Search PubMed⌕ Search

Biomedical subjects

Amit X Garg

Publications and source records attributed to Amit X Garg.

At least 37 records · Page 2Linked to original sources
PubMed2005

The International Quotidian Dialysis Registry: annual report 2005.

The International Quotidian Dialysis Registry was designed to collect data describing treatments, characteristics, and outcomes of patients treated with quotidian hemodialysis (HD) worldwide. In July 2004, North American centers were first invited to enroll patients. By March 1, 2005, a total of 70 nocturnal and 8 short-daily HD patients from three Canadian and two US centers were enrolled. As recruitment continues, projected enrollment for 2005 may exceed 200 patients from North America alone. Preliminary analyses indicate that the current registry cohort is younger (mean age, 49.5 +/- 1.6 years) and carries a lower burden of comorbidity than the overall North American HD population. The low event rate expected in this cohort underlines the need for a large sample size if an appropriately powered survival study is to be undertaken. Increasing recruitment in the United States by including HD centers owned or managed by large dialysis organizations, and beginning overseas collaborations to include Australia, New Zealand, Europe, and South America will be the primary areas of focus for 2005.

Adolescent↗
PubMed2005

Microalbuminuria three years after recovery from Escherichia coli O157 hemolytic uremic syndrome due to municipal water contamination.

BACKGROUND: Knowledge of the long-term renal prognosis of diarrhea associated hemolytic uremic syndrome (HUS) is important for patient counseling and follow-up. However, estimates of long-term risk are highly variable, with previous studies not using a healthy control group. METHODS: A municipal water system in the small rural town of Walkerton, Ontario, became contaminated with Escherichia coli O157:H7 in 2000. A cohort of 19 children who recovered from HUS was randomly age- and sex-matched to 38 children with no symptoms at the time of the outbreak. Both groups had detailed renal function testing 3 years after the outbreak, including a random urine albumin to creatinine, glomerular filtration rate estimated by Schwartz formula, and automated and manual blood pressure measurements. RESULTS: There were no baseline differences between the groups with respect to age (mean 4.8 years, range 1 to 15), sex, or birth weight (mean 3.4 kg). In follow-up there were no differences between the groups in body surface area (mean 1.0 m(2)), or in the methods by which renal function was assessed. Compared to the group with no symptoms, patients with HUS demonstrated more microalbuminuria [32% vs. 5%, relative risk 4.8 (95% CI 1.1 to 22.0)], a nonsignificant trend toward lower GFR (124 vs. 134 mL/min per 1.73 m(2)), and no difference in blood pressure. CONCLUSION: Children may demonstrate microalbuminuria 3 years after recovering from HUS. Longer follow-up is needed to determine if this finding has clinical relevance and utility.

Albuminuria↗
PubMed2005

Diabetes during diarrhea-associated hemolytic uremic syndrome: a systematic review and meta-analysis.

OBJECTIVE: To quantify the incidence of diabetes during the acute phase of diarrhea-associated hemolytic uremic syndrome (D + HUS) and to identify features associated with its development. RESEARCH DESIGN AND METHODS: A systematic review and meta-analysis of articles assessing diabetes during D + HUS was conducted. Relevant citations were identified from Medline, Embase, and Institute for Scientific Information Citation Index databases. Bibliographies of relevant articles were hand searched. All articles were independently reviewed for inclusion and data abstraction by two authors. RESULTS: Twenty-one studies from six countries were included. Only 2 studies reported a standard definition of diabetes; 14 defined diabetes as hyperglycemia requiring insulin. The incidence of diabetes during the acute phase of D + HUS could be quantified in a subset of 1,139 children from 13 studies (1966-1998, age 0.2-16 years) and ranged from 0 to 15%, with a pooled incidence of 3.2% (95% CI 1.3-5.1, random-effects model, significant heterogeneity among studies, P = 0.007). Children who developed diabetes were more likely to have severe disease (e.g., presence of coma or seizures, need for dialysis) and had higher mortality than those without diabetes. Twenty-three percent of those who developed diabetes acutely died, and 38% of survivors required long-term insulin (median follow-up 12 months). Recurrence of diabetes was possible up to 60 months after initial recovery. CONCLUSIONS: Children with D + HUS should be observed for diabetes during their acute illness. Consideration should be given to long-term screening of D + HUS survivors for diabetes.

Acute Disease↗
PubMed2004

Midodrine appears to be safe and effective for dialysis-induced hypotension: a systematic review.

BACKGROUND: Dialysis-induced hypotension is an important complication of haemodialysis. Midodrine is an oral alpha-1 agonist that has been used in several small studies to prevent intradialytic hypotension (IDH). METHODS: The authors searched MEDLINE, EMBASE, ASN conference proceedings, and references of potentially relevant articles, and contacted industry (Shire Pharmaceuticals) for unpublished data. Observational studies, randomized controlled trials, crossover studies and pre- and post-intervention design studies with >/=5 haemodialysis patients were included. Study outcomes assessed were: hypotensive symptoms, changes in systolic and/or diastolic blood pressure, dry weight and length of stay after treatment. Data were abstracted on: study design, patient characteristics, intradialytic changes in blood pressure, nadir blood pressure and symptom improvement with midodrine. Thirty-seven full text articles were retrieved and nine met the selection criteria, in addition to one unpublished study. Midodrine dosing regimens ranged from 2.5 to 10 mg of midodrine given 15-30 min before dialysis. RESULTS: Post-dialysis systolic blood pressure was higher by 12.4 mmHg [95% confidence interval (CI) 7.5-17.7] and diastolic pressure was higher by 7.3 mmHg (95% CI 3.7-10.9) during midodrine treatment vs control. Likewise, the nadir systolic blood pressure was higher by 13.3 mmHg (95% CI 8.6-18.0), with a difference in nadir diastolic pressure of 5.9 mmHg (95% CI 2.7-9.1). Six of 10 studies report improvement in symptoms of IDH, and there were no reported serious adverse events ascribed to midodrine. CONCLUSIONS: This systematic review would suggest that midodrine has a role in the therapy of haemodialysis patients experiencing IDH. This conclusion must be viewed with caution, however, given the quality and sample size of the studies included in this review.

Adrenergic alpha-Agonists↗
PubMed2004

An observational study found that authors of randomized controlled trials frequently use concealment of randomization and blinding, despite the failure to report these methods.

BACKGROUND AND OBJECTIVE: Readers of randomized controlled trials (RCTs) commonly assume that what was not reported did not occur. We undertook an observational study to determine whether concealment of randomization or blinding was used in RCTs that failed to report these bias-reducing strategies. METHODS: We recorded the reporting of concealment of randomization and blinding in 105 RCTs. We subsequently contacted the authors and determined if they had used these methodological safeguards. RESULTS: We successfully obtained data from 98 authors. The authors in the full-text publications of these 98 RCTs failed to report the presence or absence of concealment of randomization in 55%, and the blinding status of participants in 26%, health care providers in 64%, data collectors in 84%, outcome assessors in 83%, and data analysts in 96%. In direct contact, authors frequently reported concealing randomization (96%; 95% confidence interval CI=87-100%), blinding participants (20%; 95% CI=7-41%), blinding health care providers (65%; 95% CI=52-77%), blinding data collectors (65%; 95% CI=53-75%), blinding outcome assessors (79%; 95% CI=69-87%), and blinding data analysts (50%; 95% CI=40-60%), despite not reporting the use of these methodological safeguards in their publications. CONCLUSIONS: Readers should not assume that bias-reducing procedures not reported in an RCT did not occur.

Bias↗
PubMed2004

Estimating the prevalence of renal insufficiency in seniors requiring long-term care.

BACKGROUND: Renal function declines with age, but little is known about the extent of renal insufficiency among the institutionalized elderly. The objective of this study was to estimate the prevalence of low glomerular filtration rate (GFR) in a large sample of elderly adults living in long-term care facilities, and to compare two commonly used methods for estimating GFR. METHODS: A total of 9931 residents aged 65 years and older participated in a retrospective cross-sectional study of 87 long-term care facilities in Ontario. GFR was estimated by the Cockcroft-Gault and Modification of Diet in Renal Disease Study (MDRD) equations. The prevalence of low GFR, using the Cockcroft-Gault equation (<30 mL/min), was compared with the MDRD equation (<30 mL/min/1.73 m2). RESULTS: A total of 17.0% (95% CI 15.6 to 18.5) of men and 14.4% (95% CI 13.6 to 15.3) of women had a serum creatinine concentration above the laboratory reported upper reference limit of normal. The prevalence of both elevated serum creatinine and low GFR were observed to increase with age (P < 0.0001). The Cockcroft-Gault equation produced a consistently lower estimate of GFR than did the MDRD equation, a discrepancy most pronounced in the oldest residents. Among all men, a low GFR was more prevalent using the Cockcroft-Gault (10.3%, 95% CI 9.2 to 11.5) than MDRD (3.5%, 95% CI 2.8 to 4.2) equation, with a similar difference also seen in women (23.3%, 95% CI 22.4 to 24.3 versus 4.0%, 95% CI 3.6 to 4.5, respectively). Of all residents whose Cockcroft-Gault estimated GFR was under 30 mL/min, 14.7% (95% CI 13.2 to 16.3) were found to have GFR greater than 60 mL/min/1.73 m2 according to the MDRD equation. CONCLUSION: Age-associated renal impairment is common among elderly long-term care residents, but there exists a clear discrepancy between the Cockcroft-Gault and MDRD equations in predicting GFR. Consideration should be given to medication dose adjustment, based on a practical estimate of GFR. However clarification is needed about which method, if either, is most valid among the frail elderly. Complex patient and societal issues surrounding advanced care directives, treatments associated with renal insufficiency, and, if and when to initiate dialysis, require further attention.

Aged↗
PubMed2003

Effect of awareness of a randomized controlled trial on use of experimental therapy.

CONTEXT: Use of experimental therapies during but outside of randomized controlled trials (RCTs) has not been studied. OBJECTIVE: To determine whether initiation of an RCT leads to increased use of the experimental therapy outside the trial. DESIGN AND SETTING: Data on national apheresis use during 3 Canadian RCTs for multiple sclerosis (1986-1988), thrombotic thrombocytopenic purpura (1982-1988), and myeloma cast nephropathy (1998-2000) were obtained from 19 major medical centers in Canada. The multiple sclerosis and myeloma cast nephropathy trials had data on apheresis use for 3 years prior to and during the trials, which permitted a time-series analysis to determine the impact of the RCTs on the use of apheresis. The ongoing myeloma cast nephropathy trial provided data on the number of patients inside and outside of the RCTs in trial and nontrial centers. Initial and follow-up questionnaires were sent to 24 Canadian physicians in trial and nontrial centers to determine if they had noted an increase in apheresis activity during the trials and, if so, their explanation for it. MAIN OUTCOME MEASURE: Change in number of patients undergoing apheresis for thrombotic thrombocytopenic purpura, multiple sclerosis, and myeloma cast nephropathy prior to and during the respective RCTs compared with all patients undergoing apheresis during the same periods. RESULTS: During all 3 RCTs, there were large increases in use of apheresis. The majority of the increased use of apheresis was outside of the trials: for multiple sclerosis, 30 of 49 patients per year (61% of increase); thrombotic thrombocytopenic purpura, 49 of 56 patients per year (72% of increase); and myeloma cast nephropathy, 60 of 72 patients per year (57% of increase). The myeloma cast nephropathy study noted that this increase occurred in both nontrial and trial centers. Among questionnaire respondents (n = 22; 92% response rate), most physicians noted an increase in apheresis activity during the trials and attributed it to a "jumping-the-gun" phenomenon. CONCLUSIONS: During 3 Canadian RCTs, apheresis increased, but most of the increase occurred outside the trials. This behavior during an RCT, in the absence of clear efficacy, can be termed jumping the gun.

Blood Component Removal↗
PubMed2003

Long-term renal prognosis of diarrhea-associated hemolytic uremic syndrome: a systematic review, meta-analysis, and meta-regression.

CONTEXT: The long-term renal prognosis of patients with diarrhea-associated hemolytic uremic syndrome (HUS) remains controversial. OBJECTIVES: To quantify the long-term renal prognosis of patients with diarrhea-associated HUS and to identify reasons for different estimates provided in the literature. DATA SOURCES: We searched MEDLINE and Experta Medica (EMBASE) bibliographic databases and conference proceedings, and we contacted experts until February 2003. We also searched the Institute for Scientific Information index and reference lists of all studies that fulfilled our eligibility criteria. The search strategy included the terms hemolytic-uremic syndrome, purpura, thrombotic thrombocytopenic, Escherichia coli O157, longitudinal studies, kidney diseases, hypertension, and proteinuria STUDY SELECTION: Any study that followed up 10 or more patients with primary diarrhea-associated HUS for at least 1 year for renal sequelae. DATA EXTRACTION: Two authors independently abstracted data on study and patient characteristics, renal measures, outcomes, and prognostic features. Disagreements were resolved by a third author or by consensus. DATA SYNTHESIS: Forty-nine studies of 3476 patients with a mean follow-up of 4.4 years (range, 1-22 years at last follow-up) from 18 countries, 1950 to 2001, were summarized. At the time of recruitment, patients were aged 1 month to 18 years. In the different studies, death or permanent end-stage renal disease (ESRD) ranged from 0% to 30%, with a pooled incidence of 12% (95% confidence interval [CI], 10%-15%). A glomerular filtration rate lower than 80 mL/min per 1.73 m2, hypertension, or proteinuria was extremely variable and ranged from 0% to 64%, with a pooled incidence of 25% (95% CI, 20%-30%). A higher severity of acute illness was strongly associated with worse long-term prognosis. Studies with a higher proportion of patients with central nervous system symptoms (coma, seizures, or stroke) had a higher proportion of patients who died or developed permanent ESRD at follow-up (explaining 44% of the between-study variability, P =.01). Studies with a greater proportion of patients lost to follow-up also described a worse prognosis (P =.001) because these patients were typically healthier than those followed up. One or more years after diarrhea-associated HUS, patients with a predicted creatinine clearance higher than 80 mL/min per 1.73 m2, no overt proteinuria, and no hypertension appeared to have an excellent prognosis. CONCLUSIONS: Death or ESRD occurs in about 12% of patients with diarrhea-associated HUS, and 25% of survivors demonstrate long-term renal sequelae. Patients lost to follow-up contribute to worse estimates in some studies. The severity of acute illness, particularly central nervous system symptoms and the need for initial dialysis, is strongly associated with a worse long-term prognosis.

Diarrhea↗
PubMed2002

Interventions to enhance patient adherence to medication prescriptions: scientific review.

CONTEXT: Low adherence with prescribed treatments is ubiquitous and undermines treatment benefits. OBJECTIVE: To systematically review published randomized controlled trials (RCTs) of interventions to assist patients' adherence to prescribed medications. DATA SOURCES: A search of MEDLINE, CINAHL, PSYCHLIT, SOCIOFILE, IPA, EMBASE, The Cochrane Library databases, and bibliographies was performed for records from 1967 through August 2001 to identify relevant articles of all RCTs of interventions intended to improve adherence to self-administered medications. STUDY SELECTION AND DATA EXTRACTION: Studies were included if they reported an unconfounded RCT of an intervention to improve adherence with prescribed medications for a medical or psychiatric disorder; both adherence and treatment outcome were measured; follow-up of at least 80% of each study group was reported; and the duration of follow-up for studies with positive initial findings was at least 6 months. Information on study design features, interventions, controls, and findings (adherence rates and patient outcomes) were extracted for each article. DATA SYNTHESIS: Studies were too disparate to warrant meta-analysis. Forty-nine percent of the interventions tested (19 of 39 in 33 studies) were associated with statistically significant increases in medication adherence and only 17 reported statistically significant improvements in treatment outcomes. Almost all the interventions that were effective for long-term care were complex, including combinations of more convenient care, information, counseling, reminders, self-monitoring, reinforcement, family therapy, and other forms of additional supervision or attention. Even the most effective interventions had modest effects. CONCLUSIONS: Current methods of improving medication adherence for chronic health problems are mostly complex, labor-intensive, and not predictably effective. The full benefits of medications cannot be realized at currently achievable levels of adherence; therefore, more studies of innovative approaches to assist patients to follow prescriptions for medications are needed.

Acute Disease↗
PubMed2002

Helping patients follow prescribed treatment: clinical applications.

Low adherence to prescribed medical regimens is a ubiquitous problem. Typical adherence rates are about 50% for medications and are much lower for lifestyle prescriptions and other more behaviorally demanding regimens. In addition, many patients with medical problems do not seek care or drop out of care prematurely. Although accurate measures of low adherence are lacking for many regimens, simple measures, such as directly asking patients and watching for appointment nonattendance and treatment nonresponse, will detect most problems. For short-term regimens (< or =2 weeks), adherence to medications is readily achieved by giving clear instructions. On the other hand, improving adherence to long-term regimens requires combinations of information about the regimen, counseling about the importance of adherence and how to organize medication taking, reminders about appointments and adherence, rewards and recognition for the patient's efforts to follow the regimen, and enlisting social support from family and friends. Successful interventions for long-term regimens are all labor-intensive but ultimately can be cost-effective.

Diabetes Mellitus, Type 2↗
PubMed2002

Comparison of mortality between private for-profit and private not-for-profit hemodialysis centers: a systematic review and meta-analysis.

CONTEXT: Private for-profit and private not-for-profit dialysis facilities provide the majority of hemodialysis care in the United States. There has been extensive debate about whether the profit status of these facilities influences patient mortality. OBJECTIVE: To determine whether a difference in adjusted mortality rates exists between hemodialysis patients receiving care in private for-profit vs private not-for-profit dialysis centers. DATA SOURCES: We searched 11 bibliographic databases, reviewed our own files, and contacted experts in June 2001-January 2002. In June 2002, we also searched PubMed using the "related articles" feature, SciSearch, and the reference lists of all studies that fulfilled our eligibility criteria. STUDY SELECTION: We included published and unpublished observational studies that directly compared the mortality rates of hemodialysis patients in private for-profit and private not-for-profit dialysis centers and provided adjusted mortality rates. We masked the study results prior to determining study eligibility, and teams of 2 reviewers independently evaluated the eligibility of all studies. Eight observational studies that included more than 500 000 patient-years of data fulfilled our eligibility criteria. DATA EXTRACTION: Teams of 2 reviewers independently abstracted data on study characteristics, sampling method, data sources, and factors controlled for in the analyses. Reviewers resolved disagreements by consensus. DATA SYNTHESIS: The studies reported data from January 1, 1973, through December 31, 1997, and included a median of 1342 facilities per study. Six of the 8 studies showed a statistically significant increase in adjusted mortality in for-profit facilities, 1 showed a nonsignificant trend toward increased mortality in for-profit facilities, and 1 showed a nonsignificant trend toward decreased mortality in for-profit facilities. The pooled estimate, using a random-effects model, demonstrated that private for-profit dialysis centers were associated with an increased risk of death (relative risk, 1.08; 95% confidence interval, 1.04-1.13; P<.001). This relative risk suggests that there are annually 2500 (with a plausible range of 1200-4000) excessive premature deaths in US for-profit dialysis centers. CONCLUSIONS: Hemodialysis care in private not-for-profit centers is associated with a lower risk of mortality compared with care in private for-profit centers.

Health Services Research↗
PubMed2002

Moderate renal insufficiency and the risk of cardiovascular mortality: results from the NHANES I.

BACKGROUND: Conflicting evidence exists concerning whether renal insufficiency is an independent risk factor for cardiovascular disease in the general population. The objective of this study was to determine whether moderate renal insufficiency was associated with total and cardiovascular mortality, independent of traditional cardiovascular risk factors, in a community sample representative of the U.S. general non-institutionalized population. METHODS: Participants in the U.S. First National Health and Nutrition Examination Survey (NHANES I, 1974-1975) and NHANES I Epidemiologic Follow-up Study (NHEFS, 1992, 18 year follow-up) were evaluated. The primary analysis was limited to 2352 adults with complete data, and no baseline cardiovascular disease. A creatinine of 104 to 146 micromol/L in women, and 122 to 177 micromol/L in men (approximate glomerular filtration rate of 30 to 60 mL/min/1.73 m2) was defined as moderate renal insufficiency. Supplementary analyses included participants with marked renal impairment and baseline cardiovascular disease. RESULTS: The unadjusted hazard ratio for moderate renal insufficiency compared to preserved renal function was significant for total mortality (hazard ratio 1.7; 95% confidence interval 1.3 to 2.2), and for cardiovascular mortality (2.2; 1.5 to 3.1). After adjustment for traditional cardiovascular risk factors, there was no independent association between moderate renal insufficiency and total mortality (1.0; 0.8 to 1.4), or cardiovascular mortality (1.2; 0.8 to 1.8). These results were consistent in supplementary analyses. CONCLUSIONS: These results do not support moderate renal insufficiency as an independent risk factor for cardiovascular disease in the general population. The association between moderate renal insufficiency and cardiovascular disease, demonstrated in other epidemiologic studies, appears to be due to co-occurrence of renal insufficiency with traditional cardiovascular risk factors.

Adult↗
PubMed2002

Albuminuria and renal insufficiency prevalence guides population screening: results from the NHANES III.

BACKGROUND: A number of screening criteria, applied either at a single point in time or serially, can be used for the purpose of identifying individuals at risk of end-stage renal disease (ESRD). This study focused on two such criteria measured on a single occasion, proteinuria and renal insufficiency, and examined their prevalence in a sample representative of the adult U.S. non-institutionalized population. Such knowledge guides the utility of population screening to prevent ESRD. METHODS: The prevalence of albuminuria (microalbuminuria and macroalbuminuria from a random urine albumin-to-creatinine ratio) and renal insufficiency [glomerular filtration rate (GFR) estimated from serum creatinine] was determined in different age categories in various adult screening groups in the cross-sectional Third National Health and Nutrition Examination Survey (NHANES III). RESULTS: A total of 14,622 adult participants were included in the analysis. In the general population, 8.3% and 1.0% of participants demonstrated microalbuminuria and macroalbuminuria, respectively. To identify one case of albuminuria, one would need to screen three persons with diabetes mellitus, seven non-diabetic hypertensive persons, or six persons over the age of 60. When albuminuria and renal insufficiency were considered together, it was clear that these tests were identifying different segments of the population; 37% of participants with a GFR less than 30 mL/min/1.73 m2 demonstrated no albuminuria. Non-albuminuric renal insufficiency was most evident in the ages of 60 to 79; 34% of diabetics, and 63% of non-diabetic hypertensives with a GFR less than 30 mL/min/1.73 m2 demonstrated no albuminuria. CONCLUSIONS: Albuminuria is prevalent, and when considered together, screening tests of albuminuria and renal insufficiency measured on a single occasion identify different segments of the population. The prevalence of albuminuria and renal insufficiency in populations of interest should be considered, as this knowledge has implications for the effectiveness of screening.

Adult↗
PubMed2002

Prevalence of low glomerular filtration rate in nondiabetic Americans: Third National Health and Nutrition Examination Survey (NHANES III).

End-stage renal disease is an important and costly health problem. Strategies for its prevention are urgently needed. Knowledge of the population-based prevalence of renal insufficiency in nondiabetic adults would inform such strategies. Black and white nondiabetic adult participants in the Third National Health and Nutrition Examination Survey were analyzed. The analysis was stratified by age, gender, and race, and four clinically applicable methods were used to assess renal function. There were 13,251 complete records for analysis. By the Modification of Diet in Renal Diseases (MDRD) GFR (GFR) prediction Equation 7, 58% (95% confidence interval [CI], 56 to 60%) of the total adult nondiabetic black and white US population had MDRD GFR below 80 ml/min per 1.73m(2), 13% (95% CI, 11 to 14%) below 60 ml/min per 1.73m(2), and 0.26% (95% CI, 0.19 to 0.33%) below 30 ml/min per 1.73m(2). By the Cockcroft-Gault formula, the equivalent figures were 39% (95% CI, 37 to 41%), 14% (95% CI, 12% - 16%), and 0.81% (95% CI, 0.46 to 1.2%), respectively. The findings of an unexpectedly high prevalence of low clearance and the increased prevalence of low clearance with age were consistent across the four clearance estimation methods used and for each race-sex stratum. The absolute magnitude of the prevalence of low clearance was, however, dependent on the clearance method used. Assessed by estimation from serum creatinine, low clearance may be very common, particularly with advancing age. The prognosis (in terms of risk for progression and end-stage renal disease) of low clearance in unreferred populations may differ from that in referred populations and requires further study.

Adult↗