Do thiazides worsen metabolic syndrome and renal disease? The pivotal roles for hyperuricemia and hypokalemia. Curr Opin Nephrol Hypertens. 2008;17:470-476. [PMID: 18695387 DOI: 10.1097/mnh.0b013e328305b9a5]

Acetazolamide and Hydrochlorothiazide in Patients With Acute Decompensated Heart Failure: Insights From Recent Trials

Acetazolamide and thiazide diuretics have been combined with loop diuretics to overcome diuretic resistance in heart failure patients. However, recent studies have assessed the upfront combination of acetazolamide and hydrochlorothiazide with loop diuretics in hospitalized patients with acute decompensated heart failure without loop diuretic resistance. We reviewed two recent randomized controlled trials on the upfront use of acetazolamide and thiazide diuretics in acute decompensated heart failure, respectively. When the two trials on acetazolamide are considered together, adding oral or intravenous acetazolamide to loop diuretics in decompensated heart failure patients resulted in increased diuresis and natriuresis. However, the effects were significantly higher in patients with serum bicarbonate ≥ 27 mmol/L and those with higher baseline glomerular filtration rate (GFR). Similarly, when the two trials on thiazide diuretics are considered together, adding hydrochlorothiazide to loop diuretics in decompensated heart failure patients resulted in increased diuresis and weight loss. However, it increases the risk of impaired renal function. When all the trials are considered together, the upfront use of acetazolamide may be helpful in carefully selected patients, including patients with underlying elevated bicarbonate levels (≥ 27 mmol/L) and those with good renal function (GFR > 50). Conversely, though the upfront use of thiazide diuretic added to intravenous furosemide improved diuretic response in acute decompensated heart failure, it causes an increased risk of worsening renal function and lack of clear evidence of reducing hospital length of stay.

The fructose survival hypothesis as a mechanism for unifying the various obesity hypotheses

The pathogenesis of obesity remains contested. Although genetics is important, the rapid rise in obesity with Western culture and diet suggests an environmental component. Today, some of the major hypotheses for obesity include the energy balance hypothesis, the carbohydrate-insulin model, the protein-leverage hypothesis, and the seed oil hypothesis. Each hypothesis has its own support, creating controversy over their respective roles in driving obesity. Here we propose that all hypotheses are largely correct and can be unified by another dietary hypothesis, the fructose survival hypothesis. Fructose is unique in resetting ATP levels to a lower level in the cell as a consequence of suppressing mitochondrial function, while blocking the replacement of ATP from fat. The low intracellular ATP levels result in carbohydrate-dependent hunger, impaired satiety (leptin resistance), and metabolic effects that result in the increased intake of energy-dense fats. This hypothesis emphasizes the unique role of carbohydrates in stimulating intake while fat provides the main source of energy. Thus, obesity is a disorder of energy metabolism, in which there is low usable energy (ATP) in the setting of elevated total energy. This leads to metabolic effects independent of excess energy while the excess energy drives weight gain.

Fructose might be a clue to the origin of preeclampsia insights from nature and evolution

Preeclampsia is a hypertensive disorder of pregnancy and is due to abnormal placentation. The pathogenesis remains unclear. Fructose is biologically distinct from glucose and has a critical role in fetal growth in early pregnancy. Many species, including humans, produce fructose in their placenta during the first trimester to assist fetal growth and survival during a time when hypoxia is significant. Fructose is preferred over glucose in hypoxic tissues, and in the developing fetus, fructose has a critical role in stimulating the production of nucleic acids, lipids and glycosaminoglycans. Fructose production normally decreases significantly following the establishment of maternal-fetal circulation following placentation. However, if there is impaired placentation, local hypoxia will continue to drive fructose production. Excessive fructose metabolism drives endothelial dysfunction, oxidative stress, elevated blood pressure, insulin resistance, fatty liver, and a rise in uric acid and vasopressin levels, all of which are features of the preeclamptic state. In addition to fructose production, dietary fructose, for example, from soft drinks, would be additive and has been reported to be a strong independent risk factor for preeclampsia. Uric acid-associated endothelial dysfunction disturbs the invasion of the spiral artery, leading to placental ischemia and further placental hypoxia. Here, we summarize the previous literature regarding the physiological and pathological roles of fructose in pregnancy and propose studies to further investigate the pathogenesis of preeclampsia. Fructose might be a Clue to the Origin of Preeclampsia Insights from Nature and Evolution Preeclampsia is a hypertensive disorder of pregnancy. The pathogenesis remains unclear. Fructose has a critical role in fetal growth in early pregnancy, and might be a key role to developing preeclampsia. Here, we summarize the previous literatures regarding the physiological andpathological roles of fructose in pregnancy to propose studies to further investigate the pathogenesis of preeclampsia.

Thiazides in chronic kidney disease: "back to the future"

The thiazide class diuretics are first-line agents for managing hypertension either as monotherapy or as a fixed-dose combination with other antihypertensive drugs. However, despite the extensive experience with these drugs for >60 years, there is general reluctance to use these agents in patients with advanced chronic kidney disease (CKD) because of concerns about their efficacy and safety as kidney function declines. In this issue of Clinical Kidney Journal, Minutolo et al. performed an updated review of the pharmacological properties, efficacy and side effects and randomized controlled trials that tested these drugs in patients with CKD.

Gout associated with reduced renal excretion of uric acid. Renal tubular disorder that nephrologists do not treat

Gout is recurrent inflammatory arthritis caused by the deposition of monosodium urate crystals in the joints. The risk factors that predispose to suffering from gout include non-modifiable factors such as gender, age, ethnicity and genetics, and modifiable factors such as diet and lifestyle. It has been shown that the heritability of uric acid levels in the blood is greater than 30%, which indicates that genetics play a key role in these levels. Hyperuricaemia is often a consequence of reduced renal urate excretion since more than 70% is excreted by the kidneys, mainly through the proximal tubule. The mechanisms that explain that hyperuricaemia associated with reduced renal urate excretion is, to a large extent, a proximal renal tubular disorder, have begun to be understood following the identification of two genes that encode the URAT1 and GLUT9 transporters. When they are carriers of loss-of-function mutations, they explain the two known variants of renal tubular hypouricaemia. Some polymorphisms in these genes may have an opposite gain-of-function effect, with a consequent increase in urate reabsorption. Conversely, loss-of-function polymorphisms in other genes that encode transporters involved in urate excretion (ABCG2, ABCC4) can lead to hyperuricaemia. Genome-wide association study (GWAS) methods have made it possible to locate new gout-related loci associated with reduced renal urate excretion (NIPAL1, FAM35A).

Renal outcomes of diabetic patients treated with combination therapy of ACE inhibitors plus either thiazide diuretics or calcium channel blockers: comparative retrospective cohort study in Northwestern Ethiopia

OBJECTIVE

The study determined the comparative renal functions on patients with diabetes treated with ACE inhibitors (ACEIs) plus either thiazide diuretics or calcium channel blockers (CCBs) in Northwestern Ethiopia.

DESIGN

Retrospective cohort study design was employed to collect the data from medical records of patients with diabetes followed for 1-5 years (N=404).

SETTING

The medical records of patients in chronic diabetic follow-up clinics of the hospital.

PARTICIPANTS

All the patients with diabetes medical records in Northwestern Ethiopian specialised hospital.

MAIN OUTCOME MEASURES

Exposures were ACEIs plus thiazide diuretics or CCBs collected from March to June 2020. Outcomes were defined as declining in estimated glomerular filtration rate (eGFR) values by ≥30% from the baseline recorded from 2015 to 2019. Descriptive and analytical statistics were illustrated to compare the study groups. Kaplan-Meier with log- rank test was used to plot the survival analyses curve. Potential factors substantially associated to renal events were examined using cox proportional hazards model.

RESULT

About 20% of patients developed renal events and significant numbers were from hydrochlorothiazide (HCT) users. The mean eGFR levels were significantly higher in patients on CCBs users over the follow-up years compared with HCT-based users. The CCBs users had an 18.8 mL/min/1.73 m2 higher in eGFR levels at the end of the follow-up period than HCT users (p<0.001). HCT users had shorter survival probability overtime to develop the outcomes compared with CCBs users (p=0.003). The CCBs-based regimen prevented risks of declining in renal function by 56.4% than HCT (p=0.001). Hazards of declining in eGFR levels were 93% higher for the patients with initial systolic blood pressure (SBP) levels were more than 150 mm Hg (p=0.006).

CONCLUSION

Compared with HCT, patients on CCBs had significantly prevented risks of renal events. However, both groups appeared with the same cardiovascular events. HCT-based regimen and higher initial SBP levels were significantly associated with eGFR reductions.

Antihypertensive drug use and psoriasis: A systematic review, meta- and network meta-analysis

AIMS

Diverse genetic and/or external factors may induce psoriasis. Drug exposure is 1 such prominent external factor; antihypertensive drugs are reportedly associated with psoriasis, but study results have been inconsistent. In this context, we investigated the associations between antihypertensive drugs and incidence if psoriasis via a systematic literature review and meta-analysis.

METHODS

Literature search in databases such as PubMed, Embase and Web of Science was conducted on 8 January 2021, and obtained data were pooled for meta- and network meta-analysis. Fixed- or random effect models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for evaluating the strength of the associations between antihypertensive drugs and psoriasis incidence. In addition to meta-analysis, Bayesian network meta-analysis was performed. ResultsThirteen eligible studies were included for meta-analysis with 6 378 116 individuals and 8 studies for network meta-analysis with 5 615 918 individuals. All antihypertensive drugs were significantly associated with psoriasis incidence. In a meta-analysis, the pooled ORs were 1.67 (95% CI: 1.31-2.13) for angiotensin-converting enzyme (ACE) inhibitors, 1.40 (95% CI: 1.20-1.63) for β-blockers, 1.53 (95% CI: 1.23-1.89) for calcium-channel blockers (CCBs), and 1.70 (95% CI: 1.40-2.06) for thiazide diuretics. For the comparative risks of psoriasis among antihypertensive drugs in the network meta-analysis, ORs were 2.09 (95% CI: 1.39-3.18) for ACE inhibitors, 1.35 (95% CI: 0.99-1.91) for BBs, 1.53 (95% CI: 1.07-2.24) for CCBs and 1.80 (95% CI: 1.23-2.66) for thiazide diuretics.

CONCLUSION

This study confirmed the associations between antihypertensive drugs and psoriasis; ACE inhibitors, BBs, CCBs and thiazide diuretics increased the risk of psoriasis. Therefore, antihypertensive drug users should be carefully monitored for psoriasis.

Gout associated with reduced renal excretion of uric acid. Renal tubular disorder that nephrologists do not treat

Gout is recurrent inflammatory arthritis caused by the deposition of monosodium urate crystals in the joints. The risk factors that predispose to suffering from gout include non-modifiable factors such as gender, age, ethnicity and genetics, and modifiable factors such as diet and lifestyle. It has been shown that the heritability of uric acid levels in the blood is greater than 30%, which indicates that genetics play a key role in these levels. Hyperuricaemia is often a consequence of reduced renal urate excretion since more than 70% is excreted by the kidneys, mainly through the proximal tubule. The mechanisms that explain that hyperuricaemia associated with reduced renal urate excretion is, to a large extent, a proximal renal tubular disorder, have begun to be understood following the identification of two genes that encode the URAT1 and GLUT9 transporters. When they are carriers of loss-of-function mutations, they explain the two known variants of renal tubular hypouricaemia. Some polymorphisms in these genes may have an opposite gain-of-function effect, with a consequent increase in urate reabsorption. Conversely, loss-of-function polymorphisms in other genes that encode transporters involved in urate excretion (ABCG2, ABCC4) can lead to hyperuricaemia. Genome-wide association study (GWAS) methods have made it possible to locate new gout-related loci associated with reduced renal urate excretion (NIPAL1, FAM35A).

Anthropometric variables, physical activity and dietary intakes of patients with uric acid nephrolithiasis

To evaluate anthropometric variables, energy expenditure by physical activity and nutrient intake of uric acid stone formers (UA-RSFs) compared to non-forming subjects (C). The study included 33 consecutive male patients with a diagnosis of "pure" stones of anhydrous uric acid at infrared spectroscopy and 49 male control subjects with no history of urinary stones. A personal interview was conducted including questionnaires for physical activity and dietary intakes. Anthropometric parametric and blood pressure were measured. Mean age, weight, height, waist circumference, body mass index, systolic and diastolic blood pressure values, dietary energy, carbohydrate intake, lipid intake, dietary acid load, time spent for different physical activities and total energy expenditure for physical activity were not different in UA-RSFs with respect to C. Mean dietary protein (76.2 ± 19.6 vs 65.4 ± 14.7 g/day, P = 0.006) and ethanol intake (10.4 ± 8.8 vs 4.1 ± 8.6, P = 0.002) were higher in UA-RSFs than in C. History of renal disease, heart disease and treatment with thiazides or allopurinol were more frequent and mean serum glucose and triglycerides (104 ± 12 vs 97 ± 11 mg/dl, P = 0.043) (172 ± 77 vs 123 ± 52 mg/dl, P = 0.023) were higher in UA-RSFs. Metabolic syndrome was more frequent in UA-RSFs (57% vs 39%) but not significant (p = 0.09). Increased dietary animal protein (and ethanol) intake can act as co-factors for uric acid stone formation although a more complex and not fully elucidated metabolic background can have an even more crucial role in the pathogenesis of this disease even in the absence of overweight.

Association of dietary sodium:potassium ratio with the metabolic syndrome in Chinese adults

Several epidemiological studies have investigated that Na or K intakes might be associated with the metabolic syndrome (MetS). However, little evidence has evaluated the association between Na:K ratio and the MetS. In this study, we assessed the association between the dietary Na:K ratio and the MetS. The cross-sectional study was conducted among adults aged 18 years and older in Nanjing, using a multi-stage random sampling method, which resulted in a sample size of 1993 participants. Dietary Na and K intakes were assessed by 3 consecutive days of dietary recollection combined with condiments weighing method. Health-related data were obtained by standardised questionnaires, as well as physical examinations and laboratory assessments. The prevalence rate of the MetS was 36·5 % (728/1993). After adjusting for various lifestyle and dietary factors of the MetS, participants in the highest quartile of dietary Na:K ratio were at a higher risk of developing MetS (OR=1·602; 95 % CI 1·090, 2·353) compared with those in the lowest quartile. Each 1-sd increase in dietary Na:K ratio was associated with a higher risk of prevalent MetS (OR=1·166; 95 % CI: 1·018, 1·336). Among the components of the MetS, dietary Na:K ratio was positively associated with high blood pressure (quartile 3 v. quartile 1: OR=1·656; 95 % CI 1·228, 2·256) and hypertriacylglycerolaemia (quartile 4 v. quartile1: OR=1·305; 95 % CI 1·029, 1·655) in multivariate analysis. These results revealed that higher dietary Na:K ratio significantly increased the risk of the MetS in Chinese adults. Further studies are needed to verify this association.

Hyperuricemia, Acute and Chronic Kidney Disease, Hypertension, and Cardiovascular Disease: Report of a Scientific Workshop Organized by the National Kidney Foundation

Urate is a cause of gout, kidney stones, and acute kidney injury from tumor lysis syndrome, but its relationship to kidney disease, cardiovascular disease, and diabetes remains controversial. A scientific workshop organized by the National Kidney Foundation was held in September 2016 to review current evidence. Cell culture studies and animal models suggest that elevated serum urate concentrations can contribute to kidney disease, hypertension, and metabolic syndrome. Epidemiologic evidence also supports elevated serum urate concentrations as a risk factor for the development of kidney disease, hypertension, and diabetes, but differences in methodologies and inpacts on serum urate concentrations by even subtle changes in kidney function render conclusions uncertain. Mendelian randomization studies generally do not support a causal role of serum urate in kidney disease, hypertension, or diabetes, although interpretation is complicated by nonhomogeneous populations, a failure to consider environmental interactions, and a lack of understanding of how the genetic polymorphisms affect biological mechanisms related to urate. Although several small clinical trials suggest benefits of urate-lowering therapies on kidney function, blood pressure, and insulin resistance, others have been negative, with many trials having design limitations and insufficient power. Thus, whether uric acid has a causal role in kidney and cardiovascular diseases requires further study.

Perspective: A Historical and Scientific Perspective of Sugar and Its Relation with Obesity and Diabetes

Fructose-containing added sugars, such as sucrose and high-fructose corn syrup, have been experimentally, epidemiologically, and clinically shown to be involved in the current epidemics of obesity and diabetes. Here we track this history of intake of sugar as it relates to these epidemics. Key experimental studies that have identified mechanisms by which fructose causes obesity and diabetes are reviewed, as well as the evidence that the uricase mutation that occurred in the mid-Miocene in ancestral humans acted as a "thrifty gene" that increases our susceptibility for fructose-associated obesity today. We briefly review recent evidence that obesity can also be induced by nondietary sources of fructose, such as from the metabolism of glucose (from high-glycemic carbohydrates) through the polyol pathway. These studies suggest that fructose-induced obesity is driven by engagement of a "fat switch" and provide novel insights into new approaches for the prevention and treatment of these important diseases.

Plasma potassium, diuretic use and risk of developing chronic kidney disease in a predominantly White population

Objective

Both hypokalemia and hyperkalemia are associated with disease progression in patients with chronic kidney disease (CKD). It is unclear whether similar associations are present in the general population. Our aim was to examine the association of plasma potassium with risk of developing CKD and the role of diuretics in this association in a population-based cohort.

Research design and methods

We studied 5,130 subjects free of CKD at baseline of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study, a prospective, population-based cohort of Dutch men and women aged 28–75 years. Hypokalemia was defined as plasma potassium <3.5 mmol/L, and hyperkalemia as plasma potassium ≥5.0 mmol/L. Risk of CKD was defined as de novo development of eGFR <60 ml/min/1.73m² and/or albuminuria >30 mg/24h.

Results

Mean baseline plasma potassium was 4.4±0.3 mmol/L. The prevalences of hypokalemia and hyperkalemia were 0.5% and 3.8%, respectively; 3.0% of the subjects used diuretics. During a median follow-up of 10.3 years (interquartile range: 6.3–11.4 years), 753 subjects developed CKD. The potassium-CKD association was modified by diuretic use (P_interaction = 0.02). Both hypokalemia without (HR, 7.74, 95% CI, 3.43–17.48) or with diuretic use (HR, 4.32, 95% CI, 1.77–10.51) were associated with an increased CKD risk as compared to plasma potassium 4.0–4.4 mmol/L without diuretic use. Plasma potassium concentrations ≥3.5 mmol/L were associated with an increased CKD risk among subjects using diuretics (P_trend = 0.01) but not among subjects not using diuretics (P_trend = 0.74).

Conclusion

In this population-based cohort, hypokalemia was associated with an increased CKD risk, regardless of diuretic use. In the absence of hypokalemia, plasma potassium was not associated with an increased CKD risk, except among subjects using diuretics.

Gout in immigrant groups: a cohort study in Sweden

Our aim was to study the association between country of birth and incidence of gout in different immigrant groups in Sweden. The study population included the whole population of Sweden. Gout was defined as having at least one registered diagnosis in the National Patient Register. The association between incidence of gout and country of birth was assessed by Cox regression, with hazard ratios (HRs) and 95% confidence intervals (95% CI), using Swedish-born individuals as referents. All models were conducted in both men and women, and the full model was adjusted for age, place of residence in Sweden, educational level, marital status, neighbourhood socio-economic status and co-morbidities. The risk of gout varied by country of origin, with highest estimates, compared to Swedish born, in fully adjusted models among men from Iraq (HR 1.82, 95% CI 1.54-2.16), and Russia (HR 1.69, 95% CI 1.26-2.27), and also high among men from Austria, Poland, Africa and Asian countries outside the Middle East; and among women from Africa (HR 2.23, 95% CI 1.50-3.31), Hungary (HR 1.98, 95% CI 1.45-2.71), Iraq (HR 1.76, 95% CI 1.13-2.74) and Austria (HR 1.70, 95% CI 1.07-2.70), and also high among women from Poland. The risk of gout was lower among men from Greece, Spain, Nordic countries (except Finland) and Latin America and among women from Southern Europe, compared to their Swedish counterparts. The increased risk of gout among several immigrant groups is likely explained by a high cardio-metabolic risk factor pattern needing attention.

Effect of losartan combined with amlodipine or with a thiazide on uric acid levels in hypertensive patients

Hyperuricemia leads to endothelial dysfunction and insulin resistance, and has been associated with diseases such as hypertension. Antihypertensive drugs modify serum uric acid levels, however, few data are available about their combinations on uricemia. In this study we evaluate the effect of two combinations of losartan, with amlodipine or with hydrochlorothiazide, on serum uric acid levels in hypertensive patients.

METHODS

A total of 60 hypertensive patients were randomized in two groups; group LA received losartan/amlodipine (100/5 mg) once a day, whereas LH group received losartan hydrochlorothiazide (100/12.5 mg) once a day for 3 months. In both groups serum uric acid levels were measured at the beginning and end of the study. Patients were evaluated monthly for blood pressure (BP) and adverse events. Statistical analysis was performed with a two-way analysis of variance (ANOVA) for repeated measures.

RESULTS

All patients experienced a significant reduction of BP to the same extent (LA 155/94 to 123/79, LH 157/92 to 124/78 mmHg, p > 0.05). In the LA group, serum uric acid decreased from 6.5 ± 1.6 to 4.6 ± 1.3 mg/ml ( p = 0.0001), whereas in the LH group there was a nonsignificant increase from 5.82 ± 1.4 to 5.85 ± 1.5 mg/ml, ( p = 0.936). When both groups were compared, we found a significant reduction ( p < 0.00013) on serum uric acid levels in the LA group.

CONCLUSIONS

Both combinations decrease BP values to the same extent, however, LA combination showed a reduction on serum uric acid levels, which may contribute to a reduction in the metabolic risk in hypertensive patients.

Pathophysiological Mechanisms and Correlates of Therapeutic Pharmacological Interventions in Essential Arterial Hypertension

Treating arterial hypertension (HT) remains a hard task. The hypertensive patient is often a subject with several comorbidities and metabolic abnormalities. Clinicians everyday have to choose the right drug for the single patient among the different classes of antihypertensives. Apart from lowering blood pressure, a main therapeutic target should be that of counteracting all the possible pathophysiological mechanisms involved in HT itself and in existing/potential comorbidities. All the ancillary positive and negative effects of the administered drugs should be considered: in particular, since hypertensive patients are often glucose intolerant/diabetic, carrier of serum lipids disorder, have already developed atherosclerotic diseases and endothelial dysfunction, they should not be treated with drugs negatively interfering with these conditions but with molecules that, if possible, improve them. The main pathophysiological mechanisms and correlates of therapeutic pharmacological interventions in essential HT are reviewed here.

Gout and its comorbidities in the total population of Stockholm

OBJECTIVE

Study of prevalence of gout with concomitant diseases.

METHODS

Study population included all living persons in Stockholm County, Sweden, on January 1st 2013 (N=2,124,959). A diagnosis of gout was identified during 2013-2014, with information of diabetes mellitus and insulin resistance, hypertension, chronic heart failure, chronic kidney disease, alcohol abuse, and malignancies. Age-adjusted odds ratios (ORs) with 95% confidence intervals (95% CI) for women and men with gout, using individuals without gout as referents, were calculated.

RESULTS

Age-adjusted odds of co-morbidities among individuals with gout vs. those without gout were: diabetes mellitus and insulin resistance 3.97 (95% CI 3.65-4.31) in women and 1.88 (95% CI 1.78-1.99) in men; hypertension 4.02 (95% CI 3.69-4.37) in women and 3.21 (95% CI 3.06-3.37) in men; chronic heart failure 4.72 (95% CI 4.31-5.19) in women and 2.84 (95% CI 2.66-3.04) in men; chronic kidney disease 2.08 (95% CI 1.50-2.87) in women and 2.39 (95% CI 2.15-2.66) in men; alcohol abuse 8.98 (95% CI 8.15-9.80) in women and 4.38 (95% CI 4.10-4.69) in men; and malignancies 1.32 (95% CI 1.17-1.48) in women and 1.13 (95% CI 1.06-1.21) men.

CONCLUSION

Gout is a warning sign for concomitant diseases, e.g. alcoholism, diabetes, cardiovascular diseases, and cancer. KEY MESSAGES.

Metabolic syndrome and chronic kidney disease: Current status and future directions

Metabolic syndrome (MetS) is a term used to denote a combination of selected, widely prevalent cardiovascular disease (CVD)-related risk factors. Despite the ambiguous definition of MetS, it has been clearly associated with chronic kidney disease markers including reduced glomerular filtration rate, proteinuria and/or microalbuminuria, and histopathological markers such as tubular atrophy and interstitial fibrosis. However, the etiological role of MetS in chronic kidney disease (CKD) is less clear. The relationship between MetS and CKD is complex and bidirectional, and so is best understood when CKD is viewed as a common progressive illness along the course of which MetS, another common disease, may intervene and contribute. Possible mechanisms of renal injury include insulin resistance and oxidative stress, increased proinflammatory cytokine production, increased connective tissue growth and profibrotic factor production, increased microvascular injury, and renal ischemia. MetS also portends a higher CVD risk at all stages of CKD from early renal insufficiency to end-stage renal disease. Clinical interventions for MetS in the presence of CKD should include a combination of weight reduction, appropriate dietary modification and increase physical activity, plus targeting of individual CVD-related risk factors such as dysglycemia, hypertension, and dyslipidemia while conforming to relevant national societal guidelines.

Improving cardiovascular and renal outcomes in gout: what should we target?

Epidemiological and experimental studies have shown that hyperuricaemia and gout are intricately linked with hypertension, metabolic syndrome, chronic kidney disease and cardiovascular disease. A number of studies suggest that hyperuricaemia and gout are independent risk factors for the development of these conditions and that these conditions account, in part, for the increased mortality rate of patients with gout. In this Review, we first discuss the links between hyperuricaemia, gout and these comorbidities, and present the mechanisms by which uric acid production and gout might favour the development of cardiovascular and renal diseases. We then emphasize the potential benefit of urate-lowering therapies on cardiovascular and renal outcomes in patients with hyperuricaemia. The mechanisms that link elevated serum uric acid levels and gout with these comorbidities seem to be multifactorial, implicating low-grade systemic inflammation and xanthine oxidase (XO) activity, as well as the deleterious effects of hyperuricaemia itself. Patients with asymptomatic hyperuricaemia should be treated by nonpharmacological means to lower their SUA levels. In patients with gout, long-term pharmacological inhibition of XO is a treatment strategy that might also reduce cardiovascular and renal comorbidities, because of its dual effect of lowering SUA levels as well as reducing free-radical production during uric acid formation.

Comparison of effects of azelnidipine and trichlormethiazide in combination with olmesartan on blood pressure and metabolic parameters in hypertensive type 2 diabetic patients

Aims/Introduction:  Angiotensin II type 1 receptor blockers (ARB) are regarded as first-line treatment for type 2 diabetes with hypertension. However, lowering blood pressure to the target level often requires more than one antihypertensive agent as recommended by the guideline. In this open-label, prospective, crossover clinical trial, we compared the effects of combination treatment of ARB with a calcium channel blocker (CCB) or with a low-dose thiazide diuretic on blood pressure (BP) and various metabolic parameters in hypertensive patients with type 2 diabetes.

MATERIALS AND METHODS

  A total of 39 Japanese type 2 diabetics with hypertension treated with olmesartan (20 mg/day) for at least 8 weeks were recruited to this study. At study entry, treatment was switched to either olmesartan (20 mg/day)/azelnidipine (16 mg/day) or olmesartan (20 mg/day)/trichlormethiazide (1 mg/day) and continued for 12 weeks. Then, the drugs were switched and treatment was continued for another 12 weeks. We measured clinical blood pressure and various metabolic parameters before and at the end of each study arm.

RESULTS

  Compared with the olmesartan/trichlormethiazide treatment, treatment with olmesartan/azelnidipine achieved superior clinical blood pressure and pulse rate control. In contrast, the treatment with olmesartan/trichlormethiazide resulted in increased HbA1c, serum uric acid and worsening of estimated glomerular filtration rate, though there were no differences in other metabolic parameters including urine 8-hydroxy-2'-deoxyguanosine, C-reactive protein and adiponectin between the two treatments.

CONCLUSIONS

  Our results show that the combination of ARB with azelnidipine is more beneficial with regard to blood pressure control and metabolic outcome than the combination of olmesartan with low dose trichlormethiazide. This trial was registered with UMIN clinical trial registry (no. UMIN000005064). (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00135.x, 2011).

Low serum potassium level is associated with nonalcoholic fatty liver disease and its related metabolic disorders

CONTEXT

Subjects with nonalcoholic fatty liver disease (NAFLD) have a high risk of developing type 2 diabetes and cardiovascular diseases. Low serum potassium concentration or low dietary potassium intake can result in metabolic disorders.

OBJECTIVE

Our objective was to evaluate the association between low serum potassium level and prevalence of NAFLD in a Chinese population.

DESIGN

A population-based cross-sectional study.

PATIENTS

We conducted a community-based study in 8592 subjects to investigate the association of serum potassium with the risk of prevalent NAFLD. NAFLD was diagnosed by hepatic ultrasonography.

RESULTS

The prevalence rate of NAFLD was 30·3% in this population and gradually decreased across serum potassium quartiles. With the reduction in serum potassium level, participants have larger waist circumference (WC) and more severe insulin resistance. The correlations hold also in multivariate linear regression analysis. In logistic regression analysis, compared with subjects in the highest quartile of serum potassium level, the adjusted odds ratios (ORs) in the lowest quartile was 1·33 [95% confidence interval (CI), 1·11-1·60] for NAFLD, 1·81 (95% CI, 1·49-2·19) for insulin resistance and 1·58 (95% CI, 1·30-1·93) for central obesity. In subgroup analysis after multiple adjustments, significant relation between serum potassium level and prevalent NAFLD was detected in women, younger subjects, those with insulin resistance and those with central obesity, respectively.

CONCLUSION

Low serum potassium level significantly associated with prevalence of NAFLD in middle-aged and elderly Chinese.

Secondary metabolic syndrome: the frequency of factors which may underlie the parameters of metabolic syndrome

BACKGROUND AND OBJECTIVES

Each of the metabolic syndrome (MetS) components (central obesity, hypertriglyceridemia, hypertension, low high-density lipoprotein cholesterol, and insulin resistance) may arise from an underlying disease or factors such as hormonal or pharmacological factors. These components arising secondary to a reason other than life style disturbances cause secondary MetS. The present study aimed to present, for the first time, the factors affecting secondary MetS.

DESIGN AND SETTINGS

An observational study at Medeniyet University Goztepe Training and Research Hospital, Istanbul, from June 2010 to February 2011.

PATIENTS AND METHODS

The underlying causes in 902 MetS patients with a mean age of 53.5 (12.9) years, of whom 79% were female, were investigated. A detailed evaluation was made, which comprised a history for drugs, diseases and habits that may manifest MetS parameters, physical examination, and laboratory analysis.

RESULTS

In 10.6% of the patients, hypothyroidism was determined as the main factor affecting secondary MetS, and in 4.1% the use of corticosteroid was determined as the main factor. Other factors underlie affecting secondary MetS are as follows: the use of thiazide diuretics (22.8%), beta-blockers (12.5%), antiphysichotics (2.1%), insulins (12.8%), insulin secretagog oral hypoglycemics (13.8%), thiazolidinediones (4.9%), oral contraceptives (0.8%), and alcohol intake (2.2%).

CONCLUSION

Hypothyroidism and corticosteroid treatment are the leading causes of secondary MetS. While evaluating the patients, it is a prerequisite to determine the high frequency of other factors that may affect the presence and the degree of MetS parameters.

Serum potassium level is associated with metabolic syndrome: a population-based study

BACKGROUND & AIMS

Evidence has suggested that low serum potassium concentration or low dietary potassium intake can result in many metabolic disorders. Our objective was to evaluate the association between serum potassium level and risk of prevalent metabolic syndrome.

METHODS

We conducted a cross-sectional study in 10,341 participants aged 40 years or older. Metabolic syndrome was defined according to guidelines from the National Cholesterol Education Program with modification.

RESULTS

The prevalence rate of metabolic syndrome was 51.7% in participants with hypokalemia and 37.7% in those with normokalemia. With the reduction of serum potassium quartiles, participants were tended to have higher level of triglycerides and uric acid, lower level of high-density lipoprotein cholesterol (HDL-C), larger waist circumference and more severe insulin resistance. Serum potassium level significantly decreased with the increasing number of metabolic syndrome components. Compared with subjects in the highest quartile of serum potassium level, multivariate adjusted odds ratios for prevalent metabolic syndrome in the lowest quartile was 1.48 (95% confidence interval, 1.16-1.87). Moreover, compared with subjects without central obesity, hypertriglyceridemia, low HDL-C and elevated fasting plasma glucose, those with each of these metabolic syndrome components have lower level of serum potassium after adjusted for age and sex.

CONCLUSIONS

Low serum potassium level significantly associated with prevalence of metabolic syndrome in middle-aged and elderly Chinese.

Nonuremic indication for peritoneal dialysis for refractory heart failure in cardiorenal syndrome type II: review and perspective

Cardiorenal syndrome (CRS) type II is a serious condition in which chronic cardiac abnormalities cause worsening kidney function, leading to permanent chronic kidney damage. Management of CRS type II coupled with diuretic-resistant congestive heart failure (CHF) has been an issue of dispute. However, since the early 1990s, reports indicating the clinical usefulness of peritoneal dialysis (PD) as maintenance therapy for intractable CHF in this population have been accumulating. The present manuscript reviews the mechanisms by which kidney dysfunction develops within CHF, and then examines recent experiences of PD as chronic supportive therapy for intractable CRS type II, reviews the contributing mechanisms, and discusses the rationale for using PD as a new therapeutic approach in the nonuremic setting of CHF.

Hypokalemia, its contributing factors and renal outcomes in patients with chronic kidney disease

BACKGROUND

In the chronic kidney disease (CKD) population, the impact of serum potassium (sK) on renal outcomes has been controversial. Moreover, the reasons for the potential prognostic value of hypokalemia have not been elucidated.

DESIGN PARTICIPANTS & MEASUREMENTS

2500 participants with CKD stage 1-4 in the Integrated CKD care program Kaohsiung for delaying Dialysis (ICKD) prospective observational study were analyzed and followed up for 2.7 years. Generalized additive model was fitted to determine the cutpoints and the U-shape association between sK and end-stage renal disease (ESRD). sK was classified into five groups with the cutpoints of 3.5, 4, 4.5 and 5 mEq/L. Cox proportional hazard regression models predicting the outcomes were used.

RESULTS

The mean age was 62.4 years, mean sK level was 4.2±0.5 mEq/L and average eGFR was 40.6 ml/min per 1.73 m(2). Female vs male, diuretic use vs. non-use, hypertension, higher eGFR, bicarbonate, CRP and hemoglobin levels significantly correlated with hypokalemia. In patients with lower sK, nephrotic range proteinuria, and hypoalbuminemia were more prevalent but the use of RAS (renin-angiotensin system) inhibitors was less frequent. Hypokalemia was significantly associated with ESRD with hazard ratios (HRs) of 1.82 (95% CI, 1.03-3.22) in sK <3.5mEq/L and 1.67 (95% CI,1.19-2.35) in sK = 3.5-4 mEq/L, respectively, compared with sK = 4.5-5 mEq/L. Hyperkalemia defined as sK >5 mEq/L conferred 1.6-fold (95% CI,1.09-2.34) increased risk of ESRD compared with sK = 4.5-5 mEq/L. Hypokalemia was also associated with rapid decline of renal function defined as eGFR slope below 20% of the distribution range.

CONCLUSION

In conclusion, both hypokalemia and hyperkalemia are associated with increased risk of ESRD in CKD population. Hypokalemia is related to increased use of diuretics, decreased use of RAS blockade and malnutrition, all of which may impose additive deleterious effects on renal outcomes.

Potassium intake and the prevalence of metabolic syndrome: the Korean National Health and Nutrition Examination Survey 2008-2010

Lower potassium intake is considered to be correlated with diabetes incidence. However, few studies have investigated the effect of potassium intake on metabolic syndrome (MetS). Data was taken from the Korean National Health and Nutritional Examination Survey (2008–2010) using weighted adjustment. MetS was defined as per the revised National Cholesterol Education Program criteria. Homeostasis model assessment indices were calculated to diagnosis insulin resistance (IR). A total of 16,637 participants (44±0.25 years) were included. Women ingested lower amounts of potassium (2.71±0.02 g/day) than men (3.45±0.03 g/day). A curvilinear association between potassium intake and MetS prevalence was found among women. Women with less than the Adequate Intake (4.7 g/day) of potassium had an 11% risk reduction for MetS (adjusted odds ratio [OR], 0.89; 95% confidence interval [CI], 0.82–0.96; P = 0.004) and a 10% risk reduction for IR (OR, 0.90; 95% CI, 0.82–0.99; P = 0.026) for every 1 g/day potassium increase. Compared with the reference group (3.5–4.5 g/day), potassium intake was inversely associated with an increased risk of MetS (1.5–2.5 g/day; OR, 1.29; 95% CI, 1.02–1.63; P = 0.035; <1.5 g/day; OR, 1.40; 95% CI, 1.06–1.85; P = 0.017) and IR (<1.5 g/day; OR, 1.36; 95% CI, 1.05–1.76; P = 0.021). This relationship was more prominent in postmenopausal women, but not observed among men. Higher potassium intake is significantly associated with a lower MetS prevalence in women, and IR is believed to be connected.

Favourable effects of the Dietary Approaches to Stop Hypertension diet on glucose tolerance and lipid profiles in gestational diabetes: a randomised clinical trial

Although gestational diabetes mellitus (GDM) is associated with an increased risk of maternal and neonatal morbidity, there is no consensus as to the optimal approach of nutritional management in these patients. The present study was designed to assess the effect of the Dietary Approaches to Stop Hypertension (DASH) eating plan on glucose tolerance and lipid profiles of pregnant women with GDM. The present randomised controlled clinical trial was performed among thirty-four women diagnosed with GDM at 24–28 weeks of gestation. Subjects were randomly assigned to consume either the control diet (n 17) or the DASH eating pattern (n 17) for 4 weeks. The control diet was designed to contain 45–55 % carbohydrates, 15–20 % protein and 25–30 % total fat. The macronutrient composition of the DASH diet was similar to the control diet; however, the DASH diet was rich in fruits, vegetables, whole grains and low-fat dairy products, and contained lower amounts of saturated fats, cholesterol and refined grains with a total of 2400 mg Na/d. Fasting blood samples were taken at baseline and after 4 weeks of intervention to measure fasting plasma glucose, glycated Hb (HbA1c) and lipid profiles. Participants underwent a 3 h oral glucose tolerance tests and blood samples were collected at 60, 120 and 180 min to measure plasma glucose levels. Adherence to the DASH eating pattern, compared with the control diet, resulted in improved glucose tolerance such that plasma glucose levels reduced at 60 ( − 1·86 v. − 0·45 mmol/l, Pgroup= 0·02), 120 ( − 2·3 v. 0·2 mmol/l, Pgroup= 0·001) and 180 min ( − 1·7 v. 0·22 mmol/l, Pgroup= 0·002) after the glucose load. Decreased HbA1c levels ( − 0·2 v. 0·05 %, Pgroup= 0·001) was also seen in the DASH group compared with the control group. Mean changes for serum total ( − 0·42 v. 0·31 mmol/l, Pgroup= 0·01) and LDL-cholesterol ( − 0·47 v. 0·22 mmol/l, Pgroup= 0·005), TAG ( − 0·17 v. 0·34 mmol/l, Pgroup= 0·01) and total:HDL-cholesterol ratio ( − 0·6 (sd 0·9) v. 0·3 (sd 0·8), Pgroup= 0·008) were significantly different between the two diets. Additionally, consumption of the DASH diet favourably influenced systolic blood pressure ( − 2·6 v. 1·7 mmHg, Pgroup= 0·001). Mean changes of fasting plasma glucose ( − 0·29 v. 0·15 mmol/l, Pgroup= 0·09) were non-significant comparing the DASH diet with the control diet. In conclusion, consumption of the DASH eating pattern for 4 weeks among pregnant women with GDM resulted in beneficial effects on glucose tolerance and lipid profiles compared with the control diet.

Which diuretic is the preferred agent for treating essential hypertension: hydrochlorothiazide or chlorthalidone?

Since their introduction over 50 years ago thiazide and thiazide-like diuretics have been a mainstay in the treatment of hypertension. Yet despite outcome evidence with chlorthalidone, the preponderance of usage has been with hydrochlorothiazide-either as monotherapy or in combination with other drugs. There is an increasing debate as to whether or not there are significant differences between hydrochlorothiazide and chlorthalidone. Early outcome studies, upon which the recommendations were made, utilized higher doses than those not only commonly employed in clinical practice, but also studied in more recent outcome trials. In addition, data suggests that chlorthalidone may be more potent, in equal doses, in its BP response than hydrochlorothiazide. A fundamental question asked in the debate is whether or not the benefits attributed to chlorthalidone as a thiazide-like diuretic may be reasonably ascribed to thiazides given differences in their pharmacokinetic properties and perhaps some other more recently noted differences.

Hypertension and antihypertensive therapy in Hispanics and Mexican Americans living in the United States

Hypertension is a major independent risk factor for cardiovascular diseases, which are the most frequent cause of death worldwide. In addition, the risk of hypertension has been associated with racial and/or ethnic background. Hispanics are the largest and fastest-growing minority population in the United States, currently comprising about 16.3% (50.5 million) of the total population; these numbers will continue to increase into the next 10 years. The rate of uncontrolled hypertension in Hispanics significantly exceeds the rates observed among non-Hispanic blacks and whites. The reasons for these racial and ethnic differences in blood pressure control may include factors such as lack of access to health care, low socioeconomic status, language barriers, degree of acculturation, poor doctor-patient communication, and genetic factors. This article provides an up-to-date summary of epidemiological and treatment aspects of high blood pressure in the US Hispanic population. Because Mexican Americans constitute approximately 66% of US Hispanics, data sources that focus on Mexican Americans are also discussed.

Evidence-based diuretic therapy for improving cardiovascular prognosis in systemic hypertension

Diuretics are among the most commonly prescribed cardiovascular (CV) medications. The strength of evidence supporting the effectiveness of diuretics in lowering blood pressure and for preventing major adverse CV events in patients with hypertension varies considerably among diuretic classes and even among agents within the same class. Unfortunately, common prescribing habits among American physicians, including specialists in CV diseases, are not in line with the existing evidence regarding diuretic therapy for improving CV prognosis. In conclusion, although hydrochlorothiazide is the standard diuretic used for hypertension, the outcomes data suggest that chlorthalidone, indapamide, and possibly even the aldosterone receptor blockers (spironolactone and eplerenone) may be superior agents.

Mechanisms for blood pressure lowering and metabolic effects of thiazide and thiazide-like diuretics

Thiazide and thiazide-like diuretics are among the most commonly used antihypertensives and have been available for over 50 years. However, the mechanism by which these drugs chronically lower blood pressure is poorly understood. Possible mechanisms include direct endothelial- or vascular smooth muscle-mediated vasodilation and indirect compensation to acute decreases in cardiac output. In addition, thiazides are associated with adverse metabolic effects, particularly hyperglycemia, and the mechanistic underpinnings of these effects are also poorly understood. Thiazide-induced hypokalemia, as well as other theories to explain these metabolic disturbances, including increased visceral adiposity, hyperuricemia, decreased glucose metabolism and pancreatic beta-cell hyperpolarization, may play a role. Understanding genetic variants with differential responses to thiazides could reveal new mechanistic candidates for future research to provide a more complete understanding of the blood pressure and metabolic response to thiazide diuretics.

Increased fructose associates with elevated blood pressure

The recent increase in fructose consumption in industrialized nations mirrors the rise in the prevalence of hypertension, but epidemiologic studies have inconsistently linked these observations. We investigated whether increased fructose intake from added sugars associates with an increased risk for higher BP levels in US adults without a history of hypertension. We conducted a cross-sectional analysis using the data collected from the National Health and Nutrition Examination Survey (NHANES 2003 to 2006) involving 4528 adults without a history of hypertension. Median fructose intake was 74 g/d, corresponding to 2.5 sugary soft drinks each day. After adjustment for demographics; comorbidities; physical activity; total kilocalorie intake; and dietary confounders such as total carbohydrate, alcohol, salt, and vitamin C intake, an increased fructose intake of > or =74 g/d independently and significantly associated with higher odds of elevated BP levels: It led to a 26, 30, and 77% higher risk for BP cutoffs of > or =135/85, > or =140/90, and > or =160/100 mmHg, respectively. These results suggest that high fructose intake, in the form of added sugar, independently associates with higher BP levels among US adults without a history of hypertension.

Serum potassium and outcomes in CKD: insights from the RRI-CKD cohort study

BACKGROUND AND OBJECTIVES

The relationship between serum potassium (S(K)) and mortality in chronic kidney disease (CKD) has not been systematically investigated.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined the predictors and mortality association of S(K) in the Renal Research Institute CKD Study cohort, wherein 820 patients with CKD were prospectively followed at four US centers for an average of 2.6 years. Predictors of S(K) were investigated using linear and repeated measures regression models. Associations between S(K) and mortality, the outcomes of ESRD, and cardiovascular events in time-dependent Cox models were examined.

RESULTS

The mean age was 60.5 years, 80% were white, 90% had hypertension, 36% had diabetes, the average estimated GFR was 25.4 ml/min per 1.73 m(2), and mean baseline S(K) was 4.6 mmol/L. Higher S(K) was associated with male gender, lower estimated GFR and serum bicarbonate, absence of diuretic and calcium channel blocker use, diabetes, and use of angiotensin-converting enzyme inhibitors and/or statins. A U-shaped relationship between S(K) and mortality was observed, with mortality risk significantly greater at S(K) < or = 4.0 mmol/L compared with 4.0 to 5.5 mmol/L. Risk for ESRD was elevated at S(K) < or = 4 mmol/L in S(K) categorical models. Only the composite of cardiovascular events or death as an outcome was associated with higher S(K) (> or = 5.5).

CONCLUSIONS

Although clinical practice usually emphasizes greater attention to elevated S(K) in the setting of CKD, our results suggest that patients who have CKD and low or even low-normal S(K) are at higher risk for dying than those with mild to moderate hyperkalemia.

Modeling transport in the kidney: investigating function and dysfunction

Mathematical models of water and solute transport in the kidney have significantly expanded our understanding of renal function in both health and disease. This review describes recent theoretical developments and emphasizes the relevance of model findings to major unresolved questions and controversies. These include the fundamental processes by which urine is concentrated in the inner medulla, the ultrastructural basis of proteinuria, irregular flow oscillation patterns in spontaneously hypertensive rats, and the mechanisms underlying the hypotensive effects of thiazides. Macroscopic models of water, NaCl, and urea transport in populations of nephrons have served to test, confirm, or refute a number of hypotheses related to the urine concentrating mechanism. Other macroscopic models focus on the mechanisms, role, and irregularities of renal hemodynamic control and on the regulation of renal oxygenation. At the mesoscale, models of glomerular filtration have yielded significant insight into the ultrastructural basis underlying a number of disorders. At the cellular scale, models of epithelial solute transport and pericyte Ca2+ signaling are being used to elucidate transport pathways and the effects of hormones and drugs. Areas where further theoretical progress is conditional on experimental advances are also identified.