Epidemiology of de novo acute renal failure in hospitalized African Americans: comparing community-acquired vs hospital-acquired disease.

BACKGROUND: The high incidence and prevalence of end-stage kidney disease among African Americans is well known, but the epidemiology of acute renal failure (ARF) among African Americans is unknown. This study was designed to determine the incidence, associated risk factors, and prognosis of ARF in hospitalized African Americans and to compare these variables in hospital-acquired ARF (HA-ARF) against community-acquired ARF (CA-ARF). METHODS: A 3-year (1994-1996), computer-assisted retrospective analysis of hospital discharges with confirmed diagnoses of ARF. One hundred of 240 cases met the inclusion criteria for de novo ARF. Demographic, laboratory, and clinical profiles of all patients were retrieved and subdivided into CA-ARF and HA-ARF. Both analysis of variance and chi2 tests were used for analysis. Survival regression used both the Cox proportional hazards and Kaplan-Meier models. RESULTS: The incidence of CA-ARF was 3.5 times greater than that of HA-ARF (0.55% vs 0.15%). The mean age of all patients was 54 years with a 67% male predominance. There were no significant differences in age, sex, peak serum creatinine levels, or underlying medical history. Prerenal causes of ARF were more common among CA-ARF than HA-ARF (35% vs 19%; P = .07), but intra-renal causes were more common among HA-ARF (81% vs 55%; P = .07). All cases of obstruction occurred in CA-ARF. Mortality was higher in HA-ARF (59% vs 33%; P = .03), and the incidence of recognized predictors of mortality was higher in patients with HA-ARF than in those with CA-ARF: oliguria (59% vs 35%; P = .04); sepsis (73% vs 35%; P = .004); stay in the intensive care unit (ICU) or mechanical ventilation (55% vs 6%; P<.001); and multiorgan failure (59% vs 24%; P = .002). Those with HA-ARF were twice as likely to require dialysis as those with CA-ARF. The mortality was high in younger patients with CA-ARF and in older patients with HA-ARF, but the dialysis-related mortality rate was 3-fold higher among patients with HA-ARF. While mean +/- SD length of hospital stay was more prolonged in HA-ARF than CA-ARF (26 +/- 28 days vs 12 +/- 11 days; P<.001), the 120-day survival rate was lower in HA-ARF than CA-ARF (43% vs 66%; P = .05). The HA-ARF status was associated with a relative risk of 2.5 (confidence interval, 1.1-5.5; P = .03) for shortened survival. CONCLUSIONS: The overall epidemiologic characteristics of ARF among hospitalized African Americans seem to be comparable to those in whites, but the difference in incidence between CA-ARF and HA-ARF was much higher in African Americans. In view of the high mortality and morbidity rates associated with ARF and the fact that younger African American patients with CA-ARF were more likely to die than their older counterparts, we recommend that renal failure awareness be incorporated into community-based health educational programs in African American populations.

Cocaine and the kidney: a synthesis of pathophysiologic and clinical perspectives.

Cocaine abuse has reached epidemic proportions in the United States, and several forms of renal disease have been associated with this widespread use. The hemodynamic actions of cocaine, as well as its effects on matrix synthesis, glomerular inflammation, and glomerulosclerosis, may contribute to renal injury. Cocaine abuse has been associated with various forms of acute renal failure and acid-base and/or electrolyte disorders and may also have a role in the progression of chronic renal failure to end-stage renal disease. In utero exposure to cocaine has been associated with urogenital tract anomalies. Medical management of a hypertensive emergency caused by acute cocaine toxicity requires a multisystem approach, with close monitoring of cardiac, neurological, and renal functions.

A dose-titration trial of guanadrel as step-two therapy in essential hypertension.

The efficacy and safety of low-dose guanadrel sulfate were evaluated in 20 patients with essential hypertension based on seated diastolic blood pressures (SDBP) ranging from 95 to 115 mm Hg despite a trial dosage of hydrochlorothiazide 50 mg/d for up to five weeks. These patients had been resistant to, or intolerant of, one or more step-two antihypertensive drugs in the past (i.e., methyldopa, beta-adrenergic blocking agents, clonidine, or prazosin). The majority of patients demonstrated a satisfactory response (SDBP 95 mm Hg or reduction in SDBP of 10 mm Hg) to guanadrel. Nine patients responded at a low dosage, 10 to 20 mg/d and remained free from adverse effects throughout the study (up to 12 weeks of treatment). Of the remaining 11 patients titrated to higher dosages of guanadrel (30 to 60 mg/d), three had no discernible response while six developed adverse effects. The results of the study suggest that guanadrel has an acceptable benefit-to-risk ratio only when used in low dosages (10 to 30 mg/d) and may be successfully employed as step-two antihypertensive therapy in patients resistant to, or intolerant of, other step-two agents.

Acute metabolic acid-base disorders.

Metabolic acid-base disturbances commonly and predictably complicate the course of many intensive care unit patients and plague the intensivists, surgeons, and anesthesiologists beset with the task of caring for them. In this article, we offer a systematic approach to the patient with the metabolic acid-base disorders that are likely to be encountered in the setting of the intensive care unit. The discussions are in no way presented as through treatments of all metabolic disorders, but rather focus on the more practical aspects, namely, clinical scenarios, diagnostic clues, and therapeutic goals. Additionally, we interject a discussion of some of the more controversial topics with regard to the therapy of metabolic disorders.

Natriuretic effect of calcium-channel blockers in hypertensives.

This double-blind, randomized, crossover trial characterizes the acute natriuretic response to calcium-channel blockers (CCB) and investigates the role of hemodynamic and hormonal factors in mediating the natriuresis. Thirteen male subjects with essential hypertension received a single oral 20-mg dose of nifedipine or 120 mg of diltiazem. Renal functional and hemodynamic measurements were performed prior to and hourly for 4 hours following medication. Subjects then received these medications for 4 weeks at which time the above studies were repeated. Urinary sodium excretion increased within 60 minutes of CCB administration and the natriuresis was sustained for 4 hours. Cumulative sodium loss during the 4 hours of study was greater with nifedipine (43 +/- 12 mmol) than with diltiazem (18 +/- 6 mmol) (P less than 0.05). Despite natriuresis, urinary potassium excretion was decreased by both agents. Even though both drugs decreased the mean arterial pressure, inulin and paraaminohippurate (PAH) clearances were not altered. Plasma aldosterone concentrations decreased, plasma catecholamine concentrations increased, whereas plasma-renin activity was unchanged with both drugs. Body weight, glomerular filtration rate (GFR), renal plasma flow, plasma-renin activity, plasma aldosterone, and catecholamine concentrations were unchanged following 4 weeks of therapy. The acute natriuretic response after 4 weeks of therapy was similar to the response noted after the first dose. This study concludes that CCB are acutely natriuretic. Despite systemic hypotension, renal hemodynamics are unaltered during CCB therapy. Suppression of aldosterone as well as direct tubular effects of these drugs may mediate the natriuresis. Chronic therapy with CCB does not modify the acute natriuretic response to these agents.

Role of hypoalbuminemia and hypocholesterolemia as copredictors of mortality in acute renal failure.

UNLABELLED: Role of hypoalbuminemia and hypocholesterolemia as co-predictors of mortality in acute renal failure. BACKGROUND: Hypoalbuminemia (LA) and hypocholesterolemia (LC) have been reported to portend high mortality in both older patients and in patients with end-stage renal disease. Even though low levels have been reported in critically ill patients, they have not been clearly defined as predictors of mortality in acute renal failure (ARF). The impact of LA and LC on mortality in ARF is evaluated in this study. METHODS: We conducted a computer-assisted three-year retrospective review of all cases of de novo ARF seen at an inner city tertiary-care facility. One hundred cases met the criteria for inclusion in the study. We employed both univariate and multivariate logistic regression models to estimate the relative risks (RR) and 95% confidence intervals (CI) of mortality associated with several variables. RESULTS: Predictors associated with a high risk of death identified in this study include LC < or = 150 mg/dl (< or = 3.9 mmol/liter; RR, 7.4; CI, 2.7 to 20.3), LA < or =35 g/liter (RR, 5.0; CI, 1.9 to 13.2), sepsis (RR, 9.4; CI, 3.7 to 23.9), mechanical ventilation (RR, 10.8; CI, 2.8 to 41.0), oliguria (RR 17.0; CI, 6.2 to 46.6), and multisystem organ failure (RR 24.7; CI, 10.3 to 59.1). The overall gross mortality was 39%, but mortality among intensive care unit patients was 82%. Survival was 82% among patients with serum albumin >35 g/liter versus 48% among those with serum albumin < or =35 g/liter (chi2 = 11.9, P = 0.0006). Similarly, survival was higher among patients with cholesterol >150 mg/dl (>3.9 mmol/liter) than those whose levels were < or =150 mg/dl (< or =3.9 mmol/liter; 85 vs. 44%, ch 17.3, P<0.0001). Significant association between LA and LC was observed (R = 0.4, P<0.0001). Age, gender, level of plasma creatinine, and underlying chronic medical conditions were not predictive of mortality. CONCLUSION: Survival in ARF is significantly altered by the levels of albumin and cholesterol. Because both LC and LA can be cytokine mediated, their presence in ARF should be considered ominous.

Sulindac and ibuprofen inhibit furosemide-stimulated renin release but not natriuresis in men on a normal sodium diet.

We compared the effect of two commonly prescribed nonsteroidal anti-inflammatory drugs, ibuprofen and sulindac, and placebo on intravenous furosemide-induced natriuresis and renin stimulation in 11 healthy male volunteers, consuming a 100 mEq sodium, 80 mEq potassium diet. Chronic (6-day) therapy with each agent was followed by a 1-week washout period. There were no significant treatment-related differences in either urine volume or sodium excretion for any of the designated collection periods or for the cumulative value for the 4 h after furosemide administration. Similarly, differences among groups were not observed for creatinine clearance, urinary potassium and urinary chloride excretion. Mean basal plasma renin activity levels prior to furosemide administration on day 6 were significantly lower in the presence of ibuprofen (1.5 +/- 2.0 ng/ml/h;p less than 0.01) and sulindac (2,3 +/- 0.9 ng/ml/h; p less than 0.05), compared with placebo (3.3 +/- 1.1 ng/ml/h); the difference between the two NSAIDs was also significant (p less than 0.05). Mean plasma renin activity levels in the 4 h after furosemide increased significantly at all time points in comparison to basal values, but were significantly less for ibuprofen and sulindac groups in the first hour. Our data suggest that the natriuresis following intravenous furosemide in men consuming a normal sodium intake is not prostaglandin-dependent. Furthermore, the observation that sulindac suppressed basal and stimulated plasma renin activity levels, albeit to a lesser extent than ibuprofen, questions the claim that sulindac "spares' the kidney and compels further evaluation of this issue.

Crossover comparison of captopril and propranolol as step 2 agents in hypertension.

The efficacy of captopril treatment was compared with that of propranolol in a single-blind crossover study in 14 patients with essential hypertension uncontrolled on diuretic alone. Both captopril (37.5 to 75 mg daily) and propranolol (60 to 120 mg daily), in combination with hydrochlorothiazide (50 mg daily), caused a significant fall in sitting systolic and diastolic blood pressure. Heart rate, plasma renin activity, and plasma aldosterone data were consistent with the effects of converting enzyme inhibition or beta blockade. Both drugs were well tolerated. Captopril appeared to be equivalent in efficacy and safety to propranolol when added to hydrochlorothiazide. It may be considered as an alternative step 2 antihypertensive agent, especially in patients experiencing unwanted effects on beta blockers.