Model to predict mortality in critically ill adults with acute kidney injury

Summary

Background and objectives

Acute kidney injury (AKI) requiring dialysis is associated with high mortality. Most prognostic tools used to describe case complexity and to project patient outcome lack predictive accuracy when applied in patients with AKI. In this study, we developed an AKI-specific predictive model for 60-day mortality and compared the model to the performance of two generic (Sequential Organ Failure Assessment [SOFA] and Acute Physiology and Chronic Health Evaluation II [APACHE II]) scores, and a disease specific (Cleveland Clinic [CCF]) score.

Design, setting, participants, & measurements

Data from 1122 subjects enrolled in the Veterans Affairs/National Institutes of Health Acute Renal Failure Trial Network study; a multicenter randomized trial of intensive versus less intensive renal support in critically ill patients with AKI conducted between November 2003 and July 2007 at 27 VA- and university-affiliated centers.

Results

The 60-day mortality was 53%. Twenty-one independent predictors of 60-day mortality were identified. The logistic regression model exhibited good discrimination, with an area under the receiver operating characteristic (ROC) curve of 0.85 (0.83 to 0.88), and a derived integer risk score yielded a value of 0.80 (0.77 to 0.83). Existing scoring systems, including APACHE II, SOFA, and CCF, when applied to our cohort, showed relatively poor discrimination, reflected by areas under the ROC curve of 0.68 (0.64 to 0.71), 0.69 (0.66 to 0.73), and 0.65 (0.62 to 0.69), respectively.

Conclusions

Our new risk model outperformed existing generic and disease-specific scoring systems in predicting 60-day mortality in critically ill patients with AKI. The current model requires external validation before it can be applied to other patient populations.     

Hyperhomocysteinemia exacerbates the development of intimal hyperplasia in Sprague-Dawley rats: Alleviation by rosiglitazone

The amino acid intermediate homocysteine (Hcy) is formed during the metabolism of methionine to cysteine. Hyperhomocysteinemia (HHcy) is recognized as an independent risk factor for coronary atherosclerosis. The circulating levels of total Hcy (tHcy) can increase due to intake of foods rich in methionine or deficiencies of vitamins such as folate, pyridoxine and cyanocobalamin, which are required for the metabolism of Hcy. In addition, mutations in the genes coding for Hcy metabolizing enzymes can contribute to an increase in tHcy levels. Clinical and epidemiological studies have shown that an elevated level of tHcy measured in serum or plasma is a strong predictor of cardiovascular disease risk, which appears to be greatest in patients who have HHcy following a methionine load. Intimal hyperplasia (IH) (intima/media [I/M] ratio) is the universal response of a vessel to injury and may result in vasoconstriction when left unattended. The effect of dietary HHcy on balloon catheter-injured carotid artery and its modulation (if any) by the peroxisome proliferator-activated receptor agonist gamma rosiglitazone was evaluated in 12-week-old female Sprague-Dawley rats fed either a control diet or a diet containing 1% L-methionine. Once the rats were established on the diet, the group that was fed 1% L-methionine was further subdivided and either given an aqueous preparation of 3 mg/kg/day rosiglitazone or the vehicle via oral gavage for one week. This was followed by surgically injuring the left carotid artery using a Maverick Over-The-Wire catheter (2.0 mm × 20 mm, 3.2F; Boston Scientific, USA). The rats were continued on their respective diets and drug regimen for 21 days postsurgery. On day 22 of the procedure, the rats were sacrificed for collection of blood, the carotid arteries and liver for biochemical and histological evaluation. Compared with controls there was a significant increase in both tHcy levels and I/M ratio in the rats fed 1% L-methionine (5.4±0.28 μM versus 32.8±3.01 μM, P<0.002; and 0.175±0.05 versus 1.05±0.23, P<0.005, respectively). The effect of rosiglitazone in rats fed the control diet was not prominent. On the other hand, administration of rosiglitazone to the rats on the 1% L-methionine diet significantly reduced the levels of serum tHcy (16.6±2.1 μM versus 32.8±3.01 μM, P<0.001); however, the tHcy levels remained significantly elevated compared with animals on the control diet (P<0.002). The group receiving the L-methionine diet plus rosiglitazone had an inhibition in the development of IH compared with those receiving the L-methionine diet alone (I/M of 0.278±0.041 versus 1.05±0.23, P<0.01). Moreover, the development of IH in the group receiving the L-methionine diet plus rosiglitazone treatment was not significantly different from that observed in the group on the control diet without rosiglitazone (0.278±0.041 versus 0.175±0.05, respectively). These findings may have important implications in deciphering the molecular mechanisms involved in the augmentation of IH in HHcy and modulation of this process by rosiglitazone.     

Left ventricular pseudoaneurysm after mitral valve replacement

Development of left ventricular pseudoaneurysm is a rare complication of mitral valve surgery and requires urgent surgical intervention. We describe a case of pseudoaneurysm of membranous septum following repeat mitral valve replacement with the use of multimodality imaging.     

Gated MR imaging of left atrial myxomas

Two cases of left atrial myxoma were evaluated with magnetic resonance (MR) imaging. In both cases, the myxoma was clearly defined as to its location, origin, and size. In one case, the myxoma prolapsed through the mitral valve. Our study indicates that MR imaging is valuable in the diagnosis of myxomas.     

National multicenter study of HIV testing and HIV seropositivity in patients with chronic hepatitis C virus infection

BACKGROUND: Although HIV testing is recommended for persons with hepatitis C virus (HCV) infection who are at risk for HIV, little is known about HIV testing in this population. METHODS: Data were prospectively collected in 4364 HCV-infected patients at 24 Veterans Affairs medical centers across the United States, including demographics, risk factors for HIV infection, and self-reported information on HIV testing. RESULTS: Overall, 76.8% had been tested for HIV at least once, 14.8% were never tested, 6.6% did not know if they were tested, and 1.8% declined to answer. Multivariable analysis identified injection drug use, needlestick injury, sex with a same-sex partner, a greater number of lifetime sexual partners, and sex with an injection drug user as factors that were independently associated with HIV testing. At least one risk factor for HIV infection was present in 84.5% of the 646 patients who were never HIV tested. Among the 3350 subjects who were tested for HIV, 8.4% were positive, 88.3% were negative, 2.4% did not know the results of their test, and 0.9% declined to answer. Multivariable analysis identified African American and Hispanic race/ethnicity, income < or = 10,000 dollars, sex with a same-sex partner, and sex with an injection drug user as the only variables that were independently associated with HIV seropositivity. CONCLUSIONS: Although a substantial proportion of HCV-infected patients have been tested for HIV, missed opportunities for early diagnosis of HIV infection exist. Public health strategies to improve HIV testing among patients with chronic HCV infection are needed.     

Immune hemolytic anemia associated with tolmetin and suprofen

This article reports the first case of immune hemolytic anemia possibly associated with the ingestion of suprofen. The patient suffered from massive hemoglobinuria and acute renal failure. Serologic studies of the patient's serum revealed suprofen-dependent red cell antibodies. However, tolmetin-dependent antibodies were also found in the serum, showing the same properties as the suprofen antibodies and an even higher titer. The patient not only had drug-dependent antibodies in the serum, but also had developed autoantibodies, a phenomenon that has been described for several other drugs. The working mechanism by which suprofen and tolmetin caused immune hemolysis had properties of both the immune complex model and the induction of autoimmunity. Although it was unclear whether the immune hemolytic anemia was the result of suprofen, tolmetin, or cross-reacting antibodies, we feel that suprofen should be added to the list of nonsteroidal anti-inflammatory drugs associated with a positive direct antiglobulin test.