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Sample size requirements for studies of treatment effects on beta-cell function in newly diagnosed type 1 diabetes.

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  • Author(s): Lachin JM;Lachin JM; McGee PL; Greenbaum CJ; Palmer J; Pescovitz MD; Gottlieb P; Skyler J
  • Source:
    PloS one [PLoS One] 2011; Vol. 6 (11), pp. e26471. Date of Electronic Publication: 2011 Nov 10.
  • Publication Type:
    Comparative Study; Journal Article; Multicenter Study; Randomized Controlled Trial; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't
  • Language:
  • Additional Information
    • Corporate Authors:
    • Source:
      Publisher: Public Library of Science Country of Publication: United States NLM ID: 101285081 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1932-6203 (Electronic) Linking ISSN: 19326203 NLM ISO Abbreviation: PLoS One Subsets: MEDLINE
    • Publication Information:
      Original Publication: San Francisco, CA : Public Library of Science
    • Subject Terms:
    • Abstract:
      Preservation of β-cell function as measured by stimulated C-peptide has recently been accepted as a therapeutic target for subjects with newly diagnosed type 1 diabetes. In recently completed studies conducted by the Type 1 Diabetes Trial Network (TrialNet), repeated 2-hour Mixed Meal Tolerance Tests (MMTT) were obtained for up to 24 months from 156 subjects with up to 3 months duration of type 1 diabetes at the time of study enrollment. These data provide the information needed to more accurately determine the sample size needed for future studies of the effects of new agents on the 2-hour area under the curve (AUC) of the C-peptide values. The natural log(x), log(x+1) and square-root (√x) transformations of the AUC were assessed. In general, a transformation of the data is needed to better satisfy the normality assumptions for commonly used statistical tests. Statistical analysis of the raw and transformed data are provided to estimate the mean levels over time and the residual variation in untreated subjects that allow sample size calculations for future studies at either 12 or 24 months of follow-up and among children 8-12 years of age, adolescents (13-17 years) and adults (18+ years). The sample size needed to detect a given relative (percentage) difference with treatment versus control is greater at 24 months than at 12 months of follow-up, and differs among age categories. Owing to greater residual variation among those 13-17 years of age, a larger sample size is required for this age group. Methods are also described for assessment of sample size for mixtures of subjects among the age categories. Statistical expressions are presented for the presentation of analyses of log(x+1) and √x transformed values in terms of the original units of measurement (pmol/ml). Analyses using different transformations are described for the TrialNet study of masked anti-CD20 (rituximab) versus masked placebo. These results provide the information needed to accurately evaluate the sample size for studies of new agents to preserve C-peptide levels in newly diagnosed type 1 diabetes.
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    • Grant Information:
      U01 DK061034 United States DK NIDDK NIH HHS
    • Accession Number:
      0 (Antibodies, Monoclonal, Humanized)
      0 (Antibodies, Monoclonal, Murine-Derived)
      0 (C-Peptide)
      0 (Immunoglobulin G)
      0 (Immunologic Factors)
      0 (Immunosuppressive Agents)
      4F4X42SYQ6 (Rituximab)
      CUJ2MVI71Y (Daclizumab)
      HU9DX48N0T (Mycophenolic Acid)
    • Publication Date:
      Date Created: 20111122 Date Completed: 20120508 Latest Revision: 20181201
    • Publication Date:
    • Accession Number:
    • Accession Number:
    • Accession Number: