Peer tutoring in reading: The effects of role and organization on two dimensions of self-esteem

Background. Paired reading (PR) is an application of peer tutoring. It has been extensively researched, and its efficacy across a range of outcomes has been established. Benefits include improvements in key reading skills, and also in affective aspects of learning. Several studies have shown gains in self-esteem, although measurement methods have varied, and the model of self-esteem has rarely been clearly articulated.
Aims. To investigate the changes in self-esteem of children participating in a randomized trial of PR over a 15-week treatment period. To investigate the relative contribution of self-worth and self-competence to any gains in self-esteem. To investigate whether the pattern of change differs in children who take on different roles in the PR process.
Participants. The participants comprised a subset of a large-scale randomized trial of peer learning (The Fife Peer Learning Project). Four schools were randomly selected from schools allocated to the same-age PR condition, and four schools from those allocated to the cross-age PR condition. The same-age group consisted of 87 primary 6 children (10–11 years old). The cross-age group consisted of 81 primary 6 children. The controls, from schools randomly selected from a neighbouring authority, consisted of 92 primary 6 children.
Method. A pre–post design employing self-report measures of self-esteem. Rosenberg’s Self-Esteem Scale was used, with scores analysed for worth and competence. The treatment period was 15 weeks, with the participants following a prescribed PR process.
Results. Significant pre–post gains were noted in self-esteem, driven predominantly by improved beliefs about competence, in both same-age and cross-age conditions, but not for controls. Gains were also seen in self-worth in the cross-age condition. Further analyses of the influence of organizational condition (same-age or cross-age) and role played (tutor vs. tutee) showed significant differences between same-age tutors and cross-age tutors in relation to self-worth. Effect sizes were generally small or moderate.
Conclusions. The findings provide further support for the belief that PR can enhance self-esteem. Importantly, the use of a two-dimensional model provides extra information about self-perceptions in PR contexts: first, the central role of self- competence; and second, the gains in self-worth which are associated with tutoring younger children (but not same-age peers). This new information has educational significance for schools considering the potential of peer tutoring and the benefits of different organizational conditions.

Glycated Hemoglobin and Risk of Death in Diabetic Patients Treated With Hemodialysis: A Meta-analysis

Background: Studies investigating the association between glycated hemoglobin (HbA) level and mortality risk in diabetic patients receiving hemodialysis have shown conflicting results. 
Study Design: We conducted a systematic review and meta-analysis using MEDLINE, EMBASE, Web of Science, and the Cochrane Library. 
Setting & Population: Diabetic patients on maintenance hemodialysis therapy. 
Selection Criteria for Studies: Observational studies or randomized controlled trials investigating the association between HbA values and mortality risk. Study authors were asked to provide anonymized individual patient data or reanalyze results according to a standard template. 
Predictor: Single measurement or mean HbA values. Mean HbA values were calculated using all individual-patient HbA values during the follow-up period of contributing studies. 
Outcome: HR for mortality risk. 
Results: 10 studies (83,684 participants) were included: 9 observational studies and one secondary analysis of a randomized trial. After adjustment for confounders, patients with baseline HbA levels =8.5% (=69 mmol/mol) had increased mortality (7 studies; HR, 1.14; 95% CI, 1.09-1.19) compared with patients with HbA levels of 6.5%-7.4% (48-57 mmol/mol). Likewise, patients with a mean HbA value =8.5% also had a higher adjusted risk of mortality (6 studies; HR,1.29; 95% CI, 1.23-1.35). There was a small but nonsignificant increase in mortality associated with mean HbA levels =5.4% (=36 mmol/mol; 6 studies; HR, 1.09; 95% CI, 0.89-1.34). Sensitivity analyses in incident (=90 days of hemodialysis) and prevalent patients (>90 days of hemodialysis) showed a similar pattern. In incident patients, mean HbA levels =5.4% also were associated with increased mortality risk (4 studies; HR, 1.29; 95% CI, 1.23-1.35). 
Limitations: Observational study data and inability to adjust for diabetes type in all studies. 
Conclusions: Despite concerns about the utility of HbA measurement in hemodialysis patients, high levels (=8.5%) are associated with increased mortality risk. Very low HbA levels (=5.4%) also may be associated with increased mortality risk. 

Drugs affecting the renin-angiotensin system and survival from cancer: a population based study of breast, colorectal and prostate cancer patient cohorts

Background: Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) are commonly prescribed to the growing number of cancer patients (more than two million in the UK alone) often to treat hypertension. However, increased fatal cancer in ARB users in a randomized trial and increased breast cancer recurrence rates in ACEI users in a recent observational study have raised concerns about their safety in cancer patients. We investigated whether ACEI or ARB use after breast, colorectal or prostate cancer diagnosis was associated with increased risk of cancer-specific mortality.

Methods: Population-based cohorts of 9,814 breast, 4,762 colorectal and 6,339 prostate cancer patients newly diagnosed from 1998 to 2006 were identified in the UK Clinical Practice Research Datalink and confirmed by cancer registry linkage. Cancer-specific and all-cause mortality were identified from Office of National Statistics mortality data in 2011 (allowing up to 13 years of follow-up). A nested case–control analysis was conducted to compare ACEI/ARB use (from general practitioner prescription records) in cancer patients dying from cancer with up to five controls (not dying from cancer). Conditional logistic regression estimated the risk of cancer-specific, and all-cause, death in ACEI/ARB users compared with non-users.

Results: The main analysis included 1,435 breast, 1,511 colorectal and 1,184 prostate cancer-specific deaths (and 7,106 breast, 7,291 colorectal and 5,849 prostate cancer controls). There was no increase in cancer-specific mortality in patients using ARBs after diagnosis of breast (adjusted odds ratio (OR) = 1.06 95% confidence interval (CI) 0.84, 1.35), colorectal (adjusted OR = 0.82 95% CI 0.64, 1.07) or prostate cancer (adjusted OR = 0.79 95% CI 0.61, 1.03). There was also no evidence of increases in cancer-specific mortality with ACEI use for breast (adjusted OR = 1.06 95% CI 0.89, 1.27), colorectal (adjusted OR = 0.78 95% CI 0.66, 0.92) or prostate cancer (adjusted OR = 0.78 95% CI 0.66, 0.92).

Conclusions: Overall, we found no evidence of increased risks of cancer-specific mortality in breast, colorectal or prostate cancer patients who used ACEI or ARBs after diagnosis. These results provide some reassurance that these medications are safe in patients diagnosed with these cancers.

Keywords: Colorectal cancer; Breast cancer; Prostate cancer; Mortality; Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers

Local recurrence in patients with large and locally advanced breast cancer treated with primary chemotherapy

Background: Primary chemotherapy is being given in the treatment of large and locally advanced breast cancers, but a major concern is local relapse after therapy. This paper has examined patients treated with primary chemotherapy and surgery (either breast-conserving surgery or mastectomy) and has examined the role of factors which may indicate those patients who are subsequently more likely to experience local recurrence of,disease.

Methods: A consecutive series of 173 women, with data available for 166 of these, presenting with large and locally advanced breast cancer (T2 >4 cm, T3, T4, or N2) were treated with primary chemotherapy comprising cyclophosphamide, vincristine, doxorubicin, and prednisolone and then surgery (either conservation or mastectomy with axillary surgery) followed by radiotherapy were examined.

Results: The clinical response rate of these patients was 75% (21% complete and 54% partial), with a complete pathological response rate of 15%. A total of 10 patients (6%) experienced local disease relapse, and the median time to relapse was 14 months (ranging from 3 to 40). The median survival in this group was 27 months (ranging from 13 to 78). In patients having breast conservation surgery, local recurrence occurred in 2%, and in those undergoing mastectomy 7% experience local relapse of disease. Factors predicting patients most likely to experience local recurrence were poor clinical response and residual axillary nodal disease after chemotherapy.

Conclusions: Excellent local control of disease can be achieved in patients with large and locally advanced breast cancers using a combination of primary chemotherapy, surgery and radiotherapy. However, the presence of residual tumor in the axillary lymph nodes after chemotherapy is a predictor of local recurrence and patients with a better clinical response were also less likely to experience local disease recurrence. The size and degree of pathological response did not predict patients most likely to experience recurrence of disease. (C) 2003 Excerpta Medica, Inc. All rights reserved.

Lymphatic mapping and sentinel node biopsy in breast cancer

Background Sentinel lymph node biopsy is a recently developed, minimally invasive technique for staging the axilla in patients with breast cancer. It has been suggested that this technique will avoid the morbidity associated with more extensive axillary dissection. A wide range of different methods and materials has been employed for lymphatic mapping, but there has been little consensus on the most reliable and reproducible technique.

Methods This is a comprehensive review of all published literature on sentinel node biopsy in breast cancer, using the Medline and Embase databases and cross-referencing of major articles on the subject.

Results and conclusion Sentinel node biopsy is a valid technique in breast cancer management, providing valuable axillary staging information. The optimal technique of lymphatic mapping utilizes a combination of vital blue dye and radiolabelled colloid. However, there remain controversial issues which require to be resolved before sentinel node biopsy becomes a widely accepted part of breast cancer care.

The significance of combining VEGFA, FLT1, and KDR expressions in colon cancer patient prognosis and predicting response to bevacizumab

Targeting angiogenesis through inhibition of the vascular endothelial growth factor (VEGF) pathway has been successful in the treatment of late stage colorectal cancer. However, not all patients benefit from inhibition of VEGF. Ras status is a powerful biomarker for response to anti-epidermal growth factor receptor therapy; however, an appropriate biomarker for response to anti-VEGF therapy is yet to be identified. VEGF and its receptors, FLT1 and KDR, play a crucial role in colon cancer progression; individually, these factors have been shown to be prognostic in colon cancer; however, expression of none of these factors alone was predictive of tumor response to anti-VEGF therapy. In the present study, we analyzed the expression levels of VEGFA, FLT1, and KDR in two independent colon cancer datasets and found that high expression levels of all three factors afforded a very poor prognosis. The observation was further confirmed in another independent colon cancer dataset, wherein high levels of expression of this three-gene signature was predictive of poor prognosis in patients with proficient mismatch repair a wild-type KRas status, or mutant p53 status. Most importantly, this signature also predicted tumor response to bevacizumab, an antibody targeting VEGFA, in a cohort of bevacizumab-treated patients. Since bevacizumab has been proven to be an important drug in the treatment of advanced stage colon cancer, our results suggest that the three-gene signature approach is valuable in terms of its prognostic value, and that it should be further evaluated in a prospective clinical trial to investigate its predictive value to anti-VEGF treatment.

The Prenatal Distress Questionnaire:An investigation of factor structure in a high risk population

Background: The Prenatal Distress Questionnaire (PDQ) is a short measure designed to assess specific worries and concerns related to pregnancy. The aim of this study was to confirm the factor structure of the PDQ in a group of pregnant women with a small for gestational age infant (< 10th centile). Methods: The first PDQ assessment for each of 337 pregnant women participating in the Prospective Observational Trial to Optimise paediatric health (PORTO) study was analysed. All women enrolled in the study were identified as having a small for gestational age foetus (< 10th centile), thus representing an 'elevated risk' group. Data were analysed using confirmatory factor analysis (CFA). Three models of the PDQ were evaluated and compared in the current study: a theoretical uni-dimensional measurement model, a bi-dimensional model, and a three-factor model solution. Results: The three-factor model offered the best fit to the data while maintaining sound theoretical grounds(χ² (51df) = 128.52; CFI = 0.97; TLI = 0.96; RMSEA = 0.07). Factor 1 contained items reflecting concerns about birth and the baby, factor 2 concerns about physical symptoms and body image and factor 3 concerns about emotions and relationships. Conclusions: CFA confirmed that the three-factor model provided the best fit, with the items in each factor reflecting the findings of an earlier exploratory data analysis. © 2013 Society for Reproductive and Infant Psychology.

Endoscopic tri-modal imaging improves detection of gastric intestinal metaplasia among a high-risk patient population in Singapore

BACKGROUND: Detection of pre-neoplastic gastric mucosal changes and early gastric cancer (EGC) by white-light endoscopy (WLE) is often difficult. In this study we investigated whether combined autofluorescence imaging (AFI) and narrow band imaging (NBI) can improve detection of pre-neoplastic lesions and early gastric cancer in high-risk patients.

PATIENTS AND METHODS: Chinese patients who were 50-years-old or above with dyspepsia were examined by both high-resolution WLE and combined AFI followed by NBI (AFI-NBI), consecutively in a prospective randomized cross-over setting, by two experienced endoscopists. The primary outcome was diagnostic ability of the two methods for patients with pre-neoplastic lesions such as intestinal metaplasia (IM) and mucosal atrophy.

RESULTS: Sixty-five patients were recruited. One patient with large advanced gastric cancer was found and excluded from the analysis. Among the remaining 64 patients, 38 (59%) had IM; of these, 26 (68%) were correctly identified by AFI-NBI (sensitivity 68%, specificity 23%) and only 13 (34%) by WLE (sensitivity 34%, specificity 65%). AFI-NBI detected more patients with IM than did WLE (p=0.011). Thirty-one patients (48%) had mucosal atrophy. Ten patients (32%) were identified by AFI-NBI (sensitivity 32%, specificity 79%) and four patients (13%) by WLE (sensitivity 13%, specificity 88%) (p=0.100). No dysplasia or EGC was found.

CONCLUSION: AFI-NBI identified significantly more patients with IM than did WLE. Our result warrants further studies to define the role of combined AFI-NBI endoscopy for detection of precancerous conditions.

The effects of sevoflurane and ketamine on intraocular pressure in children during examination under anesthesia

PURPOSE: We studied the effects on intraocular pressure (IOP) of anesthesia administered during examination under anesthesia (EUA) in children. DESIGN: Randomized clinical trial. METHODS: This randomized trial compared IOP after inhaled sevoflurane gas to that after intramuscular ketamine hydrochloride in children undergoing EUA. IOP was measured in 30 eyes with TonoPen XL (Mentor, Inc, Norwell, Massachusetts, USA) as soon as possible after anesthesia induction (T1) and two, four, six, and eight minutes thereafter. At the same times, we recorded systolic and diastolic blood pressure (SBP, DBP) and heart rate (HR). RESULTS: Compared with the mean IOP at T1, IOP in the sevoflurane group was significantly lower for all measurements from two to eight minutes thereafter (mean decrease in IOP: two minutes = 12%, four minutes = 19%; six minutes = 19%; eight minutes = 17%, all P < or = .01). In the ketamine group, mean IOP was not significantly changed from T1 through six minutes, whereas at eight minutes, it was 7% lower (P = .03). SBP and DBP were significantly lower for sevoflurane than for ketamine at all measurements from two minutes onward, and HR was lower for sevoflurane than for ketamine at two, four, and six minutes. CONCLUSIONS: IOP measured after ketamine sedation is more likely to represent the awake IOP than that after sevoflurane anesthesia. Changes in SBP, DBP, and HR caused by sevoflurane suggest that hemodynamic alterations may underlie its effects on IOP.

Clinical evaluation of three incision size-dependent phacoemulsification systems.

PURPOSE:

To compare the outcomes of cataract surgery performed with 3 incision size-dependent phacoemulsification groups (1.8, 2.2, and 3.0 mm).

DESIGN:

Prospective randomized comparative study.

METHODS:

One hundred twenty eyes of 120 patients with age-related cataract (grades 2 to 4) were categorized according to the Lens Opacities Classification System III. Eligible subjects were randomly assigned to 3 surgical groups using coaxial phacoemulsification through 3 clear corneal incision sizes (1.8, 2.2, and 3.0 mm). Different intraoperative and postoperative outcome measures were obtained, with corneal incision size and surgically induced astigmatism as the main clinical outcomes.

RESULTS:

There were no statistically significant differences in most of the intraoperative and postoperative outcome measures among the 3 groups. However, the mean cord length of the clear corneal incision was increased in each group after surgery. The mean maximal clear corneal incision thickness in the 1.8-mm group was significantly greater than for the other groups at 1 month. The mean surgically induced astigmatism in the 1.8- and 2.2-mm groups was significantly less than that in the 3.0-mm group after 1 month, without significant difference between the 1.8- and 2.2-mm groups.

CONCLUSIONS:

With appropriate equipment, smaller incisions may result in less astigmatism, but the particular system used will influence incision stress and wound integrity, and may thus limit the reduction in incision size and astigmatism that is achievable.

Comparing impact and cost-effectiveness of primary prevention strategies for lipid-lowering.

BACKGROUND: Lipid-lowering therapy is costly but effective at reducing coronary heart disease (CHD) risk. OBJECTIVE: To assess the cost-effectiveness and public health impact of Adult Treatment Panel III (ATP III) guidelines and compare with a range of risk- and age-based alternative strategies. DESIGN: The CHD Policy Model, a Markov-type cost-effectiveness model. DATA SOURCES: National surveys (1999 to 2004), vital statistics (2000), the Framingham Heart Study (1948 to 2000), other published data, and a direct survey of statin costs (2008). TARGET POPULATION: U.S. population age 35 to 85 years. Time Horizon: 2010 to 2040. PERSPECTIVE: Health care system. INTERVENTION: Lowering of low-density lipoprotein cholesterol with HMG-CoA reductase inhibitors (statins). OUTCOME MEASURE: Incremental cost-effectiveness. RESULTS OF BASE-CASE ANALYSIS: Full adherence to ATP III primary prevention guidelines would require starting (9.7 million) or intensifying (1.4 million) statin therapy for 11.1 million adults and would prevent 20,000 myocardial infarctions and 10,000 CHD deaths per year at an annual net cost of $3.6 billion ($42,000/QALY) if low-intensity statins cost $2.11 per pill. The ATP III guidelines would be preferred over alternative strategies if society is willing to pay $50,000/QALY and statins cost $1.54 to $2.21 per pill. At higher statin costs, ATP III is not cost-effective; at lower costs, more liberal statin-prescribing strategies would be preferred; and at costs less than $0.10 per pill, treating all persons with low-density lipoprotein cholesterol levels greater than 3.4 mmol/L (>130 mg/dL) would yield net cost savings. RESULTS OF SENSITIVITY ANALYSIS: Results are sensitive to the assumptions that LDL cholesterol becomes less important as a risk factor with increasing age and that little disutility results from taking a pill every day. LIMITATION: Randomized trial evidence for statin effectiveness is not available for all subgroups. CONCLUSION: The ATP III guidelines are relatively cost-effective and would have a large public health impact if implemented fully in the United States. Alternate strategies may be preferred, however, depending on the cost of statins and how much society is willing to pay for better health outcomes. FUNDING: Flight Attendants' Medical Research Institute and the Swanson Family Fund. The Framingham Heart Study and Framingham Offspring Study are conducted and supported by the National Heart, Lung, and Blood Institute.

The management of brain metastases

Brain metastases occur in 20-50% of NSCLC and 50-80% of SCLC. In this review, we will look at evidence-based medicine data and give some perspectives on the management of BM. We will address the problems of multiple BM, single BM and prophylactic cranial irradiation. Recursive Partitioning Analysis (RPA) is a powerful prognostic tool to facilitate treatment decisions. Dealing with multiple BM, the use of corticosteroids was established more than 40 years ago by a unique randomized trial (RCT). Palliative effect is high (_80%) as well as side-effects. Whole brain radiotherapy (WBRT) was evaluated in many RCTs with a high (60-90%) response rate; several RT regimes are equivalent, but very high dose per fraction should be avoided. In multiple BM from SCLC, the effect of WBRT is comparable to that in NSCLC but chemotherapy (CXT) although advocated is probably less effective than RT. Single BM from NSCLC occurs in 30% of all BM cases; several prognostic classifications including RPA are very useful. Several options are available in single BM: WBRT, surgery (SX), radiosurgery (RS) or any combination of these. All were studied in RCTs and will be reviewed: the addition of WBRT to SX or RS gives a better neurological tumour control, has little or no impact on survival, and may be more toxic. However omitting WBRT after SX alone gives a higher risk of cerebro-spinal fluid dissemination. Prophylactic cranial irradiation (PCI) has a major role in SCLC. In limited disease, meta-analyses have shown a positive impact of PCI in the decrease of brain relapse and in survival improvement, especially for patients in complete remission. Surprisingly, this has been recently confirmed also in extensive disease. Experience with PCI for NSCLC is still limited, but RCT suggest a reduction of BM with no impact on survival. Toxicity of PCI is a matter of debate, as neurological or neuro-cognitive impairment is already present prior to PCI in almost half of patients. However RT toxicity is probably related to total dose and dose per fraction. Perspectives : Future research should concentrate on : 1) combined modalities in multiple BM. 2) Exploration of treatments in oligo-metastases. 3) Further exploration of PCI in NSCLC. 4) Exploration of new, toxicity-sparing radiotherapy techniques (IMRT, Tomotherapy etc).

Femtosecond-laser assisted cataract surgery: a review.

Introduced in 2008, the femtosecond laser is a promising new technological advance which plays an ever increasing role in cataract surgery where it automates the three main surgical steps: corneal incision, capsulotomy and lens fragmentation. The proven advantages over manual surgery are: a better quality of incision with reduced induced astigmatism; increased reliability and reproducibility of the capsulotomy with increased stability of the implanted lens; a reduction in the use of ultrasound. Regarding refractive results or safety, however, no prospective randomized study to date has shown significant superiority compared with standard manual technique. The significant extra cost generated by this laser, undertaken by the patient, is a limiting factor for both its use and study. This review outlines the potential benefits of femtosecond-laser-assisted cataract surgery due to the automation of key steps and the safety of this new technology.

Preoperative nutritional screening by the specialist instead of the nutritional risk score might prevent excess nutrition: a multivariate analysis of nutritional risk factors.

BACKGROUND: The aim of the current study was to assess whether widely used nutritional parameters are correlated with the nutritional risk score (NRS-2002) to identify postoperative morbidity and to evaluate the role of nutritionists in nutritional assessment. METHODS: A randomized trial on preoperative nutritional interventions (NCT00512213) provided the study cohort of 152 patients at nutritional risk (NRS-2002 ≥3) with a comprehensive phenotyping including diverse nutritional parameters (n=17), elaborated by nutritional specialists, and potential demographic and surgical (n=5) confounders. Risk factors for overall, severe (Dindo-Clavien 3-5) and infectious complications were identified by univariate analysis; parameters with P<0.20 were then entered in a multiple logistic regression model. RESULTS: Final analysis included 140 patients with complete datasets. Of these, 61 patients (43.6%) were overweight, and 72 patients (51.4%) experienced at least one complication of any degree of severity. Univariate analysis identified a correlation between few (≤3) active co-morbidities (OR=4.94; 95% CI: 1.47-16.56, p=0.01) and overall complications. Patients screened as being malnourished by nutritional specialists presented less overall complications compared to the not malnourished (OR=0.47; 95% CI: 0.22-0.97, p=0.043). Severe postoperative complications occurred more often in patients with low lean body mass (OR=1.06; 95% CI: 1-1.12, p=0.028). Few (≤3) active co-morbidities (OR=8.8; 95% CI: 1.12-68.99, p=0.008) were related with postoperative infections. Patients screened as being malnourished by nutritional specialists presented less infectious complications (OR=0.28; 95% CI: 0.1-0.78), p=0.014) as compared to the not malnourished. Multivariate analysis identified few co-morbidities (OR=6.33; 95% CI: 1.75-22.84, p=0.005), low weight loss (OR=1.08; 95% CI: 1.02-1.14, p=0.006) and low hemoglobin concentration (OR=2.84; 95% CI: 1.22-6.59, p=0.021) as independent risk factors for overall postoperative complications. Compliance with nutritional supplements (OR=0.37; 95% CI: 0.14-0.97, p=0.041) and supplementation of malnourished patients as assessed by nutritional specialists (OR=0.24; 95% CI: 0.08-0.69, p=0.009) were independently associated with decreased infectious complications. CONCLUSIONS: Nutritional support based upon NRS-2002 screening might result in overnutrition, with potentially deleterious clinical consequences. We emphasize the importance of detailed assessment of the nutritional status by a dedicated specialist before deciding on early nutritional intervention for patients with an initial NRS-2002 score of ≥3.

Étude de prévention de la thrombose veineuse associée au cathéter veineux central de type PICC chez les patients en oncologie recevant une chimiothérapie

Nous avons mené une étude prospective randomisée dans le but de comparer l'effet de l'irrigation du cathéter de type PICC avec deux types d'anticoagulants: Héparine standard et Tinzaparine, une héparine de faible poids moléculaire. Notre étude s'adresse aux patients de la clinique externe d'oncologie de l'hôpital Maisonneuve-Rosemont. Entre début Mai 2005 et Mars 2008, nous avons recruté 131 patients dont 70 ont été randomisés. Parmi les 61 patients exclus, 23 n'ont pas rencontré les critères d'inclusion, 30 ont refusé de participer et 8 ne sont pas inclus pour d'autres raisons. Sur les 70, 36 sujets sont randomisés dans le groupe Héparine standard et 34 dans le groupe Tinzaparine. La population en intention de traiter comprend 65 sujets dont 32 dans le groupe Héparine standard et 33 dans le groupe Tinzaparine. Le médicament a été administré pendant un mombre maximal de 30 jours et les sujets ont été suivis pendant 90 jours. La thrombose veineuse associée au cathéter (TVAC) a été objectivée par une phlébographie ou une échographie-Doppler à la fin de la période de 30 jours suivant l'installation du cathéter. L'incidence de la TVAC sur 30 jours est de 14,39 par 1000 cathéter-jours (IC à 95%:[9,0;19,79]/1000 cathéter-jours ou 41,5% (27/65). L'incidence de la thrombose veineuse profonde (TVP) symptômatique du membre supérieur sur la période de suivi de 90 jours est de 0,41 par 1000 cathéter-jours (IC à 95%:[0,08;0,81]/1000 cathéter-jours ou 3% (2/65). Nous n'avons observé aucune différence entre les deux groupes par rapport à la fréquence de la TVAC ni de la TVP. Nous ne pouvons conclure à une différence dans l'efficacité de la Tinzaparine par rapport à l'Héparine standard dans la prévention de la TVAC.