Hypertension, hypokalemia, and thiazide-induced diabetes: a 3-way connection

Solvatomorph and polymorph screening of clopamide drug and its copper(ii) complex crystals

The anhydrate and hemihydrate structures of the marketed drug, clopamide, are described the first time. Structural landscape of its copper complexes is presented: three polymorphic modifications and an isostructural series of its alcohol clathrates.

Hypokalemia is frequent and has prognostic implications in stable patients attending the emergency department

BACKGROUND

Potassium disturbances are associated with adverse prognosis in patients with chronic conditions. Its prognostic implications in stable patients attending the emergency department (ED) is poorly described.

AIMS

This study aimed to assess the prevalence of dyskalemia, describe its predisposing factors and prognostic associations in a population presenting the ED without unstable medical illness.

METHODS

Post-hoc analysis of a prospective, cross-sectional, multicenter study in the ED of 11 French academic hospitals over a period of 8 weeks. All adults presenting to the ED during this period were included, except instances of self-drug poisoning, inability to complete self-medication questionnaire, presence of an unstable medical illness and decline to participate in the study. All-cause hospitalization or deaths were assessed.

RESULTS

A total of 1242 patients were included. The mean age was 57.2±22.3 years, 51% were female. The distribution according to potassium concentrations was: hypokalemia<4mmol/L(n = 620, 49.9%), normokalemia 4-5mmol/L(n = 549, 44.2%) and hyperkalemia >5mmol/L(n = 73, 0,6%). The proportion of patients with a kalemia<3.5mmol/L was 8% (n = 101). Renal insufficiency (OR [95% CI] = 3.56[1.94-6.52], p-value <0.001) and hemoglobin <12g/dl (OR [95% CI] = 2.62[1.50-4.60], p-value = 0.001) were associated with hyperkalemia. Female sex (OR [95% CI] = 1.31[1.03-1.66], p-value = 0.029), age <45years (OR [95% CI] = 1.69 [1.20-2.37], p-value = 0.002) and the use of thiazide diuretics (OR [95% CI] = 2.04 [1.28-3.32], p-value = 0.003), were associated with hypokalemia<4mmol/l. Two patients died in the ED and 629 (52.7%) were hospitalized. Hypokalemia <3.5mmol/L was independently associated with increased odds of hospitalization or death (OR [95% CI] = 1.47 [1.00-2.15], p-value = 0.048).

CONCLUSIONS

Hypokalemia is frequently found in the ED and was associated with worse outcomes in a low-risk ED population.

Impact of long-term potassium supplementation on thiazide diuretic-induced abnormalities of glucose and uric acid metabolisms

Treatment of hypertension with thiazide diuretics may trigger hypokalemia, hyperglycemia, and hyperuricemia. Some studies suggest simultaneous potassium supplementation in hypertensive patients using thiazide diuretics. However, few clinical studies have reported the impact of long-term potassium supplementation on thiazide diuretic-induced abnormalities in blood glucose and uric acid (UA) metabolisms. One hundred hypertensive patients meeting the inclusion criteria were equally randomized to two groups: IND group receiving indapamide (1.25-2.5 mg daily) alone, and IND/KCI group receiving IND (1.25-2.5 mg daily) plus potassium chloride (40 mmol daily), both for 24 weeks. At the end of 24-week follow-up, serum K⁺ level in IND group decreased from 4.27 ± 0.28 to 3.98 ± 0.46 mmol/L (P < 0.001), and fasting plasma glucose (FPG) and UA increased from 5.11 ± 0.52 to 5.31 ± 0.57 mmol/L (P < 0.05), and from 0.404 ± 0.078 to 0.433 ± 0.072 mmol/L (P < 0.05), respectively. Serum K⁺ level in IND/KCl group decreased from 4.27 ± 0.36 to 3.89 ± 0.28 mmol/L (P < 0.001), and FPB and UA increased from 5.10 ± 0.41 to 5.35 ± 0.55 mmol/L (P < 0.01), and from 0.391 ± 0.073 to 0.457 ± 0.128 mmol/L (P < 0.001), respectively. The difference value between the serum K⁺ level and FPG before and after treatment was not statistically significant between the two groups. However, the difference value in UA in IND/KCl group was significantly higher than that in IND group (0.066 (95% confidence interval (CI): 0.041-0.090)  mmol/L vs. 0.029 (95% CI: 0.006-0.058) mmol/L, P < 0.05). The results showed that long-term routine potassium supplementation could not prevent or attenuate thiazide diuretic-induced abnormalities of glucose metabolism in hypertensive patients; rather, it may aggravate the UA metabolic abnormality.

Antihypertensive drugs and glucose metabolism

Hypertension plays a major role in the development and progression of micro- and macrovascular disease. Moreover, increased blood pressure often coexists with additional cardiovascular risk factors such as insulin resistance. As a result the need for a comprehensive management of hypertensive patients is critical. However, the various antihypertensive drug categories have different effects on glucose metabolism. Indeed, angiotensin receptor blockers as well as angiotensin converting enzyme inhibitors have been associated with beneficial effects on glucose homeostasis. Calcium channel blockers (CCBs) have an overall neutral effect on glucose metabolism. However, some members of the CCBs class such as azelnidipine and manidipine have been shown to have advantageous effects on glucose homeostasis. On the other hand, diuretics and β-blockers have an overall disadvantageous effect on glucose metabolism. Of note, carvedilol as well as nebivolol seem to differentiate themselves from the rest of the β-blockers class, being more attractive options regarding their effect on glucose homeostasis. The adverse effects of some blood pressure lowering drugs on glucose metabolism may, to an extent, compromise their cardiovascular protective role. As a result the effects on glucose homeostasis of the various blood pressure lowering drugs should be taken into account when selecting an antihypertensive treatment, especially in patients which are at high risk for developing diabetes.

The target-specific transporter and current status of diuretics as antihypertensive

The currently available diuretics increase the urinary excretion of sodium chloride by selective inhibition of specific sodium transporters in the loop of Henle and distal nephron. In recent years, the molecular cloning of the diuretic-sensitive sodium transporters at distal convoluted tubule has improved our understanding of the cellular mechanisms of action of each class of diuretics. Diuretics are tools of considerable therapeutic importance. First, they effectively reduce blood pressure. Loop and thiazide diuretics are secreted from the proximal tubule via the organic anion transporter-1 and exert their diuretic action by binding to the Na(+)-K(+)-2Cl(-) co-transporter type 2 in the thick ascending limb and the Na(+)-Cl(-) co-transporter in the distal convoluted tubule, respectively. Recent studies in animal models suggest that abundance of these ion transporters is affected by long-term diuretic administration. The WHO/ISH guidelines point out that diuretics enhance the efficacy of antihypertensive drugs and will most often be a component of combination therapy.

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.

Impact of abdominal obesity on incidence of adverse metabolic effects associated with antihypertensive medications

We assessed adverse metabolic effects of atenolol and hydrochlorothiazide among hypertensive patients with and without abdominal obesity using data from a randomized, open-label study of hypertensive patients without evidence of cardiovascular disease or diabetes mellitus. Intervention included randomization to 25 mg of hydrochlorothiazide or 100 mg of atenolol monotherapy followed by their combination. Fasting glucose, insulin, triglycerides, high-density lipoprotein cholesterol, and uric acid levels were measured at baseline and after monotherapy and combination therapy. Outcomes included new occurrence of and predictors for new cases of glucose > or =100 mg/dL (impaired fasting glucose), triglyceride > or =150 mg/dL, high-density lipoprotein < or =40 mg/dL for men or < or =50 mg/dL for women, or new-onset diabetes mellitus according to the presence or absence of abdominal obesity. Abdominal obesity was present in 167 (58%) of 395 patients. Regardless of strategy, in those with abdominal obesity, 20% had impaired fasting glucose at baseline compared with 40% at the end of study (P<0.0001). Proportion with triglycerides > or =150 mg/dL increased from 33% at baseline to 46% at the end of study (P<0.01). New-onset diabetes mellitus occurred in 13 patients (6%) with and in 4 patients (2%) without abdominal obesity. Baseline levels of glucose, triglyceride, and high-density lipoprotein predicted adverse outcomes, and predictors for new-onset diabetes mellitus after monotherapy in those with abdominal obesity included hydrochlorothiazide strategy (odds ratio: 46.91 [95% CI: 2.55 to 862.40]), female sex (odds ratio: 31.37 [95% CI: 2.10 to 468.99]), and uric acid (odds ratio: 3.19 [95% CI: 1.35 to 7.52]). Development of adverse metabolic effect, including new-onset diabetes mellitus associated with short-term exposure to hydrochlorothiazide and atenolol was more common in those with abdominal obesity.

Lack of correlation between thiazide-induced hyperglycemia and hypokalemia: subgroup analysis of results from the pharmacogenomic evaluation of antihypertensive responses (PEAR) study

STUDY OBJECTIVE

To determine whether changes in serum glucose, serum potassium, and plasma insulin levels are correlated in a cohort of hypertensive patients.

DESIGN

Prespecified subgroup analysis of results from a prospective, multicenter, randomized, open-label, parallel-group study. Setting. Primary care clinics at three tertiary care medical centers.

PATIENTS

Community-based ambulatory population of 202 patients (age range 17-65 yrs) with a new diagnosis of hypertension, untreated hypertension, or known hypertension, who were previously treated with fewer than three antihypertensive drugs and had no evidence of cardiovascular disease or diabetes mellitus. Intervention. Monotherapy with oral hydrochlorothiazide 12.5 or 25 mg/day for 9 weeks.

MEASUREMENTS AND MAIN RESULTS

Fasting serum glucose, serum potassium, and plasma insulin levels were obtained at baseline (before hydrochlorothiazide therapy was started) and after 9 weeks of therapy. Significant elevations were noted in fasting serum glucose (mean +/- SD 3.42 +/- 10.38 mg/dl, p<0.0001) and plasma insulin (2.35 +/- 9.47 microU/ml, p<0.0001) levels, and a significant reduction in serum potassium level (0.30 +/- 0.44 mEq/L, p<0.0001) was noted. No significant correlation was observed between changes in fasting serum glucose and potassium levels (r = 0.022, 95% confidence interval (CI) -0.120-0.164, p=0.757) or between changes in serum potassium and plasma insulin levels (r = -0.112, 95% CI -0.256-0.037, p=0.140). Changes in serum glucose levels did not differ significantly between patients maintaining serum potassium levels of 4.0 mEq/L or greater and those with levels below 4.0 mEq/L.

CONCLUSION

Changes in serum potassium and serum glucose levels were not correlated in individuals receiving hydrochlorothiazide monotherapy; thus maintenance of normal potassium levels may not attenuate the risk of thiazide diuretic-induced hyperglycemia.

Hypertension in diabetes: a call to action

The Canadian Hypertension Education Program, Blood Pressure Canada, Canadian Hypertension Society, Heart and Stroke Foundation of Canada, Canadian Diabetes Association, College of Family Physicians of Canada, Canadian Pharmacists Association and the Canadian Council of Cardiovascular Nurses call on Canadian health care professionals to redouble efforts to help patients achieve treatment targets (blood pressure less than 130 mmHg systolic and less than 80 mmHg diastolic) in people with diabetes. Treatment of high blood pressure in people with diabetes results in large reductions in death and disability within a short period of time and needs to be a therapeutic priority. Achieving blood pressure targets requires sustained lifestyle modification, and three or more drugs including a diuretic are often required. Antihypertensive treatment in people with diabetes is one of the few medical treatments estimated to reduce overall health costs. The cost of treatment is less than the cost of complications prevented. Blood pressure needs to be assessed at all visits and home blood pressure assessment is encouraged. Management strategies need to include assessment and management of cardiovascular risks including smoking, unhealthy eating, physical inactivity, abdominal obesity, dyslipidemia as well as dysglycemia. The risks and benefits of acetylsalicylic acid in primary prevention of cardiovascular disease are uncertain in people with hypertension and diabetes. Intensive individualized lifestyle modification is recommended to prevent and treat hypertension, dyslipidemia, dysglycemia and other vascular risks in people with diabetes.