Letter by Patel Regarding Article, “A Primer in Longitudinal Data Analysis”

A primer in longitudinal data analysis.

Longitudinal data, comprising repeated measurements of the same individuals over time, arise frequently in cardiology and the biomedical sciences in general. For example, Frison and Pocock1 used repeated measurements of the liver enzyme creatine kinase in serum of cardiac patients to study changes in liver function over a 12-month study period. The main goal, indeed the raison d’être, of a long...

Letter by Regal regarding article, "Delirium in acute stroke: a systematic review and meta-analysis".

Letter by Sanna Regarding Article, "Prognostications of Fibrillations".

Letter by Sanna Regarding Article, “Prognostications of Fibrillations” To the Editor: We read with great interest the article by Silver and Windecker but were concerned about a mistake on the reference of our study. The last sentence at the end of the first paragraph states “Event Monitor Belt for Recording Atrial Fibrillation After a Cerebral Ischemic Event (EMBRACE) followed a small number of...

Conditional Dependence in Longitudinal Data Analysis

Mixed models are widely used to analyze longitudinal data. In their conventional formulation as linear mixed models (LMMs) and generalized LMMs (GLMMs), a commonly indispensable assumption in settings involving longitudinal non-Gaussian data is that the longitudinal observations from subjects are conditionally independent, given subject-specific random effects. Although conventional Gaussian...

Letter by Hayashi et al regarding article, "Heritability of early repolarization: a population-based study".

Letter by Hayashi et al Regarding Article, “Heritability of Early Repolarization: A Population-Based Study” To the Editor: We read with much interest the article published by Reinhard et al.1 The article described a high rate of heritability of early repolarization (ER) in a general population. Early repolarization was characterized by ECG morphological features of the QRS complex (ie, notching...