[Furuncular myiasis caused by Dermatobia hominis. Fortuitous diagnosis on extemporaneous macroscopic analysis of an excised cutaneous nodule]. / Myiase furonculoïde à Dermatobia hominis: diagnostic fortuit sur la coupe macroscopique extemporanée d'un nodule cutané.

BACKGROUND: Furuncular myiasis is a parasitic disease caused by the development of human botfly larva in the skin. It affects people living in tropical countries and travelers returning from these countries and concerns a number of medical specialties. One form of treatment involves surgical extraction of the parasites. PATIENTS AND METHODS: We report the case of a 47-year-old man returning from Guyana presenting two furuncle-like nodules of the skin on the right buttock and on the right shoulder blade. Extemporaneous intraoperative macroscopic examination of the buttock nodule resulted in diagnosis of myiasis caused by the human botfly, Dermatobia hominis. DISCUSSION: The diagnosis of furuncular myiasis is made primarily on clinical grounds and should be suspected on observation of an abscess in subjects returning from a tropical region. It is consequently rare to find D. hominis in biopsy specimens. In the present case, macroscopic examination showed an extremely rare image of the edge of the intact larva in a longitudinal cut, which to our knowledge has never been published to date.

Risk factors for susceptibility to varicella in newly arrived adult migrants in Canada.

Varicella occurs at an older age in tropical compared to cold climates. Migrants from tropical countries provide the opportunity to gain insights into observed global differences in varicella epidemiology. Severity of varicella increases with age thus, description of risk factors for varicella susceptibility will identify those who would benefit most from vaccination. A total of 1480 migrants, with a mean age of 32 years, were recruited in the pre-vaccination period (2002-2004) in Montreal, Canada. A questionnaire was administered and serum varicella antibodies were measured. Overall 6% were susceptible and ranged from 0·8% to 14·1% in subgroups. Risk factors for susceptibility were younger age, recent arrival, and originating from a tropical country. This could be modified by conditions that increased the probability of person-to-person spread of varicella through direct contact in source countries such as larger community size or household crowding. Many new young adult migrants would benefit from targeted varicella vaccination programmes.

Estimating the prevalence of polymyositis and dermatomyositis from administrative data: age, sex and regional differences.

OBJECTIVE: To estimate the prevalence of polymyositis and dermatomyositis using population-based administrative data, the sensitivity of case ascertainment approaches and patient demographics and these parameters. METHODS: Cases were ascertained from Quebec physician billing and hospitalisation databases (approximately 7.5 million beneficiaries). Three different case definition algorithms were compared, and statistical methods were also used that account for imperfect case ascertainment, to generate estimates of disease prevalence and case ascertainment sensitivity. A hierarchical Bayesian latent class regression model was developed to assess patient characteristics with respect to these parameter estimates. RESULTS: Using methods that account for the imperfect nature of both billing and hospitalisation databases, the 2003 prevalence of polymyositis and dermatomyositis was estimated to be 21.5/100,000 (95% credible interval (CrI) 19.4 to 23.9). Prevalence was higher for women and for older individuals, with a tendency for higher prevalence in urban areas. Prevalence estimates were lowest in young rural men (2.7/100,000, 95% CrI 1.6 to 4.1) and highest in older urban women (70/100,000, 95% CrI 61.3 to 79.3). Sensitivity of case ascertainment tended to be lower for older versus younger individuals, particularly for rheumatology billing data. Billing data appeared more sensitive in ascertaining cases in urban (vs rural) regions, whereas hospitalisation data seemed most useful in rural areas. CONCLUSIONS: Marked variations were found in the prevalence of polymyositis and dermatomyositis according to age, sex and region. These methods allow adjustment for the imperfect nature of multiple data sources and estimation of the sensitivity of different case ascertainment approaches.

The relationship between cancer and medication exposures in systemic lupus erythaematosus: a case-cohort study.

OBJECTIVE: To examine if, in systemic lupus erythaematosus (SLE), exposure to immunosuppressive therapy (cyclophosphamide, azathioprine, methotrexate) increases cancer risk. METHODS: A case-cohort study was performed within a multi-site international SLE cohort; subjects were linked to regional tumour registries to determine cancer cases occurring after entry into the cohort. We calculated the hazard ratio (HR) for cancer after exposure to an immunosuppressive drug, in models that controlled for other medications (anti-malarial drugs, systemic glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs), aspirin), smoking, age, sex, race/ethnicity, geographic location, calendar year, SLE duration, and lupus damage scores. In the primary analyses, exposures were treated categorically (ever/never) and as time-dependent. RESULTS: Results are presented from 246 cancer cases and 538 controls without cancer. The adjusted HR for overall cancer risk after any immunosuppressive drug was 0.82 (95% CI 0.50-1.36). Age > or = 65, and the presence of non-malignancy damage were associated with overall cancer risk. For lung cancer (n = 35 cases), smoking was also a prominent risk factor. When looking at haematological cancers specifically (n = 46 cases), there was a suggestion of an increased risk after immunosuppressive drug exposures, particularly when these were lagged by a period of 5 years (adjusted HR 2.29, 95% CI 1.02-5.15). CONCLUSIONS: In our SLE sample, age > or = 65, damage, and tobacco exposure were associated with cancer risk. Though immunosuppressive therapy may not be the principal driving factor for overall cancer risk, it may contribute to an increased risk of haematological malignancies. Future studies are in progress to evaluate independent influence of medication exposures and disease activity on risk of malignancy.

Risk of hepatitis C virus transmission through drug preparation equipment: a systematic and methodological review.

The use of blood-contaminated drug preparation equipment is believed to be associated with the transmission of hepatitis C virus (HCV) among injection drug users (IDUs), but the extent of HCV infection risk is unclear. The objective of this review was to appraise the evidence regarding HCV incidence associated with the use of drug preparation equipment such as drug mixing containers, filters and water. In June 2007, cohort and case-control studies examining the association of HCV incidence with the sharing of drug preparation equipment were identified by searching electronic reference databases as well as the reference lists of published papers. Ten studies (seven cohort and three nested case-control) met the inclusion criteria for the review. The relative risk of HCV infection associated with drug preparation equipment were mainly between 2.0 and 5.9; however, the precision of the estimates from individual studies were marked by wide confidence intervals. Few studies exist to allow an adequate assessment of the individual contributions of containers, filters and water to HCV incidence. The major methodological limitations of reviewed studies were short follow-up times, inadequate control of confounders and lack of exclusion of periods when IDUs were not at risk for HCV infection through drug injection. Current evidence implicating the association of drug preparation equipment with HCV incidence is limited by several methodological concerns.

The safety of endoscopic sphincterotomy in patients receiving antiplatelet agents: a case-control study.

OBJECTIVE: To determine whether antiplatelet agents are associated with endoscopic sphincterotomy-related haemorrhage as few well-controlled data exist on this controversial issue. METHODS: A case-control study in a tertiary care setting included cases with bleeding following endoscopic sphincterotomy, matched with 2-3 controls selected according to age +/- 15 years, sex, and procedural date+/- 2 years. Cases and controls were compared for possible risk factors of postendoscopic sphincterotomy bleeding (presence of a coagulopathy and cholangitis). The main outcome measurement was the association between the use of antiplatelet medications and postendoscopic sphincterotomy bleeding after adjustment for possible confounding. RESULTS: The 40 cases [mean age 68 +/- 17 (s.d.) years, 50% female] and 86 controls [68 +/- 16 years, 50% female] were comparable except for differences noted in International Normalized Ratio (INR) (>2 in four cases vs. two controls), and pre-endoscopic sphincterotomy cholangitis (45% vs. 20%). Amongst cases, 13% were on aspirin and 3% on clopidogrel; 17% of controls took aspirin, and 4% a non-steroidal anti-inflammatory drug. 53% of cases bled immediately; the remainder haemorrhaged at 2 +/- 3 days. After adjustment for an elevated INR and cholangitis, exposure to antiplatelet agents was not significantly associated with procedure-related bleeding (odds ratio = 0.41, 95% CI [ 0.13; 1.31]). CONCLUSION: This case-control study provides controlled data suggesting that antiplatelet agents do not significantly increase the risk of clinically-important bleeding related to endoscopic sphincterotomy. The low prevalences of non-steroidal anti-inflammatory drugs and clopidogrel use limit any definite conclusion on their elective use before endoscopic sphincterotomy.

Lung cancer in systemic lupus erythematosus.

BACKGROUND: Evidence points to a link between systemic lupus erythematosus (SLE) and an increased risk of lung cancer. Our objective was to provide a brief report of the lung cancer cases from an SLE cohort, with respect to demographics, histology, and exposures to smoking and immunosuppressive medications. METHODS: Data were obtained from a multi-site international cohort study of over 9500 SLE patients from 23 centres. Cancer cases were ascertained through linkage with regional tumor registries. RESULTS: We analyzed information on histology subtype for 30 lung cancer cases that had occurred across five countries. Most (75%) of these 30 cases were female, with a median age of 61 (range 27-91) years. In eight cases, the histological type was not specified. In the remainder, the most common histological type reported was adenocarcinoma (N=8; two of the adenocarcinomas were bronchoalveolar carcinoma) followed by small cell carcinoma (N=6), and squamous cell carcinoma (N=6) with one case each of large cell carcinoma and carcinoid tumor. Most (71%) of the lung cancer cases were smokers; only the minority (20%) had been previously exposed to immunosuppressive agents. CONCLUSIONS: The histological distribution of the lung cancers from the SLE sample appeared similar to that of lung cancer patients in the general population, though the possibility of a higher proportion of more uncommon tumors (such as bronchoalveolar and carcinoid) cannot be excluded. A large proportion of the cancer cases were smokers, which is also not surprising. However, only a minority appeared to have been exposed to immunosuppressive agents. A large case-cohort study currently in progress should help shed light on the relative importance of these exposures in lung cancer risk for SLE patients.

Validated methods for identifying tuberculosis patients in health administrative databases: systematic review.

BACKGROUND: An increasing number of studies are using health administrative databases for tuberculosis (TB) research. However, there are limitations to using such databases for identifying patients with TB. OBJECTIVE: To summarise validated methods for identifying TB in health administrative databases. METHODS: We conducted a systematic literature search in two databases (Ovid Medline and Embase, January 1980-January 2016). We limited the search to diagnostic accuracy studies assessing algorithms derived from drug prescription, International Classification of Diseases (ICD) diagnostic code and/or laboratory data for identifying patients with TB in health administrative databases. RESULTS: The search identified 2413 unique citations. Of the 40 full-text articles reviewed, we included 14 in our review. Algorithms and diagnostic accuracy outcomes to identify TB varied widely across studies, with positive predictive value ranging from 1.3% to 100% and sensitivity ranging from 20% to 100%. CONCLUSIONS: Diagnostic accuracy measures of algorithms using out-patient, in-patient and/or laboratory data to identify patients with TB in health administrative databases vary widely across studies. Use solely of ICD diagnostic codes to identify TB, particularly when using out-patient records, is likely to lead to incorrect estimates of case numbers, given the current limitations of ICD systems in coding TB.

Second primary cancers following treatment of Hodgkin's disease.

A cohort study designed to evaluate the carcinogenicity of treatment for Hodgkin's disease (HD) was conducted. This report describes 2,591 patients with HD diagnosed in 1940-75 and presents an analysis of follow-up findings through 1978. Seventy-four second primary cancers (excluding basal cell and squamous cell cancers of the skin and in situ carcinomas of the cervix uteri) were observed 1 year or more after diagnosis of HD, including 21 leukemias. Twenty leukemias occurred after chemotherapy. The relative risk (RR) of leukemia after intensive chemotherapy with or without radiotherapy was 136 relative to general population incidence rates. In the subgroup with both intensive chemotherapy and intensive radiotherapy, the RR of leukemia was 125. Both RR estimates differed significantly from unity. The RR of cancers other than leukemia 10 years or more after intensive radiotherapy relative to no intensive therapy was 19.5 (95% confidence limits: 4.8-80).

Incidence of second cancers in patients treated for Hodgkin's disease.

BACKGROUND: Numerous studies of treatment for Hodgkin's disease have demonstrated large increases in the incidence of leukemia in the early years following chemotherapy, although the duration of effect and the specific agents involved are not well understood. Also, some, but not all, studies have indicated that the incidence of certain solid tumors increases following treatment for Hodgkin's disease. PURPOSE: We studied the association between treatment for Hodgkin's disease and the incidence of second cancers. METHODS: We conducted a study within a cohort that included 10,472 patients from 14 cancer centers in the United States and Canada who were first diagnosed as having Hodgkin's disease at some point from 1940 through 1987. Discounting the 1st year after diagnosis, the average length of follow-up was 7.1 years per subject. RESULTS: We observed 122 leukemias and 438 solid tumors. The relative risk (RR) of leukemia following chemotherapy, compared with no chemotherapy, was 14 (95% confidence interval [CI] = 5.6-35). Increased risks of leukemia were observed after treatment with chlorambucil (RR = 2.0; 95% CI = 1.1-3.6), procarbazine (RR = 4.9; 95% CI = 2.6-9.1), vinblastine (RR = 1.7; 95% CI = 1.1-2.8), and a group of rarely used drugs that included methotrexate, vindesine, etoposide, and 22 others (RR = 3.8; 95% CI = 1.9-7.4). RRs were also estimated for various combinations of drugs, including MOPP (mechlorethamine, vincristine, procarbazine, and prednisone) (RR = 5.9; 95% CI = 2.9-12) and ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) (RR = 1.5; 95% CI = 0.7-3.4). The RR of leukemia associated with splenectomy was 1.6 (95% CI = 1.0-2.5). The RR of solid tumors following chemotherapy was 1.4 (95% CI = 1.1-1.8). For the group of rarely used drugs, the RR of solid tumors was 3.1 (95% CI = 1.7-5.8). Chemotherapy was associated with an increased risk of cancers of the bones, joints, articular cartilage, and soft tissues (RR = 6.0; 95% CI = 1.7-20), and cancers of the female genital system (RR = 1.8; 95% CI = 1.1-3.2). In patients followed for 10 or more years after radiotherapy, increased risks were found for cancers of the respiratory system and intrathoracic organs (RR = 2.7; 95% CI = 1.1-6.8) and for cancers of the female genital system (RR = 2.4; 95% CI = 1.1-5.4). CONCLUSIONS: Procarbazine, chlorambucil, and vinblastine are associated with increased leukemia risk. Combination drug regimens have leukemogenic effects estimated as the product of RRs for individual drugs. Chemotherapy and radiotherapy increase the risk of selected solid tumors, and the effect of chemotherapy on solid tumor risk is weaker than the leukemogenic effect. IMPLICATIONS: Without doubt, the benefits of treatment of Hodgkin's disease outweigh the risk of a subsequent malignancy, but data on the carcinogenic effects of radiation and drugs beyond 10 years after treatment continue to be sparse, and future analyses should be directed at long-term survivors.

Selection of controls in database case-control studies: glucocorticoids and the risk of glaucoma.

In case-control studies conducted using computerized databases, controls are often selected as a random sample from the base population. This representative choice of controls is intended to guard against selection bias. We show, using data from a database case-control study, that such a definition of controls may also lead to selection bias under two conditions: (1) if the target disease has a prolonged asymptomatic clinical course with its detection depending on a specific physical examination and (2) if exposed patients have a higher likelihood of having the disease detected than unexposed patients. The extent of the bias that could result from the use of randomly selected controls was investigated in the context of a case-control study of the risk of ocular hypertension or glaucoma associated with the use of glucocorticoids, conducted using the Quebec universal health insurance computerized databases. This article also illustrates that a computerized database can be useful to empirically explore opportunities for bias.

Analytic epidemiologic methods for research on nosocomial infections: definitions and examples.

Two types of epidemiologic studies are presented: the cohort study and the case-control study. The fundamentals distinction between the two methods is in the definition of the population groups for study. The cohort approach identifies groups with different exposure histories, whereas the case-control approach begins with groups with different health and disease characteristics. The investigation in the cohort method involves collection of data on the disease experience of the various exposure groups from date of exposure to some later follow-up date. Data collection in the case-control study is concerned with the exposure history prior to the date of the identified health and disease status. Both approaches are satisfactory in general, but either may have distinct advantages in a given study, depending chiefly on the frequencies of exposure and disease and on the nature of biases inherent in available data.

Accuracy of telephone dietary recalls in elderly subjects.

Accuracy of telephone-administered dietary recalls was determined for 159 elderly subjects by comparing the telephone recalls of single midday meals consumed at congregate meal sites with data on actual intake for the meals. Accuracy was determined for kinds of food eaten, size of portions eaten, and content of 15 nutrients. Exact agreement between the two data sources on the kinds of food eaten occurred for only 55% of the observed food items. For 5 of the 10 food groups evaluated, the bias in mean recalled portion-size data was less than 10%. There was evidence of attenuated regression slopes relating recalled to observed portion sizes for 4 of the 10 food groups; adjusted r2 values for the recalled portion sizes ranged from 0.02 to 0.94. Because errors in the recalls of the kinds and amounts eaten tended to go in different directions, the accuracy of the nutrient data was better than that for the food-item or the portion-size data. For 12 of the 15 nutrients evaluated, the bias in mean recalled intake data was less than 10%. Although the adjusted r2 values for the recalled nutrient data ranged from 0.24 to 0.58, there was evidence of attenuated regression slopes relating recalled intake to observed intake for only 5 of the 15 nutrients. We conclude that telephone contact is an acceptable way to obtain short-term dietary recall data from elderly subjects.

Cost effectiveness of screening for primary open angle glaucoma.

OBJECTIVES AND SETTING: To determine the cost effectiveness of screening for glaucoma. METHODS: Information on treatment efficacy, diagnostic methods, epidemiological characteristics of glaucoma, and costs were determined from the literature, from administrative databases, and from experts. Scenarios with different screening frequency, age, participation in screening, compliance with treatment, treatment efficacy, and diagnostic tests were examined. RESULTS: The initial scenario comprised three-yearly screening of subjects aged 40-79 by funduscopy and tonometry, followed by perimetry when abnormalities were discovered. The assumption of levels of participation in screening and of compliance with treatment of 75%, and treatment efficacy of 50% resulted in a cost of $C100,000 per year of blindness prevented. A scenario in which screening was restricted to subjects aged 65-79, with the same input variables, would prevent 81% of the cases of blindness prevented with scenario 1, at a cost of $C42,000 per year of blindness prevented. Screening with tonometry only as the initial diagnostic test in subjects aged 65-79 would result in a cost of $C36,000 per year of blindness prevented, but would only prevent 59% of the cases prevented with scenario 1. CONCLUSIONS: There is as yet no proof that treatment of glaucoma or of high intraocular pressure will arrest the progression of glaucoma to blindness. Even when treatment efficacy is assumed to be as high as 50%, however, the cost effectiveness of most glaucoma screening programmes considered would not be competitive.

Prevalence of HIV infection and risk behaviours among Montreal street youth.

We aim to estimate HIV prevalence and associated risk factors among street youth in Montreal, Canada. We conducted a one-year cross-sectional anonymous study in 1995. We recruited youth aged 13-25 years meeting specific criteria for itinerancy through the 20 major Montreal street youth agencies. Participation included a structured interview and provision of an oral specimen for HIV testing. Among the 909 subjects studied, 99.3% had been sexually active, 25.9% had exchanged sex for money, gifts, drugs, a place to sleep, or other things; 31.8% reported anal sex; and 36.4% reported having ever injected drugs. Overall, HIV prevalence was 1.9% (1.1% in girls and 2.2% in boys). Multivariate logistic regression showed that being over 20 years of age (adjusted odds ratio (AOR) 7.09), having injected drugs (AOR 4.48), having engaged in prostitution (AOR 3.32), and being born outside Canada (AOR 4.41) were all independently associated with HIV infection.

Risk behaviours and prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae genital infections among Montreal street youth.

We estimated the prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae genital tract infections among 302 Montreal street youth (223 boys) and identified associated risk factors. Study participants, 14-25 years old (average 20.9 years), meeting specific criteria for homelessness, were recruited in street youth agencies. Participation included a structured interview and provision of a urine specimen. Among sexually active youth, (n = 300) 30.0% had more than five heterosexual partners and 13.0% had at least one homosexual partner (last year), 10.7% had received money in exchange for sex (last six months) and 47.0% reported sexual relations resulting in pregnancy (lifetime). Among all youths, 82.1% had used at least one type of illicit drug, and 30.1% injected drugs at least once (last six months). The prevalence of C. trachomatis infection was 6.6% (95% CI 4.1-10.0%). Prevalence did not vary significantly by sex, age or any other variable, except history of pregnancy (10.4% among youth with history of pregnancy vs 3.6% among others, P = 0.02). No cases of N. gonorrhoeae infection were found.

Migration and HIV: an epidemiological study of Montrealers of Haitian origin.

We aimed to determine the prevalence of HIV infection and associated risk factors among Montrealers of Haitian origin. We carried out a voluntary, anonymous survey in 7 primary care medical clinics in Montreal among 5039 persons aged 15 to 49 years born in Haiti or with at least one parent born in Haiti. The participation rate was 94.3%. Overall, HIV prevalence was 1.3% (1.6% in men and 1.1% in women). The HIV prevalence was lower among those born in Canada or who had resided in Canada longer. The prevalence among subjects who had travelled to Haiti in the previous 5 years was 2.0%, twice the rate of those who had not. The adjusted population attributable fraction of HIV infections associated with having had unprotected sex in Haiti was 10.2%. This study identified risk factors which will help in the design of more effective prevention programmes among Montrealers of Haitian origin.

Knowledge, attitudes, beliefs and practices related to AIDS among Montreal residents of Haitian origin.

We used interviews of 268 subjects to ascertain knowledge, attitudes, beliefs and practices related to AIDS among Montrealers of Haitian origin, from November 1987 through October 1988. The questions on knowledge included items on general knowledge about the disease (prevention of AIDS, treatment, nature and manifestations of the disease, screening and high-risk groups), and more specific questions about modes of HIV-1 transmission. The average correct answers to questions on general knowledge about AIDS was 81%. The questions on HIV-1 transmission concerned both modes of infection that are scientifically established, and other modes that are not scientifically recognized. The average correct answers to questions on scientifically recognized modes of infection was 94% and the average correct answers for modes of transmission that are not scientifically accepted was 74%. The attitudes and beliefs of Montrealers of Haitian origin toward persons with AIDS was only moderately favourable. Attitudes and beliefs toward condom promotion were very positive. The percentage of subjects reporting male homosexuality or injection drug use was extremely small. 23% of subjects who had experienced sexual intercourse reported that they had two or more partners during the 12 months preceding the survey.

PIP: The authors used interviews from 268 patients to ascertain knowledge, attitudes, beliefs, and practices related to AIDS among Montrealers of Haitian origin. Interviews were conducted between November 1987-October 1988 and questions queried general knowledge about the disease (prevention of AIDS, treatment, nature, and manifestations of the disease, screening, high-risk groups), and more specific questions on the modes of HIV-1 transmission. The average % of correct answers on general knowledge about AIDS was about 81%. The questions on HIV-1 transmission concerned both modes of infection that are scientifically established, and other modes that are not. The average % of correct answers to questions on scientifically recognized modes of infection was 94% and for those answers on those which are not scientifically accepted was 74%. The attitudes and beliefs of these Montrealers towards those with AIDS was only moderately favorable. Attitudes and beliefs toward condom promotion were, on the other hand, very positive. The % of subjects reporting male homosexuality or injection drug use was extremely small. 23% of subjects who had experienced sexual intercourse reported that they had 2 or more partners in the 12 months preceding the survey. (author's)

[Utilization of qualitative and quantitative methods to study the attitudes and beliefs related to AIDS in a Montreal population of Haitian origin]. / Utilisation de méthodes qualitatives et quantitatives pour étudier les attitudes et croyances reliées au sida chez les Montréalais d'origine Haïtienne.

To determine attitudes and beliefs related to AIDS among the population of metropolitan Montreal of Haitian origin, we conducted serial cross-sectional surveys between 1987 and 1990 among a random sample of 777 men and women aged 15 to 39. Data on perceived risk of AIDS and attitudes towards HIV testing were collected in home settings using a combination of face-to-face structured interviews and a self-administered questionnaire. Multivariate analysis was conducted to determine predictors of attitudes towards people with HIV. The fear of being infected with HIV is great in this population. The social representation of illness in this community is very much influenced by religious beliefs. Scores for the five-item scale suggest only moderately favourable attitudes towards persons with HIV compared to Montrealers in general. Attitudes towards persons with AIDS were positively associated with years of schooling and a higher perceived risk of getting infected (p < or = 0.01).