Jay Garg

Thiazide diuretics, potassium, and the development of diabetes: a quantitative review.

National guidelines and a recent clinical trial have supported the use of thiazide diuretics as the preferred initial pharmacological treatment for hypertension. However, evidence from this and other clinical trials have also found an increased incidence of new onset diabetes among those patients receiving thiazide diuretics. The mechanisms responsible for the increased incidence of diabetes with thiazide diuretics have not been fully elucidated. This article provides a review of intervention studies that included data on the relation between thiazide-induced hypokalemia and glucose intolerance. We conducted a literature search from 1966 to June 2004 to identify clinical trials using thiazide diuretics where the metabolic effects on potassium and glucose are reported. A total of 59 clinical trials constituting 83 thiazide diuretic study arms were identified. Trial size, length, type of thiazide diuretic, and dose varied substantially among the studies. The association between average changes in potassium and glucose in the study arms is considered jointly in a weighted statistical model. The Pearson’s correlation coefficient, weighted by study sample size, for the relationship between glucose and potassium was −0.54 (95% CI, −0.67 to −0.36; P<0.01). A sensitivity analysis, which considered subset analyses and effect of covariates, as well as inverse-variance weighting, supported this finding. These data suggest that thiazide-induced hypokalemia is associated with increased blood glucose. Treatment of thiazide-induced hypokalemia may reverse glucose intolerance and possibly prevent the future development of diabetes.

Microalbuminuria: marker of vascular dysfunction, risk factor for cardiovascular disease

Based on the data from large single and multi-center clinical trials, including the Heart Outcomes Prevention Evaluation (HOPE) study, it is clear that the presence of microalbuminuria is a signal from the kidney that cardiovascular risk is increased and that vascular responses are altered. This is exemplified by studies that have demonstrated that the compensatory vaso-dilation seen following relief from prolonged ischemia or infusion of vasodilators such as nitroglycerin is blunted in people with microalbuminuria. Thus, the presence of between 30 and 299 mg/day of albumin in the urine is associated with abnormal vascular responsiveness, which may be the result of more advanced atherosclerosis and not necessarily related to the presence of hypertension or renal disease. Agents known to reduce the rise in microalbuminuria or actually reduce the level of microalbuminuria, such as ACE inhibitors, angiotensin receptor blockers, HMG-CoA reductase inhibitors, beta blockers, non-dihydropyridine calcium channel blockers and diuretics, have all been shown to reduce cardiovascular mortality and in some cases preserve renal function. This article will present an overview of the data that support the assertion that a reduction in the rise of microalbuminuria is a significant consideration in the selection of agents to treat a given risk factor (cholesterol or blood pressure) to a recommended target goal. Achieving such a goal with agents that also impact microalbuminuria will provide for a more complete cardiovascular risk reduction.

Evaluation and Treatment of Patients With Systemic Hypertension

A 65-year-old man presented for evaluation of high blood pressure found on screening at a local health fair. History and physical examination did not show any signs or symptoms suggestive of a secondary cause, nor was there evidence of target end-organ damage except for grade 1 Keith-Wagener-Barker retinopathy. The patient denied taking any prescription or over-the-counter medications. Hypertension is the most common disease-specific reason Americans visit a physician. Despite the risks associated with an elevated blood pressure (BP), there is still woefully low achievement of recommended BP goals. From 1991 to 1994, only 27.4% of hypertensive Americans aged 18 to 74 years had a BP <140/90 mm Hg, the current stated goal for most people with hypertension, and in those with diabetes, less than half that number (11%) were controlled to the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure VI (JNC VI) recommended goal of <130/85 mm Hg.1 The present update will provide an overview of the evaluation and management of essential hypertension and help to guide clinicians in developing a management plan for a patient like the one described above. Taking a proper BP is an important first step in the diagnosis of hypertension.2 Using the proper cuff size with patients resting quietly and comfortably (with back support if seated) for at least 5 minutes before measurement, 2 or more readings separated by 2 minutes should be taken and averaged. Initial elevated BP readings should be confirmed on at least 2 subsequent visits over a period of 1 week or more. A value that is consistently ≥140/90 mm Hg is diagnostic in healthy patients; a value >130/80 mm Hg should be used for those with diabetes or kidney disease and proteinuria. Initial evaluation of the hypertensive patient focuses on the presence …

Angiotensin Receptor Blockade and Arterial Compliance in Chronic Kidney Disease: A Pilot Study

Background: Almost 20 million people in the US have chronic kidney disease (CKD). Cardiovascular disease and arterial wall abnormalities are common in this population. Because angiotensin II may have adverse effects on the arterial wall, we hypothesized that an angiotensin receptor blocker (ARB) would improve arterial compliance as compared with placebo in subjects with CKD. Methods: We performed a double-blinded, placebo-controlled pilot study in which 25 subjects with stages 2 or 3 CKD and proteinuria <1 g were randomized to either the ARB, eprosartan, or placebo and titrated to achieve a goal blood pressure (BP) <130/85 mm Hg. Arterial compliance was measured at baseline and at 8 weeks. Results: Baseline characteristics were similar between the groups and included mean estimated glomerular filtration rate 63 ± 14 ml/min/1.73 m2, heart rate 76 ± 10 beats/min, BP 142 ± 12/81 ± 8 mm Hg, 64% diabetic, 44% male, and 40% white, though subjects in the eprosartan group were younger (60 ± 12 vs. 70 ± 6 years, p = 0.01). There were no significant differences between the groups in large or small artery compliance measurements either at baseline or at 8 weeks, but there was a statistically significant improvement from baseline in small artery compliance in the eprosartan group (from median 2.5 ml/mm Hg × 100 [90% CI (1.1, 4.7)] to 4.0 ml/mm Hg × 100 [90% CI (1.9, 6.7)] (p = 0.01)) not seen in the placebo group. Conclusion: Use of an ARB to achieve recommended BP is associated with improved small artery compliance in people with CKD, though larger studies are needed to confirm these findings.

Hypertension and Peripheral Vascular Disease

The majority of deaths in western societies such as the United States are attributed in large part to arteriosclerosis, or hardening and thickening of the arterial wall (1). Underlying peripheral vascular disease as well as coronary artery and cerebrovascular disease is atherosclerosis, a disorder of larger arteries and one type of arteriosclerosis (1). Atherosclerosis is the leading cause of death in the general population in industrialized countries (1). It is well recognized that hypertension plays a major role in the pathogenesis of atherosclerotic vascular disease (2, 3, 4, 5, 6, 7, 8, 9, 10, 11). This has important implications from a public health perspective because of the high prevalence of hypertension and its amenability to effective treatment.