Trends Parasitol 2014 Nov 11;30(11):528-37. Epub 2014 Sep 11.
Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London, W2 1PG, UK.
Anthelmintic drug efficacy (ADE) is generally estimated as a population average effect, despite drug responses varying among individuals according to a variety of measurable and non-measurable factors. Model-based and/or individual-level analyses are scarce and often methodologically frail. We propose that wider application of marginal and mixed models would offer benefits to the evaluation of ADE. We demonstrate, with a worked example, how model-based analyses: (i) capture the effects of correlation among hierarchically structured longitudinal data on estimates of ADE; (ii) permit robust inference on the association of measurable factors with ADE; and (iii) enable estimation of variation among individual-level estimates of ADE. The application of modelling approaches is discussed in the context of mass drug administration-based control of human helminthiases.