A Cautionary Note Regarding Count Models of Alcohol Consumption in Randomized Controlled TrialsReport as inadecuate


A Cautionary Note Regarding Count Models of Alcohol Consumption in Randomized Controlled Trials


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Citation

Horton, Nicholas J, Eugenia Kim, Richard Saitz. -A cautionary note regarding count models of alcohol consumption in randomized controlled trials- BMC Medical Research Methodology 7:9. 2007

Abstract

BACKGROUND: Alcohol consumption is commonly used as a primary outcome in randomized alcohol treatment studies. The distribution of alcohol consumption is highly skewed, particularly in subjects with alcohol dependence. METHODS: In this paper, we will consider the use of count models for outcomes in a randomized clinical trial setting. These include the Poisson, over-dispersed Poisson, negative binomial, zero-inflated Poisson and zero-inflated negative binomial. We compare the Type-I error rate of these methods in a series of simulation studies of a randomized clinical trial, and apply the methods to the ASAP Addressing the Spectrum of Alcohol Problems trial. RESULTS: Standard Poisson models provide a poor fit for alcohol consumption data from our motivating example, and did not preserve Type-I error rates for the randomized group comparison when the true distribution was over-dispersed Poisson. For the ASAP trial, where the distribution of alcohol consumption featured extensive over-dispersion, there was little indication of significant randomization group differences, except when the standard Poisson model was fit. CONCLUSION: As with any analysis, it is important to choose appropriate statistical models. In simulation studies and in the motivating example, the standard Poisson was not robust when fit to over-dispersed count data, and did not maintain the appropriate Type-I error rate. To appropriately model alcohol consumption, more flexible count models should be routinely employed.Rights

Copyright 2007 Horton et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution 2.0 License http:-creativecommons.org-licenses-by-2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

MED: Medicine Papers - Youth Alcohol Prevention Center Papers - SPH Epidemiology Papers -



Author: Horton, Nicholas J - Kim, Eugenia - Saitz, Richard - -

Source: https://open.bu.edu/







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