Renal function during antihypertensive treatment

Metformin use in the first year after kidney transplant, correlates, and associated outcomes in diabetic transplant recipients: A retrospective analysis of integrated registry and pharmacy claims data

While guidelines support metformin as a therapeutic option for diabetic patients with mild-to-moderate renal insufficiency, the frequency and outcomes of metformin use in kidney transplant recipients are not well described. We integrated national U.S. transplant registry data with records from a large pharmaceutical claims clearinghouse (2008-2015). Associations (adjusted hazard ratio, 95% LCL aHR95% UCL ) of diabetes regimens (with and excluding metformin) in the first year post-transplant with patient and graft survival over the subsequent year were quantified by multivariate Cox regression, adjusted for recipient, donor, and transplant factors and propensity for metformin use. Among 14 144 recipients with pretransplant type 2 diabetes mellitus, 4.7% filled metformin in the first year post-transplant; most also received diabetes comedications. Compared to those who received insulin-based regimens without metformin, patients who received metformin were more likely to be female, have higher estimated glomerular filtration rates, and have undergone transplant more recently. Metformin-based regimens were associated with significantly lower adjusted all-cause (aHR 0.18 0.410.91 ), malignancy-related (aHR 0.45 0.450.99 ), and infection-related (aHR 0.12 0.320.85 ) mortality, and nonsignificant trends toward lower cardiovascular mortality, graft failure, and acute rejection. No evidence of increased adverse graft or patient outcomes was noted. Use of metformin-based diabetes treatment regimens may be safe in carefully selected kidney transplant recipients.

Microvascular injury and the kidney in hypertension

Renal macrocirculation participates in the development of arterial hypertension. The elevation in systemic blood pressure (BP) can damage the kidney starting in the microcirculation. Established arterial hypertension impinge upon the large arteries and stiffness develops. As a consequence central BP raises and BP pulsatility appear and contribute to further damage renal microcirculation by direct transmission of the elevated BP.

Impact of achieved systolic blood pressure on renal function in hypertensive patients

Aims

There is strong evidence for the association of high blood pressure (BP) with depressed renal function. Although high BP at baseline is associated with greater progression of chronic kidney disease (CKD), randomized trials in CKD patients have found no significant relationship between more intensive BP control and glomerular filtration rate (GFR) decline. However, the relationship of GFR and change in GFR over time to lower achieved systolic BP (SBP) in hypertensive patients undergoing treatment is unclear.

Methods and results

Baseline estimated GFR (eGFR) and change in eGFR during follow-up were examined in relation to average on-treatment SBP in 8778 hypertensive patients with ECG left ventricular hypertrophy (LVH) randomly assigned to losartan- or atenolol-based treatment. GFR was estimated using the Modification of Diet in Renal Disease study equation. Patients with average on-treatment SBP ≤130 mmHg (lowest quintile at last measurement) and average SBP between 131 and 141 mmHg were compared with patients with average SBP ≥142 mmHg (median SBP at last measurement). Patients with an average on-treatment SBP ≤130 mmHg had significantly lower baseline eGFR than those with average SBP between 131 and 141 or average SBP ≥142 mmHg (65.5 ± 14.3 vs. 69.3 ± 14.3 vs. 69.0 ± 14.5 mL/min/1.73 m2, P < 0.001 using analysis of covariance adjusting for age, sex, race, randomized treatment, prior antihypertensive treatment, history of diabetes, myocardial infarction, ischaemic heart disease or heart failure, smoking status, baseline serum glucose, total and HDL cholesterol, albuminuria, and baseline LVH by Cornell product and Sokolow-Lyon voltage). However, the decrease in eGFR between baseline and Year 4 was significantly lower among patients with average SBP ≤130 mmHg (-6.3 ± 10.3 vs. -7.9 ± 11.1 vs. -9.2 ± 10.6 mL/min/1.73 m2, P = 0.001 when adjusting for the same variables and for change in Cornell product and Sokolow-Lyon voltage between baseline and Year 4). These differences in eGFR change persisted even after adjusting for baseline eGFR, and there were no significant interactions with randomized treatment, sex, race, or baseline presence of proteinuria.

Conclusion

Lower average on-treatment SBP (≤130 mmHg) was associated with a lower baseline eGFR but with a slower reduction in eGFR during 4-year follow-up in hypertensive patients with ECG LVH, independent of other possible risk factors for decreased GFR. Further study is necessary to determine whether randomized treatment to lower SBP goals is more protective of renal function than treatment to standard SBP goals.

Clinical trial registration

http://clinicaltrials.gov/ct/show/NCT00338260?order=1; unique identifier: NCT00338260.

Circulating purine compounds, uric acid, and xanthine oxidase/dehydrogenase relationship in essential hypertension and end stage renal disease

Purine nucleotide liberation and their metabolic rate of interconversion may be important in the development of hypertension and its renal consequences. In the present study, blood triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) breakdown pathway was evaluated in relation to uric acid concentration and xanthine dehydrogenase/xanthine oxidase (XDH/XO) in patients with essential hypertension, patients with chronic renal diseases on dialysis, and control individuals. The pattern of nucleotide catabolism was significantly shifted toward catabolic compounds, including ADP, AMP, and uric acid in patients on dialysis program. A significant fall of ATP was more expressed in a group of patients on dialysis program, compared with the control value (p<0.001), while ADP and AMP were significantly increased in both groups of patients compared with control healthy individuals (p<0.001), together with their final degradation product, uric acid (p<0.001). The index of ATP/ADP and ATP/uric acid showed gradual significant fall in both the groups, compared with the control value (p<0.001), near five times in a group on dialysis. Total XOD was up-regulated significantly in a group with essential hypertension, more than in a group on dialysis. The activity of XO, which dominantly contributes reactive oxygen species (ROS) production, significantly increased in dialysis group, more than in a group with essential hypertension. In conclusion, the examination of the role of circulating purine nucleotides and uric acid in pathogenesis of hypertension and possible development of renal disease, together with XO role in ROS production, may help in modulating their liberation and ROS production in slowing progression from hypertension to renal failure.

The burden of hypertension and kidney disease in Northeast India: the Institute for Indian Mother and Child noncommunicable diseases project

Chronic noncommunicable diseases (NCDs) such as hypertension, atherosclerosis, acute myocardial infarction, stroke, diabetes, obesity, and chronic kidney disease are the major cause of death not only in high income, but also in medium and low income countries. Hypertension and diabetes, the most common causes of chronic kidney disease, are particularly common in southeast Asian Countries. Because early intervention can markedly slow the progression of these two killer diseases, assessment of their presence through screening and intervention program is a priority. We summarize here results of the screening activities and the perspectives of a noncommunicable diseases project started in West Bengal, India, in collaboration with the Institute for Indian Mother and Child (IIMC), a nongovernmental voluntary organization committed to promoting child and maternal health. We started investigating hypertension and chronic kidney disease with screen in school-age children and in adults >30 years old. We found a remarkable prevalence of hypertension, even in underweight subjects, in both children and adult populations. A glomerular filtration rate <60 mL/min was found in 4.1% of adult subjects significantly higher than that of 0.8% to 1.4% reported 10 years ago. Increased awareness and intervention projects to identify NCDs and block their progression are necessary in all countries.

Renal participation in cardiovascular risk inessential hypertension

The kidney plays a relevant role in the origin of essential hypertension in humans, and it suffers the consequences of sustained elevated blood pressure in the absence of therapy. Recently, a relevant prevalence of mild renal insufficiency both in general population than in hypertensive patients has been described. A direct relationship seems to exist between the level of cardiovascular risk and the prevalence of the renal disorder, whether this is detected as an elevation in serum creatinine or as a diminution of estimated creatinine clearance. This renal function impairment is a strong predictor of cardiovascular risk in patients with chronic heart failure and following myocardial infarction. Prevention of renal and cardiovascular damage in these patients will be one of the most relevant tasks in the future. The aim of this short review is to discuss the evidence in favor of a relevant prevalence of mild renal insufficiency in hypertensive patients, as well as the association of this disorder with a very significant increment in global cardiovascular risk.

[Vascular nephropathies: a fresh look at a systemic disease]

Hypertensive nephropathy represents the most prevalent cause of end-stage renal disease in France. Renal lesions are unspecific. Nephroangiosclerosis diagnosis is overestimated due to non standardized clinical criteria and available histological analysis. Other factors than hypertension contribute to vascular lesions.MYH9 and APOL1 polymorphisms are strongly associated with kidney diseases including hypertensive nephropathy. Elevated blood pressure levels are associated with CKD progression. Treatment includes angiotensin blockers which have a synergic effect on blood pressure reduction and lowering urinary protein excretion with sodium restriction and diuretics.

Treatment of proteinuria with lercanidipine associated with reninangiotensin axis-blocking drugs

Aim. Most calcium antagonists do not seem to reduce microalbuminuria or proteinuria. We have tried to assess the antiproteinuric effect of a calcium channel blocker, lercanidipine, in patients previously treated with ACE inhibitors or angiotensin receptor blockers.Design and methods. The study included 68 proteinuric (>500 mg/day) patients (age 63,1±12,9 years, 69,1 % males and 30,9 % females). All patients were receiving ACE inhibitors (51,4 %) or angiotensin II receptor blockers (48,6 %) therapy but had higher blood pressure (BP) than recommended for proteinuric patients (<130/80 mm Hg). Patients were clinically evaluated one, three, and six months after starting treatment with lercanidipine (20 mg/day). Samples for urine and blood examination were taken during the examination. When needed, a third drug was added to treatment. Creatinine clearance was measured using 24 h urine collection.Results. BP significantly decreased from 152±15/86±11 mm Hg to 135±12/77±10 mm Hg at six months of follow-up (p<0,001). After six months of treatment, the percentage of normalized patients (BP <130/80 mm Hg) was 42,5 %, and the proportion of patients whose BP was below 140/90 mm Hg was 58,8 %. Plasmatic creatinine did not change nor did creatinine clearance. Plasmatic cholesterol also decreased from 210±48 to 192±34 mg/dL (p<0,001), as did plasma triglycerides (from 151±77 to 134±72 mg/dL,p=0,022). Basal proteinuria was 1,63±1,34 g/day; it was significantly (p<0,001) reduced by 23 % at the first month, 37 % at three months, and 33 % at the last visit.

Conclusion. Lercanidipine at 20 mg dose, associated with renin-angiotensin axis-blocking drugs, showed a high antihypertensive and antiproteinuric effect. This antiproteinuric effect seems to be dose-dependent as compared with previous reports and proportionally higher than blood pressure reduction.

Treatment of proteinuria with lercanidipine associated with renin-angiotensin axis-blocking drugs

OBJECTIVE

Most calcium antagonists do not seem to reduce microalbuminuria or proteinuria. We have tried to assess the antiproteinuric effect of a calcium channel blocker, lercanidipine, in patients previously treated with ACE inhibitors or angiotensin receptor blockers.

DESIGN AND METHODS

The study included 68 proteinuric (> 500 mg/day) patients (age 63.1 +/- 12.9 years, 69.1% males and 30.9 females). All patients were receiving ACE inhibitors (51.4%) or angiotensin II receptor blockers (48.6%) therapy but had higher blood pressure than recommended for proteinuric patients (<130/80 mmHg). Patients were clinically evaluated one, three, and six months after starting treatment with lercanidipine (20 mg/day). Samples for urine and blood examination were taken during the examination. When needed, a third drug was added to treatment. Creatinine clearance was measured using 24 h urine collection.

RESULTS

BP significantly decreases from 152 +/- 15/86 +/- 11 mmHg to 135 +/- 12/77 +/- 10 mmHg at six months of follow-up (p < 0.001). After six months of treatment, the percentage of normalized patients (BP < 130/80 mmHg) was 42.5%, and the proportion of patients whose BP was below 140/90 mmHg was 58.8%. Plasmatic creatinine did not change nor did creatinine clearance. Plasmatic cholesterol also decreased from 210 +/- 48 to 192 +/- 34 mg/dL (p < 0.001), as did plasma triglycerides (from 151 +/- 77 to 134 +/- 72 mg/dL, p = 0.022). Basal proteinuria was 1.63 +/- 1.34 g/day; it was significantly (p < 0.001) reduced by 23% at the first month, 37% at three months, and 33% at the last visit.

CONCLUSIONS

Lercanidipine at 20 mg dose, associated to renin-angiotensin axis-blocking drugs, showed a high antihypertensive and antiproteinuric effect. This antiproteinuric effect seems to be dose-dependent as compared with previous reports and proportionally higher than blood pressure reduction.

Renoprotective effect of calcium channel blockers

The advancing chronic renal failure is at most the consequence of secondary haemodynamic and metabolic factors as intraglomerular hypertension and glomerular hypertrophy. Although tight blood pressure control is the major preventive mechanism for progressive renal failure, ACE inhibitors and angiotensin receptor blockers have some other renoprotective mechanisms beyond the blood pressure control. That is why these two groups of antihypertensive drugs traditionally have advantages in treating renal patients especially those with proteinuria over 400-1000 mg/day. Even if earlier experimental studies have shown renoprotective effect of calcium channel blockers, later clinical studies did not prove that calcium channel blockers have any advantages in renal protection over ACE inhibitors given as monotherapy or in combination with ACE inhibitors. It was explained by action of calcium channel blockers on afferent but not on efferent glomerular arterioles; a well known mechanism that leads to intraglomerular hypertension. New generations of dihydropiridine calcium channel blockers can dilate even efferent arterioles not causing unfavorable haemodynamic disturbances. This finding was confirmed in clinical studies which showed that renoprotection established by calcium channel blockers was not inferior to that of ACE inhibitors and that calcium channel blockers and ACE inhibitors have additive effect on renoprotection. Newer generation of dihydropiridine calcium channel blockers seem to offer more therapeutic possibilities in renoprotection by their dual action on afferent and efferent glomerular arterioles and, possibly by other effects beyond the blood pressure control.

Renal dysfunction and ischemic heart disease mortality in a hypertensive population

OBJECTIVE

While recent studies indicate that renal dysfunction may be predictive of all-cause mortality and cardiovascular disease (CVD) outcomes in hypertensive individuals, there has been little attention to the specific association of ischemic heart disease (IHD) mortality and renal function. This study examines the relationship between IHD mortality and baseline glomerular filtration rate (GFR) (estimated by the Cockcroft and Gault formula) among treated hypertensive subjects.

DESIGN

A prospective cohort study of participants in a worksite-based antihypertensive treatment program in New York City (1981-1999).

PATIENTS

We studied 9929 subjects who had at least 6 months follow-up (mean 9.6 years) with a baseline serum creatinine.

MAIN OUTCOME MEASURES

IHD death outcomes (n=343) ascertained from the National Death Index.

RESULTS

Multivariate Cox proportional hazard models were constructed adjusting for known cardiovascular risk factors. Mean GFR of the cohort was 91.6 ml/min per 1.73 m. Those with lower GFR were more likely to be older, female, White, report a history of cardiovascular disease, have higher cholesterol and blood urea nitrogen values, and lower hemoglobin and body mass index than those with highest GFR. After adjustment for known cardiovascular risk factors, the risk of IHD death increased progressively as the GFR decreased. Hazard ratio for IHD mortality for each 10-unit reduction of estimated GFR below the normal threshold of >or=90 ml/min per 1.73 m was 1.33 (95% confidence interval 1.17, 1.50; P<0.001).

CONCLUSIONS

The results of this study suggest an independent inverse association between estimated GFR and IHD mortality among treated hypertensive individuals.

Caring for patients with chronic kidney disease: a joint opinion of the ambulatory care and the nephrology practice and research networks of the American College of Clinical Pharmacy

An increasing number of patients are developing chronic kidney disease (CKD). Appropriate care for patients with CKD must occur in the earliest stages, preferably before CKD progresses to more severe stages. Therefore, recognition and treatment of CKD and its associated complications must occur in primary care settings. Patients with CKD often have comorbid conditions such as diabetes mellitus, hypertension, and dyslipidemia, creating specific considerations when treating these diseases. Also, these patients have CKD-related conditions, including anemia and renal osteodystrophy, that are not traditionally evaluated and monitored by the primary care practitioner. Collectively, many opportunities exist for pharmacists who practice in the primary care setting to improve the care of patients with CKD.

The role of the renin angiotensin system in chronic renal disease

End-stage renal disease (ESRD) is a costly and debilitating condition affecting 250,000 patients in the United States. The incidence of ESRD has doubled in the past 10 years and is expected to continue to increase well into the next century as our population ages. Over the past 20 years investigative efforts have been focused on defining the pathophysiological basis of chronic renal disease and on therapeutic interventions designed to prevent its progression to renal failure. Several experimental models of progressive renal disease have been developed and used to examine potential mechanisms which may contribute to the pathophysiology of renal failure. Data from these studies indicate that the renin-angiotensin system (RAS) contributes significantly to the pathophysiology of renal disease in the experimental models examined. Data from clinical studies also indicates that the RAS contributes to the progression of renal disease in man as well. While our knowledge in this area is far from complete, numerous experimental and clinical studies have demonstrated that the blockade of the RAS has a distinct advantage in preventing the progression of renal insufficiency to complete renal failure.

Genetic polymorphisms of the renin-angiotensin-aldosterone system and renal insufficiency in essential hypertension

OBJECTIVE

The renin-angiotensin-aldosterone system (RAAS) plays an important role in the control of renal function both in physiological and pathological conditions. The aim of the present study was to evaluate the relation between four genetic polymorphisms of the RAAS and renal insufficiency in a population of patients with essential hypertension living in north-east Italy.

DESIGN AND METHODS

Eighty-six hypertensive patients with renal insufficiency and 172 hypertensive patients without renal damage matched for age and hypertension duration to within 2 years were evaluated. Genotyping for insertion/deletion of angiotensin-converting enzyme (ACE I/D), angiotensinogen (AGT) M235T, angiotensin II type 1 receptor (AT1R) A1166C and aldosterone synthase (CYP11B2) -344C/T polymorphisms were performed using polymerase chain reaction, with further restriction analysis when required.

RESULTS

Each of the genetic polymorphisms of the RAAS genes was associated with renal failure; the adjusted odds ratios were 1.47 and 1.89 for ACE D allele, assuming a co dominant and a recessive mode of inheritance, respectively; 1.51 for AGT T235 allele assuming a co dominant, and 1.98 assuming a recessive, pattern of inheritance; 1.79 for AT1R C1166 allele considering a dominant pattern; and 3.89 for CYP11B2 -344C allele as a recessive effect. However, CYP11B2 genotypes were not in Hardy-Weinberg equilibrium among controls. The associations AGT TT-AT1R AC and CYP11B2 CC-ACE DD showed a possible positive interaction in the development of renal insufficiency among hypertensive subjects. The association AGT MM-AT1R AA and AGT MM-AT1R AA-CYP11B2 TT or TC combinations were associated with a reduced risk for renal failure.

CONCLUSIONS

Our findings suggest that in patients with essential hypertension an unfavorable genetic pattern of RAAS may contribute to the increased risk for the development of renal failure.

Essential hypertension, progressive renal disease, and uric acid: a pathogenetic link?

Hypertension and hypertension-associated ESRD are epidemic in society. The mechanisms responsible for renal progression in mild to moderate hypertension and those groups most at risk need to be identified. Historic, epidemiologic, clinical, and experimental studies on the pathogenesis of hypertension and hypertension-associated renal disease are reviewed and an overview/hypothesis for the mechanisms involved in renal progression is presented. There is increasing evidence that hypertension may exist in one of two forms/stages. The first stage, most commonly observed in early or borderline hypertension, is characterized by salt-resistance, normal or only slightly decreased GFR, relatively normal or mild renal arteriolosclerosis, and normal renal autoregulation. This group is at minimal risk for renal progression. The second stage, characterized by salt-sensitivity, renal arteriolar disease, and blunted renal autoregulation, defines a group at highest risk for the development of microalbuminuria, albuminuria, and progressive renal disease. This second stage is more likely to be observed in blacks, in subjects with gout or hyperuricemia, with low level lead intoxication, or with severe obesity/metabolic syndrome. The two major mechanistic pathways for causing impaired autoregulation at mild to moderate elevations in BP appear to be hyperuricemia and/or low nephron number. Understanding the pathogenetic pathways mediating renal progression in hypertensive subjects should help identify those subjects at highest risk and may provide insights into new therapeutic maneuvers to slow or prevent progression.

Development of chronic kidney disease in essential hypertension during long-term therapy

PURPOSE OF REVIEW

This review examines the relevance of the development of chronic kidney disease in long-term hypertensive patients on the cardiovascular prognosis.

RECENT FINDINGS

Recently published guidelines recognize the relevance of the development of chronic kidney disease in the stratification of risk for the hypertensive patient. An adequate assessment of renal function, including an estimation of the glomerular filtration rate, is mandatory in order to ensure an adequate evaluation of the global cardiovascular risk in the hypertensive patient. The presence of subtle elevations in serum creatinine concentrations is a potent predictor of a poor cardiovascular prognosis. The clustering of associated risk factors seems to justify the elevated cardiovascular risk observed in patients with essential hypertension and mild renal function derangement.

SUMMARY

Chronic kidney disease is associated with a significant increase in cardiovascular risk attributable to the simultaneous existence of other risk factors related to the metabolic syndrome. The high prevalence of chronic kidney disease in the general and hypertensive populations forces the recognition of its relevance and the need for an integrated therapeutic approach simultaneously to protect the renal and cardiovascular systems fully.

Blood pressure and decline in kidney function: findings from the Systolic Hypertension in the Elderly Program (SHEP)

The association between BP and decline in kidney function in older persons and the BP component most responsible for kidney disease are unknown. This study investigated the relationship between baseline BP and an incident decline in kidney function among 2181 men and women enrolled in the placebo arm of the Systolic Hypertension in the Elderly Program (SHEP). A decline in kidney function was defined as an increase in serum creatinine equal to or greater than 0.4 mg/dl over 5 yr of follow-up. The incidence and relative risk of a decline in kidney function increased at higher levels of BP for all BP components, independent of age, gender, ethnicity, smoking, diabetes, and history of cardiovascular disease. Systolic BP imparted the highest risk of decline in kidney function. The adjusted relative risk (95% confidence interval) associated with the highest compared with the lowest quartile of BP was 2.44 (1.67 to 3.56) for systolic; 1.29 (0.87 to 1.91) for diastolic; 1.80 (1.21 to 2.66) for pulse; and 2.03 (1.39 to 2.94) for mean arterial pressure. The risk associated with systolic BP remained strong in models containing other BP components, while diastolic, pulse, and mean arterial pressure had no significant association with a decline in kidney function in models containing systolic BP. Therefore, systolic BP is a strong, independent predictor of a decline in kidney function among older persons with isolated systolic hypertension.

The kidney as a sensor of cardiovascular risk in essential hypertension

Renal damage as a consequence of uncontrolled arterial hypertension is well recognized. Antihypertensive therapy has come to very significantly decrease the vascular damage in the kidneys of hypertensive patients. However, prevalence of mild renal insufficiency remains present in a significant proportion of the hypertensive population. This is accompanied by a marked increase in cardiovascular risk, as a consequence of the clustering of other cardiovascular risk factors and of insufficiently controlled BP. Prevention and protection of renal and cardiovascular damage in these patients will be one of the most relevant tasks in the future.

How relevant and frequent is the presence of mild renal insufficiency in essential hypertension?

Recent analyses of the influence of renal function on the cardiovascular outcome in essential hypertensive patients have confirmed the relevance of the kidney in cardiovascular prognosis even in the initial stages of renal failure. The evaluation of renal function in clinical practice is based mainly on the finding of changes in serum creatinine, but the estimation of creatinine clearance or its determination after 24-hour urine collection is not usually performed. The objective of this study was to analyze the prevalence of mild chronic renal insufficiency (MCRI) through the determination of creatinine clearance in patients with essential hypertension to reinforce the need to consider using this parameter in daily clinical practice. We analyzed clinical and biochemical data from 2686 essential hypertension patients referred to our unit from 1979-1999. MCRI was defined as a serum creatinine > or =1.5 mg/dL in men and > or =1.4 mg/dL in women, or a creatinine clearance estimated by the Cockroft-Gault formula or by a 24-hour urine collection of <60 mL/min. A prevalence of MCRI was found in 7.6% according to serum creatinine levels. This prevalence increased to 22.3% and 21.5% respectively when the diagnostic criteria for MCRI was the estimation of 24-hour creatinine clearance in urine, or its estimation using the Cockroft-Gault formula. When classified by creatinine clearance values, patients with MCRI were characterized by older age, elevated systolic blood pressure, higher serum total cholesterol, low-density lipoprotein cholesterol, and triglycerides, lower levels of high-density lipoprotein cholesterol, higher serum uric acid, fasting serum glucose, serum potassium, and higher levels of urinary albumin excretion. In summary, MCRI is more prevalent in essential hypertension than previously thought, particularly if the estimated creatinine clearance is used to define MCRI. The finding of an altered renal function is associated with a significant increase in cardiovascular risk. This fact reinforces the need to pay attention to any of the manifestations of renal damage observed in the usual clinical assessment of any hypertensive patient.

Renal protection by antihypertensive therapy

The attainment of adequate renal protection requires strict blood pressure control and a diminution of proteinuria or microalbuminuria to values as near from normalcy as possible. It has been considered that by getting the first, the second could be attained at the same price. Recent data have confirmed that renal protection in hypertensive patients, diabetics or not, requires combination therapy that has to include an angiotensin converting enzyme inhibitor or an angiotensin receptor blocker. A calcium channel blocker can be added to this without renal compromise. A diuretic will also be needed in most cases. Proteinuria will diminish with this combination in particular if up-titration of the drug blocking the effects of angiotensin II is performed. The control of other associated risk factors is also required, in particular smoking and lipids.

Does non-malignant hypertension cause renal insufficiency? Evidence-based perspective

While it is clear that malignant hypertension damages the kidneys, the question of whether non-malignant hypertension actually causes renal insufficiency remains controversial. A recent meta-analysis of 10 randomized controlled trials of antihypertensive drug therapy showed that patients randomized to antihypertensive therapy (or more-intensive therapy) did not show a significant reduction in their risk of developing renal dysfunction (relative risk, 0.97; 95% confidence interval, 0.78-1.21; P=0.77). A review of the totality of the evidence shows that there is relatively weak support for the thesis that non-malignant hypertension itself is an important de-novo cause (initiator) of renal insufficiency (as opposed to being a promoter of existing renal disease, which is a well established fact). Failure to evaluate the possibility that pre-existing renal disease could explain any observed association between elevated blood pressure and subsequent loss of renal function is an important limitation of published studies.

ACE inhibitors and appearance of renal events in hypertensive nephrosclerosis

Nephrosclerosis constitutes a major cause of end-stage renal disease. Independently of blood pressure control, ACE inhibitors (ACEIs) are considered to be more nephroprotective than other antihypertensive agents. We have reviewed the long-term evolution of renal function in our series of essential hypertensive patients diagnosed as having nephrosclerosis when first seen in our unit. The analysis was performed depending on whether or not their antihypertensive therapy contained an ACEI alone or in combination for the whole follow-up. The end point was defined as the confirmation of a 50% reduction in creatinine clearance or entry in a dialysis program. A historical cohort of 295 patients was included in the analysis. Mean follow-up was 7.4+/-3.9 years. Diabetes prevalence was higher in ACEI-treated patients (25.7% versus 7.1%, P=0.000), but the diagnosis of diabetic nephropathy could not be confirmed on clinical grounds, including renal biopsy. Twenty-three out of 183 (12.6%) patients in the ACEI group and 23 out of 112 (20.5%) patients in the non-ACEI group experienced a renal event (P=0.0104 by log rank test). Similar results were observed when only nondiabetic patients were considered for the analysis. Cox regression analysis showed that baseline serum creatinine, absence of ACEI administration, mean proteinuria during follow-up, and age were independent predictors for the development of a renal event. In hypertensive nephrosclerosis, therapy containing an ACEI alone or in combination significantly reduces the incidence of renal events. This effect is independent of blood pressure control.

Renal function and renal disease in the elderly: Part I

In all industrialized countries, life expectancy has risen in the past 100 years. The incidence of elderly patients reaching end-stage renal disease (ESRD) and requiring renal replacement therapy has also increased. During the past few decades, the pattern of ESRD has changed significantly with the emerging predominance of elderly patients. The causes of this phenomenon are manifold and include an increasing number of chronic diseases typical of the 'third age', such as type 2 diabetes mellitus and vascular disease. In many species, a consequence of aging includes deterioration of renal function, partly due to structural alterations, and partly as the result of a diminishing blood flow. In humans, the aging kidney is characterized by modifications resulting from organic and functional disturbances. In particular, type 2 diabetes mellitus has emerged as an important condition, the microvascular and macrovascular complications of which are a common cause of morbidity and mortality in older patients. In part I of this review, the morphological and functional changes of the aging kidney will be reviewed, as well as the pathological conditions leading to the loss of renal function in the elderly.

Renal function and intensive lowering of blood pressure in hypertensive participants of the hypertension optimal treatment (HOT) study

This article reports further analyses of the Hypertension Optimal Treatment (HOT) Study data with the aim to describe (1) the value of baseline serum creatinine and its clearance (estimated by Cockroft and Gault formula) as predictors of cardiovascular events, (2) the effects of intensive lowering of BP on cardiovascular events and renal function in patients with reduced renal function, and (3) the effects on cardiovascular events of adding acetylsalicylic acid to antihypertensive therapy in patients with reduced renal function. The results show that (1) baseline elevation in serum creatinine and a reduction in estimated creatinine clearance are powerful predictors of cardiovascular events and death. (2) Reduced renal function at baseline did not preclude the desired control of BP. In contrast to patients with normal renal function, the incidence of major cardiovascular events did not differ in the three groups of patients with mild renal insufficiency randomized to different diastolic BP targets. No significant changes in serum creatinine were seen at the end of the 3.8-yr treatment period in the great majority of patients. However, there was a small group of patients (0.58% of the total study population) whose renal function deteriorated (increase > or =30% over baseline and final serum creatinine concentration > or =2 mg/dl) despite satisfactory reduction of diastolic BP. (3) The results of this reanalysis of the HOT Study suggest though do not prove that the association of acetylsalicylic acid with intensive antihypertensive therapy offers additional benefit in hypertensive patients with reduced renal function.

Importance of blood pressure reduction for prevention of progression of renal disease

Despite reduction of stroke and coronary mortality rates, progression of renal disease to end stage continues to occur with increasing frequency. Recent studies emphasize common pathways of elevated arterial pressures that produce increased glomerular capillary pressures and increase filtered proteins in the urinary space. Such proteinuria, along with activation of the intrarenal renin-angiotensin system, endothelin, and inflammatory cytokines, magnifies progressive renal injury and fibrosis. Malignant forms of hypertension with severe arteriolar injury and proteinuria can be treated effectively with current antihypertensive regimens with improved patient survival. Several recent studies indicate improved renal outcomes in proteinuric diseases, generally regardless of the specific antihypertensive agent. Recent trials of hypertensive subjects with minimal proteinuria demonstrate slower rates of disease progression than that seen in subjects with proteinuria above 1 gram per day. Reduction of arterial pressures, particularly when it leads to reduced proteinuria, can slow the progression of many renal diseases.

The kidney as a target of hypertension

In spite of improvement in blood pressure control during the last decades, the incidence of hypertension-related end-stage renal disease (ESRD) is reported to have increased and has become a common cause of renal failure, especially in the United States, but also in several other countries. The clinical diagnosis of hypertensive nephrosclerosis is usually presumptive, and an important differential diagnosis in older hypertensive persons is atheromatous renal vascular disease. Many studies of renal function in treated essential hypertension have shown a small and clinically insignificant decline in glomerular filtration rate (GFR). Recent long-term studies indicate that the change in GFR may be nonlinear, with a greater fall in GFR after initiation of antihypertensive treatment, followed by a phase of minimal or normal loss of GFR. There are no available prospective studies indicating that well-treated essential hypertension leads to renal failure, but there are new data indicating that patients with nonmalignant essential hypertension without any underlying renal disease and with early and good blood pressure control do not develop renal failure.

The kidney as part of the cardiovascular system

Renal vascular damage caused by arterial hypertension brings about changes in the systemic vascular function and structure. Nephrosclerosis appears to run in parallel with systemic atherosclerosis, accounting for the increased cardiovascular morbidity and mortality in hypertensive patients. Parameters indicating a change in renal function (increased serum creatinine concentration, proteinuria, and microalbuminuria) are independent predictors of increased cardiovascular morbidity and mortality and must therefore be considered in the classification of cardiovascular risk in hypertensive patients.

Therapeutic implications and new perspectives for essential hypertension and renal damage

The kidney can suffer the consequences of a persistently elevated blood pressure. In fact end-stage renal failure caused by essential hypertension appears to be one of the most prevalent etiologies in patients entering a dialysis program. Blood pressure control is needed in order to prevent the progressive loss of renal function. Target blood pressure control has been established at values as low as 125/75 mm Hg for patients with proteinuria above 1 g/day. Attainment of this target level usually requires the combination of two or more drugs. However, the possibility that differences exist among the different classes of antihypertensive drugs beyond their capacity to simply lower blood pressure remains to be clearly elucidated. The fact that the presence of chronic renal failure is also accompanied by an enhanced cardiovascular risk potentiates the need to explore the renoprotective and cardiovascular protective capacity of the different classes of antihypertensive drugs, in patients with essential hypertension and some degree of renal involvement, characterized by the presence of microalbuminuria, proteinuria and/or an elevated serum creatinine.