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

Association of Adolescent Hypertension With Future End-stage Renal Disease

IMPORTANCE

Hypertension is a leading risk factor of cardiovascular morbidity and mortality. The role of nonmalignant hypertension as the sole initiating factor of end-stage renal disease (ESRD) in non-African American populations has recently been questioned.

OBJECTIVE

To investigate the association between hypertension and future ESRD in otherwise healthy adolescents.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study examined the data of 16- to 19-year-old healthy candidates for military service in the Israel Defense Forces between January 1, 1967, and December 31, 2013. Data were obtained from the central conscription registry of the Israel Defense Forces and the ESRD registry of the Israel Ministry of Health. Participants underwent a comprehensive medical assessment prior to their military service. Individuals with evidence of renal damage or kidney-related risk factors were excluded. The data analysis was conducted from February 12, 2017, to October 16, 2018.

MAIN OUTCOMES AND MEASURES

End-stage renal disease as recorded by the Israeli ESRD registry, including hemodialysis, peritoneal dialysis, renal transplant diagnosed between January 1, 1990, and December 31, 2014.

RESULTS

The cohort included 2 658 238 adolescents (1 596 709 [60.1%] male with a mean [SD] age of 17.4 [0.5] years), of whom 7997 (0.3%) had an established hypertension diagnosis. Half of the individuals in the hypertensive group were overweight (1559 [20.1%]) or obese (2243 [28.9%]), and most (7235 [90.5%]) were male. During a median follow-up of 19.6 years (52 287 945 person-years), 2189 individuals developed ESRD, with an incidence rate of 3.9 per 100 000 person-years. Adolescent hypertension was found to be associated with future ESRD (crude hazard ratio [HR], 5.07; 95% CI, 3.73-6.88). In a multivariable model adjusted for sex, age, years of education, body mass index, and other sociodemographic variables, the HR was 1.98 (95% CI, 1.42-2.77). When excluding participants with severe hypertension, the association with ESRD remained statistically significant (HR, 1.93; 95% CI, 1.37-2.70). In the subanalysis of nonoverweight adolescents, the association between hypertension and ESRD was statistically significant as well (HR, 2.11; 95% CI, 1.05-4.24).

CONCLUSIONS AND RELEVANCE

Hypertension appears to be associated with a doubling of the risk of future ESRD in an otherwise healthy adolescent population.

Causes and timing of end-stage renal disease after living kidney donation

End-stage renal disease (ESRD) is a risk after kidney donation. We sought, in a large cohort of kidney donors, to determine the causes of donor ESRD, the interval from donation to ESRD, the role of the donor/recipient relationship, and the trajectory of the estimated GFR (eGFR) from donation to ESRD. From 1/1/1963 thru 12/31/2015, 4030 individuals underwent living donor nephrectomy at our center, as well as ascertainment of ESRD status. Of these, 39 developed ESRD (mean age ± standard deviation [SD] at ESRD, 62.4 ± 14.1 years; mean interval between donation and ESRD, 27.1 ± 9.8 years). Donors developing ESRD were more likely to be male, as well as smokers, and younger at donation, and to have donated to a first-degree relative. Of donors with a known cause of ESRD (n = 25), 48% was due to diabetes and/or hypertension; only 2 from a disease that would have affected 1 kidney (cancer). Of those 25 with an ascertainable ESRD cause, 4 shared a similar etiology of ESRD with their recipient. Almost universally, thechange of eGFR over time was stable, until new-onset disease (kidney or systemic). Knowledge of factors contributing to ESRD after living kidney donation can improve donor selection and counseling, as well as long-term postdonation care.

Risk of End-Stage Renal Disease in HIV-Positive Potential Live Kidney Donors

New federal regulations allow HIV-positive individuals to be live kidney donors; however, potential candidacy for donation is poorly understood given the increased risk of end-stage renal disease (ESRD) associated with HIV infection. To better understand this risk, we compared the incidence of ESRD among 41 968 HIV-positive participants of North America AIDS Cohort Collaboration on Research and Design followed for a median of 5 years with the incidence of ESRD among comparable HIV-negative participants of National Health and Nutrition Examination III followed for a median of 14 years. We used risk associations from multivariable Cox proportional hazards regression to derive cumulative incidence estimates for selected HIV-positive scenarios (no history of diabetes, hypertension, AIDS, or hepatitis C virus coinfection) and compared these estimates with those from similarly selected HIV-negative scenarios. For 40-year-old HIV-positive individuals with health characteristics that were similar to those of age-matched kidney donors, viral load <400 copies/mL, and CD4⁺ count ≥500 cells/μL, the 9-year cumulative incidence of ESRD was higher than that of their HIV-negative peers, yet still low: 2.5 versus 1.1 per 10 000 among white women, 3.0 versus 1.3 per 10 000 among white men, 13.2 versus 3.6 per 10 000 among black women, and 15.8 versus 4.4 per 10 000 among black men. HIV-positive individuals with no comorbidities and well-controlled disease may be considered low-risk kidney donor candidates.

Patterns of End-Stage Renal Disease Caused by Diabetes, Hypertension, and Glomerulonephritis in Live Kidney Donors

Inferences about late risk of end-stage renal disease (ESRD) in live kidney donors have been extrapolated from studies averaging <10 years of follow-up. Because early (<10 years) and late (≥10 years) postdonation ESRD may differ by causal mechanism, it is possible that extrapolations are misleading. To better understand postdonation ESRD, we studied patterns of common etiologies including diabetes, hypertension and glomerulonephritis (GN; as reported by providers) using donor registry data linked to ESRD registry data. Overall, 125 427 donors were observed for a median of 11.0 years (interquartile range 5.3-15.7 years; maximum 25 years). The cumulative incidence of ESRD increased from 10 events per 10 000 at 10 years after donation to 85 events per 10 000 at 25 years after donation (late vs. early ESRD, adjusted for age, race and sex: incidence rate ratio [IRR] _1.3 1.7_2.3 [subscripts are 95% confidence intervals]). Early postdonation ESRD was predominantly reported as GN-ESRD; however, late postdonation ESRD was more frequently reported as diabetic ESRD and hypertensive ESRD (IRR _2.3 7.7_25.2 and _1.4 2.6_4.6 , respectively). These time-dependent patterns were not seen with GN-ESRD (IRR _0.4 0.7_1.2 ). Because ESRD in live kidney donors has traditionally been reported in studies averaging <10 years of follow-up, our findings suggest caution in extrapolating such results over much longer intervals.

Hyperuricemia as a Predictive Marker for Progression of Nephrosclerosis: Clinical Assessment of Prognostic Factors in Biopsy-Proven Arterial/Arteriolar Nephrosclerosis

Aim: The influence of serum urate on kidney disease is attracting attention, but the effects of uric acid (UA) on nephrosclerosis have not been elucidated.

Methods: We reviewed data from 45 patients diagnosed with arterial/arteriolar nephrosclerosis. The renal outcomes of the arterial/arteriolar nephrosclerosis patients were assessed by performing logistic and Cox regression analyses. A Kaplan-Meier analysis was used to evaluate the impact of hyperuricemia (HU) on kidney survival. The renal outcomes of patients with and without HU were compared by using a propensity score-matched cohort.

Results: The logistic regression models showed no significant differences in renal outcomes, according to baseline parameters or follow-up parameters, except the serum UA value and body mass index (BMI). Baseline serum UA level had the highest odds ratio (OR) for estimated glomerular filtration rate (eGFR) decline (OR, 1.86; 95% confidence interval (CI), 1.12 to 3.45), among the parameters assessed. In the multivariate Cox regression analysis, HU (UA ≥ 8.0 mg/dL) (P = 0.01) and BMI (P = 0.03) were significantly associated with a ≥ 50% eGFR decline or ESRD. The Kaplan-Meier analysis in the propensity score-matched cohort indicated that the renal survival rate of the group of arterial/arteriolar nephrosclerosis patients with HU was significantly lower than that of the group without HU (log rank, P = 0.03).

Conclusion: The results of this study suggest that the baseline serum UA value can serve as a renal outcome predictor in arterial/arteriolar nephrosclerosis patients.

Review: Renin-angiotensin-aldosterone system intervention in the cardiometabolic syndrome and cardio-renal protection

The metabolic syndrome, also known as the cardiometabolic syndrome (CMS), is a state of metabolic and vascular dysregulation that is associated with activation of the renin-angiotensin-aldosterone system (RAAS). Clinical components of the CMS include central or visceral obesity, hypertension (HTN), dyslipidemia, insulin resistance/hyperinsulinemia, and microalbuminuria that collectively convey increases in oxidative stress, inflammation, and subsequent endothelial dysfunction. The cardio-renal inflammation and oxidative stress enhanced in the CMS increases the risk for cardiovascular disease (CVD) and renal disease end-points such as stroke, congestive heart failure, and chronic kidney disease (CKD). The development of proteinuria is known to herald progressive kidney disease (e.g. CKD) and both are now well accepted as CVD risk factors. Evidence suggests a role for visceral obesity, insulin resistance/hyperinsulinemia, HTN, and other components of the CMS lead to an increased risk for proteinuria and progressive loss of renal function. Intervention with agents that block the RAAS (e.g. ACE inhibitors and Angiotensin type 1 receptor blockers) have been shown to reduce proteinuria, CKD progression, and CVD events. Herein, we will examine the relationship between RAAS intervention and reductions in CKD and CVD events.

Elevated blood pressure is not associated with accelerated glomerular filtration rate decline in the general non-diabetic middle-aged population

Although hypertension is a risk factor for end-stage renal disease, this complication develops in only a minority of hypertensive patients. Whether non-malignant hypertension itself is sufficient to cause reduced glomerular filtration rate (GFR) is unclear. Therefore, we investigated whether elevated blood pressure (BP) was associated with accelerated GFR decline in the general population. The study was based on the Renal Iohexol Clearance Survey in Tromsø 6 (RENIS-T6), which included a representative sample of 1594 individuals aged 50 to 62 years from the general population without baseline diabetes or kidney or cardiovascular disease. GFR was measured as iohexol clearance at baseline and follow-up after a median observation time of 5.6 years. BP was measured according to a standardized procedure. The mean (SD) GFR decline rate was 0.95 (2.23) ml/min/yr. In multivariable adjusted linear mixed regressions with either baseline systolic or diastolic BP as the independent variable, there were no statistically significant associations with GFR decline. Thus, elevated BP is not associated with accelerated mean GFR decline in the general middle-aged population. Hence, additional genetic and environmental factors are probably necessary for elevated BP to develop manifest chronic kidney disease in some individuals.

Living Donor Kidney Transplantation: Facilitating Education about Live Kidney Donation--Recommendations from a Consensus Conference

The Best Practice in Live Kidney Donation Consensus Conference held in June of 2014 included the Best Practices in Living Donor Education Workgroup, whose charge was to identify best practice strategies in education of living donors, community outreach initiatives, commercial media, solicitation, and state registries. The workgroup's goal was to identify critical content to include in living kidney donor education and best methods to deliver educational content. A detailed summary of considerations regarding educational content issues for potential living kidney donors is presented, including the consensus that was reached. Educational topics that may require updating on the basis of emerging studies on living kidney donor health outcomes are also presented. Enhancing the educational process is important for increasing living donor comprehension to optimize informed decision-making.

Nephrosclerosis: a term in quest of a disease

For a century, nephrosclerosis was ascribed to nonmalignant hypertension and aging. However, it was intuitively perceived that hypertension may follow rather than explain this nephrovasculopathy. Hypertensive nephrosclerosis was long considered a major cause of end-stage renal failure (ESRD). This is especially true in blacks of African descent but not in other ethnic populations. The term 'nephrosclerosis' is still an easy way out to classify a patient with renal insufficiency. This leads to neglect the possibility of an overlooked nephropathy complicated by hypertension and to believe that drastic blood pressure control may retard the progression to ESRD. Several clinical and experimental lines of evidence lead to the understanding that nephrosclerosis, especially in blacks, is a genetic renovasculopathy that precedes the rise in blood pressure. The identification of coding region variants in APOL1 encoding apolipoprotein L-1 in black but also white and Asians opens new lines of research on the genetics of nephroangiosclerosis and of FSGS. Metabolic derangements, such as obesity, oxidative stress, dyslipidemia and atherosclerosis may be considered confounding factors with regard to nephrosclerosis. Histomorphometric studies led to sorting out the lesions due to aging from those stemming from hypertension. They shed new light not only on glomerular lesions that comprise ischemic obsolescence but also on glomerulomegaly and focal-segmental sclerosis, the latter due to a loss of renal autoregulation. It appears that the control of hypertension is not credited with the expected benefit for slowing the decline of renal function. 'Nephrosclerosis' can be considered an umbrella term of poor significance that should be replaced by its pathologic description, that is, arterionephrosclerosis and incite to elucidate the various genetic and metabolic factors that lead to a lesion in quest of a specific disease.

Nephrosclerosis: update on a centenarian

Nephrosclerosis is an umbrella term defining changes in all compartments of the kidney, changes caused by hypertension and by ageing. Among other lesions, arteriolosclerosis and arteriolohyalinosis play a major role in inducing glomerular ischaemic shrinking and sclerosis along with glomerulomegaly and focal-segmental glomerulosclerosis (FSGS). These lesions are accompanied by tubulointerstitial inflammation and fibrosis that predict the decline of renal function. Nephrosclerosis is a major cause of renal insufficiency in blacks of African descent with a severe, early form of renovasculopathy and a rapid course to renal failure with predominant lesions of FSGS. It seems that in blacks, separate genetic factors independently lead to vascular lesions and to hypertension with a different time-scale of their onset and of their progression, nephroangiosclerosis preceding the onset of hypertension. Conversely, true and histologically identified nephrosclerosis in white Europeans rarely leads to end-stage renal disease in the absence of malignant hypertension. Various animal models demonstrate that renal vascular lesions may exist in the absence of hypertension. These experiments also point to a major role of angiotensin II and of a number of independent and overlapping cellular and molecular pathways in a cascade of inflammatory events that end in renal fibrosis. Two pathophysiologic mechanisms are at work in inducing glomerular lesions and tubulointerstitial fibrosis: a loss of autoregulation of the renal blood flow caused by an arteriolohyalinosis of the glomerular afferent arteriole and ischaemia that fosters the generation of hypoxia inducible-fibrosing factors. Not all antihypertensive drugs equally protect the kidney from nephrosclerosis. Angiotensin II antagonists exert a favourable effect on hyperfiltration. Conversely, dihydropyridine calcium-channel blockers and vasodilators do not withstand the derangement of renal autoregulation.

Rethinking hypertensive kidney disease: arterionephrosclerosis as a genetic, metabolic, and inflammatory disorder

PURPOSE OF REVIEW

Hypertension is the attributed cause of approximately 30% of end-stage kidney disease cases in the United States, but there has been controversy as to whether benign hypertension is a cause of chronic kidney disease.

RECENT FINDINGS

The histology of chronic kidney disease attributed to nonmalignant hypertension is arterionephrosclerosis, with pathology in the terminal branches of the interlobular arteries, together with global glomerulosclerosis. The identification of coding region variants in APOL1, encoding apolipoprotein L1, has opened a new perspective on this debate. These variants are restricted to populations of recent African descent and are strongly associated with clinically diagnosed arterionephrosclerosis, particularly when there is moderate-grade or high-grade proteinuria or progression to more advanced levels of kidney dysfunction. Nevertheless, not all African Americans with hypertension who progress to end-stage kidney disease have two APOL1 risk variants, and individuals of European and Asian descent also manifest arterionephrosclerosis. Further, we do not understand the mechanisms by which APOL1 initiates pathology in the renal microcirculation.

SUMMARY

APOL1 nephropathy comprises a disease spectrum (perhaps with distinct endophenotypes), including focal segmental glomerulosclerosis, collapsing glomerulopathy, and arterionephrosclerosis. The terms hypertensive kidney disease and hypertensive nephrosclerosis have outlived their usefulness. It may be time to use the established, etiologically neutral term, arterionephrosclerosis, to consider whether this is a disease rather than a pathologic description, and to determine the causal role of various clinical correlates including aging, obesity, hyperlipidemia, smoking, chronic inflammation, and oxidative stress.

[Blood pressure control in patient with chronic kidney disease]

Several epidemiological studies have indicated that high blood pressure is associated with deterioration of renal function in patients with renal disease. Target blood pressures in patients with renal diseases have been defined and proposed to the community in several national and international guidelines. However, some of these targets have been recently changed to take into account results of studies, including randomized clinical trials. The aim of this paper is to put into perspective the history of ideas regarding adequate blood pressure control in patients with renal disease in the light of these results, and explain how these trials have changed our perception, practice and guidelines.

Estimating risks of de novo kidney diseases after living kidney donation

De novo post donation renal diseases, such as glomerulonephritis or diabetic nephropathy, are infrequent and distinct from the loss of GFR at donation that all living kidney donors experience. Medical findings that increase risks of disease (e.g. microscopic hematuria,borderline hemoglobin A1C) often prompt donor refusal by centers. These risk factors are part of more comprehensive risks of low GFR and end-stage renal disease (ESRD) from kidney diseases in the general population that are equally relevant. Such data profile the ages of onset, rates of progression, prevalence and severity of loss of GFR from generically characterized kidney diseases. Kidney diseases typically begin in middle age and take decades to reach ESRD, at a median age of 64. Diabetes produces about half of yearly ESRD and even more lifetime near-ESRD. Such data predict that (1) 10- to 15-year studies will not capture the lifetime risks of post donation ESRD; (2)normal young donors are at demonstrably higher risk than normal older candidates; (3) low-normal predonation GFRs become risk factors for ESRD when kidney diseases arise and (4) donor nephrectomy always increases individual risk. Such population-based risk data apply to all donor candidates and should be used to make acceptance standards and counseling more uniform and defensible.

Expanded Criteria Living Donors: How Far Can We Go?

In an effort to expand the deceased donor pool, transplant centers have accepted expanded criteria donors as appropriate for many of the patients in the deceased donor pool. Translating this into the living donor pool is more complex. One must consider not only the quality of the organ procured but the consequences that the nephrectomy might have on the living donors for the rest of their lives. This review examines the available data on higher risk donors and the appropriateness, or lack thereof, of accepting them as kidney donors.

Essential hypertension and risk of nephropathy: a reappraisal

PURPOSE OF REVIEW

Treating mild-to-moderate essential hypertension in nondiabetic African Americans fails to halt nephropathy progression, whereas hypertension control slows nephropathy progression in European Americans. The pathogenesis of these disparate renal syndromes is reviewed.

RECENT FINDINGS

The nonmuscle myosin heavy chain 9 gene (MYH9) is associated with a spectrum of kidney diseases in African Americans, including idiopathic focal global glomerulosclerosis historically attributed to hypertension, idiopathic focal segmental glomerulosclerosis, and the collapsing variant of focal segmental glomerulosclerosis [HIV-associated nephropathy (HIVAN)]. Risk variants in MYH9 likely contribute to the failure of hypertension control to slow progressive kidney disease in nondiabetic African Americans.

SUMMARY

Early and intensive hypertension control fails to halt progression of 'hypertensive nephropathy' in African Americans. Genetic analyses in patients with essential hypertension and nephropathy attributed to hypertension, focal segmental glomerulosclerosis and HIVAN reveal that MYH9 gene polymorphisms are associated with a spectrum of kidney diseases in this ethnic group. Mild to moderate hypertension may cause nephropathy in European Americans with intrarenal vascular disease improved by the treatment of hypertension, hyperlipidemia and smoking cessation.

'Normal for now' or 'at future risk': a double standard for selecting young and older living kidney donors

Transplant centers medically evaluate potential living kidney donors in part to determine their baseline remaining lifetime risk for end stage renal disease (ESRD). If baseline risk is increased by the presence of a risk factor for ESRD, donation is often refused. However, as only about 13% of ESRD occurs in the general population by age 44, a normal medical evaluation cannot be expected to significantly reduce the 7% lifetime risk for a 'normal' 25-year-old black donor or the 2-3% risk for a similar white donor. About half of newly diagnosed ESRD in the United States occurs by age 65, and about half of that is from diabetic nephropathy, which takes about 25 years to develop. Therefore, the remaining baseline lifetime risk for ESRD is significantly lower in the normal, nondiabetic 55-year-old donor candidate. Some older donors with an isolated medical abnormality such as mild hypertension will be at lower or about the same overall baseline lifetime risk for ESRD as are young 'normal' donor candidates. Transplant centers use a 'normal for now' standard for accepting young donors, in place of the long-term risk estimates that must guide selection of all donors.

Systemic and glomerular hypertension and progression of chronic renal disease: the dilemma of nephrosclerosis

The link between the kidney and hypertension has been considered a villain-victim relationship. High blood pressure levels are a well-recognized feature in chronic renal disease, but the ability of mild-to-moderate hypertension to produce renal insufficiency has been questioned. Nephrosclerosis, benign nephrosclerosis, and hypertensive kidney disease are terms that clinicians use when renal damage is thought to be secondary to essential hypertension. Many cases of end-stage renal disease are ascribed to so-called benign nephrosclerosis. This entity could actually be a primary renal disease affecting the preglomerular microvasculature, perhaps genetically mediated and ethnically influenced, and showing a heterogeneous clinical expression. African Americans suffer from nephrosclerosis more frequently than Caucasians. Nephrosclerosis affecting Caucasians seems to show a less aggressive pattern and could represent early age-related renal sclerosis. The risk of end-stage renal disease is increased when atherosclerotic lesions in large renal arteries coexist. Age, systolic blood pressure, proteinuria, and concomitant cardiovascular disease are well-known promoters of renal failure. A multifactorial strategy, including antihypertensive and antiproteinuric drugs, and lipid-lowering and anti-platelet agents, could improve cardiovascular and renal outcomes in patients with nephrosclerosis.

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.

Hypothesis: obesity and the insulin resistance syndrome play a major role in end-stage renal failure attributed to hypertension and labelled 'hypertensive nephrosclerosis'

About a third of new cases of renal failure in USA are attributed to hypertension despite controversy about the frequency and pathology of so called hypertensive nephrosclerosis. In spite of good documentation that obesity causes renal failure and in spite of the global epidemic of obesity this diagnosis does not feature on most renal failure registries. New documentation that progressive renal failure in hypertension is linked to insulin resistance and analysis of NHANES III data which shows a strong positive significant dose-response relationship between insulin resistance and chronic kidney disease strengthen the view that so called hypertensive nephrosclerosis may be linked more closely to obesity and insulin resistance than to blood pressure. The pathology of the kidney in hypertension has changed. Studies 50 years ago did not show segmental glomerulosclerosis, which has recently been shown to be the key lesion in hypertensive nephrosclerosis. Recent documentation that this is a major mechanism of progression in hypertension together with the fact that similar segmental glomerulosclerosis is the key lesion in obesity and the metabolic syndrome suggests that these factors are more important than hypertension in renal failure attributed to hypertensive nephrosclerosis.

Blood Pressure and Renal Function after Kidney Donation from Hypertensive Living Donors

BACKGROUND

Rising numbers of patients reaching end-stage kidney disease intensify the demand for expansion of the living-kidney-donor pool. On the basis of low risk in white donors with essential hypertension, our transplant center undertook a structured program of accepting hypertensive donors if kidney function and urine protein were normal. This study reports outcomes of hypertensive donors 1 year after kidney donation.

METHODS

We studied detailed measurements of blood pressure (oscillometric, hypertensive therapy nurse [RN], and ambulatory blood pressure monitoring [ABPM]), clinical, and renal characteristics (iothalamate glomerular filtration rate [GFR], urine protein, and microalbumin) in 148 living kidney donors before and 6 to 12 months after nephrectomy. Twenty-four were hypertensive (awake ABPM>135/85 mm Hg and clinic/RN BP>140/90 mm Hg) before donation.

RESULTS

After 282 days, normotensive donors had no change in awake ABPM pressure (pre 121 +/- 1/75 +/- 2 vs. post 120 +/- 1/ 5 +/- 1 mm Hg), whereas BP in hypertensive donors fell with both nonpharmacologic and drug therapy (pre 142 +/- 3/85 +/- 2 to post 132 +/- 2/80 +/- 1 mm Hg, P<.01). Hypertensive donors were older (53.4 vs. 41.4 years, P<.001) and had lower GFR after kidney donation (61 +/- 2 vs. 68 +/- 1 mL/min/1.73m, P<.01). After correction for age, no independent BP effect was evident for predicting GFR either before or after nephrectomy. Urine protein and microalbumin did not change in either group after donor nephrectomy.

CONCLUSIONS

Our results indicate that white subjects with moderate, essential hypertension and normal kidney function have no adverse effects regarding blood pressure, GFR, or urinary protein excretion during the first year after living kidney donation. Although further studies are essential to confirm long-term safety, these data suggest that selected hypertensive patients may be accepted for living kidney donation.

Effect of Blood Pressure on Early Decline in Kidney Function Among Hypertensive Men

Few cohort studies have examined the longitudinal association between change in blood pressure and decline in kidney function among treated hypertensive patients without chronic kidney disease. We conducted a nonconcurrent cohort study to examine the effects of blood pressure on estimated glomerular filtration rate and early kidney function decline (rise in serum creatinine > or =0.6 mg/dL during follow-up) among 504 African-American and 218 white hypertensive patients. Our results showed that each standard deviation higher treated systolic (18 mm Hg) and diastolic (10 mm Hg) blood pressure was associated with an average annual decline (95% confidence interval [CI]) in estimated glomerular filtration rate of -0.92 ([-1.49 to -0.36] P=0.001) and -0.83 ([-1.38 to -0.28] P=0.003) mL x min(-1) x 1.73 m(-2), respectively, after adjustment for race, age, education, income, use of antihypertensive drugs, body mass index, and history of diabetes and dyslipidemia. Likewise, each standard deviation higher systolic and diastolic blood pressure was associated with relative risks (95% CIs) of 1.81 ([1.29 to 2.55] P<0.001) and 1.55 ([1.08 to 2.22] P=0.046), respectively, for early kidney function decline. Compared with patients with a blood pressure level <140/90 mm Hg, those with a blood pressure level > or =160/95 mm Hg had a -2.67 ([-4.01 to -1.32] P<0.001) mL x min(-1) x 1.73 m(-2) greater annual decline in estimated glomerular filtration rate and a 5.21-fold ([2.06 to 13.21] P<0.001) greater risk of early kidney function decline. Our study found that higher levels of treated blood pressure were positively and significantly related to early decline in kidney function among hypertensive men. These results indicate that better blood pressure control might prevent the onset of chronic kidney disease among hypertensives.