intermittently exposed to the sun. Exposure to UV light during this period should be reduced, particularly on body sites intermittently exposed to the sun, where nevi accumulate through midadolescence in all children. Increased attention to sun protection appears to be merited for boys, in general, because they accumulated more nevi overall, and for girls, specifically, during the adolescent years.


Subject(s)
Ethnicity , Nevus/ethnology , Program Evaluation , Skin Neoplasms/ethnology , Sunburn/prevention & control , Ultraviolet Rays/adverse effects , Child , Child, Preschool , Cohort Studies , Colorado/epidemiology , Female , Follow-Up Studies , Humans , Incidence , Male , Nevus/etiology , Retrospective Studies , Risk Factors , Skin Neoplasms/etiology , Sunburn/complications
16.
Am J Drug Alcohol Abuse ; 44(2): 160-166, 2018.
Article in English | MEDLINE | ID: mdl-29451414

ABSTRACT

BACKGROUND: Despite concerns over measurement error, self-report continues to be the most common measure of adolescent alcohol use used by researchers. Objective measures of adolescent alcohol use continue to advance; however, they tend to be cost prohibitive for larger studies. By combining appropriate statistical techniques and validation subsamples, the benefits of objective alcohol measures can be made more accessible to a greater number of researchers. OBJECTIVES: To compare three easily implemented methods to correct for measurement error when objective measures of alcohol use are available for a subsample of participants, regression calibration, multiple imputation for measurement error (MIME), and probabilistic sensitivity analysis (PSA), and provide guidance regarding the use of each method in scenarios likely to occur in practice. METHODS: This simulation experiment compared the performance of each method across different sample sizes, both differential and non-differential error, and differing levels of sensitivity and specificity of the exposure measure. RESULTS: Failure to adjust for measurement error led to substantial bias across all simulated scenarios ranging from a 35% to 208% change in the log-odds. For non-differential misclassification, regression calibration reduced this bias to between a 1% and 23% change in the log-odds regardless of sample size. At higher sample sizes, MIME produced approximately unbiased (between a 0% and 9% change in the log-odds) and relatively efficient corrections for both non-differential and differential misclassification. PSA provided little utility for correcting misclassification due to the inefficiency of its estimates. CONCLUSION: Concern over measurement error resulting from self-reported adolescent alcohol use persists in research. Where appropriate, methods involving validity subsamples provide an efficient avenue for addressing these concerns.


Subject(s)
Data Interpretation, Statistical , Models, Statistical , Underage Drinking/classification , Underage Drinking/statistics & numerical data , Adolescent , Computer Simulation , Humans , Sensitivity and Specificity
17.
Health Qual Life Outcomes ; 16(1): 34, 2018 Feb 13.
Article in English | MEDLINE | ID: mdl-29439718

ABSTRACT

BACKGROUND: Although Short Form (SF)-12 × 2® has been extensively studied and used as a valid measure of health-related quality of life in a variety of population groups, no systematic studies have described the reliability of the measure in patients with behavioral conditions or serious mental illness (SMI). METHODS AND RESULTS: We assessed the internal consistency, split-half reliability and annual test-retest correlations in a sample of 1587 participants with either a combination of physical and behavioral conditions or SMI. The Mosier's alpha was 0.70 for the Physical Composite Scale (PCS) and 0.69 for the Mental Health Composite Scale (MCS), indicating good internal consistency. We observed strong correlations between physical functioning, physical role and body pain scales (r = 0.55-0.56), and between social functioning, emotional role, and mental health (r = 0.53-0.58). We calculated split-half reliabilities to be 0.74 for physical functioning, 0.75 for physical role, 0.73 for emotional role and 0.65 for mental health respectively. We assessed the annual test-retest correlation using intraclass correlation (ICC) and found an ICC of 0.61 for PCS and 0.57 for MCS composite scores, adjusting for age, sex, race/ethnicity, and CRG. We found no decline in the correlations between baseline and the following study years until year 3. CONCLUSIONS: Our results encourage using SF-12v2® to assess health-related quality of life in the Medicaid population with combined physical and behavioral conditions or similar cohorts. TRIAL REGISTRATION: The WIN study was registered with clinicaltrials.gov on April 22, 2015. TRIAL REGISTRATION NUMBER: NCT02440906 . Retrospectively registered.


Subject(s)
Health Status , Health Surveys/standards , Mental Disorders/psychology , Quality of Life , Adult , Aged , Female , Humans , Male , Middle Aged , Quality of Life/psychology , Reproducibility of Results
18.
Commun Stat Theory Methods ; 27(9): 2137-2141, 2018.
Article in English | MEDLINE | ID: mdl-34305271

ABSTRACT

A derivation based on spectral decomposition allows specifying the characteristic function of the trace of a singular or nonsingular, central or noncentral, true or pseudo-Wishart. The trace equals a weighted sum of noncentral chi-squared random variables and constants. We describe computational methods.

19.
Stat Med ; 37(3): 375-389, 2018 02 10.
Article in English | MEDLINE | ID: mdl-29164637

ABSTRACT

Repeated measures are common in clinical trials and epidemiological studies. Designing studies with repeated measures requires reasonably accurate specifications of the variances and correlations to select an appropriate sample size. Underspecifying the variances leads to a sample size that is inadequate to detect a meaningful scientific difference, while overspecifying the variances results in an unnecessarily large sample size. Both lead to wasting resources and placing study participants in unwarranted risk. An internal pilot design allows sample size recalculation based on estimates of the nuisance parameters in the covariance matrix. We provide the theoretical results that account for the stochastic nature of the final sample size in a common class of linear mixed models. The results are useful for designing studies with repeated measures and balanced design. Simulations examine the impact of misspecification of the covariance matrix and demonstrate the accuracy of the approximations in controlling the type I error rate and achieving the target power. The proposed methods are applied to a longitudinal study assessing early antiretroviral therapy for youth living with HIV.


Subject(s)
Linear Models , Sample Size , Clinical Trials as Topic , Computer Simulation , Humans , Longitudinal Studies , Multivariate Analysis , Pilot Projects , Research Design , Stochastic Processes
20.
Matern Child Health J ; 20(12): 2483-2493, 2016 12.
Article in English | MEDLINE | ID: mdl-27406154

ABSTRACT

Objectives Given poor compliance by providers with adolescent health risk assessment (HRA) in primary care, we describe the development and feasibility of using a health information technology (HIT)-enhanced HRA to improve the frequency of HRAs in diverse clinical settings, asking adolescents' recall of quality of care as a primary outcome. Methods We conducted focus groups and surveys with key stakeholders (Phase I) , including adolescents, clinic staff and providers to design and implement an intervention in a practice-based research network delivering private, comprehensive HRAs via tablet (Phase II). Providers and adolescents received geo-coded community resources according to individualized risks. Following the point-of-care implementation , we collected patient-reported outcomes using post-visit quality surveys (Phase III). Patient-reported outcomes from intervention and comparison clinics were analyzed using a mixed-model, fitted separately for each survey domain. Results Stakeholders agreed upon an HIT-enhanced HRA (Phase I). Twenty-two academic and community practices in north-central Florida then recruited 609 diverse adolescents (14-18 years) during primary care visits over 6 months; (mean patients enrolled = 28; median = 20; range 1-116; Phase II). Adolescents receiving the intervention later reported higher receipt of confidential/private care and counseling related to emotions and relationships (adjusted scores 0.42 vs 0.08 out of 1.0, p < .01; 0.85 vs 0.57, p < .001, respectively, Phase III) than those receiving usual care. Both are important quality indicators for adolescent well-child visits. Conclusions Stakeholder input was critical to the acceptability of the HIT-enhanced HRA. Patient recruitment data indicate that the intervention was feasible in a variety of clinical settings and the pilot evaluation data indicate that the intervention may improve adolescents' perceptions of high quality care.


Subject(s)
Adolescent Health Services/standards , Counseling , Medical Informatics/methods , Preventive Health Services/standards , Quality Improvement , Risk Assessment/methods , Adolescent , Adult , Female , Florida , Focus Groups , Health Behavior , Health Care Surveys , Humans , Male , Middle Aged , Patient Reported Outcome Measures , Pilot Projects , Quality Indicators, Health Care
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