Change score or follow-up score? Choice of mean difference estimates could impact meta-analysis conclusions

Rongwei Fu, Haley K. Holmer

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Objectives In randomized controlled clinical trials, continuous outcomes are typically measured at both baseline and follow-up, and mean difference could be estimated using the change scores from baseline or the follow-up scores. This study assesses the impact of using change score vs. follow-up score on the conclusions of meta-analyses. Study Design and Setting A total of 63 meta-analyses from six comparative effectiveness reviews were included. The combined mean difference was estimated using a random-effects model, and we also evaluated whether the impact qualitatively varied by alternative random-effects estimates. Results Based on the Dersimonian–Laird (DL) method, using the change vs. the follow-up score led to five meta-analyses (7.9%) showing discrepancy in conclusions. Based on the profile likelihood (PL) method, nine (14.3%) showed discrepancy in conclusions. Using change score was more likely to show a significant difference in effects between interventions (DL method: 4 of 5; PL method: 7 of 9). A significant difference in baseline scores did not necessarily lead to discrepancies in conclusions. Conclusions Using the change vs. the follow-up score could lead to important discrepancies in conclusions. Sensitivity analyses should be conducted to check the robustness of results to the choice of mean difference estimates.

Original languageEnglish (US)
Pages (from-to)108-117
Number of pages10
JournalJournal of Clinical Epidemiology
StatePublished - Aug 1 2016


  • Baseline difference
  • Change score
  • Follow-up score
  • Mean difference
  • Meta-analysis
  • Random-effects estimates

ASJC Scopus subject areas

  • Epidemiology


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