Analyzing incomplete longitudinal clinical trial data

Molenberghs, Geert; Thijs, Herbert; Jansen, Ivy; Beunckens, Caroline; Kenward, Michael G.; Mallinckrodt, Craig; Carroll, Raymond J.

doi:10.1093/biostatistics/5.3.445

Cited by 229 publications

(265 citation statements)

References 43 publications

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“…A secondary analysis of the primary outcome variable used a repeated-measures analysis of covariance model (ie, the so-called mixed model repeated measures [MMRM] analysis strategy 22 ) that included treatment group as the factor of interest, center as a stratification factor, and baseline PMD and papilledema grade in the study eye as covariates. The model also included terms for visit (categorical), the interaction between baseline PMD and visit, and the interaction between treatment group and visit.…”

Section: Methodsmentioning

confidence: 99%

Effect of Acetazolamide on Visual Function in Patients With Idiopathic Intracranial Hypertension and Mild Visual Loss

Wall

McDermott

Kieburtz

et al. 2014

JAMA

438

323

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IMPORTANCE Acetazolamide is commonly used to treat idiopathic intracranial hypertension (IIH), but there is insufficient information to establish an evidence base for its use. OBJECTIVE To determine whether acetazolamide is beneficial in improving vision when added to a low-sodium weight reduction diet in patients with IIH and mild visual loss. DESIGN, SETTING, AND PARTICIPANTS Multicenter, randomized, double-masked, placebo-controlled study of acetazolamide in 165 participants with IIH and mild visual loss who received a low-sodium weight-reduction diet. Participants were enrolled at 38 academic and private practice sites in North America from March 2010 to November 2012 and followed up for 6 months (last visit in June 2013). All participants met the modified Dandy criteria for IIH and had a perimetric mean deviation (PMD) between −2 dB and −7 dB. The mean age was 29 years and all but 4 participants were women. INTERVENTIONS Low-sodium weight-reduction diet plus the maximally tolerated dosage or acetazolamide (up to 4 g/d) or matching placebo for 6 months. MAIN OUTCOMES AND MEASURES The planned primary outcome variable was the change in PMD from baseline to month 6 in the most affected eye, as measured by Humphrey Field Analyzer. Perimetric mean deviation is a measure of global visual field loss (mean deviation from age-corrected normal values), with a range of 2 to −32 dB; larger negative values indicate greater vision loss. Secondary outcome variables included changes in papilledema grade, quality of life (Visual Function Questionnaire 25 [VFQ-25] and 36-Item Short Form Health Survey), headache disability, and weight at month 6. RESULTS The mean improvement in PMD was greater with acetazolamide (1.43 dB, from −3.53 dB at baseline to −2.10 dB at month 6; n = 86) than with placebo (0.71 dB, from −3.53 dB to −2.82 dB;n = 79); the difference was 0.71 dB (95% CI, 0 to 1.43 dB; P= .050). Mean improvements in papilledema grade (acetazolamide: −1.31, from 2.76 to 1.45; placebo: −0.61, from 2.76 to 2.15; treatment effect, −0.70; 95% CI, −0.99 to −0.41; P < .001) and vision-related quality of life as measured by the National Eye Institute VFQ-25 (acetazolamide: 8.33, from 82.97 to 91.30; placebo: 1.98, from 82.97 to 84.95; treatment effect, 6.35; 95% CI, 2.22 to 10.47; P = .003) and its 10-item neuro-ophthalmic supplement (acetazolamide: 9.82, from 75.45 to 85.27; placebo: 1.59, from 75.45 to 77.04; treatment effect, 8.23; 95% CI, 3.89 to 12.56; P < .001) were also observed with acetazolamide. Participants assigned to acetazolamide also experienced a reduction in weight (acetazolamide: −7.50 kg, from 107.72 kg to 100.22 kg; placebo: −3.45 kg, from 107.72 kg to 104.27 kg; treatment effect, −4.05 kg, 95% CI, −6.27 to −1.83 kg; P < .001). CONCLUSIONS AND RELEVANCE In patients with IIH and mild visual loss, the use of acetazolamide with a low-sodium weight-reduction diet compared with diet alone resulted in modest improvement in visual field function. The clinical importance of this improvement remains to be d...

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Section: Methodsmentioning

confidence: 99%

Effect of Acetazolamide on Visual Function in Patients With Idiopathic Intracranial Hypertension and Mild Visual Loss

Wall

McDermott

Kieburtz

et al. 2014

JAMA

438

323

View full text Add to dashboard Cite

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“…Further sensitivity models allowing for missing not-at-random mechanism were also considered. 38 They were based on a pattern mixture approach, considering a large range of possible differences in outcomes between participants who completed the follow-up and those who did not. Mean difference and confidence intervals (CIs) were estimated using the 'rctmiss' 39 user-written command in Stata.…”

Section: Discussionmentioning

confidence: 99%

The clinical effectiveness and cost-effectiveness of brief intervention for excessive alcohol consumption among people attending sexual health clinics: a randomised controlled trial (SHEAR)

Crawford

Sanatinia

Barrett

et al. 2014

Health Technology Assessment

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“…In the primary statistical analyses, we used a repeated measures analysis of covariance model (i.e., the mixed model repeated measures [MMRM] analysis strategy) 22 that included change from baseline in Need Satisfaction with Mentor score as the dependent variable and treatment group as the independent variable of interest. Geographic region and baseline Need Satisfaction with Mentor score were included as covariates.…”

Section: Methodsmentioning

confidence: 99%

A Randomized Controlled Trial of Mentoring Interventions for Underrepresented Minorities

et al. 2016

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Purpose To conduct a randomized controlled trial (RCT) to evaluate the effects of different mentoring interventions on the basic psychological need satisfaction of underrepresented minorities and women in academia. Method Participants were 150 mentor/protégé dyads from three academic medical centers and eight other colleges and universities in western and central New York, randomized from 2010–2013 into: mentor training (using principles of self-determination theory); peer mentoring for protégés; mentor training and peer mentoring for protégés combined; or control/usual practice. Protégé participants were graduate students, fellows and junior faculty who were from underrepresented groups based on race, ethnicity, gender, or disability. The primary analysis was a comparison of intervention effects on changes in protégés’ satisfaction of their basic psychological needs (competence, autonomy and relatedness) with their mentor. They completed a well-validated, online questionnaire every 2 months for 1 year. Results There was no significant effect at the end of 1 year of either mentor training or peer mentoring on protégés’ psychological basic need satisfaction with mentor specifically or at work in general. Exploratory analyses showed a significant effect of the mentor-based intervention on the protégés’ overall psychological need satisfaction with their mentor at 2 months, the time point closest to completing mentor training. Conclusions This RCT showed a potential short-term effect of mentor training on changing basic psychological need satisfaction of underrepresented scholars with their mentors. Despite the lack of sustained effect of either mentor training or peer mentoring, these short-term changes suggest feasibility and potential for future study.

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Analyzing incomplete longitudinal clinical trial data

Cited by 229 publications

References 43 publications

Effect of Acetazolamide on Visual Function in Patients With Idiopathic Intracranial Hypertension and Mild Visual Loss

Effect of Acetazolamide on Visual Function in Patients With Idiopathic Intracranial Hypertension and Mild Visual Loss

The clinical effectiveness and cost-effectiveness of brief intervention for excessive alcohol consumption among people attending sexual health clinics: a randomised controlled trial (SHEAR)

A Randomized Controlled Trial of Mentoring Interventions for Underrepresented Minorities

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