In the eye of the beholder.
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Clinical Trials as Topic↗
Biomedical subjects
C D Naylor
Publications and source records attributed to C D Naylor.
Intermittent warm blood cardioplegia. Warm Heart Investigators.
BACKGROUND: Warm heart surgery implies continuous perfusion with normothermic blood cardioplegia. Interruption of cardioplegia, however, facilitates construction of distal coronary anastomoses and is the method practiced by many surgeons. To determine whether intermittency is harmful, we present results from 720 coronary bypass patients, protected with intermittent antegrade warm blood cardioplegia, that were derived from a previous study of normothermic versus hypothermic cardioplegia. METHODS AND RESULTS: Mean +/- SD age was 60.8 +/- 9.0 years; 27% of cases were urgent; 16% of patients had > 50% left main stenosis, and 19% had grade III or IV ventricles. A mean of 3.2 +/- 0.9 grafts was constructed. The average aortic cross-clamp time was 61.8 +/- 22.2 minutes. The longest single time off cardioplegia (LTOC) averaged 11.4 +/- 4.0 minutes per patient. The cumulative time off cardioplegia as a percentage of the cross-clamp time (PTOC) was 48.2 +/- 18.6% per patient. LTOC and PTOC were divided into quartiles (LTOC, < 10, 10 to 11, 12 to 13, and > 13 minutes; PTOC, < 36%, 36% to 49%, 50% to 62%, and > 62%) and related to the prespecified composite outcome of mortality, myocardial infarction according to serial CK-MB sampling, and low-output syndrome (LOS). Longer LTOC was harmful (event rates per quartile, 13.5%, 10.3%, 10.9%, and 19.0%; P = .046), whereas longer PTOC was protective (16.1%, 17.2%, 9.4%, and 10.6%; P = .07). Stepwise logistic regression was performed, controlling for demographic and angiographic predictors. In the multivariate models, LTOC remained detrimental (P = .07) and PTOC remained beneficial (P = .053). Additional modeling after entering surgeon identity (P < .001) into the risk equation eliminated the PTOC effect, whereas LTOC remained predictive of adverse outcomes (P = .053; odds ratio, 1.06; 95% CI, 1.00, 1.13). CONCLUSIONS: The data indicate that a reasonable margin of safety exists with intermittent, antegrade warm blood cardioplegia. Repeated interruptions of warm blood cardioplegia are unlikely to lead to adverse clinical results if single interruptions are < or = 13 minutes.
Aged↗
Multicentre trial to introduce the Ottawa ankle rules for use of radiography in acute ankle injuries. Multicentre Ankle Rule Study Group.
OBJECTIVE: To assess the feasibility and impact of introducing the Ottawa ankle rules to a large number of physicians in a wide variety of hospital and community settings over a prolonged period of time. DESIGN: Multicentre before and after controlled clinical trial. SETTING: Emergency departments of eight teaching and community hospitals in Canadian communities (population 10,000 to 3,000,000). SUBJECTS: All 12,777 adults (6288 control, 6489 intervention) seen with acute ankle injuries during two 12 month periods before and after the intervention. INTERVENTION: More than 200 physicians of varying experience were taught to order radiography according to the Ottawa ankle rules. MAIN OUTCOME MEASURES: Referral for ankle and foot radiography. RESULTS: There were significant reductions in use of ankle radiography at all eight hospitals and within a priori subgroups: for all hospitals combined 82.8% control v 60.9% intervention(P < 0.001); for community hospitals 86.7% v 61.7%; (P < 0.001); for teaching hospitals 77.9% v 59.9%; (P < 0.001); for emergency physicians 82.1% v 61.6%; (P < 0.001); for family physicians 84.3% v 60.1%; (P < 0.001); and for housestaff 82.3% v 60.1%; (P < 0.001). Compared with patients without fracture who had radiography during the intervention period those who had no radiography spent less time in the emergency department (54.0 v 86.9 minutes; P < 0.001) and had lower medical charges ($70.20 v $161.60; P < 0.001). There was no difference in the rate of fractures diagnosed after discharge from the emergency department (0.5 v 0.4%). CONCLUSIONS: Introduction of the Ottawa ankle rules proved to be feasible in a large variety of hospital and community settings. Use of the rules over a prolonged period of time by many physicians of varying experience led to a decrease in ankle radiography, waiting times, and costs without an increased rate of missed fractures. The multiphase methodological approach used to develop and implement these rules may be applied to other clinical problems.
Ankle Injuries↗
Reflections on supply-demand mismatch in dialysis services in Ontario.
The population-based dialysis rate in Ontario more than doubled between 1981 and 1992; yet there is concern about over-loaded facilities, delayed treatment and denial of dialysis through nonreferral and implicit rationing. A working party involving several stakeholders has been established in Ontario to address these issues. However, clinical policy making concerning dialysis services is impeded in all provinces by a lack of information. The causes of the moderately large variations in dialysis rates from province to province remain unclear. The exact extent and risks of delayed therapy have not been well defined. Dialysis protocols vary inexplicably among centres, and cost data on different methods of providing dialysis are limited. Many steps could be taken in Ontario and other provinces to generate a better information base for planning and managing dialysis services. Predialysis clinics with outreach programs could help to ensure equitable access to this life-saving therapy. Criteria for choosing modes and intensities of renal-replacement therapy must be reviewed. In areas of clear disagreement and uncertainty, patients could be randomly assigned to different protocols and outcomes studied. In areas of agreement, the criteria should be standardized. Advance directives may help ascertain patients' wishes concerning the initiation or continuation of dialysis, and more accurate data on prognosis of different patient subgroups would aid in early identification of patients in a hopelessly deteriorating situation. Last, studies comparing the "output" (e.g., hours on hemodialysis) per dollar of different dialysis units and modalities are also needed to ensure that all facilities are opening efficiently without compromising patient outcomes.
Health Policy↗
Canadian Medicare: prognosis guarded.
Beset by unprecedented fiscal pressures, Canadian medicare has reached a crossroads. The authors review the impact of recent cuts in federal transfer payments on provincial health care programs and offer seven suggestions to policymakers trying to accommodate these reductions. (1) Go slowly: public health care spending is no longer rising and few provinces have the necessary systems in place to manage major reductions. (2) Target reductions, rewarding quality and efficiency instead of making across-the-board cuts. (3) Replace blame with praise:give health care professionals and institutions credit for their contributions. (4) Learn from the successful programs and policies already in place across the country. (5) Foster horizontal and vertical integration of services. (6) Promote physician leadership by rewarding efforts to promote the efficient use of resources. (7) Monitor the effects of cutbacks: physician groups should cooperate with government in maintaining a national "report card" on services, costs and the health status of Canadians.
Canada↗
Cost effectiveness of thrombolytic therapy with tissue plasminogen activator as compared with streptokinase for acute myocardial infarction.
BACKGROUND: Patients with acute myocardial infarction who were treated with accelerated tissue plasminogen activator (t-PA) (given over a period of 1 1/2 hours rather than the conventional 3 hours, and with two thirds of the dose given in the first 30 minutes) had a 30-day mortality that was 15 percent lower than that of patients treated with streptokinase in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) study. This was equivalent to an absolute decrease of 1 percent in 30-day mortality. We sought to assess whether the use of t-PA, as compared with streptokinase, is cost effective. METHODS: Our primary, or base-case, analysis of cost effectiveness used data from the GUSTO study and life expectancy projected on the basis of the records of survivors of myocardial infarction in the Duke Cardiovascular Disease Database. In the primary analysis, we assumed that there were no additional treatment costs due to the use of t-PA after the first year and that the comparative survival benefit of t-PA was still evident one year after enrollment. RESULTS: One year after enrollment, patients who received t-PA had both higher costs ($2,845) and a higher survival rate (an increase of 1.1 percent, or 11 per 1000 patients treated) than streptokinase-treated patients. On the basis of the projected life expectancy of each treatment group, the incremental cost-effectiveness ratio--with both future costs and benefits discounted at 5 percent per year--was $32,678 per year of life saved. The use of t-PA was least cost effective in younger patients and most cost effective in older patients. At all ages, the use of t-PA in patients with anterior infarctions yielded more favorable cost-effectiveness values. In our secondary analyses, the cost-effectiveness values were most sensitive to a lowering of the projected long-term survival benefits of t-PA and to moderate or greater increases in the projected medical costs for patients in the t-PA group after the first year. In contrast, our results were not sensitive to even very unfavorable assumptions about the additional costs associated with the higher rate of disabling stroke that was noted in patients treated with t-PA in the GUSTO study. CONCLUSIONS: The cost effectiveness of treatment with accelerated t-PA rather than streptokinase compares favorably with that of other therapies whose added medical benefit for dollars spent is judged by society to be worthwhile.
Adult↗
Diagnostic accuracy and short-term surgical outcomes in cases of suspected acute appendicitis.
OBJECTIVE: To test the hypothesis that, with modern diagnostic methods and antibiotics, more conservative use of surgery in cases of suspected appendicitis would not result in increased rates of short-term complications in confirmed cases. DESIGN: Population-based observational study using administrative data. SETTING: All Ontario hospitals in which primary appendectomy was performed from Apr. 1, 1981, to Mar. 31, 1992. PATIENTS: All 126,815 patients admitted to hospital for a primary appendectomy during the study period. OUTCOME MEASURES: Diagnostic accuracy rate (acute appendicitis as the primary diagnosis), perforation rate, in-hospital death rate and length of stay. RESULTS: The diagnostic accuracy rate among the male patients was stable throughout the decade; among the female patients it rose significantly, from 71.7% in 1981 to 75.3% in 1991 (p < 0.01). The perforation rates increased significantly among both the female and male patients (p < 0.01), whereas the mean length of stay decreased (p < 0.05). Despite sex-related differences in the accuracy rates, the male and female patients had similar in-hospital death rates and mean lengths of stay. The institutional diagnostic accuracy rates, as determined from data for 1989-90 to 1991-92, ranged from 50.0% to 96.7%. Multivariate analyses of 27,189 confirmed cases of appendicitis at 175 hospitals revealed that perforation was a strong predictor of in-hospital death (odds ratio [OR] 2.46, 95% confidence interval [CI] 1.24 to 4.88), but comorbidity was the strongest predictor (OR 11.50, 95% CI 5.96 to 22.10). For each 10% increase in the diagnostic accuracy rate, the perforation rate increased 14% (OR 1.14, 95% CI 1.10 to 1.19), but the accuracy rate was not significantly related to the in-hospital death rate or the length of stay. CONCLUSION: A higher diagnostic accuracy rate is associated with more perforated appendixes. Although perforation itself leads to adverse outcomes, a higher accuracy rate does not. This suggests that hospitals with higher accuracy rates incur more perforations, but, with close observation, timely laparotomy and the use of modern antibiotics, these patients have favourable outcomes. This contrasts with adverse effects of perforation among patients at high risk for perforation (especially very young children and elderly people) in centres at all accuracy levels. The variation in hospitals' diagnostic accuracy rates suggests that some proportion of appendectomies could be safely avoided.
Abdominal Pain↗
Grey zones of clinical practice: some limits to evidence-based medicine.
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Clinical Medicine↗
Maximizing the benefits of thrombolytic therapy for acute myocardial infarction.
Thrombolytic therapy is a huge advance in the management of acute myocardial infarction (AMI). The results of large clinical trials over the past 9 years have unequivocally demonstrated its benefit: of every 1000 patients treated 30 will be saved, at a cost of two cases of nonfatal cerebral hemorrhage and seven of noncerebral major hemorrhage. The concurrent use of acetylsalicylic acid increases the benefit of thrombolytic therapy. Sales figures for thrombolytic agents indicate that their use in Canada is less than optimal and lags behind that in several European countries. Major educational efforts are needed to promote awareness of the efficacy of thrombolytic therapy and of optimal approaches for maximizing its potential benefit for patients with AMI.
Clinical Trials as Topic↗
Good judgement or sex bias in the referral of patients for the diagnosis of coronary artery disease? An exploratory study.
OBJECTIVE: To examine the sex-specific prevalence of referral to a cardiologist for noninvasive ischemic testing (NIIT) or angiography among outpatients with clinical suspicion of new coronary artery disease (CAD). DESIGN: Retrospective records-based cohort study. SETTING: Group cardiology referral practice in a tertiary care teaching hospital in Toronto. PATIENTS: Of 1212 new patients referred between Mar. 1, 1991, and Mar. 31, 1993, 339 (232 men and 107 women) had symptoms of CAD and had initiation or modification of antianginal therapy, or were prescribed NIIT or angiography by their cardiologist. OUTCOME MEASURES: Rates of prior NIIT and of subsequent diagnostic procedures for women and men. RESULTS: Women were less likely than men to have had prior NIIT (51 [47.7%] v. 162 [69.8%]) (p < 0.001). Women with class I or II angina were less likely than their male counterparts to have had prior NIIT (20/40 [50.0%] v. 84/109 [77.1%]) (p = 0.001); a similar difference was found between women and men with class III or IV angina (5/15 [33.3%] v. 43/60 [71.7%]) (p = 0.006). Men and women with atypical angina were equally likely to have had prior NIIT. Among patients with a positive initial NIIT result a higher proportion of women than of men did not have any further testing done by the cardiologist (53.5% v. 33.7%) (p = 0.02). Cardiologists referred a higher proportion of women (40.2%) than of men (25.4%) for NIIT (p = 0.006) and, for patients with a positive prior NIIT result, were also more likely to refer women (25.7% [9/43]) than men (12.0% [16/133]) for further NIIT (p = 0.04). Women with a positive prior NIIT result were more likely than their male counterparts to have a negative retest result (42.8% v. 18.2%). After adjustment for age, anginal class and overall result of NIIT, women were less likely than men to be referred for angiography (odds ratio 1.4), although the difference was not significant. CONCLUSIONS: In this exploratory study sex-related differences in patterns of use of NIIT by cardiologists seem largely based on differences in testing before referral by family physicians and general internists.
Adult↗
Multicenter validation of a risk index for mortality, intensive care unit stay, and overall hospital length of stay after cardiac surgery. Steering Committee of the Provincial Adult Cardiac Care Network of Ontario.
BACKGROUND: A multicenter population-based study was conducted to develop and validate a risk index for mortality, intensive care unit (ICU) length of stay, and postoperative length of stay after cardiac surgery. METHODS AND RESULTS: Data were collected from 13,098 patients undergoing cardiac surgery between April 1, 1991, and March 31, 1993, at all nine adult cardiac surgery institutions in Ontario, Canada. A six-variable risk index (age, sex, left ventricular function, type of surgery, urgency of surgery, and repeat operation) was developed using logistic regression analysis to predict in-hospital mortality, ICU stay in days, and postoperative stay in days after cardiac surgery in a derivation set of 6213 patients who had cardiac surgery during fiscal year 1991 (April 1, 1991, to March 31, 1992). The index predicted mortality, prolonged ICU stay (> or = 6 days), and prolonged postoperative length of stay (> or = 17 days) after cardiac surgery with areas under the receiver-operating characteristic (ROC) curve of 0.75, 0.66, and 0.69, respectively, in an independent validation set of 6885 patients who had cardiac surgery during fiscal year 1992 (April 1, 1992, to March 31, 1993). Increasing risk scores were associated with greater mortality rates and longer ICU and postoperative stays at all nine institutions. CONCLUSIONS: Mortality, ICU length of stay, and postoperative length of stay after cardiac surgery can be predicted using a simple six-variable risk index. The index has potential application as a risk stratification tool for comparing patient outcomes and resource use among different hospitals and surgeons.
Adult↗
Impact of increasing carbohydrate intolerance on maternal-fetal outcomes in 3637 women without gestational diabetes. The Toronto Tri-Hospital Gestational Diabetes Project.
OBJECTIVE: Our purpose was to assess maternal-fetal outcomes in patients with increasing carbohydrate intolerance not meeting the current criteria for the diagnosis of gestational diabetes. STUDY DESIGN: We conducted a prospective analytic cohort study in which nondiabetic women aged > or = 24 years, receiving prenatal care in three Toronto teaching hospitals, were eligible for enrollment. A glucose challenge test and an oral glucose tolerance test were administered at 26 and 28 weeks' gestation, respectively; risk factors for unfavorable maternal-fetal outcomes were recorded. Caregivers and patients were blinded to glucose values except when test results met the current criteria for gestational diabetes. RESULTS: Of 4274 patients screened, 3836 (90%) continued to the diagnostic oral glucose tolerance test. The study cohort was formed by the 3637 (95%) patients without gestational diabetes, carrying singleton fetuses. Increasing carbohydrate intolerance in women without overt gestational diabetes was associated with a significantly increased incidence of cesarean sections, preeclampsia, macrosomia, and need for phototherapy, as well as an increased length of maternal and neonatal hospital stay. Multivariate analysis showed that increasing carbohydrate intolerance is an independent predictor for various unfavorable outcomes. CONCLUSION: Increasing maternal carbohydrate intolerance in pregnant women without gestational diabetes is associated with a graded increase in adverse maternal-fetal outcomes.
Adult↗
Interferon alfa treatment of chronic hepatitis B: randomized trial in a predominantly homosexual male population.
BACKGROUND/AIMS: It has been suggested that human immunodeficiency virus (HIV) coinfection and male homosexuality predict poor response to interferon alfa therapy of chronic hepatitis B. The aim of this study was to examine the effect of HIV coinfection on the response of chronic hepatitis B virus (HBV) infection to interferon alfa therapy in a predominantly homosexual male population. METHODS: Fifty patients (82% male homosexuals, 50% HIV positive) with evidence of chronic HBV infection were randomized, stratified by HIV status, to undergo either treatment with interferon alfa (10 MU/m2 three times weekly for 12 weeks) or no treatment. Response was predefined as loss of serum HBV DNA, loss of hepatitis B e antigen, and the appearance of antibody to hepatitis B e antigen. HIV status and the interferon alfa-associated enzyme, 2',5'-oligoadenylate synthetase, were evaluated as potential predictors of response to therapy. RESULTS: Six treated patients responded with development of antibodies to hepatitis B e antigen (P < 0.05). HIV-positive patients were about one-fifth as likely to respond to interferon alfa therapy (relative risk, 0.22; 95% confidence interval, 0.03-1.78). Pretreatment alanine aminotransferase levels were significantly higher in responders than in nonresponders (P = 0.0005). Pretreatment 2',5'-oligoadenylate synthetase levels did not predict response. CONCLUSIONS: Interferon alfa, 10 MU/m2 three times weekly for 12 weeks, is effective in eradicating HBV replication in a predominantly homosexual male population not coinfected with HIV.
2',5'-Oligoadenylate Synthetase↗
The case for failed meta-analyses.
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Bias↗
Life-sustaining treatment preferences of hemodialysis patients: implications for advance directives.
The purpose of this study was to describe the life-sustaining treatment preferences of dialysis patients and to compare the acceptability of two generic and a disease-specific advance directive (AD). Of 532 potentially eligible hemodialysis patients, 95 (17.9%) participated in the study. These patients completed two generic (the Centre for Bioethics Living Will and the Medical Directive) and one disease-specific (the Dialysis Living Will) AD in a randomized cross-over trial. Treatment preferences were measured by using the Centre for Bioethics Living Will. Acceptability of the AD was measured by using a 13-item advance directive acceptability questionnaire (ADAQ) for each AD, and the advance directive choice questionnaire (ADCQ) to elicit participants' preferred AD. Twenty-five percent of the participants wanted to continue dialysis in case of severe stroke, 19% in severe dementia, and 14% in permanent coma. Averaged across treatments, proportions of participants wanting treatment in various health states were: current health (86%), mild stroke (84%), moderate stroke (60%), severe stroke (21%), mild dementia (78%), moderate dementia (51%), severe dementia (14%), terminal illness (41%), and permanent coma (10%). Averaged across health states, proportions of participants wanting various types of treatment were: dialysis (58%), antibiotics (53%), transfusion (53%), surgery (48%), cardiopulmonary resuscitation (48%), respirator (47%), and tube feeding (41%). Mean ADAQ scores were: Dialysis Living Will, 71%; Centre for Bioethics Living Will, 70%; and Medical Directive, 60% (F = 8.27, P < 0.001 (repeat measures analysis of variance); the Dialysis Living Will and Centre for Bioethics Living Will scored significantly higher than the Medical Directive). The proportion of participants who said they would choose to complete each AD was: Dialysis Living Will, 28%; Centre for Bioethics Living Will, 38%; Medical Directive, 31%; and unsure, 3% (chi 2 = 1.465, df = 2, P = 0.48). In conclusion, twenty-five percent or less of hemodialysis patients want to continue dialysis in three specific health states: severe stroke, severe dementia, and permanent coma. Health states and illness severity, far more than treatment descriptions, influence preferences. Dialysis patients should be offered a generic AD, and some generic AD are more acceptable than others. Only a minority of dialysis patients will complete any AD, but the completion of written AD forms is only one element in the process of advance care planning.
Adolescent↗
Orchidectomy and hormonal therapy of prostate cancer.
The objective of this study is to document the use of hormonal therapies in treating prostate cancer in Ontario in the last decade. Drug utilization data were extracted from the Ontario Drug Benefit Program, while surgical orchidectomy rates were calculated from Hospital Medical Records Institute data. The provincial rate of orchidectomy showed a 55% relative increase from 1981 to 1991. There was a 6.4-fold variation in orchidectomy rates among counties in Ontario. As well, the expenditures on new hormonal therapies rose 38-fold between 1985 and 1990, and doubled between 1990 and 1992. There was no consistent relationship between use of orchidectomy and hormonal drug therapy at the county level. We conclude that both forms of hormonal therapy have increased in Ontario. The wide variation in surgical orchidectomy rates observed in Ontario suggests differences in practice styles and possible medical uncertainty. Guidelines for the hormonal therapy of prostate cancer may be a helpful step forward for practitioners and patients.
Journal Article↗
Regional revascularization patterns after myocardial infarction in Ontario.
OBJECTIVE: To determine whether regional differences exist within Ontario in the use and timing of coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA) among patients who have recently suffered an acute myocardial infarction (AMI). BACKGROUND: Regional variations have been documented in the use of CABG in Canada, but previous findings do not fully account for either an alternative procedure (PTCA) or the impact of geographic variations in disease incidence or severity. By following persons after AMI, one can address both issues simultaneously in a subpopulation of patients where substitution of PTCA for CABG may be occurring. PATIENTS AND METHODS: Hospital discharge abstracts were used to define an inception cohort of 6565 patients with a primary diagnosis of AMI in the first six months of fiscal 1990. Subjects were tracked longitudinally for subsequent CABG or PTCA over the remainder of the fiscal year. Procedures were attributed by site of patient residence to one of five major Ontario referral regions. Proportions of patients undergoing revascularization and time in days from AMI to intervention were compared by chi 2 tests and nonparametric analysis of variance, respectively. RESULTS: Overall, 9.7% of patients underwent revascularization, with regional rates ranging from 7.2 to 13.6% (P < 0.0001). Elapsed time to revascularization also varied by region (P < 0.01). Use of CABG and PTCA varied separately by region (both P < 0.0001). Two regions with significantly elevated CABG rates were statistically similar to the provincial mean for overall revascularization owing to proportionately lower use of PTCA. CONCLUSIONS: Regional variations in use and timing of coronary revascularization were evident in this post-AMI cohort. Longitudinal tracking for substitutable procedures in a defined inception cohort may yield perspectives that complement conventional small area analyses.
Age Factors↗
From thrombolytic megatrials to clinical policy-making: facing the facts.
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Canada↗