Glycaemic control and insulin therapy are significant confounders of the obesity paradox in patients with heart failure and diabetes mellitus

BACKGROUND

A high body mass index (BMI) confers a paradoxical survival benefit in patients with heart failure (HF) or diabetes mellitus (DM). There is, however, controversy whether an obesity paradox is also present in patients with HF and concomitant DM. In addition, the influence of glycaemic control and diabetes treatment on the presence or absence of the obesity paradox in patients with HF and DM is unknown.

METHODS

We identified 2936 patients with HF with reduced ejection fraction (HFrEF) in the HF registries of the universities of Heidelberg, Germany, and Hull, UK (general sample). Of these, 598 (20%) were treated for concomitant DM (DM subgroup). The relationship between BMI and all-cause mortality was analysed in both the general sample and the DM subgroup. Patients with concomitant DM were stratified according to HbA1c levels or type of diabetes treatment and analyses were repeated.

RESULTS

We found an inverse BMI-mortality relationship in both the general sample and the DM subgroup. However, the obesity paradox was less pronounced in patients with diabetes treated with insulin and it disappeared in those with poor glycaemic control as defined by HbA1c levels > 7.5%.

CONCLUSION

In patients with HFrEF, a higher BMI is associated with better survival irrespective of concomitant DM. However, insulin treatment and poor glycaemic control make the relationship much weaker.

Metabolic syndrome is associated with better quality of sleep in the oldest old: results from the "Mugello Study"

BACKGROUND AND AIMS

Reduced sleep quality is common in advanced age. Poor sleep quality is associated with adverse outcomes, chiefly cardiovascular, in young and middle-aged subjects, possibly because of its association with metabolic syndrome (MetS). However, the correlates of sleep quality in oldest populations are unknown. We evaluated the association of sleep quality with MetS in a cohort of subjects aged 90+.

METHODS AND RESULTS

We analysed data of 343 subjects aged 90+ living in the Mugello area (Tuscany, Italy). Quality of sleep was assessed using the Pittsburgh Sleep Quality Assessment Index (PSQI). Good quality of sleep was defined by a PSQI score < 5. MetS was diagnosed according to the National Cholesterol Education Program's ATP-III criteria; 83 (24%) participants reported good quality of sleep. MetS was diagnosed in 110 (24%) participants. In linear and logistic models, MetS was inversely associated with PSQI score ((B = - 1.04; 95% CI - 2.06 to - .03; P = .044), with increased probability of good sleep quality (OR = 2.52; 95% CI 1.26-5.02; P = .009), and with a PSQI below the median (OR = 2.11; 95% CI 1.11-3.40, P = .022), after adjusting. None of the single components of MetS were associated with PSQI (all P values > .050). However, an increasing number of MetS components was associated with increasing probability of good quality of sleep (P for trend = .002), and of PSQI below the median (P for trend = .007). Generalized Additive Model analysis documented no smoothing function suggestive of nonlinear association between PSQI and MetS.

CONCLUSION

Our results confirm a high prevalence of poor sleep quality in oldest age; however, in these subjects, MetS seems to be associated with better sleep quality. Additional larger, dedicated studies are required to confirm our results, and, if so, to identify the subsystems involved and the potential therapeutic implications of such an association.

The reverse metabolic syndrome in the elderly: Is it a "catabolic" syndrome?

Traditional risk factors of cardiovascular death in the general population, including body mass index (BMI), serum cholesterol, and blood pressure are also found to relate to outcomes in the geriatric population, but in a differing direction. A higher body mass index, hypercholesterolemia and hypertension are not harmful but even permit better survival at advancing age. This phenomenon is called "reverse epidemiology" or "risk factor paradox" and is also detected in a variety of chronic disease states such as chronic heart failure. Accordingly, a low BMI, blood pressure and cholesterol values are associated with a worse prognosis. Several possible causes are hypothesized to explain this elderly paradox, but this phenomenon remains controversial and its underlying reasons are poorly understood. The aim of this review is to recognize the factors behind this intriguing phenomenon and analyse the consequences that it can bring in the management of the cardiovascular therapy in elderly patient. Finally, a new phenotype identified as "catabolic syndrome" has been postulated.

Association of preexisting hypertension with the morality in patients with systolic heart failure in Taiwan: The TSOC-HFrEF registry

Purpose

To investigate the association of preexisting hypertension at admission with the mortality in patients with systolic heart failure (HF).

Method

We prospectively investigated the association of preexisting hypertension with the mortality among 1351 patients with HF in Taiwan during an average 12 months (range: 8 months–18 months) follow-up period. A multivariate cox regression analysis for the overall cohort and a subgroup analysis by age were performed.

Results

After adjustment for all potential risk factors, the associations of preexisting hypertension with cardiovascular mortality were significantly reduced in the overall cohort and those aged less than 65 years (hazard ratios (HR): 0.53, 95% confidence intervals (CI): 0.33–0.84, and 0.28, 95% CI: 0.11–0.67, respectively). However, the associations with all-cause mortality were not significantly different in these two groups (HR: 0.77, 95% CI: 0.54–1.09, and 0.59, 95% CI: 0.32–1.07, respectively). Furthermore, the associations were all nonsignificant in the patients aged older than 65 years.

Conclusion

Preexisting hypertension have an inverse association with cardiovascular mortality in the Asian patients with systolic HF, particularly for those with younger ages.

Reverse epidemiology of elevated blood pressure among chronic hemodialysis black patients with stroke: a historical cohort study

Background

Stroke is the third leading cause of cardiovascular mortality in dialysis patients. The objective of this study was to assess the extent of stroke in chronic hemodialysis patients.

Methods

Historical cohort of patients enrolled in two hemodialysis (HD) centers from January 1, 2010 to December 31, 2011, including 191 patients (mean age 52 years, 68% men). Incidence curves and survival time analysis between the first day of HD and the end of the study were described by the Kaplan-Meier method. Independent stroke predictors were identified by multiple logistic regression analysis. P < 0.05 defined the level of statistical significance.

Results

12 incident stroke were recorded during the study period, with 1622.1 person-months (PM), a stroke incidence rate of 7.4 cases per 1000 PM (95% CI = 7.35–7.44) at the point date. The incidence of stroke at 6 months, 12 months and 24 months was 9.8%, 11.9% and 13%, respectively. Only the absence of arterial hypertension (RR = 5.7, 95% CI: 1.52–21.42) emerged as an independent determinant of stroke.

Conclusion

The high incidence of stroke in Kinshasa HD centers is partially explained by reverse epidemiology. Efforts must be made to understand this phenomenon in order to reduce its impact.

Influence of blood pressure at the beginning of decompensations in the prognosis of patients with heart failure

BACKGROUND AND OBJECTIVE

An inverse relationship has been described between blood pressure and the prognosis in heart failure (HF). The characteristics of this relationship are not well unknown. The objective of this study was to determine if this relationship is maintained in a non-selected cohort of patients with HF and if it can be modified by treatment.

MATERIAL AND METHODS

Prospective study of cohorts including patients hospitalized for decompensated HF in Internal Medicine departments and followed as outpatients in a monographic consultation. Patients were classified according to their levels of systolic (SBP) and diastolic blood pressure (DBP). Clinical characteristics, all-cause mortality and readmissions after the first, third and sixth month of follow-up were analysed.

RESULTS

Two hundred and twenty-one patients were included after their admission to the hospital for acute HF. Mean patient age was 79.5 years(SD 8.09); 115 patients were male. No significant differences between SBP quartiles and basal characteristics were found. Patients with lower SBP (Q1) had higher mortality rates (20%, P<.05). No significant differences between mortality/readmissions and DBP were found. However, the Kaplan-Meier analysis showed higher all-cause mortality rates for the group of patients with lower SBP and DBP (log-rank=0.011 and 0.041, respectively). The pharmacological treatment did not differ significantly between both study groups.

CONCLUSION

For non-selected patients suffering HF, higher SBP upon the admission is associated with significantly lower all-cause mortality rates during follow-up. Pharmacological treatment of HF does not seem to influence this inverse relationship between SBP at admission and patient mortality.

Statins attenuate but do not eliminate the reverse epidemiology of total serum cholesterol in patients with non-ischemic chronic heart failure

BACKGROUND

In patients with chronic heart failure (CHF) increasing levels of total serum cholesterol are associated with improved survival - while statin usage is not. The impact of statin treatment on the "reverse epidemiology" of cholesterol is unclear.

METHODS

2992 consecutive patients with non-ischemic CHF due to left ventricular systolic dysfunction from the Norwegian CHF Registry and the CHF Registries of the Universities of Hull, UK, and Heidelberg, Germany, were studied. 1736 patients were individually double-matched on both cholesterol levels and the individual propensity scores for statin treatment. All-cause mortality was analyzed as a function of baseline cholesterol and statin use in both the general and the matched sample.

RESULTS

1209 patients (40.4%) received a statin. During a follow-up of 13,740 patient-years, 360 statin users (29.8%) and 573 (32.1%) statin non-users died. When grouped according to total cholesterol levels as low (≤3.6mmol/L), moderate (3.7-4.9mmol/L), high (4.8-6.2mmol/L), and very high (>6.2mmol/L), we found improved survival with very high as compared with low cholesterol levels. This association was present in statin users and non-users in both the general and matched sample (p<0.05 for each group comparison). The negative association of total cholesterol and mortality persisted when cholesterol was treated as a continuous variable (HR 0.83, 95%CI 0.77-0.90, p<0.001 for matched patients), but it was less pronounced in statin users than in non-users (F-test p<0.001).

CONCLUSIONS

Statins attenuate but do not eliminate the reverse epidemiological association between increasing total serum cholesterol and improved survival in patients with non-ischemic CHF.

Reverse Epidemiology of Traditional Cardiovascular Risk Factors in the Geriatric Population

Traditional risk factors of cardiovascular death in the general population, including body mass index (BMI), serum cholesterol, and blood pressure (BP), are also found to relate to outcomes in the geriatric population, but in an opposite direction. Some degrees of elevated BMI, serum cholesterols, and BP are reportedly associated with lower, instead of higher, risk of death among the elderly. This phenomenon is termed "reverse epidemiology" or "risk factor paradox" (such as obesity paradox) and is also observed in a variety of chronic disease states such as end-stage renal disease requiring dialysis, chronic heart failure, rheumatoid arthritis, and AIDS. Several possible causes are hypothesized to explain this risk factor reversal: competing short-term and long-term killers, improved hemodynamic stability in the obese, adipokine protection against tumor necrosis factor-α, lipoprotein protection against endotoxins, and lipophilic toxin sequestration by the adipose tissue. It is possible that the current thresholds for intervention and goal levels for such traditional risk factors as BMI, serum cholesterol, and BP derived based on younger populations do not apply to the elderly, and that new levels for such risk factors should be developed for the elderly population. Reverse epidemiology of conventional cardiovascular risk factors may have a bearing on the management of the geriatric population, thus it deserves further attention.

Reverse epidemiology in different stages of heart failure

BACKGROUND

In heart failure (HF), traditional cardiovascular risk factors (RF) as body mass index (BMI), total cholesterol (TC) and systolic blood pressure (SBP) are associated with better survival. It is unknown at which time point along the disease continuum the adverse impact of these RF ceases and may 'start to reverse'. We analyzed the distribution of RF and their association with survival across HF stages.

METHODS

We pooled data from four cohort studies from the German Competence Network HF. Employing ACC/AHA-criteria, patients were allocated to stage A (n=218), B (n=1324), C1 (i.e., New York Heart Association [NYHA] classes I & II; n=1134), and C2+D (NYHA III & IV; n=639).

RESULTS

With increasing HF severity median age increased (63/67/67/70 years), whereas the proportion of females (56/52/37/35%), median BMI (26.1/28.8/27.7/26.6 kg/m(2)), TC (212/204/191/172 mg/dl), and SBP (140/148/130/120 mmHg) decreased (P<0.001 for trend for all). In the total cohort, higher levels of all RF were associated with better survival, even after extensive adjustment for multiple confounders. If analyses were stratified, however, a higher RF burden predicted better survival only in clinically symptomatic patients: hazard ratio (HR) per +2 kg/m(2) BMI 0.91 (95% confidence interval 0.88; 0.95); per +10 mg/dl TC 0.93 (0.92; 0.95); per +5 mmHg SBP 0.94 (0.92; 0.95).

CONCLUSION

In this well-characterized sample of patients representing the entire HF continuum, reverse associations were only consistently observed in symptomatic HF stages. Our data indicate that the phenomenon of a "reverse epidemiology" in HF is subject to significant selection bias in less advanced disease.

Hemoglobin A1c, comorbid conditions and all-cause mortality in older patients with diabetes: a retrospective 9-year cohort study

AIMS

To examine whether hemoglobin A1c levels and comorbid conditions are related to all-cause mortality in a cohort of patients with type 1 or 2 diabetes receiving continuous care for 9 years. In patients with comorbid congestive heart failure (CHF), we test for 'reverse epidemiology,' or whether greater HbA1c values are associated with lower risk of mortality.

METHODS

The population for this longitudinal cohort study was 8820 Group Health enrollees in the Seattle area with type 1 or 2 diabetes in 1997 and enrolled continuously from 1997 to 2006. Comorbid conditions were hypertension, coronary artery disease, congestive heart failure, depression, and chronic pulmonary disease. Mistimed HbA1c scores were addressed by multiple imputation, and Cox proportional hazards models estimated associations controlling for other risk factors.

RESULTS

About 30% of the enrollees died in 1998-2006. CHF had the strongest association with all-cause mortality. Compared to enrollees with HbA1c ≥ 7.1% (54 mmol/mol) and < 7.5% (58 mmol/mol; 5th decile), enrollees with HbA1c < 6.4% (46 mmol/mol) had a significantly greater risk of death (HR range: 1.28-2.26). HbA1c > 7.5% had HR < 1.0 but were not significant. For enrollees with diabetes and CHF at baseline, HbA1c scores ≥ 8.7% (72 mmol/mol) had a significantly lower risk of death (HR range: 0.64-0.69).

CONCLUSIONS

In our patient population, HbA1c scores<6.4% have significantly higher all-cause mortality. CHF is a major determinant of all-cause mortality. Adults with comorbid CHF and high HbA1c scores have lower all-cause mortality.

Obesity paradox in end-stage kidney disease patients

In the general population, obesity is associated with increased cardiovascular risk and decreased survival. In patients with end-stage renal disease (ESRD), however, an "obesity paradox" or "reverse epidemiology" (to include lipid and hypertension paradoxes) has been consistently reported, i.e. a higher body mass index (BMI) is paradoxically associated with better survival. This survival advantage of large body size is relatively consistent for hemodialysis patients across racial and regional differences, although published results are mixed for peritoneal dialysis patients. Recent data indicate that both higher skeletal muscle mass and increased total body fat are protective, although there are mixed data on visceral (intra-abdominal) fat. The obesity paradox in ESRD is unlikely to be due to residual confounding alone and has biologic plausibility. Possible causes of the obesity paradox include protein-energy wasting and inflammation, time discrepancy among competitive risk factors (undernutrition versus overnutrition), hemodynamic stability, alteration of circulatory cytokines, sequestration of uremic toxin in adipose tissue, and endotoxin-lipoprotein interaction. The obesity paradox may have significant clinical implications in the management of ESRD patients especially if obese dialysis patients are forced to lose weight upon transplant wait-listing. Well-designed studies exploring the causes and consequences of the reverse epidemiology of cardiovascular risk factors, including the obesity paradox, among ESRD patients could provide more information on mechanisms. These could include controlled trials of nutritional and pharmacologic interventions to examine whether gain in lean body mass or even body fat can improve survival and quality of life in these patients.