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Biomedical subjects

R L Mehta

Publications and source records attributed to R L Mehta.

At least 19 recordsLinked to original sources
PubMed2006

Mortality after acute renal failure: models for prognostic stratification and risk adjustment.

To adjust adequately for comorbidity and severity of illness in quality improvement efforts and prospective clinical trials, predictors of death after acute renal failure (ARF) must be accurately identified. Most epidemiological studies of ARF in the critically ill have been based at single centers, or have examined exposures at single time points using discrete outcomes (e.g., in-hospital mortality). We analyzed data from the Program to Improve Care in Acute Renal Disease (PICARD), a multi-center observational study of ARF. We determined correlates of mortality in 618 patients with ARF in intensive care units using three distinct analytic approaches. The predictive power of models using information obtained on the day of ARF diagnosis was extremely low. At the time of consultation, advanced age, oliguria, hepatic failure, respiratory failure, sepsis, and thrombocytopenia were associated with mortality. Upon initiation of dialysis for ARF, advanced age, hepatic failure, respiratory failure, sepsis, and thrombocytopenia were associated with mortality; higher blood urea nitrogen and lower serum creatinine were also associated with mortality in logistic regression models. Models incorporating time-varying covariates enhanced predictive power by reducing misclassification and incorporating day-to-day changes in extra-renal organ system failure and the provision of dialysis during the course of ARF. Using data from the PICARD multi-center cohort study of ARF in critically ill patients, we developed several predictive models for prognostic stratification and risk-adjustment. By incorporating exposures over time, the discriminatory power of predictive models in ARF can be significantly improved.

APACHE↗
PubMed2006

The male neck of femur.

Fractured neck of femur in elderly is associated with mortality which is reported in literature to vary between 20 and 40%. One of the factors which is suggested to be a risk factor is male sex. We reviewed 83 male necks of femur patients admitted over a period of a year to assess the patient's physical status, influence of co-morbidities, postoperative course and mortality. The in-hospital mortality was 26.5% and 1-year mortality was 44.6%. The in-hospital mortality for female neck of femur patients during the same period was 18%. Increasing age, high ASA category and post-operative chest infections were associated with high peri-operative mortality, and fall sustained in an acute hospital ward was associated with high 1-year mortality in addition to ASA grade and chest infection. Patients who had a chest infection in the post-operative period had in-hospital mortality of 46.2% (P value 0.006) and a 1-year mortality of 73.1% (P value 0.001). Patients who fell in the ward as inpatients under geriatric care had 60% mortality.

Accidental Falls↗
PubMed2005

Cardiac structural and functional abnormalities in end stage renal disease patients with elevated cardiac troponin T.

OBJECTIVES: To identify in a prospective observational study the cardiac structural and functional abnormalities and mortality in patients with end stage renal disease (ESRD) with a raised cardiac troponin T (cTnT) concentration. METHODS: 126 renal transplant candidates were studied over a two year period. Clinical, biochemical, echocardiographic, coronary angiographic, and dobutamine stress echocardiographic (DSE) data were examined in comparison with cTnT concentrations dichotomised at cut off concentrations of < 0.04 microg/l and < 0.10 microg/l. RESULTS: Left ventricular (LV) size and filling pressure were significantly raised and LV systolic and diastolic function parameters significantly impaired in patients with raised cTnT, irrespective of the cut off concentration. The proportions of patients with diabetes and on dialysis were higher in both groups with raised cTnT. With a cut off cTnT concentration of 0.04 microg/l but not 0.10 microg/l, significantly more patients had severe coronary artery disease and a positive DSE result. The total ischaemic burden during DSE was similar in cTnT positive and negative patients, irrespective of the cut off concentration used. LV end systolic diameter index and E:Ea ratio were independent predictors of cTnT rises > or = 0.04 microg/l and > or = 0.10 microg/l, respectively. Diabetes was independently associated with cTnT at both cut off concentrations. Mortality was higher in all patients with raised cTnT. CONCLUSIONS: Patients with ESRD with raised cTnT concentrations have increased mortality. Raised concentrations are strongly associated with diabetes, LV dilatation, and impaired LV systolic and diastolic function, but not with severe coronary artery disease.

Cardiomyopathy, Dilated↗
PubMed2005

Mucosal expression of cyclooxygenase isoforms 1 and 2 is increased with worsening damage to the gastric mucosa.

AIMS: To test the hypothesis that both COX-1 and COX-2 expression in human gastric mucosa is up-regulated in the presence of inflammation as seen in patients with gastritis and gastric ulcers. METHODS AND RESULTS: We performed immunohistochemistry using COX-1 and COX-2 monoclonal antibodies on gastric biopsies from 59 patients with normal mucosa, gastritis and gastric ulcers. Expression of COX-1 and COX-2 was quantified using an intensity proportion scoring system. Expression of COX-1 was primarily seen in the lamina propria mononuclear cells with some expression in deep gastric glands in the ulcer group. Expression of COX-2 was primarily seen in the deep gastric glands with focal expression in the lamina propria mononuclear cells. We found a stepwise increase in the expression of both COX-1 and COX-2 as mucosal damage progressed from normal to gastritis to gastric ulcer. CONCLUSIONS: We conclude that both COX-1 and COX-2 expression in the gastric mucosa are increased in the setting of gastritis and gastric ulceration. Although this increased expression may be due, at least in part, to an increase in inflammatory cell numbers, this study raises the possibility that both COX-1 and COX-2 are inducible, contrary to the traditionally held view of only COX-2 being inducible.

Aged↗
PubMed2005

Prognostic value of the Framingham cardiovascular risk equation and the UKPDS risk engine for coronary heart disease in newly diagnosed Type 2 diabetes: results from a United Kingdom study.

AIMS: To determine the prognostic value of the Framingham equation and the United Kingdom Prospective Diabetes Study (UKPDS) risk engine in patients with newly diagnosed Type 2 diabetes. METHODS: A community-based cohort (n=428; aged 30-74 years) free of clinically evident CVD and newly diagnosed with Type 2 diabetes were studied over a median 4.2 (sd+/-0.62) years. Predicted (using baseline variables at diagnosis) and observed proportions of primary CVD and CHD events were compared using the Framingham equations and the UKPDS risk engine (only CHD events). The discrimination (c-statistic) and calibration (HLchi2) of the risk equations were calculated. The sensitivity and specificity of the Framingham equation at a 15%, 10-year CHD risk threshold (NICE guidelines) was compared with that of the ADA lipid threshold (LDLc>or=2.6 mmol/l or triglycerides>or=4.5 mmol/l). RESULTS: The Framingham equations underestimated the overall number of cardiovascular events by 33% and coronary events by 32% and showed modest discrimination and poor calibration for CVD [c=0.673; HLchi2=32.8 (P<0.001)] and CHD risk [c=0.657; HLchi2=19.8 (P=0.011)]. Although the overall underestimate was lower and non-significant with the UKPDS risk engine for CHD (13%), its performance in terms of discrimination and calibration were similar [c=0.670; HLchi2=17.1 (P=0.029)]. The 15%, 10-year CHD risk threshold with both the Framingham and UKPDS risk engines had similar sensitivity for primary CVD as the lipid level threshold [85.7 and 89.8% vs. 93.9% (P=0.21 and 0.34)] and both had greater specificity [33.0 and 30.3% vs. 12.1% (P<0.001 and P<0.001)]. CONCLUSIONS: In people with newly diagnosed Type 2 diabetes, both the Framingham equation and UKPDS risk engine are moderately effective at identifying those at high-risk (discrimination) and are poor at quantifying risk (calibration). Nonetheless, at a population level, a 15% 10-year CHD risk threshold using either risk calculator has similar sensitivity as an approach based on a single lipid risk factor level and may have benefits in terms of cost-effectiveness given the improved specificity.

Adult↗
PubMed2004

Dash and Boston questionnaire assessment of carpal tunnel syndrome outcome: what is the responsiveness of an outcome questionnaire?

This prospective study evaluates if the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire is an adequately responsive outcome measure in carpal tunnel syndrome by comparing it with the disease-specific Boston questionnaire (BQ). To measure responsiveness (sensitivity to clinical change), 57 patients with a clinical diagnosis of carpal tunnel syndrome completed the DASH and BQ preoperatively and again 3 months after open carpal tunnel decompression. A second group of 31 patients completed the questionnaires in the outpatient clinic and again 2 weeks later to assess test-retest reliability. The time to complete all questionnaires was recorded. Responsiveness of the DASH is comparable with the BQ with standardized response means of 0.66, 1.07 and 0.62 for the DASH, BQ-symptoms and BQ-function, respectively. Test-retest data show both questionnaires are reliable. Mean times to complete questionnaires were 6.8minutes (DASH) and 5.6minutes (BQ). This study concludes that the DASH questionnaire is a reliable, responsive and practical outcome instrument in carpal tunnel syndrome.

Age Factors↗
PubMed2004

Effect of video display on the grading of diabetic retinopathy.

PURPOSE: Digital images are increasingly being used in ophthalmology. These may be viewed either on thin-film transistor (TFT) or on cathode-ray tube (CRT) displays. However, there is little data showing which is superior. In this study, we compared the performance of CRT and TFT displays for grading of both compressed and uncompressed images of diabetic retinopathy. METHODS: A total of 49 35 mm transparencies of diabetic retinopathy were scanned and compressed. The images comprised 17 with no retinopathy, eight with background, five with preproliferative, and 19 with proliferative retinopathy. Four levels of compression were used: 0, 70, 80, and 90%. A total of 196 randomised images were presented to two masked graders using both TFT and CRT displays under uniform lighting conditions, 2 months apart. The grade of retinopathy was assessed. Statistical analysis of grading accuracy was performed using receiver operator characteristic curves of sensitivity and specificity and the Stuart-Maxwell test for paired, nonparametric data. RESULTS: Both displays showed high sensitivity and specificity for the detection of any retinopathy. For the specific grade of retinopathy, the CRT performed slightly better with a sensitivity of 0.80 for uncompressed images, compared with 0.75 using the TFT. Compression reduced these sensitivities to 0.73 on the CRT and 0.63 on the TFT. Grading of uncompressed images magnified to four times their original size was more accurate on the TFT. CONCLUSIONS: Grading on both displays met sensitivity and specificity criteria proposed by Diabetes UK (formerly British Diabetic Association) for screening of diabetic retinopathy. The CRT generally performed slightly better than the TFT in relation to the detection of the specific grade of retinopathy.

Computer Peripherals↗
PubMed2004

Endobronchial ultrasound to assess airway wall thickening: validation in vitro and in vivo.

Endobronchial ultrasound (EBUS) allows identification of airway wall structures and could potentially be utilised for in vivo studies of airway thickening in asthma. The present study investigated whether inflation of the fluid-filled balloon sheath over the transducer (necessary to provide sonic coupling with the airway wall) influenced in vitro measurements. In vivo comparability of EBUS with high resolution computed tomography scanning (HRCT), an established method for measuring wall thickness, was determined in control subjects. The airway diameter and wall thickness were studied using EBUS in 24 cartilaginous airways obtained from four sheep, before and after balloon sheath inflation during immersion in saline. To assess EBUS versus HRCT comparability of airway measures in vivo, 12 control subjects underwent imaging of the posterior basal bronchus of the right lower lobe by both techniques. Intra- and interobserver agreement were also assessed. Results with and without the balloon sheath gave comparable measures of airway internal diameter and wall thickness in vitro. Statistical analysis showed agreement between EBUS and HRCT, and intra- and interobserver variability in vivo. The current study concludes that endobronchial ultrasound, which does not present a radiation risk, could be utilised in the in vivo study of cartilaginous airway wall remodelling in respiratory diseases, such as asthma.

Adult↗
PubMed2001

Assessing fluid change in hemodialysis: whole body versus sum of segmental bioimpedance spectroscopy.

BACKGROUND: Accurate estimation of extracellular fluid (ECF) is an important factor in assessing dry weight in hemodialysis patients. Bioimpedance spectroscopy (BIS) is a simple method to determine the compartmental distribution of body water in HD patients. Recent studies have shown that sum of segmental BIS (SBIS) is less affected by the change of body position and may be more accurate in measuring ECF change than whole body BIS (WBIS). We have compared SBIS and WBIS in estimating change in fluid volume during hemodialysis. METHODS: Twenty-eight patients (male 10, female 18) were studied during their regular hemodialysis. ECF changes estimated by both techniques were compared with actual weight change during the inter- and intradialytic periods. RESULTS: Both techniques tracked fluid changes that correlated well with fluid loss during the dialysis run (WBIS, r = 0.75, P < 0.001; SBIS, r = 0.65, P < 0.001) and fluid gain in the interdialytic period (WBIS, r = 0.73, P < 0.01; SBIS, r = 0.6, P < 0.01). ECF changes estimated by SBIS and WBIS underestimated weight loss 0.78 +/- 0.01 L and 0.6 +/- 0.01 L, respectively; and underestimated weight gain 0.66 +/- 0.18 L and 0.76 +/- 0.18 L, respectively. CONCLUSIONS: While both WBIS and SBIS can be used to track relative ECF volume changes in HD patients, they are not accurate in quantifying changes in ECF volume. More studies are needed to evaluate the benefit of SBIS over WBIS in clinical practice.

Adult↗
PubMed2001

A randomized clinical trial of continuous versus intermittent dialysis for acute renal failure.

BACKGROUND: Acute renal failure (ARF) requiring dialysis in critically ill patients is associated with an in-hospital mortality rate of 50 to 80%. The worldwide standard for renal replacement therapy is intermittent hemodialysis (IHD). Continuous hemodialysis and hemofiltration techniques have recently emerged as alternative modalities. These two therapies have not been directly compared. METHODS: A multicenter, randomized, controlled trial was conducted comparing two dialysis modalities (IHD vs. continuous hemodiafiltration) for the treatment of ARF in the intensive care unit (ICU). One hundred sixty-six patients were randomized. Principal outcome measures were ICU and hospital mortality, length of stay, and recovery of renal function. RESULTS: Using intention-to-treat analysis, the overall ICU and in-hospital mortalities were 50.6 and 56.6%, respectively. Continuous therapy was associated with an increase in ICU (59.5 vs. 41.5%, P < 0.02) and in-hospital (65.5 vs. 47.6%, P < 0.02) mortality relative to intermittent dialysis. Median ICU length of stay from the time of nephrology consultation was 16.5 days, and complete recovery of renal function was observed in 34.9% of patients, with no significant group differences. Despite randomization, there were significant differences between the groups in several covariates independently associated with mortality, including gender, hepatic failure, APACHE II and III scores, and the number of failed organ systems, in each instance biased in favor of the intermittent dialysis group. Using logistic regression to adjust for the imbalances in group assignment, the odds of death associated with continuous therapy was 1.3 (95% CI, 0.6 to 2.7, P = NS). A detailed investigation of the randomization process failed to explain the marked differences in patient assignment. CONCLUSIONS: A randomized controlled trial of alternative dialysis modalities in ARF is feasible. Despite the potential advantages of continuous techniques, this study provides no evidence of a survival benefit of continuous hemodiafiltration compared with IHD. This study did not control for other major clinical decisions or other supportive management strategies that are widely variable (for example, nutrition support, hemodynamic support, timing of initiation, and dose of dialysis) and might materially influence outcomes in ARF. Standardization of several aspects of care or extremely large sample sizes will be required to answer optimally the questions originally posed by this investigation.

Acute Kidney Injury↗
PubMed2001

What do American nephologists think about dialysis modality selection? .

In the United States, 87.3% of the patients with end-stage renal disease (ESRD) requiring dialysis are treated with hemodialysis (HD) and 12.7% with peritoneal dialysis (PD). This represents a greater use of HD than in many other nations. We mailed a survey questionnaire to members of the National Kidney Foundation Council on Dialysis to better understand the attitudes of American nephrologists toward dialysis modality decisions. We received responses from 240 of 507 nephrologists (47.3%). The respondents were heavily involved in clinical dialysis work. Results showed that decisions regarding modality selection were strongly based on patient preference (4.54 on a scale of 1 to 5), quality of life (4.18), morbidity (4.02), and mortality (3.90), whereas the least important factors reported were facility reimbursement (2.09) and physician reimbursement (1.98). When asked about the current use of modalities, hospital-based HD and full-care HD were believed to be overused (2.63 for each on a scale of 1 [vastly overused] to 5 [vastly underused]), whereas home HD (4.29), continuous ambulatory PD (3.71), and cycler PD (3.59) were underused. A hypothetical question about optimal modality distribution to maximize survival or cost-effectiveness showed that HD should constitute 71% or 66% of dialysis (with 11% or 14% in the form of home HD, respectively). PD use would increase between two- and threefold over current practices. Our results suggest that American nephrologists believe home therapies are underused. Because modality distribution is an important determinant of costs and possibly outcomes in patients with ESRD, there is an urgent need for further research in this area.

Cost-Benefit Analysis↗
PubMed2001

Clinical benefit and approach of ultrafiltration in acute heart failure.

Because of the increasing incidence of acute heart failure admissions to critical care units, nephrologists have been asked to become more involved in the management of these patients. Renal dysfunction is a major element in impeding clinical recovery. In acute heart failure, renal function is often abnormal. The judicious application of ultrafiltration techniques may represent an efficacious adjunct to present conventional practice. In patients with refractory congestive heart failure, the ability to provide continuous, daily, large volume removal not only improves volume status but also the clinical symptoms of the decompensated patient. A thorough literature review supports the premise that starting hemofiltration is an appropriate alternative for difficult and unstable cardiac patients. An optimal strategy utilizing continuous renal replacement therapy can dramatically improve the patient's clinical condition, mitigate the neurohumoral stimulation, increase urinary output and promote absorption of excessive extravascular fluid.

Aged↗
PubMed2001

Fluid management in CRRT.

Fluid management with CRRT requires an understanding of the principles of fluid removal and fluid balance. Although these appear to be similar to intermittent hemodialysis, there are significant differences. In order to utilize these techniques to their full ability, a variety of strategies can be used. No matter which method is used it is imperative that the goals for fluid management be well defined and monitoring for errors be a part of the protocol.

Fluid Therapy↗
PubMed1999

Current status of renal replacement therapy for acute renal failure. A survey of US nephrologists. The National Kidney Foundation Council on Dialysis.

Although the management of acute renal failure (ARF) constitutes a major component of the activities of practicing nephrologists, minimal information is available on the dialysis techniques utilized to treat ARF in the USA. It is evident from several recent publications that there are wide variations in the dialytic and nondialytic management of ARF. In order to obtain a better understanding of the current practice for dialytic management of ARF, the National Kidney Foundation (NKF) Council on Dialysis commissioned a survey of NKF members. This article describes the results of this survey and provides a snapshot of the current management practices for ARF. It is our hope that this information will provide a baseline for further research in this area.

Acute Kidney Injury↗