Beta blockers and glucose metabolism in chronic heart failure: friend or foe?

Mandatory oral glucose tolerance tests identify more diabetics in stable patients with chronic heart failure: a prospective observational study

BACKGROUND

Many patients with chronic heart failure (CHF) are believed to have unrecognized diabetes, which is associated with a worse prognosis. This study aimed to describe glucose tolerance in a general stable CHF population and to identify determinants of glucose tolerance focusing on body composition and skeletal muscle strength.

METHODS

A prospective observational study was set up. Inclusion criteria were diagnosis of CHF, stable condition and absence of glucose-lowering medication. Patients underwent a 2 h oral glucose tolerance test (OGTT), isometric strength testing of the upper leg and dual energy x-ray absorptiometry. Health-related quality of life and physical activity level were assessed by questionnaire.

RESULTS

Data of 56 participants were analyzed. Despite near-normal fasting glucose values, 55% was classified as prediabetic, 14% as diabetic, and 20% as normal glucose tolerant. Of all newly diagnosed diabetic patients, 79% were diagnosed because of 2 h glucose values only and none because of HbA1c. Univariate mixed model analysis revealed ischaemic aetiology, daily physical activity, E/E', fat trunk/fat limbs and extension strength as possible explanatory variables for the glucose curve during the glucose tolerance test. When combined in one model, only fat trunk/fat limbs and E/E' remained significant predictors. Furthermore, fasting insulin was correlated with fat mass/height2 (r = 0.51, p < 0.0001), extension strength (r = -0.33, p < 0.01) and triglycerides (r = 0.39, p < 0.01).

CONCLUSIONS

Our data confirm that a large majority of CHF patients have impaired glucose tolerance. This glucose intolerance is related to fat distribution and left ventricular end-diastolic pressure.

Why cachexia kills: examining the causality of poor outcomes in wasting conditions

Weight loss is the hallmark of any progressive acute or chronic disease state. In its extreme form of significant lean body mass (including skeletal muscle) and fat loss, it is referred to as cachexia. It has been known for millennia that muscle and fat wasting leads to poor outcomes including death. On one hand, conditions and risk factors that lead to cachexia and inadequate nutrition may independently lead to increased mortality. Additionaly, cachexia per se, withdrawal of nutritional support in progressive cachexia, and advanced age may lead to death via cachexia-specific pathways. Despite the strong and consistent association of cachexia with mortality, no unifying mechanism has yet been suggested as to why wasting conditions are associated with an exceptionally high mortality risk. Hence, the causality of the cachexia-death association, even though it is biologically plausible, is widely unknown. This century-long uncertainty may have played a role as to why the field of cachexia treatment development has not shown major advances over the past decades. We suggest that cachexia-associated relative thrombocytosis and platelet activation may play a causal role in cachexia-related death, while other mechanisms may also contribute including arrhythmia-associated sudden deaths, endocrine disorders such as hypothyroidism, and immune system compromise leading to infectious events and deaths. Multidimensional research including examining biologically plausible models is urgently needed to investigate the causality of the cachexia-death association.

Individuals at risk of beta-blocker discontinuation: a cohort study in 19,177 Chinese patients

PURPOSE

This cohort study evaluated the factors associated with discontinuation of antihypertensive pharmacotherapy among Chinese patients who were prescribed beta-blockers. We tested the hypothesis that patients' age, gender, socioeconomic status, clinical settings and the number of comorbidities were significantly associated with the discontinuation of beta-blockers.

METHODS

From a validated clinical database we included all adult patients 18 years or older who were prescribed a beta-blocker in any government primary care clinic in one large territory of Hong Kong during 01 January 2004-30 June 2007. We evaluated the cumulative incidence of drug discontinuation within 180 days of the prescriptions and the factors associated with discontinuation of beta-blockers by multivariable regression analysis.

RESULTS

From a total of 19,177 eligible patients (mean age = 59.1 years), 20.8% discontinued their medication. Younger patients [aged <50 years; adjusted odds ratios (aOR) 0.41-0.52 for patients aged >or=50 years; p < 0.001], female gender (aOR 0.87 for males, p = 0.001), fee-waivers (aOR 0.78 for fee-payers, p < 0.001), attendances in family medicine specialist clinics (FMSC) (aOR 1.49, p < 0.001) and staff clinics (aOR 2.32, p < 0.001), residence in more urbanized areas (aOR 0.80 for North District, p < 0.001), new visits (aOR 0.55 for follow-up visits, p < 0.001) and absence of concomitant comorbidities (aOR 0.60 for one comorbidity, p < 0.001; aOR 0.56 for two comorbidities, p = 0.002) were positively associated with drug discontinuation.

CONCLUSIONS

Patients who were prescribed beta-blockers with these associated factors should be monitored more closely for antihypertensive drug adherence.

The burden of chronic obstructive pulmonary disease in patients hospitalized with heart failure

OBJECTIVES

Like chronic heart failure, chronic obstructive pulmonary disease (COPD) is an enormous public health problem in industrialized countries. Our aim was to determine the prevalence and clinical impact of COPD among patients hospitalized for heart failure in a community hospital serving a population of 125,000 people.

METHODS

Between 2001 and 2003 a total of 638 patients (73 +/- 10 years, 48% men, 74% NYHA class III) were identified with a discharge diagnosis of heart failure. Medical charts were reviewed and vital status was obtained from a Central Population Registry.

RESULTS

COPD was diagnosed in 106 (17%) patients whose age was similar to those without COPD (73 +/- 9 vs. 73 +/- 11 years, P = 0.35). Patients with COPD were more often males (65% vs. 45%, P < 0.001). There were no differences in arterial hypertension, atrial fibrillation, diabetes mellitus and most laboratory markers except hemoglobin (141 +/- 20 vs. 132 +/- 20 g/l, P < 0.001) and uric acid (453 +/- 136 vs. 414 +/- 139 mmol/l, P = 0.013). At discharge, patients with COPD were less likely to receive beta-blockers (12% vs. 28%, odds ratio 0.35, 95% CI0.19-0.64). During follow-up, patients with COPD had higher mortality (73% vs. 60%, P = 0.016, hazard ratio 1.48, 95% CI 1.15-1.90). Kaplan-Meier (log-rank test, P = 0.002) and Cox proportional hazard analysis, adjusted for age, sex, hemoglobin, uric acid, and treatment with beta-blockers and furosemide (hazard ratio 1.38, 95% CI1.04-1.83, P = 0.024) demonstrated the prognostic importance of COPD.

CONCLUSIONS

COPD is frequent among hospitalized patients with heart failure. Beta-blockers are largely underused, which is probably a major reason for the higher mortality observed in patients with concomitant chronic heart failure and COPD.