The use of complete-case and multiple imputation-based analyses in molecular epidemiology studies that assess interaction effects

Abstract Background In molecular epidemiology studies biospecimen data are collected, often with the purpose of evaluating the synergistic role between a biomarker and another feature on an outcome. Typically, biomarker data are collected on only a proportion of subjects eligible for study, leading to a missing data problem. Missing data methods, however, are not customarily incorporated into analyses. Instead, complete-case (CC) analyses are performed, which can result in biased and inefficient estimates. Methods Through simulations, we characterized the performance of CC methods when interaction effects are estimated. We also investigated whether standard multiple imputation (MI) could improve estimation over CC methods when the data are not missing at random (NMAR) and auxiliary information may or may not exist. Results CC analyses were shown to result in considerable bias and efficiency loss. While MI reduced bias and increased efficiency over CC methods under specific conditions, it too resulted in biased estimates depending on the strength of the auxiliary data available and the nature of the missingness. In particular, CC performed better than MI when extreme values of the covariate were more likely to be missing, while MI outperformed CC when missingness of the covariate related to both the covariate and outcome. MI always improved performance when strong auxiliary data were available. In a real study, MI estimates of interaction effects were attenuated relative to those from a CC approach. Conclusions Our findings suggest the importance of incorporating missing data methods into the analysis. If the data are MAR, standard MI is a reasonable method. Auxiliary variables may make this assumption more reasonable even if the data are NMAR. Under NMAR we emphasize caution when using standard MI and recommend it over CC only when strong auxiliary data are available. MI, with the missing data mechanism specified, is an alternative when the data are NMAR. In all cases, it is recommended to take advantage of MI's ability to account for the uncertainty of these assumptions

The Association Between Self-Reported Major Life Events and the Presence of Uterine Fibroids

Uterine fibroids are the most common benign tumors in reproductive age women. Factors associated with condition such as psychosocial stress are still being elucidated. This paper explores the association between major life events (MLE) stress and fibroids

Analysis of Binary Adherence Data in the Setting of Polypharmacy: A Comparison of Different Approaches

Older community dwelling adults often take multiple medications for numerous chronic diseases. Non-adherence to these medications can have a large public health impact. Therefore, the measurement and modeling of medication adherence in the setting of polypharmacy is an important area of research. We apply a variety of different modeling techniques (standard linear regression; weighted linear regression; adjusted linear regression; naïve logistic regression; beta-binomial (BB) regression; generalized estimating equations (GEE)) to binary medication adherence data from a study in a North Carolina based population of older adults, where each medication an individual was taking was classified as adherent or non-adherent. In addition, through simulation we compare these different methods based on Type I error rates, bias, power, empirical 95% coverage, and goodness of fit. We find that estimation and inference using GEE is robust to a wide variety of scenarios and we recommend using this in the setting of polypharmacy when adherence is dichotomously measured for multiple medications per person

Racial Disparities in Quality of Medication Use in Older Adults: Findings From a Longitudinal Study

The quality of medication use in older adults is suboptimal with a large percentage of individuals not receiving recommended care. Most efforts to evaluate the quality of medication use target high-risk drugs, appropriate treatment of prevalent chronic disease states, or a set of predefined quality indicators of medication use, rather than the patient. It is also suggested that racial differences in the quality of medication use may exist in older adults

Self-Efficacy and Adherence to Antiviral Treatment for Chronic Hepatitis C

Investigate the role of self-efficacy during HCV treatment

Chronic Mycobacterium abscessus infection and lung function decline in cystic fibrosis

Although nontuberculous mycobacteria (NTM) are recognized pathogens in cystic fibrosis (CF), associations with clinical outcomes remain unclear

Social support and clinical outcomes during antiviral therapy for chronic hepatitis C

To determine if social support (SS) is associated with clinical outcomes during antiviral therapy for chronic hepatitis C virus (HCV)

Development and Testing of a Tool for Assessing and Resolving Medication-Related Problems in Older Adults in an Ambulatory Care Setting: The Individualized Medication Assessment and Planning (iMAP) Tool

Medications are one of the most important interventions for improving the health of older adults, yet have great potential for causing harm. Clinical pharmacists are well positioned to engage in medication assessment and planning. The individualized Medication Assessment and Planning (iMAP) tool was developed to aid clinical pharmacists in documenting medication-related problems (MRPs) and associated recommendations

Motor Vehicle Collision-Related Emergency Department Visits by Older Adults in the United States

Motor vehicle collisions (MVCs) are the second most common cause of non-fatal injury among U.S. adults age 65 years and older. However, the frequency of emergency department (ED) visits, disposition, pain locations, and pain severity for older adults experiencing MVCs have not previously been described. The authors sought to determine these characteristics using information from two nationally representative data sets

The quality of medication use in older adults: Methods of a longitudinal study

The quality of medication use in older adults is a recurring problem of substantial concern. Efforts to both measure and improve the quality of medication use often define quality too narrowly and fall short of addressing the complexity of an older adult's medication regimen