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Featured researches published by Joel Singer.


The New England Journal of Medicine | 1985

Aspirin, sulfinpyrazone, or both in unstable angina. Results of a Canadian multicenter trial.

John A. Cairns; Michael Gent; Joel Singer; Keith J. Finnie; Gordon M. Froggatt; Douglas Holder; George Jablonsky; William J. Kostuk; Libardo J. Melendez; Martin G. Myers; David L. Sackett; Brian J. Sealey; Paul H. Tanser

We performed a randomized, double-blind, placebo-controlled trial in 555 patients with unstable angina who were hospitalized in coronary care units. Patients received one of four possible treatment regimens: aspirin (325 mg four times daily), sulfinpyrazone (200 mg four times daily), both, or neither. They were entered into the trial within eight days of hospitalization and were treated and followed for up to two years (mean, 18 months). The incidence of cardiac death and nonfatal myocardial infarction, considered together, was 8.6 per cent in the groups given aspirin and 17.0 per cent in the other groups, representing a risk reduction with aspirin of 51 per cent (P = 0.008). The corresponding figures for either cardiac death alone or death from any cause were 3.0 per cent in the groups given aspirin and 11.7 per cent in the other groups, representing a risk reduction of 71 per cent (P = 0.004). Analysis by intention to treat yielded smaller risk reductions with aspirin of 30 per cent (P = 0.072), 56 per cent (P = 0.009), and 43 per cent (P = 0.035) for the outcomes of cardiac death or nonfatal acute myocardial infarction, cardiac death alone, and all deaths, respectively. There was no observed benefit of sulfinpyrazone for any outcome event, and there was no evidence of an interaction between sulfinpyrazone and aspirin. Considered together with the results of a previous clinical trial, these findings provide strong evidence for a beneficial effect of aspirin in patients with unstable angina.


The New England Journal of Medicine | 2008

Vasopressin versus Norepinephrine Infusion in Patients with Septic Shock

James A. Russell; Keith R. Walley; Joel Singer; Anthony C. Gordon; Paul C. Hébert; D. James Cooper; Cheryl L. Holmes; Sangeeta Mehta; John Granton; Michelle Storms; Deborah J. Cook; Jeffrey J. Presneill; Dieter Ayers

BACKGROUND Vasopressin is commonly used as an adjunct to catecholamines to support blood pressure in refractory septic shock, but its effect on mortality is unknown. We hypothesized that low-dose vasopressin as compared with norepinephrine would decrease mortality among patients with septic shock who were being treated with conventional (catecholamine) vasopressors. METHODS In this multicenter, randomized, double-blind trial, we assigned patients who had septic shock and were receiving a minimum of 5 microg of norepinephrine per minute to receive either low-dose vasopressin (0.01 to 0.03 U per minute) or norepinephrine (5 to 15 microg per minute) in addition to open-label vasopressors. All vasopressor infusions were titrated and tapered according to protocols to maintain a target blood pressure. The primary end point was the mortality rate 28 days after the start of infusions. RESULTS A total of 778 patients underwent randomization, were infused with the study drug (396 patients received vasopressin, and 382 norepinephrine), and were included in the analysis. There was no significant difference between the vasopressin and norepinephrine groups in the 28-day mortality rate (35.4% and 39.3%, respectively; P=0.26) or in 90-day mortality (43.9% and 49.6%, respectively; P=0.11). There were no significant differences in the overall rates of serious adverse events (10.3% and 10.5%, respectively; P=1.00). In the prospectively defined stratum of less severe septic shock, the mortality rate was lower in the vasopressin group than in the norepinephrine group at 28 days (26.5% vs. 35.7%, P=0.05); in the stratum of more severe septic shock, there was no significant difference in 28-day mortality (44.0% and 42.5%, respectively; P=0.76). A test for heterogeneity between these two study strata was not significant (P=0.10). CONCLUSIONS Low-dose vasopressin did not reduce mortality rates as compared with norepinephrine among patients with septic shock who were treated with catecholamine vasopressors. (Current Controlled Trials number, ISRCTN94845869 [controlled-trials.com].).


American Journal of Kidney Diseases | 1999

Left ventricular mass index increase in early renal disease: Impact of decline in hemoglobin

Adeera Levin; Christopher R. Thompson; Jean Ethier; Euan Carlisle; Sheldon W. Tobe; David C. Mendelssohn; Ellen Burgess; Kailash Jindal; Brendan J. Barrett; Joel Singer; Ognjenka Djurdjev

Cardiovascular disease occurs in patients with progressive renal disease both before and after the initiation of dialysis. Left ventricular hypertrophy (LVH) is an independent predictor of morbidity and mortality in dialysis populations and is common in the renal insufficiency population. LVH is associated with numerous modifiable risk factors, but little is known about LV growth (LVG) in mild-to-moderate renal insufficiency. This prospective multicenter Canadian cohort study identifies factors associated with LVG, measured using two-dimensional-targeted M-mode echocardiography. Eight centers enrolled 446 patients, 318 of whom had protocol-mandated clinical, laboratory, and echocardiographic measurements recorded. We report 246 patients with assessable echocardiograms at both baseline and 12 months with an overall prevalence of LVH of 36%. LV mass index (LVMI) increased significantly (>20% of baseline or >20 g/m2) from baseline to 12 months in 25% of the population. Other than baseline LVMI, no differences in baseline variables were noted between patients with and without LVG. However, there were significant differences in decline of Hgb level (-0.854 v -0.108 g/dL; P = 0.0001) and change in systolic blood pressure (+6.50 v -1.09 mm Hg; P = 0.03) between the groups with and without LVG. Multivariate analysis showed the independent contribution of decrease in Hgb level (odds ratio [OR], 1.32 for each 0.5-g/dL decrease; P = 0.004), increase in systolic blood pressure (OR, 1.11 for each 5-mm Hg increase; P = 0.01), and lower baseline LVMI (OR, 0.85 for each 10-g/m2; P = 0.011) in predicting LVG. Thus, after adjusting for baseline LVMI, Hgb level and systolic blood pressure remain independently important predictors of LVG. We defined the important modifiable risk factors. There remains a critical need to establish optimal therapeutic strategies and targets to improve clinical outcomes.


American Journal of Kidney Diseases | 1996

Prevalent left ventricular hypertrophy in the predialysis population: Identifying opportunities for intervention

Adeera Levin; Joel Singer; Christopher R. Thompson; Heather Ross; Mary Lewis

Left ventricular hypertrophy (LVH) is present in over 70% of patients commencing dialysis. It is an independent risk factor for cardiac death, which is the cause of death in approximately 45% of patients in dialysis. The prevalence of LVH in patients earlier in the course of renal insufficiency is unknown. As part of a prospective longitudinal study evaluating the progression of comorbid diseases in patients with progressive renal disease, we evaluated LVH. In 175 consecutive patients attending a renal insufficiency clinic we obtained technically adequate echocardiograms and estimated left ventricular mass index (LVMI) using two-dimensional targeted M-mode echocardiography. We calculated LVMI using the American Society of Echocardiography cube formula method regressed to anatomic validation. The population consisted of 115 men and 60 women ranging in age from 20 to 82 years (mean age, 51.5 years). The mean creatinine was 403 +/- 207 micro mol/L (+/-SD), representing a creatinine clearance (Ccr) of 25.5 +/- 17 mL/min. Left ventricular hypertrophy was defined as LVMI greater than 131 g/m(2) in men and greater than 100 g/m(2) in women, and was present in 38.9% of the population studied. We demonstrate that the prevalence of LVH increased with progressive renal decline: 26.7% of patients with Ccr greater than 50 mL/min had LVH, 30.8% of those with Ccr between 25 and 49 mL/min had LVH, and 45.2% of patients with severe renal impairment (Ccr <25 L/min) had LVH (P = 0.05). The mean LVMI was significantly different among the three groups (97.5 g/m(2) v 114.4 g/m(2), respectively; P < 0.001). Univariate analyses revealed that age, hemoglobin, systolic blood pressure and Ccr were significantly different between the groups with and without LVH. The logistic regression model confirmed the findings of the univariate analysis: an increase in age of 5 years was associated with an increase of 3% in risk of LVH (P = 0.0094), as was an increase in systolic blood pressure of 5 mm Hg (P = 0.0018). For each 10 g/L decrease in hemoglobin, the risk of LVH increased by 6% (P = 0.0062), and for each 5 mL/min decline in Ccr the risk increased by 3% (P = 0.0168). We demonstrate the high prevalence of LVH in patients with renal insufficiency prior to the need for dialysis, which is associated with severity of renal impairment, and identify two modifiable factors (systolic blood pressure and anemia) as important predictors of LVH. We suggest that future studies should focus on interventions aimed at attenuating the impact of these factors.


The New England Journal of Medicine | 1994

The Role of the Plasma from Platelet Concentrates in Transfusion Reactions

Nancy M. Heddle; Luba Klama; Joel Singer; Carl Richards; Paul Fedak; Irwin Walker; John G. Kelton

BACKGROUND Febrile, nonhemolytic transfusion reactions are the most frequent adverse reactions to platelets. A number of observations argue against the widely held view that these reactions result from the interaction between antileukocyte antibodies in the recipient and leukocytes in the platelet product. We sought to determine whether substances in the plasma or the cells in the product cause reactions to transfused platelets. METHODS We separated standard platelet concentrates into their plasma and cellular components and then transfused both portions in random order. Patients were monitored for reactions during all transfusions. Before each transfusion, the concentration of cytokines (interleukin-1 beta and interleukin-6) was measured in the platelet products. Studies were also performed on the platelet products to determine the effect of storage on the concentration of cytokines. RESULTS Sixty-four pairs of platelet-product components (the plasma supernatant and the cells) were administered to 12 patients. There were 20 reactions to the plasma supernatant and 6 reactions to the cells (chi-square = 6.50, P = 0.009). Eight transfusions were associated with reactions to both products. The plasma component was more likely to cause severe reactions than the cells (chi-square = 9.6, P < 0.01). A strong positive correlation was observed between the reactions and the concentration of interleukin-1 beta and interleukin-6 in the plasma supernatant (P < 0.001 and P = 0.034, respectively). In vitro studies demonstrated that interleukin-1 beta and interleukin-6 concentrations rise progressively in stored platelets and that these concentrations are related to the leukocyte count in the platelet product. CONCLUSIONS Bioreactive substances in the plasma supernatant of the platelet product cause most febrile reactions associated with platelet transfusions. Removing the plasma supernatant before transfusion can minimize or prevent these reactions.


The New England Journal of Medicine | 1996

A Comparison of Two Regimens for the Treatment of Mycobacterium avium Complex Bacteremia in AIDS: Rifabutin, Ethambutol, and Clarithromycin versus Rifampin, Ethambutol, Clofazimine, and Ciprofloxacin

Stephen D. Shafran; Joel Singer; Donald P. Zarowny; Peter Phillips; Irving E. Salit; Sharon Walmsley; Ignatius W. Fong; M. John Gill; Anita Rachlis; Richard Lalonde; Mary M. Fanning; Christos M. Tsoukas

BACKGROUND Bacteremia with the Mycobacterium avium complex is common in patients with the acquired immunodeficiency syndrome (AIDS), but the most effective treatment for this infection remains unclear. METHODS We randomly assigned 229 patients with AIDS and M. avium complex bacteremia to receive either rifampin (600 mg daily), ethambutol (approximately 15 mg per kilogram of body weight daily), clofazimine (100 mg daily), and ciprofloxacin (750 mg twice daily) (the four-drug group) or rifabutin (600 mg daily), ethambutol (as above), and clarithromycin (1000 mg twice daily) (the three-drug group). In the three-drug group the dose of rifabutin was reduced by half after 125 patients were randomized, because 24 of 63 patients had uveitis. RESULTS Among 187 patients who could be evaluated, blood cultures became negative more often in the three-drug group than in the four-drug group (69 percent vs. 29 percent, P<0.001). Among patients treated for at least four weeks, the bacteremia resolved more frequently in the three-drug group (78 percent vs. 40 percent, P<0.001). In the three-drug group, bacteremia resolved more often with the 600-mg dose of rifabutin than with the 300-mg dose (P=0.025), but the latter regimen was more effective than the four-drug regimen (P<0.05). The median survival was 8.6 months in the three-drug group and 5.2 months in the four-drug group (P = 0.001). The median Karnofsky performance score was higher in the three-drug group than in the four-drug group from week 2 to week 16 (P<0.05). Mild uveitis developed in 3 of the 53 patients receiving the 300-mg dose of rifabutin, an incidence about one quarter that observed with the 600-mg dose (P<0.001). CONCLUSIONS In patients with AIDS and M. avium complex bacteremia, treatment with the three-drug regimen of rifabutin, ethambutol, and clarithromycin leads to resolution of the bacteremia more frequently and more rapidly than treatment with rifampin, ethambutol, clofazimine, and ciprofloxacin, and survival rates are better.


JAMA | 2013

Immunogenicity of 2 Doses of HPV Vaccine in Younger Adolescents vs 3 Doses in Young Women: A Randomized Clinical Trial

Simon Dobson; Shelly McNeil; Marc Dionne; Meena Dawar; Gina Ogilvie; Mel Krajden; Chantal Sauvageau; David W. Scheifele; Tobias R. Kollmann; Scott A. Halperin; Joanne M. Langley; Julie A. Bettinger; Joel Singer; Deborah M. Money; Dianne Miller; Monika Naus; Fawziah Marra; Eric W. Young

IMPORTANCE Global use of human papillomavirus (HPV) vaccines to prevent cervical cancer is impeded by cost. A 2-dose schedule for girls may be possible. OBJECTIVE To determine whether mean antibody levels to HPV-16 and HPV-18 among girls receiving 2 doses was noninferior to women receiving 3 doses. DESIGN, SETTING, AND PATIENTS Randomized, phase 3, postlicensure, multicenter, age-stratified, noninferiority immunogenicity study of 830 Canadian females from August 2007 through February 2011. Follow-up blood samples were provided by 675 participants (81%). INTERVENTION Girls (9-13 years) were randomized 1:1 to receive 3 doses of quadrivalent HPV vaccine at 0, 2, and 6 months (n = 261) or 2 doses at 0 and 6 months (n = 259). Young women (16-26 years) received 3 doses at 0, 2, and 6 months (n = 310). Antibody levels were measured at 0, 7, 18, 24, and 36 months. MAIN OUTCOMES AND MEASURES Primary outcome was noninferiority (95% CI, lower bound >0.5) of geometric mean titer (GMT) ratios for HPV-16 and HPV-18 for girls (2 doses) compared with young women (3 doses) 1 month after last dose. Secondary outcomes were noninferiority of GMT ratios of girls receiving 2 vs 3 doses of vaccine; and durability of noninferiority to 36 months. RESULTS The GMT ratios were noninferior for girls (2 doses) to women (3 doses): 2.07 (95% CI, 1.62-2.65) for HPV-16 and 1.76 (95% CI, 1.41-2.19) for HPV-18. Girls (3 doses) had GMT responses 1 month after last vaccination for HPV-16 of 7736 milli-Merck units per mL (mMU/mL) (95% CI, 6651-8999) and HPV-18 of 1730 mMU/mL (95% CI, 1512-1980). The GMT ratios were noninferior for girls (2 doses) to girls (3 doses): 0.95 (95% CI, 0.73-1.23) for HPV-16 and 0.68 (95% CI, 0.54-0.85) for HPV-18. The GMT ratios for girls (2 doses) to women (3 doses) remained noninferior for all genotypes to 36 months. Antibody responses in girls were noninferior after 2 doses vs 3 doses for all 4 vaccine genotypes at month 7, but not for HPV-18 by month 24 or HPV-6 by month 36. CONCLUSIONS AND RELEVANCE Among girls who received 2 doses of HPV vaccine 6 months apart, responses to HPV-16 and HPV-18 one month after the last dose were noninferior to those among young women who received 3 doses of the vaccine within 6 months. Because of the loss of noninferiority to some genotypes at 24 to 36 months in girls given 2 doses vs 3 doses, more data on the duration of protection are needed before reduced-dose schedules can be recommended. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00501137.


European Journal of Clinical Microbiology & Infectious Diseases | 1997

Multicenter randomized trial of fluconazole versus amphotericin B for treatment of candidemia in non-neutropenic patients

Peter Phillips; Steve Shafran; Gary Garber; Coleman Rotstein; Fiona Smaill; Ignatius W. Fong; Irving E. Salit; Mark A. Miller; Kurt E. Williams; Conly Jm; Joel Singer; Ioannou S

A randomized trial was conducted to compare the efficacy and safety of fluconazole versus that of amphotericin B in the treatment of candidemia in non-neutropenic adults. Enrollment was stratified by disease severity (APACHE II score). Patients were randomized (1∶:1) to receive amphotericin B 0.6 mg/kg/day (cumulative dose 8 mg/kg) or fluconazole 800 mg intravenous loading dose, then 400 mg daily for four weeks (intravenous for at least 10 days). Patients were monitored for six months. A total of 106 patients were enrolled. A protocol amendment implemented midway through the trial required patients to be removed from the study and treated with amphotericin B if species identification indicated candidemia due toCandida glabrata orCandida krusei. Baseline characteristics were similar for the two groups; 103 patients (fluconazole, 50; amphotericin B, 53) met the major enrollment criteria. The intention-to-treat analysis indicated successful therapy in 50% of fluconazole recipients compared to 58% of the amphotericin B group (p=0.39; one-sided 95% Cl, −8 to 24%). The efficacy analysis included 84 patients (fluconazole, 42; amphotericin B, 42); successful outcomes were observed in 57% and 62% of cases in the fluconazole and amphotericin B groups, respectively (p=0.66: one-sided 95% Cl, −12 to 22%). The mortality at day 14 for the fluconazole group was 26% and for the amphotericin B group 21% (p=0.52; chi-square test) and remained similar throughout the course of follow-up. Drug-related adverse events were more frequent with amphotericin B than with fluconazole and prompted switching of therapy for two (4%) and zero cases, respectively. Fluconazole and amphotericin B were associated with similar clinical response rates and survival in the treatment of candidemia among non-neutropenic patients; however, drug-related adverse events were more frequent with amphotericin B.


The New England Journal of Medicine | 2015

Less-Tight versus Tight Control of Hypertension in Pregnancy

Laura A. Magee; Peter von Dadelszen; Evelyne Rey; Susan Ross; Elizabeth Asztalos; Kellie Murphy; Jennifer Menzies; Johanna Sanchez; Joel Singer; Amiram Gafni; Andrée Gruslin; Michael Helewa; Eileen K. Hutton; Shoo K. Lee; Terry Lee; Alexander G. Logan; Wessel Ganzevoort; Ross Welch; Jim Thornton; Jean Marie Moutquin

BACKGROUND The effects of less-tight versus tight control of hypertension on pregnancy complications are unclear. METHODS We performed an open, international, multicenter trial involving women at 14 weeks 0 days to 33 weeks 6 days of gestation who had nonproteinuric preexisting or gestational hypertension, office diastolic blood pressure of 90 to 105 mm Hg (or 85 to 105 mm Hg if the woman was taking antihypertensive medications), and a live fetus. Women were randomly assigned to less-tight control (target diastolic blood pressure, 100 mm Hg) or tight control (target diastolic blood pressure, 85 mm Hg). The composite primary outcome was pregnancy loss or high-level neonatal care for more than 48 hours during the first 28 postnatal days. The secondary outcome was serious maternal complications occurring up to 6 weeks post partum or until hospital discharge, whichever was later. RESULTS Included in the analysis were 987 women; 74.6% had preexisting hypertension. The primary-outcome rates were similar among 493 women assigned to less-tight control and 488 women assigned to tight control (31.4% and 30.7%, respectively; adjusted odds ratio, 1.02; 95% confidence interval [CI], 0.77 to 1.35), as were the rates of serious maternal complications (3.7% and 2.0%, respectively; adjusted odds ratio, 1.74; 95% CI, 0.79 to 3.84), despite a mean diastolic blood pressure that was higher in the less-tight-control group by 4.6 mm Hg (95% CI, 3.7 to 5.4). Severe hypertension (≥160/110 mm Hg) developed in 40.6% of the women in the less-tight-control group and 27.5% of the women in the tight-control group (P<0.001). CONCLUSIONS We found no significant between-group differences in the risk of pregnancy loss, high-level neonatal care, or overall maternal complications, although less-tight control was associated with a significantly higher frequency of severe maternal hypertension. (Funded by the Canadian Institutes of Health Research; CHIPS Current Controlled Trials number, ISRCTN71416914; ClinicalTrials.gov number, NCT01192412.).


Critical Care Medicine | 2000

Changing pattern of organ dysfunction in early human sepsis is related to mortality.

James A. Russell; Joel Singer; Gordon R. Bernard; Arthur P. Wheeler; William Fulkerson; Leonard D. Hudson; Roland M. H. Schein; Warren R. Summer; Patrick Wright; Keith R. Walley

ObjectiveWe examined the pattern of organ system dysfunction, the evolution of this pattern over time, and the relationship of these features to mortality in patients who had sepsis syndrome. DesignProspective, multicenter, observational study. SettingIntensive care units in tertiary referral teaching hospitals. PatientsA total of 287 patients who had sepsis syndrome were prospectively identified in intensive care units. Materials and MeasurementsCardiovascular, pulmonary, neurologic, coagulation, renal, and hepatic dysfunction were assessed at onset and on day 3 of sepsis syndrome. Organ dysfunction was classified as normal, mild, moderate, severe, and extreme dysfunction. We calculated the occurrence rate and associated 30-day mortality rate of organ dysfunction at the onset of sepsis syndrome. We then measured the change in organ dysfunction from onset to day 3 of sepsis syndrome and determined, for individual organ systems, the associated 30-day mortality rate. ResultsAt the onset of sepsis syndrome, clinically significant pulmonary dysfunction was the most common organ failure, but was not related to 30-day mortality. Clinically significant cardiovascular, neurologic, coagulation, renal, and hepatic dysfunction were less common at the onset of sepsis syndrome but were significantly associated with the 30-day mortality rate. Worsening neurologic, coagulation, and renal dysfunction from onset to day 3 of sepsis syndrome were associated with significantly higher 30-day mortality than with improvement or no change in organ dysfunction. ConclusionsIncreased mortality rate in sepsis syndrome is associated with a pattern characterized by failure of nonpulmonary organ systems and, in particular, worsening neurologic, coagulation, and renal dysfunction over the first 3 days. Although initial pulmonary dysfunction is common in patients with sepsis syndrome, it is not associated with an increased mortality rate.

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Hubert Wong

University of British Columbia

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Anona Thorne

University of British Columbia

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Terry Lee

University of British Columbia

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Jacek A. Kopec

University of British Columbia

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John M. Esdaile

University of British Columbia

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Jolanda Cibere

University of British Columbia

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Eric C. Sayre

University of British Columbia

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S. Nicolaou

University of British Columbia

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