Analysing cluster randomised controlled trials using GLMM, GEE1, GEE2, and QIF: results from four case studies

Table 4 A summary of the results obtained from fitting the different statistical models to Informed Choice postnatal trial data (N = 1547)

^aModel adjusted for mother’s age, age mother left education, parity, and delivering style. Note that SE Standard error, CI Confidence interval, ICC Intracluster correlation coefficient, GLMM Generalized linear mixed model, mGLM Marginal generalized linear model, GEE Generalized estimating equations, QIF Quadratic inference function
1. Knowledge of informed choice leaflets score at 8 weeks postnatally. Knowledge is scored on a 0 to 10 scale with higher scores indicating greater knowledge of the leaflets
2. Proportion of women who answered “yes” to the question “Have you had enough information and discussion with midwives or doctors to make a choice together about all the things that happened during maternity care?” with the options “yes,” “partly,” “no,” “there was no choice,” and “did not apply”
3. The intervention effect for the continuous outcome is the difference in the mean 6-week knowledge scores between the intervention and control groups; with a positive mean difference favouring (better outcomes) in the intervention group. The intervention effect for the binary outcome informed choice (yes or no) is the odds ratio for yes to overall informed choice in the intervention group compared to the control group with an odds ratio > 1 favouring better outcomes (higher odds of an informed choice) in the intervention group

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