A comparison of imputation strategies in cluster randomized trials with missing binary outcomes.
In cluster randomized trials, clusters of subjects are randomized rather than subjects themselves, and missing outcomes are a concern as in individual randomized trials. We assessed strategies for handling missing data when analysing cluster randomized trials with a binary outcome; strategies included complete case, adjusted complete case, and simple and multiple imputation approaches. We performed a simulation study to assess bias and coverage rate of the population-averaged intervention-effect estimate. Both multiple imputation with a random-effects logistic regression model or classical logistic regression provided unbiased estimates of the intervention effect. Both strategies also showed good coverage properties, even slightly better for multiple imputation with a random-effects logistic regression approach. Finally, this latter approach led to a slightly negatively biased intracluster correlation coefficient estimate but less than that with a classical logistic regression model strategy. We applied these strategies to a real trial randomizing households and comparing ivermectin and malathion to treat head lice.
INSERM, U1153, Paris, France agnes.caille@med.univ-tours.fr.|INSERM, CIC 1415, Tours, France.|CHRU de Tours, Tours, France.|Université François-Rabelais de Tours, PRES Centre-Val de Loire Université, Tours, France.
Agnès
A
Caille
INSERM, U1153, Paris, France.|INSERM, CIC 1415, Tours, France.|CHRU de Tours, Tours, France.
Clémence
C
Leyrat
INSERM, U1153, Paris, France.|INSERM, CIC 1415, Tours, France.|CHRU de Tours, Tours, France.|Université François-Rabelais de Tours, PRES Centre-Val de Loire Université, Tours, France.
Bruno
B
Giraudeau
D000818:Animals; D015982:Bias; D003627:Data Interpretation, Statistical; D005260:Female; D006197:Hair / Q000033:anatomy & histology; D006801:Humans; D007559:Ivermectin / Q000627:therapeutic use; D010373:Lice Infestations / Q000188:drug therapy; D016015:Logistic Models; D008297:Male; D010374:Pediculus / Q000187:drug effects; D016032:Randomized Controlled Trials as Topic / Q000379:methods*
D007559:Ivermectin
cluster randomized trial; missing data; multiple imputation; outcome