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Wende ME, Hughey SM, McLain AC, Hallum S, Hipp JA, Schipperijn J, Stowe EW, Kaczynski AT. Identifying multilevel predictors of behavioral outcomes like park use: A comparison of conditional and marginal modeling approaches. PLoS One 2024; 19:e0301549. [PMID: 38626162 PMCID: PMC11020402 DOI: 10.1371/journal.pone.0301549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 03/18/2024] [Indexed: 04/18/2024] Open
Abstract
This study compared marginal and conditional modeling approaches for identifying individual, park and neighborhood park use predictors. Data were derived from the ParkIndex study, which occurred in 128 block groups in Brooklyn (New York), Seattle (Washington), Raleigh (North Carolina), and Greenville (South Carolina). Survey respondents (n = 320) indicated parks within one half-mile of their block group used within the past month. Parks (n = 263) were audited using the Community Park Audit Tool. Measures were collected at the individual (park visitation, physical activity, sociodemographic characteristics), park (distance, quality, size), and block group (park count, population density, age structure, racial composition, walkability) levels. Generalized linear mixed models and generalized estimating equations were used. Ten-fold cross validation compared predictive performance of models. Conditional and marginal models identified common park use predictors: participant race, participant education, distance to parks, park quality, and population >65yrs. Additionally, the conditional mode identified park size as a park use predictor. The conditional model exhibited superior predictive value compared to the marginal model, and they exhibited similar generalizability. Future research should consider conditional and marginal approaches for analyzing health behavior data and employ cross-validation techniques to identify instances where marginal models display superior or comparable performance.
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Affiliation(s)
- Marilyn E. Wende
- Department of Health Education & Behavior, College of Health & Human Performance, University of Florida, Gainesville, FL, United States of America
| | - S. Morgan Hughey
- Department of Health and Human Performance, School of Health Sciences, College of Charleston, Charleston, SC, United States of America
| | - Alexander C. McLain
- Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, United States of America
| | - Shirelle Hallum
- Department of Health Promotion, Education, and Behavior, Arnold School of Public Health, University of South Carolina, Columbia, SC, United States of America
| | - J. Aaron Hipp
- Department of Parks, Recreation, and Tourism Management, Center for Geospatial Analytics, North Carolina State University, Raleigh, NC, United States of America
| | - Jasper Schipperijn
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Ellen W. Stowe
- Department of Health Promotion, Education, and Behavior, Arnold School of Public Health, University of South Carolina, Columbia, SC, United States of America
| | - Andrew T. Kaczynski
- Department of Health Promotion, Education, and Behavior, Prevention Research Center, Arnold School of Public Health, University of South Carolina, Columbia, SC, United States of America
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Shaw ZA, Conway CC, Starr LR. Distinguishing Transdiagnostic versus Disorder-Specific Pathways between Ruminative Brooding and Internalizing Psychopathology in Adolescents: A Latent Variable Modeling Approach. Res Child Adolesc Psychopathol 2021; 49:1319-1331. [PMID: 33914186 DOI: 10.1007/s10802-020-00714-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2020] [Indexed: 12/01/2022]
Abstract
Rumination is correlated with diverse types of internalizing problems, but the extent to which it relates to a higher-order internalizing spectrum versus disorder-specific pathology is unclear. Using a quantitative model of the internalizing dimension, we compared the strength of transdiagnostic versus diagnosis-specific pathways from brooding-the most depressogenic component of rumination-to major depressive disorder (MDD) in adolescents. Community-recruited mid-adolescents (N = 241, Mage = 15.90 years, 53% female) completed semi-structured interviews of anxiety and depressive conditions and a self-report brooding measure. Confirmatory factor analysis revealed good fit for a one-factor model of internalizing conditions. Results revealed a large, significant factor correlation between brooding and the internalizing factor (r = 0.55), with some evidence for a more modest specific link between brooding and the unique component of the MDD diagnosis (r = 0.17; approximately one-third as large as the transdiagnostic pathway). These cross-sectional associations were generally consistent across two assessment waves separated by 19 months. We concluded that brooding is better conceptualized as a common characteristic of all internalizing problems in adolescence, rather than a specific feature of MDD. Preregistered hypotheses, data analysis code, and correlation matrices for this study are posted at https://osf.io/dax7u/ .
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Affiliation(s)
- Zoey A Shaw
- Department of Psychology, University of Rochester, 491 Meliora Hall, Box 270266, Rochester, NY, 14627-0266, USA.
| | | | - Lisa R Starr
- Department of Psychology, University of Rochester, 491 Meliora Hall, Box 270266, Rochester, NY, 14627-0266, USA
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Chen CLH, Sharma PR, Tan BY, Low C, Venketasubramanian N. The Alzheimer's disease THErapy with NEuroaid ( ATHENE) study protocol: Assessing the safety and efficacy of Neuroaid II (MLC901) in patients with mild-to-moderate Alzheimer's disease stable on cholinesterase inhibitors or memantine-A randomized, double-blind, placebo-controlled trial. ALZHEIMERS & DEMENTIA-TRANSLATIONAL RESEARCH & CLINICAL INTERVENTIONS 2019; 5:38-45. [PMID: 30723778 PMCID: PMC6352850 DOI: 10.1016/j.trci.2018.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Background Dementia is a large and growing health care burden globally, and its major cause is Alzheimer's disease (AD). MLC901 (Neuroaid II) is a simplified form of MLC601 (Neuroaid), a Traditional Chinese Medicine with neuroprotective and neuroproliferative properties in cellular and animal models of brain injury. MLC601 has been shown to modulate amyloid precursor protein (APP) processing in human neuroblastoma cell cultures and increase the levels of soluble APPα. In addition, MLC901 has been shown to reduce tau phosphorylation in vitro. Hence, MLC901 may have possible multimodal actions and a disease-modifying effect in AD. In previous clinical studies, MLC601 has shown promising effects in AD. Objective To investigate the safety and efficacy of MLC901 add-on therapy to standard treatment in mild-to-moderate probable AD patients stable on standard treatment and to evaluate if MLC901 has a disease-modifying effect in AD. Methods This is a 6-month randomized, double-blind, placebo-controlled trial in mild-to-moderate probable AD where MLC901 will be given as an add-on therapy to standard AD treatment, followed by an extension study for another 6 months, where all subjects will be treated with open-label MLC901 in addition to standard treatment. The primary outcome is safety as measured by adverse events, vital signs, electrocardiogram, laboratory tests, and physical and neurological examinations. Secondary outcomes evaluating cognition, behavior, and activities of daily living at various time points include the Alzheimer's Disease Assessment Scale-cognitive subscale, Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change, Alzheimer's Disease Cooperative Study-Activities of Daily Living Inventory, Neuropsychiatric Inventory, and Mini-Mental State Examination. Conclusion MLC901 has the potential to improve cognition in AD patients. It may also have a role in delaying disease progression. This study will be the first to provide safety and efficacy data for MLC901 in mild-to-moderate probable AD patients already receiving standard therapy.
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Affiliation(s)
- Christopher L H Chen
- Department of Pharmacology, National University of Singapore, Clinical Research Centre, Singapore
| | | | | | - Casuarine Low
- Memory Ageing and Cognition Centre (MACC), National University Health System, Singapore
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Abstract
BACKGROUND The Behavioral Health Laboratory (BHL), a telephone-based mental health assessment, is a cost-effective approach that can improve mental illness identification and management. The individual BHL instruments, which were originally designed to be administered in-person, have not yet been validated with an in-person BHL assessment. This study therefore aims to characterize the concordance between the BHL data gathered by telephone and in-person interviews. METHODS A cross-sectional study was conducted with English-speaking aging services network (ASN) clients aged 60 years and older in Monroe County, NY who were randomized to a BHL interview either in-person (n = 55) or by telephone (n = 53). RESULTS There was strong evidence of equivalence between telephone and in-person interviews for depressive disorders, generalized anxiety, panic disorder, drug misuse, psychosis, PTSD, mental illness symptom severity, and five of the six questions assessing suicidality. There was marginal equivalence in PHQ-9 total scores and one of the six questions assessing suicidal ideation, and no evidence of equivalence between interview modalities for assessing cognitive impairment. CONCLUSIONS With a few exceptions, the BHL gathered nearly equivalent information via telephone as compared to in-person interviews. This suggests that the BHL may be a cost-effective approach appropriate for dissemination in a wide variety of settings including the ASN. Dissemination of the BHL has the potential to strengthen the linkages between primary care, mental healthcare, and social service providers and improve identification and management of those with late-life mental illness.
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Venketasubramanian N, Young SH, Tay SS, Umapathi T, Lao AY, Gan HH, Baroque AC, Navarro JC, Chang HM, Advincula JM, Muengtaweepongsa S, Chan BPL, Chua CL, Wijekoon N, de Silva HA, Hiyadan JHB, Suwanwela NC, Wong KSL, Poungvarin N, Eow GB, Lee CF, Chen CLH. CHInese Medicine NeuroAiD Efficacy on Stroke Recovery - Extension Study (CHIMES-E): A Multicenter Study of Long-Term Efficacy. Cerebrovasc Dis 2015; 39:309-318. [PMID: 25925713 DOI: 10.1159/000382082] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 04/02/2015] [Indexed: 09/03/2023] Open
Abstract
BACKGROUND The CHInese Medicine NeuroAiD Efficacy on Stroke recovery (CHIMES) study was an international randomized double-blind placebo-controlled trial of MLC601 (NeuroAiD) in subjects with cerebral infarction of intermediate severity within 72 h. CHIMES-E (Extension) aimed at evaluating the effects of the initial 3-month treatment with MLC601 on long-term outcome for up to 2 years. METHODS All subjects randomized in CHIMES were eligible for CHIMES-E. Inclusion criteria for CHIMES were age ≥18, baseline National Institute of Health Stroke Scale of 6-14, and pre-stroke modified Rankin Scale (mRS) ≤1. Initial CHIMES treatment allocation blinding was maintained, although no further study treatment was provided in CHIMES-E. Subjects received standard care and rehabilitation as prescribed by the treating physician. mRS, Barthel Index (BI), and occurrence of medical events were ascertained at months 6, 12, 18, and 24. The primary outcome was mRS at 24 months. Secondary outcomes were mRS and BI at other time points. RESULTS CHIMES-E included 880 subjects (mean age 61.8 ± 11.3; 36% women). Adjusted OR for mRS ordinal analysis was 1.08 (95% CI 0.85-1.37, p = 0.543) and mRS dichotomy ≤1 was 1.29 (95% CI 0.96-1.74, p = 0.093) at 24 months. However, the treatment effect was significantly in favor of MLC601 for mRS dichotomy ≤1 at 6 months (OR 1.49, 95% CI 1.11-2.01, p = 0.008), 12 months (OR 1.41, 95% CI 1.05-1.90, p = 0.023), and 18 months (OR 1.36, 95% CI 1.01-1.83, p = 0.045), and for BI dichotomy ≥95 at 6 months (OR 1.55, 95% CI 1.14-2.10, p = 0.005) but not at other time points. Subgroup analyses showed no treatment heterogeneity. Rates of death and occurrence of vascular and other medical events were similar between groups. CONCLUSIONS While the benefits of a 3-month treatment with MLC601 did not reach statistical significance for the primary endpoint at 2 years, the odds of functional independence defined as mRS ≤1 was significantly increased at 6 months and persisted up to 18 months after a stroke.
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Hindmarch P, Hawkins A, McColl E, Hayes M, Majsak-Newman G, Ablewhite J, Deave T, Kendrick D. Recruitment and retention strategies and the examination of attrition bias in a randomised controlled trial in children's centres serving families in disadvantaged areas of England. Trials 2015; 16:79. [PMID: 25886131 PMCID: PMC4359386 DOI: 10.1186/s13063-015-0578-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 01/22/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Failure to retain participants in randomised controlled trials and longitudinal studies can cause significant methodological problems. We report the recruitment and retention strategies of a randomised controlled trial to promote fire-related injury prevention in families with pre-school children attending children's centres in disadvantaged areas in England. METHODS Thirty-six children's centres were cluster randomised into one of three arms of a 12-month fire-related injury prevention trial. Two arms delivered safety interventions and there was one control arm. Retention rates compared the numbers of participants responding to the 12-month questionnaire to the number recruited to the trial. Multivariable random effects logistic regression was used to explore factors independently associated with participant retention. RESULTS The trial exceeded its required sample size through the use of multiple recruitment strategies. All children's centres remained in the study, despite increased reorganisation. Parent retention was 68% at 12 months, ranging from 65% to 70% across trial arms and from 62% to 74% across trial sites. There was no significant difference in the rates of retention between trial arms (p = 0.58) or between trial sites (p = 0.16). Retention was significantly lower amongst mothers aged 16-25 years than older mothers [adjusted odds ratio (AOR) 0.57, 95% CI 0.41, 0.78], those living in non-owner occupied accommodation than in owner occupied accommodation (AOR 0.53, 95% CI 0.38, 0.73) and those living in more disadvantaged areas (most versus least disadvantaged quintiles AOR 0.50, 95% CI 0.30, 0.82). CONCLUSIONS Studies recruiting disadvantaged populations should measure and report attrition by socioeconomic factors to enable determination of the extent of attrition bias and estimation of its potential impact on findings. Where differential attrition is anticipated, consideration should be given to over-sampling during recruitment and targeted and more intensive strategies of participant retention in these sub-groups. In transient populations collection of multiple sources of contact information at recruitment and throughout the study may aid retention. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT01452191 ; Date of registration: 10 October 2011, ISRCTN65067450.
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Affiliation(s)
- Paul Hindmarch
- Institute of Health & Society, Baddiley-Clark Building, Newcastle University, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK.
| | - Adrian Hawkins
- Institute of Health & Society, Baddiley-Clark Building, Newcastle University, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK.
| | - Elaine McColl
- Institute of Health & Society, Baddiley-Clark Building, Newcastle University, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK.
| | - Mike Hayes
- Child Accident Prevention Trust, Canterbury Court (1.09), 1-3 Brixton Road, London, SW9 6DE, UK.
| | - Gosia Majsak-Newman
- Clinical Research & Trials Unit, Norfolk and Norwich University Hospital NHS Foundation Trust, Norwich, NR4 7UY, UK.
| | - Joanne Ablewhite
- Division of Primary Care, School of Medicine, Floor 13, Tower Building, University Park, Nottingham, NG7 2RD, UK.
| | - Toity Deave
- Faculty of Health and Applied Sciences, University of the West of England, Bristol, BS16 1QY, UK.
| | - Denise Kendrick
- Division of Primary Care, School of Medicine, Floor 13, Tower Building, University Park, Nottingham, NG7 2RD, UK.
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Rullier L, Atzeni T, Husky M, Bouisson J, Dartigues JF, Swendsen J, Bergua V. Daily life functioning of community-dwelling elderly couples: an investigation of the feasibility and validity of Ecological Momentary Assessment. Int J Methods Psychiatr Res 2014; 23:208-16. [PMID: 24375556 PMCID: PMC6878448 DOI: 10.1002/mpr.1425] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 03/13/2013] [Accepted: 04/12/2013] [Indexed: 11/10/2022] Open
Abstract
Although ambulatory data collection techniques have been used in elderly populations, their feasibility and validity amongst elderly individuals with cognitive impairment and amongst couples remains unexplored. The main objective of this study is to examine the validity of Ecological Momentary Assessment (EMA) in elderly persons with or without cognitive impairment and their spouses. The sample included 58 retired farmers (mean 77.3 years, standard deviation [SD] 5.5) with or without cognitive impairment, recruited within a French cohort and 60 spouses (mean 73.4 years, SD 6.9). The presence of cognitive impairment determining by a panel of specialized neurologists permitted to define two groups: "The Cognitive Impairment Group" and "The Control Group". EMA procedures consisted of repeated telephone interviews five times per day during four days for each spouse. Our results demonstrate the validity of EMA procedures through a 92.1% level of compliance, the absence of fatigue effects, and the lack of evidence for major reactivity to the methods. However, the specificity of our sample may explain the acceptance (42%) and response (75%) rates and may reduce the generalizability of the results to the general population of elderly individuals. Finally, the validation of such techniques may contribute to future research examining community-dwelling elderly individuals and their spouses.
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Affiliation(s)
- Laetitia Rullier
- Psychologie, Université Bordeaux, Santé et Qualité de vie, EA 4139, F-33000, Bordeaux, France
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Hedman E, Ljótsson B, Blom K, El Alaoui S, Kraepelien M, Rück C, Andersson G, Svanborg C, Lindefors N, Kaldo V. Telephone versus internet administration of self-report measures of social anxiety, depressive symptoms, and insomnia: psychometric evaluation of a method to reduce the impact of missing data. J Med Internet Res 2013; 15:e229. [PMID: 24140566 PMCID: PMC3806436 DOI: 10.2196/jmir.2818] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 08/06/2013] [Accepted: 08/29/2013] [Indexed: 11/29/2022] Open
Abstract
Background Internet-administered self-report measures of social anxiety, depressive symptoms, and sleep difficulties are widely used in clinical trials and in clinical routine care, but data loss is a common problem that could render skewed estimates of symptom levels and treatment effects. One way of reducing the negative impact of missing data could be to use telephone administration of self-report measures as a means to complete the data missing from the online data collection. Objective The aim of the study was to compare the convergence of telephone and Internet administration of self-report measures of social anxiety, depressive symptoms, and sleep difficulties. Methods The Liebowitz Social Anxiety Scale-Self-Report (LSAS-SR), Montgomery-Åsberg Depression Rating Scale-Self-Rated (MADRS-S), and the Insomnia Severity Index (ISI) were administered over the telephone and via the Internet to a clinical sample (N=82) of psychiatric patients at a clinic specializing in Internet-delivered treatment. Shortened versions of the LSAS-SR and the ISI were used when administered via telephone. Results As predicted, the results showed that the estimates produced by the two administration formats were highly correlated (r=.82-.91; P<.001) and internal consistencies were high in both administration formats (telephone: Cronbach alpha=.76-.86 and Internet: Cronbach alpha=.79-.93). The correlation coefficients were similar across questionnaires and the shorter versions of the questionnaires used in the telephone administration of the LSAS-SR and ISI performed in general equally well compared to when the full scale was used, as was the case with the MADRS-S. Conclusions Telephone administration of self-report questionnaires is a valid method that can be used to reduce data loss in routine psychiatric practice as well as in clinical trials, thereby contributing to more accurate symptom estimates.
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Affiliation(s)
- Erik Hedman
- Osher Center for Integrative Medicine, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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Ruud KL, Leblanc A, Mullan RJ, Pencille LJ, Tiedje K, Branda ME, Van Houten HK, Heim SR, Kurland M, Shah ND, Yawn BP, Montori VM. Lessons learned from the conduct of a multisite cluster randomized practical trial of decision aids in rural and suburban primary care practices. Trials 2013; 14:267. [PMID: 23965227 PMCID: PMC3765278 DOI: 10.1186/1745-6215-14-267] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 08/07/2013] [Indexed: 11/24/2022] Open
Abstract
Background The decision aids for diabetes (DAD) trial explored the feasibility of testing the effectiveness of decision aids (DAs) about coronary prevention and diabetes medications in community-based primary care practices, including rural clinics that care for patients with type 2 diabetes. Methods As originally designed, we invited clinicians in eight practices to participate in the trial, reviewed the patient panel of clinicians who accepted our invitation for potentially eligible patients, and contacted these patients by phone, enrolling those who accepted our invitation. As enrollment failed to meet targets, we recruited four new practices. After discussing the study with the clinicians and receiving their support, we reviewed all clinic panels for potentially eligible patients. Clinicians were approached to confirm participation and patient eligibility, and patients were approached before their visit to provide written informed consent. This in-clinic approach required study coordinators to travel and stay longer at the clinics as well as to screen more patient records for eligibility. The in-clinic approach was associated with better recruitment rates, lower patient retention and outcome completion rates, and a better intervention effect. Results We drew four lessons: 1) difficulties identifying potentially eligible patients threaten the viability of practical trials of DAs; 2) to improve the recruitment yield, recruit clinicians and patients for the study at the clinic, just before their visit; 3) approaches that improve recruitment may be associated with reduced retention and survey response; and 4) procedures that involve working closely with the practice may improve recruitment and may also affect the quality of the implementation of the interventions. Conclusion Success in practice-based trials in usual primary care including rural clinics may require the smallest possible research footprint on the practice while implementing a streamlined protocol favoring in-clinic, in-person interactions with clinicians and patients. Trial registration ClinicalTrials.gov NCT01029288
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Affiliation(s)
- Kari L Ruud
- Knowledge and Evaluation Research Unit, Mayo Clinic, Rochester, MN, USA
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Vickers AJ, Bennette C, Touijer K, Coleman J, Laudone V, Carver B, Eastham JA, Scardino PT. Feasibility study of a clinically-integrated randomized trial of modifications to radical prostatectomy. Trials 2012; 13:23. [PMID: 22364367 PMCID: PMC3298715 DOI: 10.1186/1745-6215-13-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 02/24/2012] [Indexed: 02/01/2023] Open
Abstract
Abstract Trial registration ClinicalTrials.gov NCT00928850
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Affiliation(s)
- Andrew J Vickers
- Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY 11215, USA.
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Abstract
Missing data can pose substantial risk of reaching incorrect conclusions from clinical studies. Imputation for the missing values is common, but can supply only an approximate result desired to be "close enough" to the intended true result. Prevention optimally addresses the issue. Knowledge of the effective techniques to minimize the problem, likely to vary with clinical setting, is presently inadequate. Formal evaluation of preventative methods should be encouraged and lead to publication of the assessments. Designers of clinical trials should also plan for study analysis where missing values occur. Simple imputation methods have been used and may be sufficient in some settings, but have potential to introduce bias and inaccuracy into the statistical analysis. More complex methods such as multiple imputation potentially offer reduced risk of bias. Multiple imputation also offers the potential for study designers to include some auxiliary outcome assessments that may substantially improve the quality of the imputation with limited added burden to the study. In all cases, sensitivity analyses examining the importance of the specific preferred method as compared to methods with different underlying assumptions is essential to assessing how adequately the missing data issue has been addressed.
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Affiliation(s)
- Marc K Walton
- Office of Translational Science, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
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