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Biomedical subjects

C D Naylor

Publications and source records attributed to C D Naylor.

At least 127 records · Page 7Linked to original sources
PubMed1995

Higher in-hospital mortality in female patients following coronary artery bypass surgery: a population-based study. Provincial Adult Cardiac Care Network of Ontario.

This study examined the relationship between gender and in-hospital mortality using data from patients undergoing coronary artery bypass surgery (CABS) in the province of Ontario. All patients who underwent CABS between April 1, 1991 and March 31, 1992 at the 9 cardiac surgery institutions were included for study (n = 5,175). The unadjusted in-hospital mortality rate was 3.3% and was higher among females (5.3%) than males (2.8%). Using logistic regression analysis to adjust for several predictors of in-hospital mortality the odds ratio estimate (OR) for female sex was 1.55 and was statistically significant (95% confidence interval (CI) 1.09 to 2.20). Women experienced rates of in-hospital mortality that are 1.6 times greater than males following bypass surgery after case-mix adjustment for age, anatomical disease severity, anginal class, and comorbid conditions. Severe unstable angina had the greatest potential contribution to in-hospital mortality (OR = 7.51, 95% CI = 3.71-15.23) and was more prevalent in women, indicating that excess mortality may be due to delayed diagnosis in women.

Adult↗
PubMed1994

Population-wide mortality trends among patients hospitalized for acute myocardial infarction: the Ontario experience, 1981 to 1991.

OBJECTIVES: This study attempted to determine population-based trends in in-hospital patient fatality from acute myocardial infarction. BACKGROUND: The in-hospital prognosis for patients with acute myocardial infarction should be improving as a result of adoption of treatments proved in randomized trials (e.g., thrombolytic, beta-adrenergic blocking and anticoagulant agents and aspirin). However, all trials are subject to selection biases, eligibility is limited for some therapies, and proved therapies may be underused even among eligible patients. METHODS: Using administrative data from all general hospitals in Ontario, Canada, we analyzed 17,489, 17,839, 18,393, 18,794, 18,716 and 19,748 records of patients with a primary discharge diagnosis of myocardial infarction for fiscal years 1981, 1983, 1985, 1987, 1989 and 1991, respectively. RESULTS: After age and gender adjustment, the overall relative reduction in in-hospital case fatality rates for the 10-year period was 26.9% (99% confidence interval [CI] 26.8% to 26.9%), corresponding to an absolute reduction of 6% (99% CI 5.6% to 6.4%). Age- and gender-standardized case fatality rate decreased from 22.3% in 1981 to 21.4% in 1985, followed by a highly significant decline to 16.3% in 1991. On the basis of the relation of comparative mortality to days of hospital stay, declining mortality was not an artifact of decreasing length of stay. CONCLUSIONS: There have been encouraging improvements in survival after acute myocardial infarction over the past 6 years. Further improvements may require development of new therapies that can be more widely applied to this patient population.

Age Distribution↗
PubMed1994

Use of medical resources and quality of life after acute myocardial infarction in Canada and the United States.

BACKGROUND: Much attention has been directed to the use of medical resources and to patients' outcomes in Canada as compared with the United States. We compared U.S. and Canadian patients with respect to their use of medical resources and their quality of life during the year after acute myocardial infarction. METHODS: A total of 2600 U.S. and 400 Canadian patients were randomly selected from the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) trial. Base-line data from their initial hospitalizations were analyzed, and the patients were then interviewed by telephone 30 days, 6 months, and 1 year after myocardial infarction to determine their use of medical care and quality of life. RESULTS: The Canadian patients typically stayed in the hospital one day longer (P = 0.009) than the U.S. patients but had a much lower rate of cardiac catheterization (25 percent vs. 72 percent, P < 0.001), coronary angioplasty (11 percent vs. 29 percent, P < 0.001), and coronary bypass surgery (3 percent vs. 14 percent, P < 0.001). At one year 24 percent of the Canadian and 53 percent of the U.S. patients had undergone angioplasty or bypass surgery at least once (P < 0.001). The Canadian had more visits to physicians during the follow-up year (P < 0.001), but fewer visits to specialists (P < 0.001). At 30 days, functional status was equivalent in the patients from the two countries. However, after one year the U.S. patients had substantially more improvement than the Canadian patients (P < 0.001). The prevalence of chest pain and dyspnea at one year was higher among the Canadian patients (34 percent vs. 21 percent and 45 percent vs. 29 percent, respectively; P < 0.001). CONCLUSIONS: The Canadian patients had more cardiac symptoms and worse functional status one year after acute myocardial infarction than the U.S. patients. The Canadian patients also underwent fewer invasive cardiac procedures and had fewer visits to specialist physicians. These results suggest, but do not prove, that the more aggressive pattern of care in the United States may have been responsible for the better quality of life.

Aged↗
PubMed1994

Comparison of the appropriateness of coronary angiography and coronary artery bypass graft surgery between Canada and New York State.

OBJECTIVE: To compare the appropriateness of coronary angiography and coronary artery bypass graft (CABG) use between the United States and Canada. DESIGN: Retrospective randomized medical record review. SETTING: All hospitals performing coronary angiography and/or CABG surgery in two Canadian provinces (Ontario and British Columbia); in New York State, 15 randomly selected hospitals that provide coronary angiography and 15 randomly selected hospitals that provide CABG surgery. PATIENTS: All patients were randomly selected. For coronary angiography, 533 patients in Canada and 1333 patients in New York were selected; for CABG, 556 patients in Canada and 1336 patients in New York were selected. MAIN OUTCOME MEASURES: Percentage of patients in each country who had coronary angiography or CABG for necessary, appropriate, uncertain, or inappropriate indications as rated by criteria developed separately in each country and the complications of those procedures. RESULTS: For coronary angiography, 9% of Canadian cases and 10% of New York cases were rated inappropriate using Canadian criteria compared with 5% and 4%, respectively, using US criteria. For CABG, 4% of Canadian cases and 6% of New York cases were rated inappropriate by Canadian criteria compared with 3% and 2%, respectively, using US criteria. A lower proportion of procedures were performed on persons aged 75 years or older in Canada than in New York for both coronary angiography (5% vs 11%; P < .001) and CABG (6% vs 14%; P < .001). Women were also represented in lower proportions among angiography cases in Canada than in New York (28% vs 35%; P = .023). Canadian patients with left main coronary disease waited significantly longer between angiography and CABG than did New York patients (P < .0001). CONCLUSIONS: Rates of inappropriate use of cardiac procedures were low in Canada and New York, which suggests that the regionalization of cardiac procedures that characterizes both health care systems contributes to better clinical decision making. Differences in the use of cardiac procedures among the elderly in the two countries merits further comparative examination.

Aged↗
PubMed1994

Regionalized delivery and variable utilization of coronary artery bypass grafting in Ontario from 1981 to 1991.

OBJECTIVE: To analyse the geographic variation in the rates of coronary artery bypass grafting (CABG) between 1981 and 1991. DESIGN: Retrospective study of discharge abstracts (from the provincial hospital discharge database) for odd fiscal years. SETTING: Ontario. PARTICIPANTS: All Ontario residents undergoing CABG between 1981 and 1991. OUTCOME MEASURES: Age- and sex-standardized median, maximum and minimum (plus 25th and 75th percentile) rates of CABG per 100,000 population aged 20 years and over, as well as interregional variation. RESULTS: The median rate of CABG rose from 46.2 to 72.7 per 100,000 adults between 1981 and 1991. The minimum rate varied from 1.9 to 12.4 per 100,000 and the maximum rate from 110.4 to 172.1 per 100,000 during the study period. Variations in the area-specific rates were significant in all years (p < 0.0001, based on the likelihood ratio chi 2 test after adjustment for age and sex). None of the four summary statistical measures showed any obvious diminution between 1981 and 1989, nor was there a change in the utilization pattern during the waiting-list crisis years of 1987 and 1989. However, the summary measures did reach their lowest level in 1991. The relative consistency of local practice patterns was tested by means of ranking area-specific rates and comparing the rankings for different years. Correlation coefficients varied from 0.50 to 0.82 (p < 0.0001); the correlation coefficient for 1991 on 1981 was 0.61 (p < 0.0001). CONCLUSIONS: Consistent and marked variations in the use of CABG existed across the counties of Ontario from 1981 to 1991. Despite a major expansion in provincial caseload capacity and planned regionalization of CABG as a surgical service, incremental resources were apparently not allocated in a manner that reduced interregional discrepancies.

Coronary Artery Bypass↗
PubMed1994

A predictive index for length of stay in the intensive care unit following cardiac surgery.

OBJECTIVE: To develop a predictive index for length of stay in the intensive care unit (ICU) following cardiac surgery. DESIGN: Univariate and multivariate logistic regression analysis of a cohort of 1404 patients divided into a derivation set of 713 patients and a validation set of 691 patients. SETTING: St. Michael's Hospital, Toronto, a tertiary care cardiovascular centre. PATIENTS: A consecutive sample of all patients undergoing cardiac surgery between Jan. 1 and Dec. 31, 1990 (derivation set), and Jan. 1 and Dec. 31, 1991 (validation set). MAIN OUTCOME MEASURE: A long ICU stay (more than 2 days). Other outcomes analysed were ICU stays over 4, 7 and 10 days, and death. RESULTS: In the derivation set increasing age, female sex, left ventricular function, type of surgery, and urgency of surgery were found to be independent risk factors for a long ICU stay in a multivariate logistic regression analysis. A predictive index was created by assigning risk scores based on the odds ratios of the significant variables in the logistic regression analysis. The predictive index was found to predict lengths of ICU stay greater than 2, 4, 7 and 10 days, and patient death in the validation set. CONCLUSIONS: Length of ICU stay and death following cardiac surgery can be predicted with a multivariate predictive index. The index has potential application as a means of stratifying cardiac surgical risk as well as in optimizing ICU resource planning when resources are limited.

Age Factors↗
PubMed1994

Temporal trends in breast cancer surgery in Ontario: can one randomized trial make a difference?

OBJECTIVE: To assess the effect of a single randomized clinical trial, the National Surgical Adjuvant Breast Project (NSABP) B-06, on the surgical management of breast cancer in women. DESIGN: Retrospective cohort study. SETTING: All hospitals in Ontario. PATIENTS: A consecutive sample of 37,447 women with breast cancer newly diagnosed from Jan. 1, 1980, to Dec. 31, 1989, linked to a surgical procedure record in the Ontario Cancer Registry. MAIN OUTCOME MEASURE: The most invasive surgical procedure used within 90 days of diagnosis. RESULTS: Unilateral breast-ablative surgery (BAS) was performed in 57.3% of the women and breast-conserving surgery (BCS) in 31.6%. The annual rate of BAS declined from 77.5% in 1980 to 44.2% in 1989 and the rate of BCS rose from 12.5% in 1980 to 43.5% in 1989. The decline was linear from 1980 to 1984 and then accelerated significantly in 1985 (p < 0.0001), after the results of the NSABP B-06 trial were published. CONCLUSION: One randomized clinical trial can have an immediate and profound effect on medical practice.

Age Distribution↗
PubMed1994

Variation in breast cancer surgery in Ontario.

OBJECTIVES: To analyse the extent of variation by county and hospital in the use of breast-conserving surgery in the initial management of breast cancer and to assess some factors that might explain the observed variation. DESIGN: Population-based retrospective cohort study. SETTING: Ontario. PATIENTS: All women with breast cancer newly diagnosed from Jan. 1, 1989, to Dec. 31, 1991. MAIN OUTCOME MEASURE: Proportion of women undergoing unilateral breast cancer surgery who had breast-conserving surgery in each hospital and county. RESULTS: Of the 14,570 women with newly diagnosed breast cancer 12,815 (88.0%) underwent unilateral breast cancer surgery. The mean proportion of breast-conserving procedures by county was 52% and ranged from 11% to 84%. The proportion of breast-conserving procedures in individual hospitals with one or more cases of breast cancer per month ranged from 6% to 84%. The variations in the rates between hospitals was greater than that expected by chance alone (p < 0.0001). CONCLUSIONS: There was marked variation at the hospital and county level in the use of breast-conserving surgery in the initial management of breast cancer. This variation was strongly associated with the hospital where the surgery was performed.

Analysis of Variance↗
PubMed1994

Revascularization after acute myocardial infarction: impact of hospital teaching status and on-site invasive facilities.

OBJECTIVE: To investigate the influence of hospital teaching status and service availability on rates of revascularization following myocardial infarction. DESIGN: Retrospective cohort study based on province-wide hospital discharge abstracts. SETTING: All acute care hospitals in Ontario, Canada's most populous province (9.7 million). PATIENTS: Patients admitted to hospital between April 1, 1991, and September 30, 1991, with a principal diagnosis of acute myocardial infarction. MEASUREMENTS: The odds of a patient's having been referred for revascularization (angioplasty or bypass surgery) within six months of a myocardial infarction were calculated based on the type of hospital to which he or she had initially presented, defined as "teaching" or "nonteaching" or as having or not having interventional facilities on-site (cardiac catheterization and/or revascularization). Odds ratios were adjusted for potential confounding variables, and for possible joint effects of teaching status and on-site interventional capabilities. RESULTS: The patients were more likely to have had revascularization (OR 1.79; 95% CI 1.47-2.14, p = 0.0001) when they had been admitted to a teaching hospital, and independently were more likely to have been referred for revascularization (OR 1.34; 95% CI 1.09-1.66, p = 0.0067) when they had been admitted to a hospital with on-site interventional facilities. There was no interaction between teaching status and service availability regarding referral for revascularization. CONCLUSION: Teaching status is an important determinant of revascularization following acute myocardial infarction and is independent of service availability, which also influences revascularization rates.

Adult↗
PubMed1994

Prescribing propensity: influence of life-expectancy gains and drug costs.

OBJECTIVE: To determine whether physician willingness to prescribe drugs for primary prevention of cardiovascular disease is influenced by information about the resultant life-expectancy gains (presented in one of two formats) and about drug costs. MATERIALS AND METHODS: Mailed survey (four versions randomly allocated) asking physicians to assess hypothetical preventive interventions with outcomes expressed either as averaged or as stratified gains in life expectancy (e.g., average gain of 15 weeks, versus 5% of treated patients gain 2 to 6 years, 10% gain up to 2 years, and 85% remain unchanged). Both costs and gains were varied to high and low values. The subjects rated their willingness to prescribe treatments on an 11-point scale from "strongly oppose" to "strongly favor." PARTICIPANTS: Internists randomly selected from two Canadian academic centers (n = 330). RESULTS: 231 usable responses were received (76% of the deliverable questionnaires). For low-yield scenarios typical of very effective primary prevention strategies, the physicians gave significantly higher ratings in response to stratified life-expectancy data than to equivalent averaged data (p < 0.0001). The same trend was not observed for high-yield scenarios (p = NS). The ratings were strongly influenced by cost: 34% of the physicians reversed their treatment decisions in response to a tenfold price increase. Despite this, the rankings of the treatments differed from those expected on the basis of cost-effectiveness criteria (p < 0.0001). CONCLUSIONS: Physician enthusiasm for a therapy designed to prolong life expectancy may be influenced by the format in which that life-expectancy gain is presented. Knowledge of drug cost also affects physicians' choices, but their greater focus on treatment effects causes their rankings to depart from those expected with cost-effectiveness criteria.

Attitude of Health Personnel↗
PubMed1994

Impact of time since last meal on the gestational glucose challenge test. The Toronto Tri-Hospital Gestational Diabetes Project.

OBJECTIVE: The purpose of the study was to evaluate the impact of time since the last meal on the glucose challenge test and to find cut points that are most likely to predict the outcome of the oral glucose tolerance test in patients screened for gestational diabetes. STUDY DESIGN: This prospective analytic cohort study was carried out at the University of Toronto Perinatal Complex. A 50 gm glucose load was given at 26 weeks' gestation and the time since previous meal ingestion was recorded. At 28 weeks' gestation a 100 gm oral glucose tolerance test was administered. A total of 4274 eligible patients were screened. RESULTS: Time since the last meal had a marked effect on mean plasma glucose. Receiver-operator characteristic curve analysis with National Diabetes Data Group criteria to interpret the oral glucose tolerance allowed the selection of the most efficient cut points for the glucose challenge test on the basis of time since the last meal. These cut points were 8.2, 7.9, and 8.3 mmol/L for elapsed postprandial times of < 2, 2 to 3, and > 3 hours, respectively. With this change from the current threshold of 7.8 mmol/L the number of patients with a positive screening test dropped from 18.5% to 13.7%. There was an increase in positive predictive value from 14.4% to 18.7%. The rate of patient misclassification fell from 18.0% to 13.1%. CONCLUSION: We suggest that screening strategies for detection of gestational diabetes be reconsidered, to account for the impact of variable postprandial status on the test results.

Adult↗
PubMed1994

Metaanalysis of prophylactic drug treatment in the prevention of postoperative bleeding.

Prophylactic drug treatment is one of several strategies to reduce postoperative blood loss and potentially limit homologous blood use in open heart surgery. A computerized MEDLINE search supplemented with manual bibliography reviews was performed for randomized clinical trials published in peer-reviewed English-language journals from January 1980 to June 1993. A metaanalysis was conducted of trials evaluating desmopressin (group DD, n = 13), epsilon-aminocaproic acid or tranexamic acid (group EA, n = 4), and aprotinin (group AP, n = 16). Eligible studies used placebo controls and administered the drug in a prophylactic manner. The primary study end point was postoperative chest tube loss (mL, mean +/- standard deviation). There was a significant reduction in postoperative chest tube loss detected for each of the active treatments versus the placebo (DD versus controls: percent reduction 0.11, p = 0.0021; EA versus controls: percent reduction 0.30, p < 0.0001; and AP versus controls: percent reduction 0.36, p < 0.0001). Therapy with EA or AP was associated with a greater reduction in chest tube loss than DD (EA versus DD, p = 0.0033, and AP versus DD, p < 0.0001). Secondary study end points were transfusion requirements, chest reexploration, and perioperative mortality. The volume of postoperative red cell transfusion (mean +/- standard deviation) was reduced with EA (p < 0.0001) or AP treatment (p < 0.0001) compared with a placebo or DD, whereas the proportion of patients given transfusions was limited only in the AP-treated patients (odds ratio 0.23; 95% confidence interval, 0.16 to 0.33; p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aminocaproic Acid↗