Long-Chain Omega-3 Fatty Acid Supplements in Depressed Heart Failure Patients: Results of the OCEAN Trial.

OBJECTIVES: The goal of this study was to test the effects of long-chain omega-3 fatty acid supplementation on omega-3 levels, depressive symptoms, and other psychosocial factors, as well as other chronic heart failure (CHF)-related functional measures. BACKGROUND: Patients with CHF and depression had low blood omega-3 concentrations that were associated with an elevated risk of mortality. METHODS: This study was a randomized, double-blind, placebo-controlled pilot clinical trial using a 400/200 eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) fish oil at 2 g and an almost pure EPA at 2 g, compared with a matched placebo, daily for 12 weeks for patients with CHF and major depressive disorder. Statistical analyses included the intention-to-treat population and "completers" (defined as participants consuming ≥70% of the capsules and completing the final endpoint evaluation between 10 and 14 weeks). RESULTS: A total of 108 patients with CHF and major depressive disorder and a score ≥18 on the Hamilton Depression Scale who were randomized at 1:1:1 to the 3 interventions at 3 enrolling centers from June 12, 2014, to May 19, 2016; 80 (74.1%) qualified as completers. Intention-to-treat analyses revealed that the levels of all omega-3 variables were significantly elevated in the omega-3 groups, whereas the placebo group showed little change; there were no between-group differences with overall depression measurements. Per-protocol exploratory analyses showed that scores on the social functioning measurement of the 36-item Short Form Health Survey improved notably in the 400/200 EPA/DHA (p = 0.040) and EPA (p = 0.10) groups compared with the placebo group. Spearman correlation analysis indicated that increased omega-3 indices were associated with improved cognitive depressive symptoms. CONCLUSIONS: Omega-3 supplementation resulted in significant increases in omega-3 levels in red blood cell counts, corresponding to a particular compound of omega-3. Changes in cognitive depressive symptoms and social function were in favor of the omega-3 supplementation. Further studies with larger sample sizes are necessary to confirm the benefits of omega-3 supplementation on modifying psychosocial factors for patients with CHF. (Omega-3 Supplementation for Co-Morbid Depression and Heart Failure Treatment [OCEAN]; NCT02057406).

Confirmatory factor analysis: an introduction for psychosomatic medicine researchers.

We present an introduction to the basic concepts essential to understanding confirmatory factor analysis (CFA). We initially discuss the underlying mathematical model and its graphical representation. We then show how parameters are estimated for the CFA model based on the maximum likelihood function. Finally, we discuss several ways in which model fit is evaluated as well as introduce the concept of model identification. In our presentation, we use an example to illustrate the application of CFA to psychosomatic research and touch on the more general role of structural equation modeling in psychosomatic research.

Association between n-3 fatty acid consumption and ventricular ectopy after myocardial infarction.

BACKGROUND: n-3 (omega-3) Fatty acids are associated with a reduced risk of cardiovascular disease; however, the relation between dietary intake of n-3 fatty acids and ventricular arrhythmias has not been investigated among acute post-myocardial infarction (AMI) patients-a group at elevated risk of malignant arrhythmias. OBJECTIVE: The objective was to examine the association between n-3 fatty acid consumption and ventricular ectopy among AMI patients. DESIGN: In 260 AMI patients, dietary intake of n-3 fatty acids was assessed by using the Harvard food-frequency questionnaire, and ventricular ectopy was estimated from 24-h electrocardiograph recordings. RESULTS: A greater intake of n-3 fatty acids (eicosapentaenoic acid + docosahexaenoic acid + docosapentaenoic acid + alpha-linolenic acid) was associated with lower ventricular ectopy (beta = -0.35, P = 0.011), and this effect remained after cardiovascular comorbidities were controlled for (beta = -0.47, P = 0.003). Higher concentrations of both marine-based (eicosapentaenoic acid + docosahexaenoic acid) (beta = -0.21, P = 0.060) and plant-based (alpha-linolenic acid) (beta = -0.33, P = 0.024) fatty acids remained associated with lower ventricular ectopy after cardiovascular comorbidities were controlled for. CONCLUSION: These findings extend existing evidence linking n-3 fatty acid consumption to a reduced risk of ventricular arrhythmias by showing that a greater intake of n-3 fatty acids may be associated with low ventricular ectopy among AMI patients.

Spirituality, religion, and clinical outcomes in patients recovering from an acute myocardial infarction.

OBJECTIVE: To assess the prospective relationship between spiritual experiences and health in a sample of patients surviving an acute myocardial infarction (AMI) with depression or low social support. METHODS: A subset of 503 patients participating in the enhancing recovery in coronary heart disease (ENRICHD) trial completed a Daily Spiritual Experiences (DSE) questionnaire within 28 days from the time of their AMI. The questionnaire assessed three spirituality variables-worship service/church attendance, prayer/meditation, and total DSE score. Patients also completed the Beck Depression Inventory to assess depressive symptoms and the ENRICHD Social Support Inventory to determine perceived social support. The sample was subsequently followed prospectively every 6 months for an average of 18 months to assess all-cause mortality and recurrent AMI. RESULTS: Of the 503 participants who completed the DSE questionnaire at the time of index AMI, 61 (12%) participants either died or sustained a recurrent MI during the follow-up period. After adjustment for gender, education level, ethnicity, and a composite medical prognosis risk score derived specifically for the ENRICHD trial, we observed no relationship between death or nonfatal AMI and total spirituality as measured by the DSE (p = .446), worship service attendance (p = .120), or frequency of prayer/meditation (p = .679). CONCLUSION: We found little evidence that self-reported spirituality, frequency of church attendance, or frequency of prayer is associated with cardiac morbidity or all-cause mortality post AMI in patients with depression and/or low perceived support.

What you see may not be what you get: a brief, nontechnical introduction to overfitting in regression-type models.

OBJECTIVE: Statistical models, such as linear or logistic regression or survival analysis, are frequently used as a means to answer scientific questions in psychosomatic research. Many who use these techniques, however, apparently fail to appreciate fully the problem of overfitting, ie, capitalizing on the idiosyncrasies of the sample at hand. Overfitted models will fail to replicate in future samples, thus creating considerable uncertainty about the scientific merit of the finding. The present article is a nontechnical discussion of the concept of overfitting and is intended to be accessible to readers with varying levels of statistical expertise. The notion of overfitting is presented in terms of asking too much from the available data. Given a certain number of observations in a data set, there is an upper limit to the complexity of the model that can be derived with any acceptable degree of uncertainty. Complexity arises as a function of the number of degrees of freedom expended (the number of predictors including complex terms such as interactions and nonlinear terms) against the same data set during any stage of the data analysis. Theoretical and empirical evidence--with a special focus on the results of computer simulation studies--is presented to demonstrate the practical consequences of overfitting with respect to scientific inference. Three common practices--automated variable selection, pretesting of candidate predictors, and dichotomization of continuous variables--are shown to pose a considerable risk for spurious findings in models. The dilemma between overfitting and exploring candidate confounders is also discussed. Alternative means of guarding against overfitting are discussed, including variable aggregation and the fixing of coefficients a priori. Techniques that account and correct for complexity, including shrinkage and penalization, also are introduced.