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J W Hogan

Publications and source records attributed to J W Hogan.

39 records · Page 3Linked to original sources
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Model-based approaches to analysing incomplete longitudinal and failure time data.

Since Wu and Carroll (Biometrics 44, 175-188) proposed a model for longitudinal progression in the presence of informative dropout, several researchers have developed and studied models for situations where both a vector of repeated outcomes and an event time is available for each subject. These models have been developed for either longitudinal studies with dropout or for survival studies in which a random, time-varying covariate is measured repeatedly across time. When inference about the longitudinal variable is of interest, event times are treated as covariates and are often incomplete due to censoring. If survival or event time is the primary endpoint, repeated outcomes observed prior to the event are viewed as covariates; this covariate process is often incomplete, measured with error, or observed at unscheduled times during the study. We review several models which are used to handle incomplete response and covariate data in both survival and longitudinal studies.

Algorithms↗
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Age and the role of symptomatology in readiness to quit smoking.

To develop effective age-appropriate strategies for smoking cessation, it is important to understand factors associated with readiness to quit smoking. This article presents results from an analysis of the role of symptomatology in the decisions to quit smoking among three age groups (18-34, 35-54, and > or = 55 years) from a larger sample of smokers in a managed-care setting. Two measures of readiness to quit smoking were used: stages of change and intention to stop. Using ordinal logistic regression, we found that smokers in the middle and oldest age groups who had experienced at least three of five symptoms in the previous 2 weeks were more likely to be in higher stages of readiness. Regardless of age, smokers who attributed symptoms to smoking were more motivated to try to quit, whereas those who attributed symptoms to aging were less likely to intend to stop smoking. Findings from this study indicate a symptom-based approach to smoking cessation may be a useful strategy, especially in provider-based interventions.

Adult↗