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Biomedical subjects

D Menzies

Publications and source records attributed to D Menzies.

At least 19 recordsLinked to original sources
PubMed2002

Chest radiograph abnormalities associated with tuberculosis: reproducibility and yield of active cases.

SETTING: Tertiary care referral centre specialising in respiratory diseases. OBJECTIVES: Chest radiography is a major screening and diagnostic tool for tuberculosis (TB). We evaluated the reproducibility of a radiographic classification system for screening for active TB of immigration applicants to Canada. We also evaluated the validity of this classification system for detection of prevalent active TB among the screened applicants, as well as tuberculin-positive close contacts and symptomatic patients. METHODS: Reproducibility was assessed by re-reading a randomly selected 10% sample of screening chest films. Validity was estimated from the final clinical and microbiologic diagnosis of patients undergoing detailed clinical evaluation. RESULTS: Inter-reader agreement using five broad categories was moderate (kappas of 0.44-0.56), while intra-reader agreement was substantial (kappas of 0.59-0.72). After adjustment for age and patient group, the adjusted odds of active tuberculosis, relative to normal or minor findings or granulomas, for fibronodular changes was 10.2 (95% confidence interval [CI] 3.2-33), for mass or pleural effusion it was 11.6 (95%CI 3.6-37), and for parenchymal infiltrate it was 46.1 (95%CI 18-117). Among tuberculin-positive close contacts, the probability of active tuberculosis was more than 50% if the radiographs showed any mass, pleural disease, or parenchymal infiltrates. CONCLUSION: A simple classification of TB-related chest radiographic abnormalities into five broad categories had moderate to substantial reproducibility of readings, with reasonable validity.

Adolescent↗
PubMed2001

Postoperative adhesions: ten-year follow-up of 12,584 patients undergoing lower abdominal surgery.

PURPOSE: Postoperative adhesions are a significant problem after colorectal surgery. However, the basic epidemiology and clinical burden are unknown. The Surgical and Clinical Adhesions Research Study has investigated the scale of the problem in a population of 5 million. METHODS: Validated data from the Scottish National Health Service Medical Record Linkage Database were used to define a cohort of 12,584 patients undergoing open lower abdominal surgery in 1986. Readmissions for potential adhesion-related disease in the subsequent ten years were analyzed. The methodology was conservative in interpreting adhesion-related disease. RESULTS: In the study cohort 32.6 percent of patients were readmitted a mean of 2.2 times in the subsequent ten years for a potential adhesion-related problem. Although 25.4 percent of readmissions were in the first postoperative year, they continued steadily throughout the study period. After open lower abdominal surgery 7.3 percent (643) of readmissions (8,861) were directly related to adhesions. This varied according to operation site: colon (7.1 percent), rectum (8.8 percent), and small intestine (7.6 percent). The readmission rate was assessed to provide an indicator of relative risk of adhesion-related problems after initial surgery. The overall average rate of readmissions was 70.4 per 100 initial operations, with 5.1 directly related to adhesions. This rose to 116.4 and 116.5, respectively, after colonic or rectal surgery-with 8.2 and 10.3 directly related to adhesions. CONCLUSIONS: There is a high relative risk of adhesion-related problems after open lower abdominal surgery and a correspondingly high workload associated with these readmissions. This is influenced by the initial site of surgery, colon and rectum having both the greatest impact on workload and highest relative risk of directly adhesion-related problems. The study provides sound justification for improved adhesion prevention strategies.

Abdomen↗
PubMed2001

Small bowel obstruction due to postoperative adhesions: treatment patterns and associated costs in 110 hospital admissions.

The workload and costs of the emergency admissions and treatment of adhesive small bowel obstruction (ASBO) are unclear. This review details and costs the admission workload of ASBO. All admissions over a 2-year period for ASBO at two district general hospitals were identified through ICD10 diagnostic codes. Diagnostic investigations, treatment patterns, ward stay and outcome information for admissions were detailed from clinical records to develop mean cost estimates and assess the associated workload. Of the 298 admissions identified, 188 were not due to ASBO and were excluded from analysis. Of the 110 admissions detailed, 41 (37%) were treated surgically and 69 (63%) conservatively. Most admissions occurred through general practitioner referral (86.4%) to accident and emergency (90.0%). Mean (SD) length of stay was 16.3 days (11.0 days) for surgical treatment and 7.0 days (4.6 days) for conservative treatment. In-patient mortality was 9.8% for the surgical group and 7.2% for the conservative group. Costs were based on the mean values from both centres for surgical and conservative admissions and detailed according to the cost of referral and follow-up (100.98 Pounds surgical versus 102.61 Pounds conservative), hospital ward and ICU stay (3,327.48 Pounds versus 1,267.92 Pounds), theatre time (832.32 Pounds surgical only), investigations (282.73 Pounds versus 207.33 Pounds) and drug costs (133.90 Pounds versus 28.29 Pounds). Total treatment cost per admission for ASBO was 4,677.41 Pounds for surgically treated admissions and 1,606.15 Pounds for conservatively treated admissions. The impact of admissions for ASBO is considerable in terms of both costs and workload. Bed stay for these admissions represents the equivalent of almost one surgical bed per year and at least 2 days theatre time, impacting on surgical capacity and waiting lists. Adhesion prevention strategies may reduce the workload associated with ASBO. The review provides useful information for planning resource allocation.

Adolescent↗
PubMed2001

Yield of smear, culture and amplification tests from repeated sputum induction for the diagnosis of pulmonary tuberculosis.

OBJECTIVES: To assess the yield of repeated sputum induction for the diagnosis of active tuberculosis in patients who do not produce spontaneous sputum, or with smear-negative spontaneous samples. METHODS: Induced sputum was examined with fluorescent microscopy, two amplification methods (PCR Amplicor MTB, and MTD2), and cultured for mycobacteria using liquid (Bactec 12B) and Lowenstein-Jensen media. Bronchoscopy and collection of other specimens were performed at the discretion of the treating physician. RESULTS: A total of 1115 sputum inductions performed in 500 patients without adverse events yielded an adequate specimen in 1113 (99.8%), and microbiological confirmation in 43 of 44 (98%) culture-positive active TB cases. Yield increased with repeated sputum induction. The cumulative yield for acid-fast bacilli smear and mycobacterial culture was 64% and 70% respectively for one, 81% and 91% for two, 91% and 99% for three, and 98% and 100% for four induced samples. Yield of PCR also increased with the greater number of induced samples tested. CONCLUSIONS: Repeated sputum induction could considerably improve diagnostic accuracy for pulmonary TB.

Analysis of Variance↗
PubMed2000

Hospital ventilation and risk for tuberculous infection in canadian health care workers. Canadian Collaborative Group in Nosocomial Transmission of TB.

BACKGROUND: The risk for and determinants of transmission of tuberculosis in hospitals caring for moderate numbers of patients with tuberculosis remain uncertain. OBJECTIVE: To study the association of tuberculin conversion among health care workers with ventilation of patient care areas. DESIGN: Cross-sectional observational survey. SETTING: 17 acute-care community or university hospitals. PARTICIPANTS: All personnel who worked at least 2 days per week in the respiratory and physiotherapy departments or in selected nursing units. MEASUREMENTS: Participating workers underwent tuberculin skin testing and completed self-administered questionnaires. Previous tuberculin tests and bacille Calmette-Guérin vaccinations were verified. Records of patients with tuberculosis who were hospitalized in the 3 years preceding the study were reviewed. Air exchanges per hour in patient care areas were measured by using a tracer gas technique. Multivariate proportional hazards regression was used to estimate the effect of occupational factors on documented tuberculin conversion, after adjustment for nonoccupational factors, among participants with at least one previous negative result on tuberculin skin testing. RESULTS: Tuberculin conversion was associated with ventilation of general or nonisolation patient rooms of less than 2 air exchanges per hour (adjusted hazard ratio, 3.4 [95% CI, 2.1 to 5.8]); with work in moderate- to high-risk hospitals (adjusted hazard ratio, 2.2 [CI, 1.3 to 3.5]); and with work in the nursing (adjusted hazard ratio, 4.3 [CI, 2.7 to 6.9]), respiratory therapy (adjusted hazard ratio, 6.1 [CI, 3.1 to 12.0]), and physiotherapy (adjusted hazard ratio, 3.3 [CI, 1.5 to 7.2]) departments or housekeeping (adjusted hazard ratio, 4.2 [CI, 2.3 to 7.6]). Conversion was not associated with inadequate ventilation of respiratory isolation rooms (adjusted hazard ratio, 1.0 [CI, 0.8 to 1.3]). CONCLUSION: Tuberculin conversion among health care workers was strongly associated with inadequate ventilation in general patient rooms and with type and duration of work, but not with ventilation of respiratory isolation rooms.

Canada↗
PubMed2000

Minimally invasive surgery for posterior gastric stromal tumors.

BACKGROUND: Because involvement is extremely rare, surgery for gastric stromal tumors consists of local excision with clear resection margins. The aim of this study was to report the results of a consecutive series of nine patients with posterior gastric stromal tumors that were excised using a minimally invasive method. METHODS: Patients received a general anesthetic before placement of three laparoscopic ports- a 10-mm (umbilical) port for the telescope and two working ports, a 12-mm port (left upper quadrant) and a 10-mm port (right upper quadrant). Grasping forceps were placed through an anteriorly placed gastrotomy to deliver the tumor through the gastrotomy into the abdominal cavity, thus allowing an endoscopic linear cutter to excise the tumor with a cuff of normal gastric tissue. RESULTS: Nine consecutive patients with a median age of 73 years (range, 47-83) were treated. In seven patients, laparoscopic removal of the tumor was achieved. Two patients required conversion to an open operation because the tumor could not be delivered into the abdominal cavity. The median length of postoperative stay for the seven patients in whom the procedure was completed laparoscopically was 3 days (range, 2-6). CONCLUSIONS: Posterior gastric stromal tumors can be removed safely using this minimally invasive method. Delivery of the tumor through the gastrotomy is essential for success.

Aged↗
PubMed2000

What does tuberculin reactivity after bacille Calmette-Guérin vaccination tell us?

The effect of bacille Calmette-Guérin (BCG) vaccination on tuberculin reactivity is briefly reviewed. BCG vaccination will almost invariably result in tuberculin conversion with a positive tuberculin skin test developing 4-8 weeks after vaccination. However, these tuberculin reactions will wane-rapidly in all individuals who receive the vaccine in the neonatal period and more slowly in those who are vaccinated at an older age such as during the primary-school years. Of BCG vaccine recipients whose initial tuberculin skin test is negative, 10%-25% will have a positive tuberculin skin test if they are retested within 1-4 weeks-the so-called "booster phenomenon. " There is no relationship between tuberculin reactivity after BCG vaccination and the protective efficacy of the vaccine against development of active tuberculosis. Therefore, the ideal BCG vaccine would produce a scar at the site of injection to identify individuals who have been vaccinated but would have no effect on tuberculin reactivity.

Adolescent↗
PubMed2000

Tuberculosis screening of immigrants to low-prevalence countries. A cost-effectiveness analysis.

All adult immigrant applicants to Canada undergo chest radiographic screening for tuberculosis (TB). Tuberculin skin testing could reduce the number of chest X-rays, and identify more candidates for prophylaxis. We modeled the cost-effectiveness of chest radiography and tuberculin skin testing for TB prevention over a 20-yr time frame, among three simulated cohorts of 20-yr-old immigrants. Compared with no screening, radiographic screening prevented 4.3% of expected active TB cases in the highest risk cohort (50% TB-infected, 10% human immunodeficiency virus [HIV] seroprevalence), and 8.0% in the lowest risk cohort (5% TB-infected, 1% HIV seroprevalence). Tuberculin skin testing further reduced the expected incidence 8.0% and 4.0%, respectively. Compared with no screening, radiographic screening cost $3,943 Canadian per active TB case prevented in the highest risk cohort, and $236,496 per case prevented in the lowest risk group. Compared with radiographic screening, mass tuberculin skin testing cost $32,601 per additional case prevented in the highest risk group, and $68,799 per additional case prevented in the lowest risk group. Chest radiographic screening of young immigrants from countries with a high prevalence of TB is a relatively inexpensive means of TB prevention. Tuberculin skin testing is considerably less cost-effective. For immigrants from low-prevalence countries, both interventions are extremely costly with negligible impact. The cost-effectiveness of either strategy would be greatly enhanced by increased adherence to chemoprophylaxis recommendations. Radiographic screening of groups with a high prevalence of tuberculous infection will then likely save money.

AIDS-Related Opportunistic Infections↗
PubMed2000

Does size matter? Utility of size of tuberculin reactions for the diagnosis of mycobacterial disease.

It is a common belief that larger tuberculin reactions are more serious, and more likely to indicate patients with active tuberculosis (TB) or at high risk of disease in the future. Among 182 close contacts, and 502 patients suspected of possible active TB, 529 underwent tuberculin skin testing (TST) and 605 had a chest radiograph. Final diagnoses, based on all available clinical, microbiological, histological, and radiographic information, were active TB, 68; inactive TB, 274; nontuberculous mycobacterial disease, 14; conditions associated with anergy, 36; no detectable abnormality (except a positive TST) or condition unrelated to TB, 213; and negative TST, no further evaluation, 79. Among these patients, TST of 5 mm or larger was significantly more likely to indicate active or inactive TB (p < 0.001). However, among patients with TST of 5 mm or greater, the size and frequency distribution of tuberculin reactions were not different between subjects with different diagnoses, nor between subjects with different types or extent of radiographic findings. As well, TST reactions were no different in 121 subjects with or 176 subjects without a history of BCG vaccination. In close contacts or patients suspected of active TB, reactions less than 5 mm indicated lower likelihood of active or inactive disease, but above that threshold, size of tuberculin reaction did not matter.

Cohort Studies↗
PubMed2000

Accuracy and utility of commercially available amplification and serologic tests for the diagnosis of minimal pulmonary tuberculosis.

Diagnosis of patients with minimal active tuberculosis (TB) is difficult, as there is no single test with high sensitivity and specificity. The yield and clinical utility of a combination of diagnostic tests were prospectively studied among 500 consecutive patients referred for sputum induction for diagnosis of possible active TB. Patients underwent sputum induction, chest X-ray, tuberculin testing, and had blood drawn for serologic testing (Detect-TB test; Biochem ImmunoSystems). Sputum was examined with fluorescent microscopy and PCR (Amplicor MTB-Roche) and cultured for mycobacteria using liquid (BACTEC) and solid media. For the diagnosis of the 60 cases of active TB, sensitivity and specificity, respectively, of the following diagnostic tests were mycobacterial culture, 73% and 100%; PCR, 42% and 100%; chest X-ray, 67-77% and 66-76%; tuberculin testing, 94% and 20%; and serology, 33% and 87%. After consideration of PCR and radiographic and clinical characteristics, a positive serologic test was independantly associated with diagnosis of active disease (adjusted odds of disease if positive, 2.6; 95% confidence limits, 1.1,6.1). No currently available test has sensitivity and specificity high enough for the accurate diagnosis of minimal pulmonary TB. Utilization of a combination of tests, together with consideration of key clinical characteristics, could improve diagnostic accuracy.

Adult↗
PubMed2000

Comparison of cost-effectiveness of tuberculosis screening of close contacts and foreign-born populations.

Although tuberculosis (TB) screening of immigrants has been conducted for over 50 yr in many industrialized countries, its cost- effectiveness has never been evaluated. We prospectively compared the yield and cost-effectiveness of two immigrant TB screening programs, using close-contact investigation and passive case detection. Study subjects included all immigration applicants undergoing radiographic screening, already arrived immigrants requiring surveillance for inactive TB, and close contacts of active cases resident in Montreal, Quebec, Canada, who were referred from June 1996 to June 1997 to the Montreal Chest Institute (MCI), a referral center specializing in respiratory diseases. For all subjects seen, demographic data, investigations, diagnoses, and therapy were abstracted from administrative data bases and medical charts. Estimated costs of detecting and treating each prevalent active case and preventing future active cases, based on federal and provincial health reimbursement schedules, were compared with the costs for passively diagnosed cases of active TB. Over a period of 1 yr, the three programs detected 27 cases of prevalent active TB and prevented 14 future cases. As compared with passive case detection, close-contact investigation resulted in net savings of $815 for each prevalent active case detected and treated and of $2,186 for each future active case prevented. The incremental cost to treat each case of prevalent active TB was $39,409 for applicant screening and $24,225 for surveillance, and the cost of preventing each case was $33,275 for applicants and $65,126 for surveillance. Close-contact investigation was highly cost effective and resulted in net savings. Immigrant applicant screening and surveillance programs had a significant impact but were much less cost effective, in large part because of substantial operational problems.

Cohort Studies↗
PubMed2000

Agreement in measuring socio-economic status: area-based versus individual measures.

Area-based socio-economic status (SES) measures are frequently used in epidemiology. Such an approach assumes socio-economic homogeneity within an area. To quantify the agreement between area-based SES measures and SES assessed at the individual level, we conducted a cross-sectional study of 943 children who resided in 155 small enumeration areas and 117 census tracts from 18 schools in Montreal, Quebec. We used street address information together with 1986 census data and parental occupation to establish area-based and individual level SES indicators, respectively. As compared with the SES score determined at the level of the individual, 13 different area-based SES indices classified the children within the same quintile 28.7% (+/- 2.8%) of the time. The discrepancy was within one quintile in 35.3% (+/- 2.3%) of cases, two quintiles in 20.6% (+/- 3.6%), three quintiles in 11.3% (+/- 4.2%) and four quintiles in 4.1% (+/- 0.2%). In conclusion, we observed a substantial discrepancy between area- based SES measures and SES assessed at the individual level. Caution should therefore be used in designing or interpreting the results of studies in which area-based SES measures are used to test hypotheses or control for confounding.

Bias↗