Skip Navigation Bar

Storing Results Data

Storing Results Data

Clement McDonald, M.D.

Director, Lister Hill Center National Center for Biomedical Comm Communications unications

National Library of Medicine

February 11, 2008


  • The focus is on summary data of the kind one sees in publication
  • Characteristics of patients at base line
  • Differences between the outcomes of the various study arms
  • Not patient level data


  • Represent this data in a generalized but “structured structured” format
  • Take advantage of what is in the registry data base to ease entry of results data
  • Minimize entry work
  • Accommodate most study designs

Three parts to the problem

  • Define the variables - used in the study
    • To characterize population
    • To measure outcomes
    • Etc.
    - E.g. Age, creatinine, PHQ PHQ-9

For each variable

  • Name
  • Description
  • Data type (e.g. continuous, categorical, time to event)
  • Additional informatino depending upon data type e.g.:
    • For categorical variables - the categories
    • For continuous variables - the units of measure

Define the study arms and phases.

  • Name
  • Description
  • E.g.
    • Arm 1 - treat with new drug or device X
    • Arm 2 - placebo
  • Statistical analyses – as descriptive text.

Define tables

  • Rows variables
  • Columns study arm phase - and one column for statistical analysis.
  • List the discrete summary observations per cell depends on data type
    - E.g. for continuous
    • N
    • Mean
    • Coefficient of variation
    • (more)

Data structures

  • XML for current testing phase

As relational data base - simplest incarnation

  • Table for study – with record per study
  • Table for variables - one record per variable
  • Table for study arms/phases - one record per study arm phase
  • Table for overview of each tables – one record per cell
  • Table to define each table - one record per cell

Non trivial problem

  • Especially for newer study designs