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1.

Background

Opinion leaders represent one way to disseminate new knowledge and influence the practice behaviors of physicians. This study explored the stability of opinion leaders over time, whether opinion leaders were polymorphic (i.e., influencing multiple practice areas) or monomorphic (i.e., influencing one practice area), and reach of opinion leaders in their local network.

Methods

We surveyed surgeons and pathologists in Ontario to identify opinion leaders for colorectal cancer in 2003 and 2005 and to identify opinion leaders for breast cancer in 2005. We explored whether opinion leaders for colorectal cancer identified in 2003 were re-identified in 2005. We examined whether opinion leaders were considered polymorphic (nominated in 2005 as opinion leaders for both colorectal and breast cancer) or monomorphic (nominated in 2005 for only one condition). Social-network mapping was used to identify the number of local colleagues identifying opinion leaders.

Results

Response rates for surgeons were 41% (2003) and 40% (2005); response rates for pathologists were 42% (2003) and 37% (2005). Four (25%) of the surgical opinion leaders identified in 2003 for colorectal cancer were re-identified in 2005. No pathology opinion leaders for colorectal cancer were identified in both 2003 and 2005. Only 29% of surgical opinion leaders and 17% of pathology opinion leaders identified in the 2005 survey were considered influential for both colorectal cancer and breast cancer. Social-network mapping revealed that only a limited number of general surgeons (12%) or pathologists (7%) were connected to the social networks of identified opinion leaders.

Conclusions

Opinion leaders identified in this study were not stable over a two-year time period and generally appear to be monomorphic, with clearly demarcated areas of expertise and limited spheres of influence. These findings may limit the practicability of routinely using opinion leaders to influence practice.  相似文献   

2.
Data from a number of studies of breast cancer have suggested that after the ages associated with the menopause the rates of estrogen-receptor-positive tumours increase with age, whereas the rates of estrogen-receptor-negative tumours do not. Previous investigators studied cases in specific treatment centres, so there was a possibility that the findings were influenced by differences in patterns of case referral by age. A review of all the cases of breast cancer diagnosed in Ontario women in 1981 and assayed for estrogen receptors, however, confirmed the earlier findings. The results showed that the incidence of estrogen-receptor-positive and estrogen-receptor-negative tumours increased at about the same rate before age 45, but thereafter an increase in incidence was seen only for estrogen-receptor-positive tumours. These differences in patterns of incidence suggest the possibility that the two types of tumour may have different etiologic factors.  相似文献   

3.
4.
Background:Coronary artery bypass grafting (CABG) and surgical aortic valve replacement (AVR) are the 2 most common cardiac surgery procedures in North America. We derived and externally validated clinical models to estimate the likelihood of death within 30 days of CABG, AVR or combined CABG + AVR.Methods:We obtained data from the CorHealth Ontario Cardiac Registry and several linked population health administrative databases from Ontario, Canada. We derived multiple logistic regression models from all adult patients who underwent CABG, AVR or combined CABG + AVR from April 2017 to March 2019, and validated them in 2 temporally distinct cohorts (April 2015 to March 2017 and April 2019 to March 2020).Results:The derivation cohorts included 13 435 patients who underwent CABG (30-d mortality 1.73%), 1970 patients who underwent AVR (30-d mortality 1.68%) and 1510 patients who underwent combined CABG + AVR (30-d mortality 3.05%). The final models for predicting 30-day mortality included 15 variables for patients undergoing CABG, 5 variables for patients undergoing AVR and 5 variables for patients undergoing combined CABG + AVR. Model discrimination was excellent for the CABG (c-statistic 0.888, optimism-corrected 0.866) AVR (c-statistic 0.850, optimism-corrected 0.762) and CABG + AVR (c-statistic 0.844, optimism-corrected 0.776) models, with similar results in the validation cohorts.Interpretation:Our models, leveraging readily available, multidimensional data sources, computed accurate risk-adjusted 30-day mortality rates for CABG, AVR and combined CABG + AVR, with discrimination comparable to more complex American and European models. The ability to accurately predict perioperative mortality rates for these procedures will be valuable for quality improvement initiatives across institutions.

Coronary artery bypass grafting (CABG) and surgical aortic valve replacement (AVR) are 2 of the most common cardiac surgical procedures in North America.1 Accurate risk models of perioperative mortality for CABG and AVR are not only useful for operative decision-making,2 but also valuable for quality improvement initiatives across surgeons and institutions.In North America, the most widely used 30-day mortality risk score is the Society of Thoracic Surgeons (STS)–Predicted Risk of Mortality tool, derived from more than 1000 hospitals in the United States and encompassing more than 50 variables.3 An ideal risk model should be built and validated on the patient population in which it will be applied. Although the STS–Predicted Risk of Mortality tool was derived from a large surgical population, regional differences in patient sociodemographics and health care delivery systems may preclude this model from performing optimally in the health system where cardiac surgery is publicly funded. Furthermore, collecting more than 50 variables is resource intensive and is not feasible for all institutions. Similar limitations apply to the EuroSCORE II, which was derived from a population-based cohort in Europe.4 Given these limitations, we developed a more parsimonious model using readily available, linked clinical and administrative data sets in Ontario, Canada, to efficiently and accurately calculate risk-adjusted 30-day mortality rates for the purpose of province-wide quality improvement after CABG, AVR and combined CABG + AVR.  相似文献   

5.
Processes of novelty learning and keeping the results in Alzheimer's disease in two groups of rhesus-monkeys (three monkeys in each group), were studied: following neurotoxins administrati- on (I group) and saline administration (II group). In two months after the injections (the C1 stage), considerable differences between the groups were revealed in the task of differentiation among contour shapes. For the I group monkeys the learning was difficult: the correct decision making did not reach 85 %, and the probability of refusing to make a decision increased. For the II group monkeys the learning characteristics were not disturbed. In six months after the injections (the C3 stage) the differences between the groups in the task of differentiation among new stimuli (heads of two monkeys) remained at the same level. When studying characteristics of the operative memory associated with keeping the learning results achieved at the C1 stage, a considerable worsening of these characteristics was revealed: diminishing of the correct decision making probability at the C1 stage (actually to the level of 0.5), increase in the probability of refusing to make a decision. The structural-functional organization of interaction between sensory and cognitive processes in learning and keeping the information in the operative memory, is discussed in association with the control of motivation and attention system and the role of the cortex associative areas.  相似文献   

6.
Objective To determine whether the improved outcome of a surgical procedure in high volume hospitals is specific to the volume of the same procedure.Design and setting Analysis of secondary data in Ontario, Canada.Participants Patients having an oesophagectomy, colorectal resection for cancer, pancreaticoduodenectomy, major lung resection for cancer, or repair of an unruptured abdominal aortic aneurysm between 1994 and 1999.Main outcome measures Odds ratio for death within 30 days of surgery in relation to the hospital volume of the same surgical procedure and the hospital volume of the other four procedures. Estimates were adjusted for age, sex, and comorbidity and accounted for hospital level clustering.Results With the exception of colorectal resection, 30 day mortality seemed to be inversely related not only to the hospital volume of the same procedure but also to the hospital volume of most of the other procedures. In some cases the effect of the volume of a different procedure was stronger than the effect of the volume of the same procedure. For example, the association of mortality from pancreaticoduodenectomy with hospital volume of lung resection (odds ratio for death in hospitals with a high volume of lung resection compared with low volume 0.36, 95% confidence interval 0.23 to 0.57) was much stronger than the association of mortality from pancreaticoduodenectomy with hospital volume of pancreaticoduodenectomy (0.76, 0.44 to 1.32).Conclusion The inverse association between high volume of procedure and risk of operative death is not specific to the volume of the procedure being studied.  相似文献   

7.
ABSTRACT: BACKGROUND: Abattoir condemnations may play an important role in a food animal syndromic surveillance system. Portion condemnation data may be particularly useful, as these data can provide more specific information on health outcomes than whole carcass condemnation data. Various seasonal, secular, disease, and non-disease factors have been previously identified to be associated with whole carcass condemnation rates in Ontario provincial abattoirs; and if ignored, may bias the results of quantitative disease surveillance methods. The objective of this study was to identify various seasonal, secular, and abattoir characteristic factors that may be associated with bovine portion condemnation rates and compare how these variables may differ from previously identified factors associated with bovine whole carcass condemnation rates. RESULTS: Data were collected from the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and the Ontario Cattlemen's Association regarding "parasitic liver" and pneumonic lung condemnation rates for different cattle classes, abattoir compliance ratings, and the monthly sales-yard price for commodity classes from 2001-2007. To control for clustering by abattoirs, multi-level Poisson modeling was used to investigate the association between the following variables and "parasitic liver" as well as pneumonic lung condemnation rates: year, season, annual abattoir audit rating, geographic region, annual abattoir operating time, annual total number of animals processed, animal class, and commodity sales price. CONCLUSIONS: In this study, "parasitic liver" condemnation rates were associated with year, season, animal class, audit rating, and region. Pneumonic lung condemnation rates were associated with year, season, animal class, region, audit rating, number of cattle processed per year, and number of weeks abattoirs processed cattle. Unlike previous models based on whole carcass condemnations, commodity price was not associated with partial condemnations in this study. The results identified material-specific predictor variables for condemnation rates. This is important for syndromic surveillance based on abattoir data and should be modeled and controlled for during quantitative surveillance analysis on a portion specific basis.  相似文献   

8.
E. N. MacKay  A. H. Sellers 《CMAJ》1966,94(17):889-899
For the 827 patients with malignant testicular tumours registered at the Ontario Cancer Foundation''s regional clinics in the period 1938-1961, the probability of surviving for five years after treatment was 59.8%; for the 731 patients who received all or part of their initial treatment at the clinics or were not treated anywhere, five-year survival probability was 62.7%. Most deaths from testicular cancer took place in the first two years after treatment, and 90% of recorded recurrences were diagnosed before the third anniversary. Survival rates were strongly influenced by histological type and extent of disease, and to some degree by age. Survival did not seem to be closely correlated with delay after first symptom, site or size of primary lesion, ectopia, surgical treatment of the abdominal nodes, site or dosage of radiation, or chemotherapy. The survival rates in this series of cases compare favourably with those of other large series.  相似文献   

9.
During the past five years, 127 newborn infants with marked anoxia, severe cardiac failure or respiratory problems secondary to a cardiac lesion were operated upon at l''Hôpital Ste-Justine, Montreal, Quebec.Infants in cardiorespiratory distress from a cardiac lesion for which the surgical treatment is well established, such as complicated coarctation of the aorta, were either cured or improved in 78% of cases. The fatal outcome following medical treatment of patients suffering from lesions for which the surgical treatment is not yet well established, e.g. interruption of the aortic arch, led us to operate upon these infants with the hope of salvaging some of them despite the high surgical risk.The decision to operate was usually based on clinical grounds; however, cine-angiocardiography was at times required to establish the exact diagnosis. Light anesthesia was essential to the success of the operation. Postoperative care was facilitated by a team of nurses well experienced in the treatment of newborn subjects with heart lesions. Fluids were administered in a minimum quantity of 700 c.c./m.2 for 24 hours, and potassium was the only electrolyte added to the replacement fluids. Respiratory problems were reduced to a minimum by active physiotherapy. However, intubation with aspiration of tracheobronchial secretions was carried out when necessary.  相似文献   

10.
W A Ghali  H Quan  R Brant 《CMAJ》1998,159(1):25-31
BACKGROUND: Despite a body of research on outcomes of coronary artery bypass grafting (CABG) in Canada, little is known about Canada-wide outcome trends and interregional differences in outcome. The objectives of this study were to examine Canadian trends in rates of in-hospital death after CABG and to compare provincial risk-adjusted death rates. METHODS: Hospital discharge data were obtained from the Canadian Institute for Health Information and were used to identify complete cohorts of patients who underwent CABG in 8 provinces in fiscal years 1992/93 through 1995/96. Data from Quebec hospitals were not available. A logistic regression model was used to calculate risk-adjusted death rates by year, province, and province and year. RESULTS: A total of 50,357 CABG cases were studied, with an overall death rate of 3.6%. A national trend of decreasing mortality was found, with a risk-adjusted death rate of 3.8% in 1992/93 versus 3.2% in 1995/96 (relative decrease of 17%) (p < 0.001 for difference across years). Some provinces (e.g., Alberta, Manitoba and Ontario) achieved overall declines in death rates over the study period, whereas others (e.g., British Columbia and Saskatchewan) did not. The average severity of illness of patients who underwent CABG differed considerably across provinces. Despite risk adjustment for these differences, provincial death rates varied significantly (p < 0.001). INTERPRETATION: Rates of death after CABG in Canada decreased significantly in a relatively short period. Despite this encouraging finding, there were interprovincial differences in severity of illness and risk-adjusted death rates. This finding raises the possibility of unequal access to CABG and variable quality of care for patients undergoing the surgery across Canadian provinces.  相似文献   

11.
Hidalgo DA 《Plastic and reconstructive surgery》2000,105(6):2202-16; discussion 2217-8
A retrospective study of 220 patients was performed to review surgical design in breast augmentation. Three specific issues were studied: incision site, implant variables, and pocket plane selection. The influence of these three factors on aesthetic results in both primary and secondary cases was the focus of the analysis. No attempt was made to address long-term issues such as capsular contracture or saline implant deflation rates. In 77 primary augmentation patients and 80 unilateral augmentations for symmetry in breast reconstruction, there were the following untoward results: 11 revisions for unilateral malposition, change to a different implant shape, or change to a larger implant size; four deflations of saline implants requiring replacement; and four conversions of saline to silicone gel implants. In 63 secondary cases, there were two hematomas and two infections requiring implant removal and subsequent replacement. Operative technique in breast augmentation is described, as are recommendations for each of the options associated with the three variables studied.  相似文献   

12.
Factors affecting outcome in free-tissue transfer in the elderly   总被引:5,自引:0,他引:5  
Free-tissue transfers have become the preferred surgical technique to treat complex reconstructive defects. Because these procedures typically require longer operative times and recovery periods, the applicability of free-flap reconstruction in the elderly continues to require ongoing review. The authors performed a retrospective analysis of 100 patients aged 65 years and older who underwent free-tissue transfers to determine preoperative and intraoperative predictors of surgical complications, medical complications, and reconstructive failures. The parameters studied included patient demographics, past medical history, American Society of Anesthesiology (ASA) status, site and cause of the defect, the free tissue transferred, operative time, and postoperative complications, including free-flap success or failure. The mean age of the patients was 72 years. A total of 46 patients underwent free-tissue transfer after head and neck ablation, 27 underwent lower extremity reconstruction in the setting of peripheral vascular disease, 10 had lower extremity traumatic wounds, nine had breast reconstructions, four had infected wounds, two had chronic wounds, and two underwent transfer for lower extremity tumor ablation. Two patients had an ASA status of 1, 49 patients had a status of 2, 45 patients had a status of 3, and four had a status of 4. A total of 104 flaps were transferred in these 100 patients. There were 49 radial forearm flaps, 34 rectus abdominis flaps, seven latissimus dorsi flaps, seven fibular osteocutaneous flaps, three omental flaps, three jejunal flaps, and one lateral arm flap. Four patients had planned double free flaps for their reconstruction. Mean operative time was 7.8 hours (range, 3.5 to 16.5 hours). The overall flap success rate was 97 percent, and the overall reconstructive success rate was 92 percent. There were six additional reconstructive failures related to flap loss, all of which occurred more than 1 month after surgery. Patients with a higher ASA designation experienced more medical complications (p = 0.03) but not surgical complications. Increased operative time resulted in more surgical complications (p = 0.019). All eight cases of reconstructive failure occurred in patients undergoing limb salvage surgery in the setting of peripheral vascular disease. Free-tissue transfer in the elderly population demonstrates similar success rates to those of the general population. Age alone should not be considered a contraindication or an independent risk factor for free-tissue transfer. ASA status and length of operative time are significant predictors of postoperative medical and surgical morbidity. The higher rate of reconstructive failure in the elderly peripheral vascular disease population compares favorably with other treatment modalities for this disease process.  相似文献   

13.
The morphometric differences between benign and malignant serous effusions, as diagnosed by standard cytologic criteria in 95 unselected cases (50 benign and 45 malignant), were studied using the IBAS semi-automated image analysis system, which calculates various parameters from tracings of cellular and nuclear outlines. Fourteen cases were also stained for cytokeratin proteins (with the CAM 5.2 antibody) by the immunoperoxidase technique and reanalyzed for positive cells. Significant differences were found for mean values between cytologically benign and malignant cases for cellular and nuclear areas, perimeters and maximum diameters, but not for two form factors. Some differences were enhanced in the CAM 5.2-stained cases. Real morphometric differences in samples of cells from benign and malignant cases are the basis of cytologic diagnosis. Fully automated diagnostic systems could operate on arbitrary threshold values, but there is considerable overlap in specimen means for all parameters between benign and malignant cases.  相似文献   

14.
The relative influences of density-dependent and -independent processes on vital rates and population dynamics have been debated in ecology for over half a century, yet it is only recently that both processes have been shown to operate within the same population. However, generalizations on the role of each process across species are rare. Using a process-orientated generalized linear modelling approach we show that variations in fecundity rates in populations of three species of ungulates with contrasting life histories are associated with density and winter weather in a remarkably similar manner. However, there are differences and we speculate that they are a result of differences in size between the species. Much previous research exploring the association between vital rates, population dynamics and density-dependent and -independent processes has used pattern-orientated approaches to decompose time-series into contributions from density-dependent and -independent processes. Results from these analyses are sometimes used to infer associations between vital rates, density and climatic variables. We compare results from pattern-orientated analyses of time-series with process-orientated analyses and report that the two approaches give different results. The approach of analysing relationships between vital rates, density and climatic variables may detect important processes influencing population dynamics that time-series methodologies may overlook.  相似文献   

15.
Ecological differences among clones of Daphnia pulex Leydig   总被引:12,自引:0,他引:12  
Summary Natural populations of Daphnia pulex that reproduce by obligate parthenogenesis include a number of clones. Studies on two common and two rare clones from southwestern Ontario revealed significant differences in their intrinsic rates of increase, competitive abilities, rates of ephippial egg production, and lifespans. Environmental factors such as temperature and food type had large inluences on the rate of increase of each clone. Differences in rates of increase among clones were most pronounced at temperatures higher than those encountered in nature. In general, the covariance of life history traits among clones was high. The outcome of competitive encounters between clones was deterministic and in most cases was unaffected by temperature. Clones with high rates of increase tended to be better competitors than those with low rates of increase.  相似文献   

16.
The combined effects of temperature, sex and length of pre-experimental starvation period on respiration, ammonia and inorganic phosphate excretion of the mysid shrimp Neomysis integer were studied in laboratory experiments. Of these variables, temperature had the strongest effect. A rise in experimental temperature from 6 to 16 °C increased the metabolic rates by a factor of 2 to 3.Weight-specific respiration rates of females were slightly lower than those of males. However, these differences could be attributed to differences in size. Sex did not significantly affect ammonia and inorganic phosphate excretion.A prolongation of the pre-experimental starvation period from 6 to 30 h reduced ammonia excretion of Neomys integer, but had no impact on oxygen consumption rates. Accordingly, the atomic O : N ratio increased in starved specimens. There were no discernables effects of the variables studied on atomic O : P and N : P ratios.  相似文献   

17.
目的:探讨在介入室X线电视系统下摘出眶内及眶周金属异物的临床效果。方法:选择2002年7月至2012年7月我院收治的金属异物患者86例86只眼,在介入室X线电视系统直视引导下,根据影像学特点制定个体化手术方法,经皮肤或结膜进路摘出眶内及眶周金属异物。结果:86例均成功取出异物,其中一次手术取出83例(96.5%),二次手术取出3例(3.5%)。随访2~18(9.2±5.3)月。末次随访时视力达术前水平62例(72.1%),视力提高21例(24.4%)。术前及术后末次随访时眼球运动障碍分别为34例(39.5%)和16例(18.6%),术前及术后末次随访时外伤性上睑下垂分别为5例(5.8%)和3例(3.5%)。结论:在介入室X线电视系统下摘出眶内及眶周金属异物对眶内及眶周组织损伤小,手术时间短,疗效满意,便于操作,值得推广。  相似文献   

18.
目的:探讨不同术式对早期卵巢颗粒细胞瘤初治患者预后的影响。方法:收集2000年1月~2008年12月我院收治的39例早期卵巢颗粒细胞瘤患者的临床资料,分析不同术式对肿瘤复发和预后的影响。结果:39例患者中,行全面分期手术者20例,其中7例仅予盆腔及腹主动脉旁淋巴结活检而未予淋巴结清扫,所有淋巴结术后病理皆提示无淋巴转移;19例行非全面分期手术。随访期间,全面分期手术组皆无复发,而非全面分期手术组4例复发,两组患者术后3年的复发率分别为0和21%,具有统计学差异(P〈0.05);非全面分期手术组有1例患者于术后29月死亡,死亡年龄为72岁,全面分期手术组无死亡病例,两组患者的死亡率不具有统计学差异(P〉0.05)。结论:原发性卵巢颗粒细胞瘤罕有淋巴结转移,早期卵巢颗粒细胞瘤行全面分期手术对于明确肿瘤分期、治疗及预后有重要意义,而全面分期手术中行盆腔及腹主动脉旁淋巴结清扫对于肿瘤的复发意义有限,初治患者全面分期手术时可不予淋巴清扫。  相似文献   

19.
J Abelson  J Lomas  J Eyles  S Birch  G Veenstra 《CMAJ》1995,153(4):403-412
OBJECTIVE: To obtain and contrast the informed opinions of people in five decision-making groups that could have a role in devolved governance of health care and social services. DESIGN: Deliberative polling. SETTING: Three rural and three urban communities selected from the 32 areas covered by a district health council in Ontario. PARTICIPANTS: A total of 280 citizens from five potential decision-making groups: randomly selected citizens, attendees at town-hall meetings, appointees to district health councils, elected officials and experts in health care and social services. INTERVENTION: Participants'' opinions were polled during 29 structured 2-hour meetings. MAIN OUTCOME MEASURES: Participants'' opinions on their personal willingness and their group''s suitability to be involved in devolved decision making, desired type of decision-making involvement, information preferences, preferred areas of decision-making involvement and preferred composition of decision-making bodies. RESULTS: Mean attendance at each meeting was 9.6 citizens. Although there were some significant differences in opinion among the five potential decision-making groups, there were few differences among citizens from different geographic areas. A total of 189 (72%) of people polled were personally willing to take on a role involving responsibility for overall decision-making, but far fewer thought that their group was suited to taking on responsibility (30%) or a consulting role (55%). Elected officials were the most willing (85% personally willing, 50% thought their group was suitable) and randomly selected citizens the least willing (60% personally willing, 17% thought their group was suitable) to take responsibility for overall decision making. Most citizens polled indicated less interest in involvement in specific types of decisions, except for planning and setting priorities, than in overall decision making. Only 24 participants (9%) rated their own group as suitable to take responsibility for raising revenue, 91 (33%) deemed their group suited to distribution of funds and 108 (39%) felt their group was suitable for management of services. People in all five groups ranked health care needs (mean rank 1.5 out of four options) as the most important and preferences (mean rank 3.6) as the least important information. They rated a combination body involving several community groups as the most suitable overall decision-making body (8.8 on 10-point scale). Participants favoured the representation of elected officials, the provincial government and experts on combination bodies responsible for the specific types of decisions. Overall, as the complexity of devolved decision making became clear, participants tended to assign authority to traditional decision makers such as elected officials, experts and the provincial government, but also favoured a consulting role for attendees at town-hall meetings (i.e., interested citizens). CONCLUSION: There are significant differences among groups in the community in their willingness to be involved, desired roles and representation in devolved decision making on health care and social services in Ontario.  相似文献   

20.
E. A. Clarke  S. Hilditch 《CMAJ》1983,129(12):1271-1273
Since cancer registries have different recording practices, the incidence rates that they report must be compared with caution. Indexes of reliability of recording indicated that in 1971 the reported incidence of cervical cancer in Ontario was too high. In 1971 Ontario used a method of passive reporting of cancer cases: the Ontario Cancer Registry linked hospital reports, death certificates and reports from the Ontario Cancer Treatment and Research Foundation''s treatment centres to produce a single record for each case. Pathological confirmation was requested for cases thus recorded by the registry. In 26% of cases a diagnosis other than cervical cancer was indicated. With these cases omitted, the incidence rate became 15.1/100 000, as opposed to the 20.5/100 000 reported by the registry.  相似文献   

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