Log-Normal Versus Gamma Models for Analyzing Data from Quality-Improvement Experiments

Determinants of Cardiac Ejection Fraction for the Patients with Dobutamine Stress Echocardiography

“…Note that the DSE is widely and successfully applied to identify an individual with or without known coronary artery disease has ischemia [27][28][29]. The patient population, data collection method, and the DSE used are clearly described in [24]. We have not reproduced the detailed data description in the report as it would increase its length.…”

“…The present report aims to identify the determinants of the baseline cardiac ejection fraction (baseEF), and the ejection fraction on dobutamine dose (dobEF) of the DSE data set [24]. Generally, interested hypotheses of the article are: What are the determinants of the (i) baseEF and (ii) dobEF?…”

“…Generally, interested hypotheses of the article are: What are the determinants of the (i) baseEF and (ii) dobEF? The present study has identified many cardiac EF determinants of 558 patients [24] who underwent DSE by separately analyzing the baseEF and dobEF, based on the remaining other explanatory variables (Table 1). These two non-replicated, positive response distributions are non-normal with non-constant variances.…”

“…The present data set is positive, its variance is non-constant, distribution is non-normal, and the earlier used statistical methods are inappropriate. These issues have motivated us to identify the cardiac EF determinants of the DSE data set [24].…”

“…So, what are the appropriate statistical modelling techniques for these two responses? Joint generalized linear gamma model [21,25] is the most appropriate statistical technique for the DSE data set [24] which is described in the following section.…”