Skip to main content

Table 1 Evaluated approaches to missing outcome data during follow-up when using data from an observational study as an external control arm to a clinical trial

From: Using observational study data as an external control group for a clinical trial: an empirical comparison of methods to account for longitudinal missing data

Approach

Missing outcome data at visitf

Intermittent missing visitsg

Drop-outsh

Complete follow-up case analysesa

Exclusion

Exclusion

Exclusion

Strict censoring + IPCWb

Censoring (set as drop-out)

Censoring (set as drop-out)

IPCW

MI + censoring + IPCWc

MI

Censoring (set as drop-out)

IPCW

MI + IPCWd

MI

MI

IPCW

MI for alle

MI

MI

MI

  1. IPCW Inverse probability of censoring weighting, MI Multiple imputation
  2. aAssumptions: Patients with complete follow-up data are exchangeable with patients with missing data
  3. b Assumptions: The IPCW model is correctly specified when modeling the missing mechanism given previous observations in individuals with missing data due to drop-out (naturally occurring or created due to artificial censoring)
  4. c Assumptions: Both the MI model and the IPCW model are correctly specified. MI models missing outcome variables at visits given available information in the dataset. IPCW models the missing mechanism given the observed past for missing data due to drop-out (naturally occurring or created due to artificial censoring)
  5. d Assumptions: Both the MI model and the IPCW model are correctly specified. MI models missing outcome variables at visits and intermittent missing visits given information in the dataset. IPCW models the missing mechanism given the observed past for missing data due to naturally occurring drop-out
  6. eAssumptions: The MI model is correctly specified when modeling all missing outcome data given information in the dataset. Separate models were specified for each cohort and the imputed datasets were thereafter combined
  7. fA visit is recorded at the required time point, but the disease activity measure is missing
  8. gA visit is missing for the 6-month and/or 12-month follow-up, but there is a later visit within the timeframe of the study
  9. hA follow-up visit and all subsequent visits are missing within the timeframe of the study
Back to article page

BMC Medical Research Methodology

ISSN: 1471-2288

Contact us