History of hypertension in patients treated for end-stage renal disease

Blood Pressure and Chronic Kidney Disease Stratified by Gender and the Use of Antihypertensive Drugs

Background

The present study assessed the association between blood pressure (BP) and the risk of chronic kidney disease (CKD) according to gender and the use of antihypertensive drugs using data from a large‐scale health checkup.

Methods and Results

We conducted a retrospective cohort study using the JMDC database, which contains annual health checkup data of Japanese employees and their dependents aged <75 years. We included 154 692 participants (men, 69.68%; mean age, 44.74 years) without CKD. CKD was indicated by an estimated glomerular filtration rate <60 mL/min per 1.73 m² or the presence of proteinuria. During the mean follow‐up period of 4.78 years, new‐onset CKD occurred in 14 888 participants. When the normal BP group (systolic/diastolic BP <120/<80 mm Hg) without treatment was used as a reference, the hazard ratios of the high BP (130–139/80–89 mm Hg) and grade 1 (140–159/90–99 mm Hg) and grade 2 or 3 hypertension (≥160/≥100 mm Hg) groups were 1.11 (95% CI, 1.06–1.17), 1.36 (95% CI, 1.28–1.45), and 1.76 (95% CI, 1.56–1.99) for untreated men, respectively. However, in treated men, even normal BP was associated with a 1.5‐fold higher risk of CKD. The association between BP and the risk of CKD was weaker in untreated women than in untreated men. The risk of CKD in treated women with normal BP was similar to that of untreated women with normal BP.

Conclusions

Gender differences were found in the association between BP and CKD risk. Kidney function in treated individuals should be followed carefully, especially in men.

Relative risk of end-stage renal disease requiring dialysis in treated ankylosing spondylitis patients compared with individuals without ankylosing spondylitis: A nationwide, population-based, matched-cohort study

Objective

To examine the relative risk of end-stage renal disease (ESRD) requiring dialysis among treated ankylosing spondylitis (AS) patients compared with non-AS individuals.

Methods

We used claims data from Taiwan’s National Health Insurance Research Database obtained between 2003 and 2012, and enrolled 37,070 newly treated AS patients and randomly selected 370,700 non-AS individuals matched (1:10) for age, sex and year of index date. Those with a history of chronic renal failure or dialysis were excluded. After adjusting for age, sex, diabetes mellitus, hypertension, IgA nephropathy, frequency of serum creatinine examinations, use of methotrexate, sulfasalazine, ciclosporis, corticosteroid, aminoglycoside, amphotericin B, cisplatin, contrast agents and annual cumulative defined daily dose (cDDD) of traditional NSAIDs, selective cyclooxygenase-2 inhibitors (COX-2i) and preferential COX-2i, we calculated the adjusted hazard ratios (aHRs) with 95% confidence intervals using the Cox proportional hazard model to quantify the risk of ESRD in AS patients. We re-selected 6621 AS patients and 6621 non-AS subjects by further matching (1:1) for cDDDs of three groups of NSAIDs to re-estimate the aHRs for ESRD.

Results

Fifty-one (0.14%) of the 37,070 AS patients and 1417 (0.38%) of the non-AS individuals developed ESRD after a follow-up of 158,846 and 1,707,757 person-years, respectively. The aHR for ESRD was 0.59 (0.42–0.81) in AS patients compared with non-AS individuals. However, after further matching for cDDD of NSAIDs, the aHR of ESRD was 1.02 (0.41–2.53). Significant risk factors included hypertension, IgA nephropathy and use of COX-2i.

Conclusions

The risk of ESRD was not significantly different between treated AS patients and non-AS individuals matched for age, sex, year of index date and dose of NSAID.

Branch vessel complications are increased in aortic dissection patients with renal insufficiency

Morbidity and mortality from aortic dissection remain high despite advances in diagnosis and treatment. Simple markers to identify patients at high risk for non-aortic complications of dissection are lacking. We investigated the effect of renal insufficiency on the presentation, complications, and outcome of patients with acute aortic dissection. We evaluated 638 patients with type A and 365 patients with type B aortic dissection enrolled in the International Registry of Acute Aortic Dissection (IRAD) between January 1996 and December 2000. Chi-squared and Student’s t testing were performed to identify the effect of renal insufficiency on patient presentation, management, and outcome. Patients with renal insufficiency more often required nitroprusside for blood pressure control (type A: 40.7% vs 31.1%, p 1/4-0.049; type B: 66.7% vs 37.3, p 1/4-0.0001) and had a greater risk of mesenteric ischemia (type A: 10.7% vs 1.4%, p < 0.0001; type B: 17.7% vs 3.0%, p < 0.0001). In conclusion, aortic dissection patients with renal insufficiency are at increased risk for drug-resistant hypertension and aortic branch vessel compromise. Routine measurement of serum creatinine provides a readily accessible clinical marker for important complications. Upon recognition, renal impairment indicates a need for close monitoring, aggressive blood pressure control, and evaluation of aortic branch vessel circulations.

Reducing Disparities in Hypertension Control: A Community-Based Hypertension Control Project (CHIP) for an Ethnically Diverse Population

The Community Hypertension Intervention Project (CHIP) is investigating medical, environmental, and psychosocial factors related to adherence to treatment for hypertension and examining the efficacy of three interventions designed to improve treatment adherence in a high-risk, underserved, ethnically diverse population. There were 1,367 Black (76%) and Hispanic (21%) adults who participated in a 4-year longitudinal study. Participants were randomized to either usual care or one of three interventions: (a) individualized counseling sessions with community health workers (CHWs), (b) a computerized appointment tracking system, or (c) home visits/focus group discussions with CHWs. At baseline, a total of 33% of the participants had one or more comorbidities in addition to hypertension; only 35% had their blood pressure under control. Participants assigned to the patient tracking intervention exhibited the most significant improvement in appointment keeping and blood pressure control status at 6 months; however, the 12-month follow-up assessments indicated that individualized counseling and home visits resulted in significant, sustained improvements in appointment keeping and blood pressure control status. These findings are now being integrated into the patient care delivery system of the participating outpatient clinics.

Cardiovascular risk factors in CKD associate with both ESRD and mortality

The American Heart Association's Life's Simple 7 initiative allows individuals to assess health factors (BP, cholesterol, and glucose) and health behaviors (cigarette smoking, physical activity, diet, and body mass index) to promote improved cardiovascular health. Because several cardiovascular risk factors also associate with progressive kidney disease, Life's Simple 7 may also inform an individual's risk for ESRD. Here, we investigated the association of Life's Simple 7 components with both ESRD incidence and all-cause mortality among 3093 participants with an estimated GFR (eGFR) <60 ml/min per 1.73 m(2) from the population-based Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study. During a median 4 years of follow-up, 160 participants developed ESRD, and 610 participants died. Compared with individuals who had zero or one of the Life's Simple 7 components in the ideal range, those individuals with two, three, and four ideal factors had progressively lower risks for ESRD; furthermore, no participant with five to seven ideal factors developed ESRD. The risk for all-cause mortality exhibited a similar trend. Adjusting for eGFR and albuminuria, however, completely attenuated the associations between the number of ideal factors and the risks for both ESRD and all-cause mortality. In conclusion, a favorable cardiovascular risk profile among individuals with CKD associates with a reduced risk for ESRD and mortality, but whether the severity of kidney disease confounds or mediates this association requires additional investigation.

End-stage renal disease in Taiwan: a case-control study

Background

Taiwan has the highest incidence of end-stage renal disease (ESRD) in the world. The epidemiologic features of ESRD, however, have not been investigated. In this case–control study, we evaluated the risk of ESRD associated with a number of putative risk factors.

Methods

We studied 200 patients among whom ESRD had been newly diagnosed between 1 January 2005 and 31 December 2005; 200 controls were selected from among relatives of patients treated in the general surgery unit. Using a structured questionnaire, we collected information related to socioeconomic factors, history of disease, regular blood or urine screening, lifestyle, environmental exposure, consumption of vitamin supplements, and regular drug use at 5 years before disease onset.

Results

Our primary multivariate risk models indicated that low socioeconomic status was a strong predictor of ESRD (education: odds ratio [OR], 2.78; 95% confidence interval [CI], 1.49–5.19; income: OR, 2.86, 95% CI, 1.48–5.52), even after adjusting for other risk factors. Other significant predictors for ESRD were a history of hypertension (OR, 3.63–3.90), history of diabetes (OR, 3.85–5.50), and regular intake of folk remedies or over-the-counter Chinese herbs (OR, 10.84–12.51). Regular intake of a multivitamin supplement 5 years before diagnosis was associated with a decreased risk of ESRD (OR, 0.12–0.14).

Conclusions

Our findings indicate that low socioeconomic status, history of hypertension, diabetes, and regular use of folk remedies or over-the-counter Chinese herbs were significant risk factors for ESRD, while regular intake of a multivitamin supplement was associated with a decreased risk of ESRD.

Inhibition of the Renin-Angiotensin System Abolishes the Proatherogenic Effect of Uremia in Apolipoprotein E-Deficient Mice

Objective— Uremia accelerates atherosclerosis in apolipoprotein E-deficient (apoE −/− ) mice. We examined whether this effect may be preventable by pharmacological blockade of the renin-angiotensin system (RAS).

Methods and Results— Uremia was induced in apoE −/− mice by 5/6 nephrectomy (NX). Treatment with the angiotensin converting enzyme inhibitor enalapril (2 or 12 mg/kg/d) from week 4 to 36 after NX reduced the aortic plaque area fraction from 0.23±0.02 (n=20) in untreated mice to 0.11±0.01 (n=21) and 0.08±0.01 (n=23), respectively ( P <0.0001); the aortic plaque area fraction was 0.09±0.01 (n=22) in sham-operated controls. Enalapril from week 20 to 44 after NX also retarded the progression of atherosclerosis. Plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1) and concentrations of IgM antibodies against oxidized low density lipoprotein (OxLDL) increased after NX ( P <0.01). Enalapril (12 mg/kg/d) attenuated these increases ( P <0.05) and reduced aortic expression of vascular cell adhesion molecule (VCAM)-1 mRNA ( P <0.05). Atherosclerosis in NX mice was also reduced by losartan (an angiotensin II receptor-blocker), but not when blood pressure was lowered with hydralazine (a non-RAS-dependent vasodilator).

Conclusion— The results suggest that inhibition of RAS abolishes the proatherogenic effect of uremia independent of its blood pressure-lowering effect, possibly because of antiinflammatory and antioxidative mechanisms.

Risk for Incident Renal Dialysis in a Managed Care Population

BACKGROUND

The influence of poorly controlled blood pressure (BP) on progression to end-stage renal disease typically has been studied in qualified populations. Few observational studies examined the influence of change in BP.

METHODS

We conducted a retrospective observational study of a cohort of adults 18 years or older with glomerular filtration rates of 15 to 89 mL/min/1.73 m(2) (0.25 to 1.48 mL/s) in 2001 (N = 16,299) in a managed care organization. The cohort generally was representative of many urban areas in the United States. The principal outcome was incident renal dialysis in 2002 (N = 73). BP was measured in 1999 and 2001. Risk for incident dialysis therapy was estimated in the entire cohort by using Cox proportional hazards regression and in a subset of 4 randomly selected controls (n = 292) matched (for 2001 glomerular filtration rate, age, and sex) with incident dialysis cases by using conditional logistic regression.

RESULTS

Within this cohort, dialysis incidence was 4.5 cases/1,000 adults. For incident dialysis cases, mean time to dialysis therapy in 2002 (from December 31, 2001) was 167 days. Greater levels of systolic or diastolic BP in 1999 were associated significantly with greater risk for incident dialysis treatment in 2002 (controlling for age, sex, coronary artery disease, diabetes, and tobacco use). Decreased systolic or diastolic BP from 1999 to 2001 was associated with significantly reduced risk for incident dialysis treatment in 2002.

CONCLUSION

Improving BP control in adults with early or advanced kidney disease and moderately to severely elevated BP should continue to be a focus of care management programs seeking to decrease the risk for incident dialysis treatment.

Traditional and nontraditional risk factors predict coronary heart disease in chronic kidney disease: results from the atherosclerosis risk in communities study

Some risk factors for coronary heart disease (CHD) incidence in the general population are not associated with CHD incidence among patients with ESRD but have not been well characterized in chronic kidney disease (CKD). The association of several risk factors with CHD incidence was studied among participants with CKD in the population-based Atherosclerosis Risk in Communities (ARIC) Study. CHD risk factors and estimated GFR using serum creatinine were measured among 807 ARIC participants with CKD (estimated GFR between 15 and 59 ml/min per 1.73 m(2)). The incidence of CHD during 10.5 yr of follow-up was 6.3, 8.5, and 14.4 per 1000 person-years among ARIC participants with an estimated GFR of >/=90, 60 to 89, and 15 to 59 ml/min per 1.73 m(2), respectively. After adjustment for age, race, gender, and ARIC field center, among those with CKD, the relative risk (95% confidence interval) of CHD was 1.65 (1.01 to 2.67) for current smoking, 2.02 (1.27 to 3.22) for hypertension, 3.06 (2.01 to 4.67) for diabetes, and 1.96 (1.14 to 3.36) for anemia. The comparably adjusted relative risks of CHD for each standard deviation higher total and HDL cholesterol were 1.50 (1.25 to 1.71) and 0.79 (0.62 to 1.01), respectively, and 1.38 (1.13 to 1.69), 1.24 (1.06 to 1.46), 0.65 (0.54 to 0.79), and 1.38 (1.19 to 1.59) for waist circumference, leukocyte count, serum albumin, and fibrinogen, respectively. CHD risk factors in the general population remain predictive among patients with CKD. Given the high risk for CHD among patients with CKD, control of these risk factors may have a substantial impact on their excess burden of CHD.

Effects of Losartan and Chlorthalidone on Blood Pressure and Renal Vascular Resistance Index in Non-Diabetic Patients with Essential Hypertension and Normal Renal Function

Antihypertensive drugs can differ in target organ protection despite similar blood pressure (BP) control. We compared the effects of losartan (L) and chlorthalidone (C) on renal vascular resistance index (RVRI) in 194 grade I to II, non-diabetic hypertensive patients with increased RVRI (>0.68 m/s by echo-Doppler) but normal renal function. Patients were randomly allocated to C 25 mg/d or L 50 mg/d according to a single blind, PROBE study design. After 4 weeks of treatment, 92 patients (48 L/44 C) with BP <140/90 mm Hg were enrolled in the long-term phase of the study. After 12 months a normalization of RVRI was observed in 47 of 48 patients treated with L (97.5%) and only in 14 of 44 of those treated with C (25.8%) despite no differences in BP control. Patients whose RVRI remained elevated during C therapy underwent a 2-week washout period and then were treated with L 50 mg/d for 12 additional months. After that period 28 of 30 (95%) of patients who were nonresponders to C showed a normalization of RVRI despite no differences in BP control. In conclusion, our data suggest that treatment with L can improve renal hemodynamic and exert a protective renal effect beyond BP control in patients with hypertension.

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.

Chronic Renal Failure Accelerates Atherogenesis in Apolipoprotein E–Deficient Mice

ABSTRACT. Cardiovascular mortality is 10 to 20 times increased in patients with chronic renal failure (CRF). Risk factors for atherosclerosis are abundant in patients with CRF. However, the pathogenesis of cardiovascular disease in CRF remains to be elucidated. The effect of CRF on the development of atherosclerosis in apolipoprotein E–deficient male mice was examined. Seven-week-old mice underwent 5/6 nephrectomy (CRF, n = 28), unilateral nephrectomy (UNX, n = 24), or no surgery (n = 23). Twenty-two weeks later, CRF mice showed increased aortic plaque area fraction (0.266 ± 0.033 versus 0.045 ± 0.006; P < 0.001), aortic cholesterol content (535 ± 62 versus 100 ± 9 nmol/cm2 intimal surface area; P < 0.001), and aortic root plaque area (205,296 ± 22,098 versus 143,662 ± 13,302 μm2; P < 0.05) as compared with no-surgery mice; UNX mice showed intermediate values. The plaques from uremic mice contained CD11b-positive macrophages and showed strong staining for nitrotyrosine. Systolic BP and plasma homocysteine concentrations were similar in uremic and nonuremic mice. Plasma urea and cholesterol concentrations were elevated 2.6-fold (P < 0.001) and 1.5-fold (P < 0.001) in CRF compared with no-surgery mice. Both variables correlated with aortic plaque area fraction (r2 = 0.5, P < 0.001 and r2 = 0.3, P < 0.001, respectively) and with each other (r2 = 0.5, P < 0.001). On multiple linear regression analysis, only plasma urea was a significant predictor of aortic plaque area fraction. In conclusion, the present findings suggest that uremia markedly accelerates atherogenesis in apolipoprotein E–deficient mice. This effect could not be fully explained by changes in BP, plasma homocysteine levels, or total plasma cholesterol concentrations. Thus, the CRF apolipoprotein E–deficient mouse is a new model for studying the pathogenesis of accelerated atherosclerosis in uremia. E-mail: susannebro@dadlnet.dk

Predicting end-stage renal disease: Bayesian perspective of information transfer in the clinical decision-making process at the individual level

BACKGROUND

Predicting outcomes such as end-stage renal disease (ESRD) by integration and better utilization at individual level of epidemiologic data may facilitate clinical decision-making processes.

METHODS

To predict individual ESRD risk in an average patient in the United States, ESRD prevalence and levels of uncertainty and conditional risk factors independence were considered by population data (1998) and pooled analysis of 11 randomized trials. Data integration and input were by decision-tree simulation approach (simple, parallel, and sequential scenarios) and Bayes' theorem. Sensitivity analysis and risk profiles were employed to address uncertainty and assess different risk factor combinations. A health state values, associated with ESRD outcome levels, were taken from the literature.

RESULTS

In this theoretical study, we provided a scholarly example about the use of two known risk factors (urinary protein >/=3 g/day and systolic blood pressure >/=140 mm Hg) to predict individual ESRD risk in an average patient in the United States. The highest posterior (decisional) probability of ESRD occurrence (risk of 3.61% to 5.07%) in the individual patient was associated with the worst health state, as assessed by multidimensional scenarios when both risk factors were present.

CONCLUSION

Decision tree models through an empirical Bayesian approach may serve to predict the individual ESRD risk on the basis of simple epidemiologic, demographic, and clinical information that is easily available already at the first patient evaluation.

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.

Cardiovascular disease in patients with chronic kidney disease

Cardiovascular disease (CVD) is the major cause of morbidity and mortality in patients with renal failure. Patients with chronic kidney disease have significant CVD, and carry a high cardiovascular burden by the time they commence renal replacement therapy (RRT). The severity of CVD that has been observed in dialysis patients lead to a growing body of research examining the pathogenesis and progression of CVD during the progression of chronic kidney disease (CKD) to end-stage renal disease (ESRD) (ie, predialysis phase). Multiple factors are involved in the development of CVD in CKD. More importantly, critical and key factors seem to develop early in the course of CKD, and result in preventable worsening of CVD in this patient population. Anemia is common in patients with CKD, and has been shown to have an independent role in the genesis of left ventricular hypertrophy (LVH) and subsequent CVD. Unfortunately, it is underdiagnosed and undertreated in patients with CKD. Early intervention, and better correction of anemia, seems to gain a great momentum in the prevention and management of CVD in CKD. Hypertension is another risk factor that has been targeted by the National Kidney Foundation Task Force on CVD in chronic kidney disease. This article reviews the different factors involved in the pathogenesis of CVD in CKD and the evidence supporting early and aggressive intervention.

Comparative effects on dynamic renal potassium excretion of ACE inhibition versus angiotensin receptor blockade in hypertensive patients with type II diabetes mellitus

Both ACE inhibitors (ACEI) and angiotensin receptor blockers (ARB) are renoprotective beyond their effects on blood pressure (BP), but their widespread use is limited by their tendency to provoke hyperkalemia. The comparative effects of ACEI and ARB on potassium handling have not been investigated. The objective of this study was to determine whether there are differences in dynamic renal potassium handling between ACEI and ARB in response to an oral potassium challenge. This was a randomized crossover study of candesartan versus lisinopril titrated to control BP followed by an inpatient study of renal potassium handling in 24 hypertensive patients with type II diabetes mellitus (DMII) and preserved renal function. Following an oral potassium challenge (0.75 mmol/kg), differences in hourly serum K (mmol/L), rate of urinary potassium excretion (UkV, micromol/min), and fractional excretion of potassium (FEK) were assessed by repeated-measures ANOVA. Hourly UkV(p = .45) and FEK (p = .19) were similar for candesartan and lisinopril, although FEK at 2 hours for candesartan tended to exceed that for lisinopril (.34 [.04] vs. .26 [.03]) and approached significance (p = .096). UkVfor candesartan at hour 2 was 177 (26) and 121 (21) for lisinopril and also approached significance (p = .10). Serial serum potassium did not differ (p = .70). No statistical differences were discovered in renal potassium handling between candesartan and lisinopril in patients with DMII and preserved renal function. Whether there are differences between the drug classes in renal impairment remains to be determined.

Renal insufficiency and subsequent death resulting from cardiovascular disease in the United States

Several epidemiologic studies reported that persons with renal insufficiency might have increased cardiovascular disease-related mortality rates in select populations. The association between renal insufficiency and increased cardiovascular disease-related and all-cause mortality rates during 16 yr of follow-up monitoring was examined among participants who were 30 to 74 yr of age at the baseline examinations in 1976 to 1980, with urinary protein dipstick measurements (n = 8786) or serum creatinine levels of <or=3.0 mg/dl (n = 6354), from the Second National Health and Nutrition Examination Survey Mortality Study. GFR were estimated by adjusting serum creatinine levels for age, race, and gender, using the Modification of Diet in Renal Disease formula. Cardiovascular disease-related mortality rates were 6.2, 17.9, and 37.2 deaths/1000 person-yr among subjects with urinary protein levels of <30, 30 to 299, and >or=300 mg/dl and were 4.1, 8.6, and 20.5 deaths/1000 person-yr among participants with estimated GFR of >or=90, 70 to 89, and <70 ml/min, respectively. After adjustment for potential confounders, the relative hazards (and 95% confidence intervals) for cardiovascular disease-related death were 1.57 (0.99 to 2.48) and 1.77 (0.97 to 3.21) among subjects with urinary protein levels of 30 to 299 and >or=300 mg/dl, respectively, compared with <30 mg/dl (P trend = 0.02). The corresponding relative hazards for all-cause-related death were 1.64 (1.23 to 2.18) and 2.00 (1.13 to 3.55; P trend < 0.001). Compared with subjects with estimated GFR of >or=90 ml/min, those with estimated GFR of <70 ml/min exhibited higher relative risks of death from cardiovascular disease and all causes [1.68 (1.33 to 2.13) and 1.51 (1.19 to 1.91), respectively]. This study indicates that, in a representative sample of the United States general population, renal insufficiency is independently associated with increased cardiovascular disease-related and all-cause mortality rates.

Recreational drug use: a neglected risk factor for end-stage renal disease

Case series have suggested that heroin and cocaine users are at increased risk for renal failure, but the contribution of heroin and other addictive drugs to the incidence of end-stage renal disease (ESRD) in the general population remains unknown. To clarify this issue, we conducted a case-control study in the general population to examine associations between drug use and treated ESRD. Cases were 716 patients who started therapy for ESRD in 1991, identified through a regional registry. Controls were 361 persons of similar age (20 to 65 years) selected by random digit dialing. Main risk factors examined were the lifetime use of heroin, cocaine, and other addictive drugs, assessed by telephone interview. After adjustment for age, sex, race, socioeconomic status, and history of hypertension and diabetes, persons who had ever used heroin or other opiates (any amount) were at increased risk for ESRD (adjusted odds ratio, 19.1; 95% confidence interval, 1.7 to 208.7). After adjustment for the same sociodemographic and medical history variables, the use of cocaine or crack and psychedelic drugs was also associated with ESRD, but these associations could not be separated from the effects of heroin use.

The future of clinical trials in chronic renal disease: outcome of an NIH/FDA/Physician Specialist Conference. Evaluation of Clinical Trial Endpoints in Chronic Renal Disease Study Group

For people with chronic renal insufficiency, the therapeutic goal is to prevent progression to end-stage renal disease, a serious condition that can only be treated with dialysis and kidney transplantation. Although restriction of dietary protein slows the progression of renal disease somewhat, the principal treatment to slow chronic renal disease is appropriate reduction of blood pressure. Antihypertensive agents, particularly those that produce sustained, long-term reductions in proteinuria, such as angiotensin-converting enzyme inhibitors, not only decrease blood pressure but also preserve renal function. Clinical trials to evaluate these and other drug therapies in renal disease progression have used both "hard end points" (e.g., dialysis, transplantation, death) and intermediate end points of renal disease progression (e.g., doubling of serum creatinine concentration, reductions in proteinuria). Trials that have used hard end points typically recruited patients with advanced renal disease to demonstrate a difference in therapies within a period of 2 to 5 years. However, proteinuria reduction, along with a decrease in the time to doubling of serum creatinine in very early diabetic renal disease, could demonstrate an altered natural history of renal disease. Although hard end points are indicators of a drug's efficacy in reducing cardiovascular events or preserving renal function, they do not assess the impact of a treatment on altering the natural history of early renal disease. For clinical trials of people with all but the most advanced renal disease, use of intermediate end points of renal disease progression is the only practical option for assessment of treatment efficacy and effectiveness. Given the available data on proteinuria reduction and doubling of serum creatinine from clinical trials, these end points, taken together, appear to provide an acceptable means of assessing a treatment's impact on slowing renal disease progression.

A clinic and community-based approach to hypertension control for an underserved minority population: design and methods

This paper describes the design and methodology of the Community Hypertension Intervention Project (CHIP). CHIP is investigating the environmental and psychosocial factors related to treatment adherence and examining the effects of combining usual hypertension care with the effects of three interventions designed to improve patient compliance with treatment for high blood pressure in a high-risk, underserved minority population. Thirteen hundred and sixty-seven inner-city hypertension patients (75% black and 25% Hispanic) have agreed to participate in the 4-year longitudinal study. These participants were randomized to usual care or one of three intervention groups: individualized counseling sessions; home visits/discussion groups; or computerized appointment-tracking system. Participants are representative of the surrounding, predominantly low-income minority community and are treated in a hospital-based clinic and in a private clinic in the community. About 65% have blood pressure levels considered to be out of control. It was concluded that structural changes at the clinic site, along with the targeted interventions, would improve patient satisfaction, increase treatment adherence, and improve blood pressure control.

Cardiovascular disease and the kidney: an epidemiologic overview

Essential hypertension and congestive heart failure (CHF) are examples of cardiovascular disorders that may cause renal failure, although sometimes a primary kidney defect may lead to hypertension. Renal damage in malignant and severe hypertension is dramatic, extensive, and rapidly progressive, although nephrosclerotic damage, which develops slowly and appears late in hypertension, is a rare cause of morbidity because mild to moderate hypertension is now the most common form. However, the incidence of end-stage renal failure associated with hypertension is markedly increasing, perhaps because of underdiagnosis of renal damage in hypertension, insufficient lowering of blood pressure in clinical practice, or inability of antihypertensive drugs to lower blood pressure sufficiently to preserve the kidney, a goal that may need specific drugs that act, for example, on the renin-angiotensin system (RAS). Renal vasoconstriction and reduction of renal blood flow are early companions of cardiac insufficiency and may be involved in the development of sodium and water retention. Profound reduction of cardiac output and arterial hypotension in severe CHF may lead to acute renal failure. Chronic renal insufficiency is associated with elevated cardiovascular morbidity and mortality. Renal impairment is often caused by a disease process, such as diabetes mellitus, that involves both the cardiovascular system and the kidney. When the primary disease is renal, possible reasons for an association include renal-dependent increase in blood pressure, activation of the RAS, overproduction of other vasoactive substances of renal origin, and electrolyte imbalances leading to fatal arrhythmias.

Nephroprotective effect of antihypertensive drugs in essential hypertension

BACKGROUND

Effective antihypertensive treatment has prevented target-organ involvement in hypertension, markedly reducing morbidity and mortality from strokes, coronary heart disease, cardiac failure, and hypertensive emergencies. However, the incidence of hypertension-related end-stage renal disease continues to increase, suggesting that therapeutic reduction in arterial pressure by itself is not sufficient to prevent the development of hypertensive renal failure.

OBJECTIVE

To examine experimental and clinical data concerning the protective effect of reduction of arterial pressure on the progression of hypertension-related renal disease, and the evidence indicating that some antihypertensive agents may afford more nephroprotection, over and above that attributable to reduction of arterial pressure.

RESULTS

Results of numerous studies clearly indicate that adequate control of arterial pressure, irrespective of the antihypertensive agent used, slowed the progression of renal disease. Results of some studies suggest that lowering arterial pressure below the level that is usually considered adequate has an additional beneficial effect by slowing the progression of renal injury.

CONCLUSION

Results of a number of studies evaluating nephroprotective effects of various drugs and regimens have indicated that certain agents, most notably angiotensin converting enzyme inhibitors and their combination with calcium antagonists, afford more protection than do others at similar levels of reduction of arterial pressure. Results of still other studies suggest that certain agents that exert greater nephroprotection are more efficient at controlling arterial pressure. Therefore, further data are needed before any final conclusion can be drawn. However, it is clear that, in order to establish nephroprotection in patients with essential hypertension, the problem should not be further complicated by additional comorbid diseases such as diabetes mellitus.