Exposure‒response relationships for silicosis and its progression in industrial sand workers

Objectives This study aimed to characterize the relationship between radiographic silicosis and exposure to respirable quartz and determine how exposure affects disease progression. Methods Surveillance chest radiographs from a cohort of 1902 workers were examined to identify 67 cases of radiographic silicosis and 167 matched controls. Exposures were estimated by linking work histories to a job exposure matrix (JEM) based on samples collected by the participating companies and historical estimates. Conditional logistic regression was used to examine exposure‒response relationships. Sequential radiographs from silicosis cases were used to assess associations between exposure and disease progression. Results Risk of silicosis increased with cumulative exposure [odds ratio (OR) 1.43 per 1 mg/m ³years, 95% confidence interval (CI) 1.23-1.66], average exposure concentration (OR 1.30 per 0.10 mg/m ³, 95% CI 1.11-1.51) and net exposure duration (OR 1.10 per year, 95% CI 1.05-1.16). Multivariate analyses indicated that the risk associated with cumulative exposure varied depending on exposure duration and concentration. Analysis of the time worked at differing exposure levels indicated that exposures ≤0.05 mg/m ³were not significantly associated with silicosis risk after adjustment for years worked at higher concentrations. Disease progression was related to subsequent exposure concentration, with a yearly increase in small opacity profusion of 0.052 subcategory per each 0.10 mg/m ³increase in concentration. Conclusions Workers with longer exposure at lower concentrations were at higher risk for silicosis than those with the same cumulative exposure who worked for a shorter time at higher concentrations. The rate of silicosis progression was related to subsequent exposure concentration.

Mediastinal hibernoma simulates a malignant lesion on dual time point FDG imaging

Dual time point 2-deoxy-2-[18F] fluoro-d-glucose (FDG) positron emission tomography (PET) imaging has been shown to be useful in helping differentiate benign from malignant lesions. An enhancing mediastinal mass of fat and water density was incidentally detected on computed tomography (CT) in a patient being evaluated for thoracic trauma. He subsequently underwent dual time point FDG PET/CT imaging which revealed a significant rise in standard uptake value (SUV) within the lesion over time, favoring a malignant etiology. Biopsy proved the lesion to represent a hibernoma, an uncommon benign fatty tumor. This case exemplifies the complexity of tissue metabolic properties, and the difficulty in establishing absolute criteria for benign and malignant processes.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery and previous reviews have found them to be effective in reducing blood loss and the need for transfusion. Recently, questions have been raised regarding the comparative performance of the drugs and the safety of the most popular agent, aprotinin.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, and the internet. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2006.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

This review summarises data from 211 RCTs that recruited 20,781 participants. Data from placebo/inactive controlled trials, and from head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of operative blood loss, but the differences were small. Aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.61 to 0.71). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.54 to 0.69) and it was 0.75 (95% CI 0.58 to 0.96) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared superior in reducing the need for RBC transfusion: RR 0.83 (95% CI 0.69 to 0.99). Aprotinin reduced the need for re-operation due to bleeding: RR 0.48 (95% CI 0.35 to 0.68). This translates into an absolute risk reduction of just under 3% and a number needed-to-treat (NNT) of 37 (95% CI 27 to 56). Similar trends were seen with TXA and EACA, but the data were sparse and the differences failed to reach statistical significance. The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias. Evidence of publication bias was not observed in trials reporting re-operation rates. Adjustment for these effects reduced the magnitude of estimated benefits but did not negate treatment effects. However, the apparent advantage of aprotinin over the lysine analogues was small and may be explained by publication bias and non-equivalent drug doses. Aprotinin did not increase the risk of myocardial infarction (RR 0.92, 95% CI 0.72 to 1.18), stroke (RR 0.76, 95% CI 0.35 to 1.64) renal dysfunction (RR 1.16, 95% CI 0.79 to 1.70) or overall mortality (RR 0.90, 95% CI 0.67 to 1.20). The analyses of myocardial infarction and death included data from the majority of subjects recruited into the clinical trials of aprotinin. However, under-reporting of renal events could explain the lack of effect seen with aprotinin. Similar trends were seen with the lysine analogues but data were sparse. These results conflict with the results of recently published non-randomised studies.

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the need for allogeneic red cell transfusion. Based on the results of randomised trials their efficacy does not appear to be offset by serious adverse effects. In most circumstances the lysine analogues are probably as effective as aprotinin and are cheaper; the evidence is stronger for tranexamic acid than for aminocaproic acid. In high risk cardiac surgery, where there is a substantial probability of serious blood loss, aprotinin may be preferred over tranexamic acid. Aprotinin does not appear to be associated with an increased risk of vascular occlusion and death, but the data do not exclude an increased risk of renal failure. There is no need for further placebo-controlled trials of aprotinin or lysine analogues in cardiac surgery. The principal need is for large comparative trials to assess the relative efficacy, safety and cost-effectiveness of anti-fibrinolytic drugs in different surgical procedures.

Cell salvage for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood, have prompted reconsideration of the use of allogeneic (blood from an unrelated donor) red blood cell (RBC) transfusion, and a range of techniques to minimise transfusion requirements.

OBJECTIVES

To examine the evidence for the efficacy of cell salvage in reducing allogeneic blood transfusion and the evidence for any effect on clinical outcomes.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Current Contents and the websites of international health technology assessment agencies. The reference lists in identified trials and review articles were also searched, and study authors were contacted to identify additional studies. The searches were updated in January 2004.

SELECTION CRITERIA

Controlled parallel group trials in which adult patients, scheduled for non-urgent surgery, were randomised to cell salvage, or to a control group, who did not receive the intervention.

DATA COLLECTION AND ANALYSIS

Two authors independently screened search results, extracted data and assessed methodological quality. The main outcomes measures were the number of patients exposed to allogeneic red cell transfusion, and the amount of blood transfused. Other outcomes measured were re-operation for bleeding, blood loss, post-operative complications (thrombosis, infection, non-fatal myocardial infarction, renal failure), mortality, and length of hospital stay (LOS).

MAIN RESULTS

Overall, the use of cell salvage reduced the rate of exposure to allogeneic RBC transfusion by a relative 39% (relative risk [RR] = 0.61: 95% confidence interval [CI] 0.52 to 0.71). The absolute reduction in risk (ARR) of receiving an allogeneic RBC transfusion was 23% (95% CI 16% to 30%). In orthopaedic procedures the RR of exposure to RBC transfusion was 0.42 (95% CI 0.32 to 0.54) compared to 0.77 (95% CI 0.68 to 0.87) for cardiac procedures. The use of cell salvage resulted in an average saving of 0.67 units of allogeneic RBC per patient (weighted mean difference was -0.64; 95% CI -0.89 to -0.45). Cell salvage did not appear to impact adversely on clinical outcomes.

AUTHORS' CONCLUSIONS

The results suggest cell salvage is efficacious in reducing the need for allogeneic red cell transfusion in adult elective surgery. However, the methodological quality of trials was poor. As the trials were unblinded and lacked adequate concealment of treatment allocation, transfusion practices may have been influenced by knowledge of the patients' treatment status biasing the results in favour of cell salvage.

Giving and receiving of gifts between pharmaceutical companies and medical specialists in Australia

BACKGROUND

This study investigated the 'gift-relationship' between pharmaceutical companies and doctors.

METHODS

The study was based on a survey questionnaire of 823 medical specialists from across Australia. The aim of this study was to investigate gifts offered to medical specialists in Australia by pharmaceutical companies, financial support actively sought by medical specialists for activities other than research and to consider what is ethically appropriate.

RESULTS

A high percentage of specialists received offers of food (96%), items for the office (94%), personal gifts (51%) and journals or textbooks (50%). Most specialists were invited to product launches, symposia or educational events (75-84%) and 52% received offers of travel to conferences. A high proportion of offers were accepted (66-79%) except invitations to product launches (49%), sponsored symposia (53%) and offers of travel that included partners (27%). Fifteen per cent of specialists requested financial support from pharmaceutical companies for activities and items, including conferences, travel, educational activities, salaries and donations to specific funds. The study outlined guidelines on gifts from pharmaceutical companies and differing standards applying to gifts and grants for travel. We found that, although most gifts and requests for support complied with professional and pharmaceutical industry guidelines, some--including personal gifts, tickets to sporting events, entertainment and travel expenses for specialists' partners--did not.

CONCLUSION

To ensure that physicians' judgements are free from real or perceived influence from industry and to maintain public trust, we support a shift towards more conservative standards on gifts and support for travel evident in recent guidelines.

Systematic review and meta-analysis of the use of fibrin sealant to prevent seroma formation after breast cancer surgery

Background

The use of fibrin sealant has been proposed as a means of preventing seroma formation following breast cancer surgery. Conflicting trial results require the efficacy of fibrin sealant to be reviewed critically.

Methods

A systematic review of randomized controlled trials was conducted to examine the efficacy of fibrin sealants in reducing postoperative drainage and seroma formation after breast cancer surgery. Studies were identified by computer searches of Medline, Embase, the Cochrane Central Register of Controlled Trials and manufacturer websites (to June 2005), and bibliographic searches of published articles. Trials were eligible for inclusion if they reported data on postoperative drainage and the number of patients who developed a seroma.

Results

Eleven trials met the criteria for inclusion. Generally, the trials were small and of poor methodological quality. Fibrin sealant did not reduce the rate of postoperative seroma (relative risk 1·14, 95 per cent confidence interval (c.i.) 0·88 to 1·46), the volume of drainage (weighted mean difference − 117·7, 95 per cent c.i. − 259·2 to 23·8 ml), or the length of hospital stay (weighted mean difference − 0·38, 95 per cent c.i. − 1·58 to 0·83 days).

Conclusions

The current evidence does not support the use of fibrin sealant in breast cancer surgery to reduce postoperative drainage or seroma formation.

Blood transfusion and autologous donation: a survey of post-surgical patients, interest group members and the public

Before planned surgery, patients may choose autologous donation in order to avoid the small, but potential, risks of receiving an allogeneic blood transfusion. This study examined the perceived risks of allogeneic blood transfusions, preferences and willingness to pay for autologous donation and the desired role in the decision-making process in three populations: post-surgical patients, special interest group members and the general public. Quantitative and qualitative data were collected from 206 respondents with the help of computer-assisted semi-structured telephone interviews. Thirty-three per cent of the sample voiced concerns about receiving allogeneic blood transfusions. The risks of hepatitis C virus, human immunodeficiency virus, variant Creutzfeldt-Jakob disease and a haemolytic reaction were perceived as being low, but were rated as numerically higher than those of other life events that have equal probability. Autologous donation was perceived as removing all the risks associated with transfusion, and respondents were willing to pay a median $976 AUD ($664 US) to use this technique. Over 80% of respondents preferred to be involved in making the decision about whether to use autologous donation. Even though autologous donation is not 'risk-free' and the blood supply is very safe, people overestimate the associated risks and have a preference for their own blood. Decision aids presenting balanced information on the advantages and disadvantages of both allogeneic and autologous blood may be required.

Aggressive and atypical manifestations of Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a disseminated non-Langerhans' cell histiocytosis with multisystem involvement, including characteristic sclerotic musculoskeletal lesions. We present the case of a 27-year-old woman with a fulminant course and atypical involvement by ECD manifesting as extensive cerebrovascular disease and lytic musculoskeletal lesions. This case represents an unusual and aggressive presentation of ECD owing to the patient's young age, the severity of the cerebrovascular involvement and the lytic osseous lesions.

Platelet-rich-plasmapheresis for minimising peri-operative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have generated considerable enthusiasm for the use of technologies intended to reduce the use of allogeneic blood (blood from an unrelated donor). Platelet-rich plasmapheresis (PRP) offers an alternative approach to blood conservation.

OBJECTIVES

To examine the evidence for the efficacy of PRP in reducing peri-operative allogeneic red blood cell (RBC) transfusion, and the evidence for any effect on clinical outcomes such as mortality and re-operation rates.

SEARCH STRATEGY

Studies were identified by: computer searches of MEDLINE, EMBASE, Current Contents, and the Cochrane Library (to June 2001). These searches were supplemented by checking the reference lists of published articles, reports, and reviews.

SELECTION CRITERIA

Controlled parallel group trials in which adult patients, scheduled for non-urgent surgery, were randomised to PRP, or to a control group who did not receive the intervention.

DATA COLLECTION AND ANALYSIS

Main outcomes measured were: the number of patients receiving an allogeneic RBC transfusion, and the amount of RBC transfused. Trial quality was assessed using criteria proposed by Schulz et al. (Schulz 1995) and Jadad et al. (Jadad 1996).

MAIN RESULTS

Nineteen trials of PRP were identified that reported data for the number of patients exposed to allogeneic RBC transfusion. These trials evaluated a total of 1452 patients. The pooled relative risk (RR) of exposure to allogeneic blood transfusion in those patients randomised to PRP was 0.71 (95%CI: 0.56, 0.90), equating to a relative risk reduction (RRR) of 29%; the average absolute risk reduction (ARR) was 19% (RD = -0.19: 95%CI: -0.29, -0.09). On average, PRP did not significantly reduce the total volume of RBC transfused (weighted mean difference [WMD] = -0.69: 95%CI: -1.93, 0.56 units). Substantial statistical heterogeneity was observed (p < 0.001). Trials provided inadequate data regarding the impact of PRP on morbidity, mortality, and hospital length of stay. The majority of trials were small and of poor methodological quality.

REVIEWER'S CONCLUSIONS

Although the results suggest that PRP is effective in reducing allogeneic RBC transfusion in adult patients undergoing elective surgery, there was considerable heterogeneity in treatment effects and the trials were of poor methodological quality. As the majority of trials were unblinded, transfusion practices may have been influenced by knowledge of the patient's allocation status, potentially exaggerating the true magnitude of the beneficial effect of PRP. The available studies provided inadequate data for firm conclusions to be drawn regarding the impact of PRP on clinically important endpoints.

Cell salvage for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood, have prompted reconsideration of the use of allogeneic (blood from an unrelated donor) red blood cell (RBC) transfusion, and a range of techniques to minimise transfusion requirements.

OBJECTIVES

To examine the evidence for the efficacy of cell salvage in reducing allogeneic blood transfusion and the evidence for any effect on clinical outcomes.

SEARCH STRATEGY

Articles were identified by: computer searches of MEDLINE, EMBASE, Current Contents (to July 2002), the Cochrane Controlled Trials Register (Issue 2, 2002) and websites of international health technology assessment agencies. References in the identified trials and review articles were searched and authors contacted to identify additional studies.

SELECTION CRITERIA

Controlled parallel group trials in which adult patients, scheduled for non-urgent surgery, were randomised to cell salvage, or to a control group, who did not receive the intervention.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed using criteria proposed by Schulz et al. (Schulz 1995) and Jadad et al. (Jadad 1996). Main outcomes measured were: the number of patients exposed to allogeneic red cell transfusion, and the amount of blood transfused. Other outcomes measured were: re-operation for bleeding, blood loss, post-operative complications (thrombosis, infection, non-fatal myocardial infarction, renal failure), mortality, and length of hospital stay (LOS).

MAIN RESULTS

Overall, the use of cell salvage reduced the rate of exposure to allogeneic RBC transfusion by a relative 40% (relative risk [RR] = 0.60: 95% confidence interval [CI] = 0.51 to 0.70). The absolute reduction in risk (ARR) of receiving an allogeneic RBC transfusion was 23% (95%CI = 16% to 30%). In orthopaedic procedures the relative risk (RR) of exposure to RBC transfusion was 0.42 (95%CI = 0.32 to 0.54) compared to 0.78 (95%CI = 0.68 to 0.88) for cardiac procedures. The use of cell salvage resulted in an average saving of 0.64 units of allogeneic RBC per patient (weighted mean difference [WMD] = -0.64: 95%CI = -0.86 to -0.46). Cell salvage did not appear to impact adversely on clinical outcomes.

REVIEWER'S CONCLUSIONS

The results suggest cell salvage is efficacious in reducing the need for allogeneic red cell transfusion in adult elective surgery. However, the methodological quality of trials was poor. As the trials were unblinded and lacked adequate concealment of treatment allocation, transfusion practices may have been influenced by knowledge of the patient's treatment status biasing the results in favour of cell salvage.

Fibrin sealant use for minimising peri-operative allogeneic blood transfusion

BACKGROUND

Fibrin sealants have gained increasing popularity as interventions to improve peri-operative (intra/post-operative) haemostasis and diminish the need for allogeneic red cell transfusion (blood from an unrelated donor).

OBJECTIVES

To examine the efficacy of fibrin sealants in reducing peri-operative blood loss and allogeneic red blood cell (RBC) transfusion.

SEARCH STRATEGY

Studies were identified by: searches of MEDLINE, EMBASE, Current Contents, the Cochrane Library (July 2002), manufacturer web sites (to July 2002), and bibliographies of published articles.

SELECTION CRITERIA

Controlled trials in which adult patients, scheduled for elective surgery, were randomised to fibrin sealant treatment or to a control group who did not receive fibrin sealant treatment. Trials were eligible if they reported data on the number of patients exposed to allogeneic red cell transfusion, the volume of blood transfused, or blood loss (assessed objectively).

DATA COLLECTION AND ANALYSIS

Primary outcomes measured were: the number of patients exposed to allogeneic red cells, the amount of blood transfused, and blood loss. Other outcomes measured were: re-operation due to bleeding, infection, mortality, and length of hospital stay. Treatment effects were pooled using a random effects model.

MAIN RESULTS

Seven trials, including a total of 388 patients, reported data on peri-operative exposure to allogeneic RBC transfusion. Fibrin sealant treatment, on average, reduced the rate of exposure to allogeneic red cell transfusion by a relative 54% (relative risk [RR] = 0.46: 95%CI = 0.32 to 0.68). Eight trials, including a total of 442 patients, provided data for post-operative blood loss. Fibrin sealant treatment reduced blood loss on average by around 134 per patient (95%CI = 51 to 217 ). However the trials reviewed were small and of poor methodological quality (91% unblinded).

REVIEWER'S CONCLUSIONS

Overall the results suggest that fibrin sealants are efficacious in reducing both post-operative blood loss and peri-operative exposure to allogeneic RBC transfusion. However, due to the lack of blinding, transfusion practices may have been influenced by knowledge of the patient's treatment status. This raises concerns about the use of blood transfusion practice as an outcome variable in trials of fibrin sealant. In the case of blood loss, the results must be interpreted with caution, in view of the statistically significant heterogeneity in treatment effect observed. Large, methodologically rigorous, randomised controlled trials of fibrin sealants are needed.

International Labor Office Classification System in the age of imaging: relevant or redundant

The 1980 International Labor Office International Classification of Radiographs of Pneumoconioses is a widely used epidemiologic tool with a storied past. This article reviews its development and examines its applications to occupational lung disease and the controversies generated in that process. The question of its relevancy to current imaging practices is discussed.

Systematic review of the use of fibrin sealant to minimize perioperative allogeneic blood transfusion

BACKGROUND

Fibrin sealants have become popular in improving perioperative haemostasis and reducing the need for allogeneic red cell transfusion.

METHODS

A systematic review of randomized controlled trials was conducted to examine the efficacy of fibrin sealants in reducing perioperative blood loss and allogeneic red blood cell transfusion. Studies were identified by computer searches of Medline, Embase, Current Contents, the Cochrane Library, manufacturer websites (to January 2001), and bibliographic searches of published articles. Trials were eligible for inclusion if they involved adult elective surgery and reported quantitative data on blood loss, the proportion of patients exposed to allogeneic red cell transfusion and/or the volume of blood transfused.

RESULTS

Twelve trials met the criteria for inclusion. Fibrin sealants reduced the rate of allogeneic blood transfusion (relative risk 0.40 (95 per cent confidence interval (c.i.) 0.26 to 0.61); five trials with 275 subjects) and reduced blood loss (weighted mean difference--151.68 (95 per cent c.i. - 251.91 to - 51.46) ml; seven trials with 391 subjects). Generally, the trials were small and of poor methodological quality.

CONCLUSION

Overall the results suggest that fibrin sealants are efficacious. Owing to lack of blinding, transfusion practices may have been influenced by knowledge of the patient's treatment status. This raises concern about blood transfusion practice as a response variable. Large methodologically rigorous trials of fibrin sealants with clinical outcomes are needed.

Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion

BACKGROUND

Most clinical practice guidelines recommend restrictive red cell transfusion practices with the goal of minimising exposure to allogeneic blood (from an unrelated donor). The purpose of this review is to compare clinical outcomes in patients randomised to restrictive versus liberal transfusion thresholds (triggers).

OBJECTIVES

To examine the evidence on the effect of transfusion thresholds, on the use of allogeneic and/or autologous blood, and the evidence for any effect on clinical outcomes.

SEARCH STRATEGY

Trials were identified by: computer searches of OVID Medline (1966 to December 2000), Current Contents (1993 to Week 48 2000), and the Cochrane Controlled Trials Register (2000 Issue 4). References in identified trials and review articles were checked and authors contacted to identify any additional studies.

SELECTION CRITERIA

Controlled trials in which patients were randomised to an intervention group or to a control group. Trials were included where the intervention groups were assigned on the basis of a clear transfusion "trigger", described as a haemoglobin (Hb) or haematocrit (Hct) level below which a RBC transfusion was to be administered.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed using criteria proposed by Schulz et al. (1995). Relative risks of requiring allogeneic blood transfusion, transfused blood volumes and other clinical outcomes were pooled across trials using a random effects model.

MAIN RESULTS

Ten trials were identified that reported outcomes for a total of 1780 patients. Restrictive transfusion strategies reduced the risk of receiving a red blood cell (RBC) transfusion by a relative 42% (RR=0.58: 95%CI=0.47,0.71). This equates to an average absolute risk reduction (ARR) of 40% (95%CI=24% to 56%). The volume of RBCs transfused was reduced on average by 0.93 units (95%CI=0.36,1.5 units). However, heterogeneity between these trials was statistically significant (p<0.00001) for these outcomes. Mortality, rates of cardiac events, morbidity, and length of hospital stay were unaffected. Trials were of poor methodological quality.

REVIEWER'S CONCLUSIONS

The limited published evidence supports the use of restrictive transfusion triggers in patients who are free of serious cardiac disease. However, most of the data on clinical outcomes were generated by a single trial. The effects of conservative transfusion triggers on functional status, morbidity and mortality, particularly in patients with cardiac disease, need to be tested in further large clinical trials. In countries with inadequate screening of donor blood the data may constitute a stronger basis for avoiding transfusion with allogeneic red cells.

Pre-operative autologous donation for minimising perioperative allogeneic blood transfusion

BACKGROUND

Public concerns regarding the safety of transfused blood have prompted re-consideration of the indications for the transfusion of allogeneic red cells (blood from an unrelated donor), and a range of techniques designed to minimise transfusion requirements.

OBJECTIVES

To examine the evidence for the efficacy of pre-operative autologous blood donation (PAD) in reducing the need for peri-operative allogeneic red blood cell (RBC) transfusion.

SEARCH STRATEGY

Articles were identified by: computer searches of OVID MEDLINE, EMBASE, and Current Contents (to March 2001) and web sites of international health technology assessment agencies (to January 2001). References in the identified trials were checked and authors contacted to identify additional studies.

SELECTION CRITERIA

Randomised controlled trials with a concurrent control group in which adult patients, scheduled for non-urgent surgery, were randomised to PAD, or to a control group who did not receive the intervention.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed using criteria proposed by Schulz et al (1995) and Jadad et al (1996). The principle outcomes were: the number of patients exposed to allogeneic red blood cells, and the amount of blood transfused. Other clinical outcomes are detailed in the review.

MAIN RESULTS

Overall PAD reduced the risk of receiving an allogeneic blood transfusion by a relative 63% (RR=0.37: 95%CI:0.26,0.54). The absolute reduction in risk of allogeneic transfusion was 43.8% (RD=-0.438: 95%CI: -0.607,-0.268). In contrast the results show that the risk of receiving any blood transfusion (allogeneic and/or autologous) is actually increased by pre-operative autologous blood donation (RR=1.29: 95%CI: 1.12,1.48). Trials were unblinded and allocation concealment was not described in 87.5% of the trials.

REVIEWER'S CONCLUSIONS

Although the trials of PAD showed a reduction in the need for allogeneic blood the methodological quality of the trials was poor and the overall transfusion rates (allogeneic and/or autologous) in these trials were high, and were increased by recruitment into the PAD arms of the trials. This raises questions about the true benefit of PAD. In the absence of large, high quality trials using clinical endpoints, it is not possible to say whether the benefits of PAD outweigh the harms.

Emergence of penicillin-nonsusceptible Streptococcus pneumoniae invasive clones in Canada

Distinctive international clones of penicillin-nonsusceptible and multidrug-resistant Streptococcus pneumoniae are increasingly being reported. We investigated the spread of these clones in Canada through an active surveillance that was carried out at 11 Canadian pediatric tertiary care centers from 1991 to 1998. All penicillin-nonsusceptible isolates were serotyped, tested for antibiotic susceptibility, and genotyped by pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD). Forty-five penicillin-nonsusceptible S. pneumoniae isolates were evaluated. Eleven serotype 9V isolates and six serotype 14 isolates displayed identical RAPD and PFGE fingerprint profiles. Twelve (70%) of these isolates were encountered in Quebec. The 9V/14 clone and the Spanish-French clone had similar PFGE fingerprint patterns. Eight isolates of serotype 23F and two isolates of serogroup 14 had the same fingerprint profiles and displayed resistance to three or more antibiotic drug classes. This clone was first detected in Calgary (Alberta) and in 1996 appeared simultaneously in various regions of Canada. This clone showed a PFGE fingerprint pattern similar to that of the Spanish-U.S. 23F clone. Our data show the emergence across Canada of two international clones of penicillin-nonsusceptible S. pneumoniae: (i) serotypes 9V and 14 related to the Spanish-French clone and (ii) the 23F Spanish-U.S. clone. The source of the first clone was in Quebec and the second international clone was probably originated from the United States. The exact reasons for the successful spread of these clones within Canada and their contribution to increased resistance to antibiotics have yet to be explored.

Drug information for consumers: should it be disease or medication specific? Results of a community survey

OBJECTIVE

To investigate the information-seeking behaviour of medicine users.

METHODS

A telephone survey and follow-up in-depth interviews of a random sample of the adult population in the Hunter Region, NSW, Australia. The survey sought information on medicine use, information seeking, and satisfaction and understanding of the information received. In-depth interviews examined the barriers and facilitators of information seeking.

RESULTS

Seven hundred and eighty-six people completed the telephone survey and 58 completed the follow-up interviews. Over half (51%) of the medicine users sought information, primarily to 'manage' their medicines, such as how to use the medicine. Over 30% of the questions asked by users related to 'therapeutic choices', such as how well the medicine worked for a particular condition. Doctors and pharmacists were the most frequent sources of information. A small proportion (10%) reported a potential unmet need for medicines information by indicating they would have liked to ask a question, but did not, or were dissatisfied with the information they received. Barriers to information seeking included perceptions that health care professionals were 'too busy', and that they were unwilling to provide information.

CONCLUSIONS

Physicians and pharmacists continue to play an important role in providing consumers with medicines information. Although the reported level of unmet need was low, a significant proportion identified needs relating to information on therapeutic choice, rather than 'classical' drug information.

IMPLICATIONS

Medicines-related information for the public should include advice on comparative performance of drugs, and be provided within the wider framework of general health information.

Infection with Burkholderia cepacia complex genomovars in patients with cystic fibrosis: virulent transmissible strains of genomovar III can replace Burkholderia multivorans

Infection with Burkholderia cepacia complex in patients with cystic fibrosis (CF) results in highly variable clinical outcomes. The purpose of this study was to determine if there are genomovar-specific disparities in transmission and disease severity. B. cepacia complex was recovered from 62 patients with CF on > or =1 occasions (genomovar III, 46 patients; genomovar II [B. multivorans], 19 patients; genomovar IV [B. stabilis], 1 patient; genomovar V [B. vietnamiensis], 1 patient; and an unclassified B. cepacia complex strain, 1 patient). Patient-to-patient spread was observed with B. cepacia genomovar III, but not with B. multivorans. Genomovar III strains replaced B. multivorans in 6 patients. Genomovar III strains were also associated with a poor clinical course and high mortality. Infection control practices should be designed with knowledge about B. cepacia complex genomovar status; patients infected with transmissible genomovar III strains should not be cohorted with patients infected with B. multivorans and other B. cepacia genomovars.

The impact of specialists on prescribing by general practitioners

OBJECTIVE

To investigate the direct impact of specialists on prescribing by general practitioners.

DESIGN

Cross-sectional, prescription-based study.

SUBJECTS AND SETTING

88 GPs in the Hunter Urban Division of General Practice, Hunter Valley, NSW.

MAIN OUTCOME MEASURE

Proportions of specialist-initiated prescriptions for eight commonly prescribed drug classes.

RESULTS

The proportion of specialist-initiated prescriptions was greatest for proton pump inhibitors (85%), and lowest for diuretics (8%), newer antidepressants (10%) and H2-receptor antagonists (13%). Specialists initiated 29% of prescriptions for beta-blockers, 26% for calcium-channel blockers, 20% for statins and 19% for angiotensin-converting enzyme inhibitors or angiotensin II antagonists. Specialists were more likely to have been involved in starting therapy with metoprolol than other beta-blockers (51% v 23%) and diltiazem than other calcium-channel blockers (48% v 19%), and this was related to indication for treatment. In contrast, prescriptions for the more recently introduced drugs (angiotensin II antagonists and atorvastatin) were not more likely to have been specialist-initiated than prescriptions for established angiotensin-converting enzyme inhibitors and statins.

CONCLUSIONS

The direct impact of specialists on prescribing in the Hunter Urban Division of General Practice is substantial and varies with the drug class. This highlights the need to engage both GPs and specialists in efforts to improve prescribing practices.

Personal formularies. An index of prescribing quality?

OBJECTIVES

(1) To determine the extent to which Australian general practitioners (GPs) restrict the numbers of agents they prescribe within a drug class ('personal formularies'); (2) To assess concordance of these drug choices with standards based on established guidelines or recognised good prescribing practices; (3) To assess the potential of these measures as indicators of the quality of prescribing.

METHODS

Australian Health Insurance Commission (HIC) prescription data (1994 1997) for around 15,400 GPs providing 1500 or more Medicare services per year were analysed. Measures of an individual GP's use of a personal formulary (determined by number of agents) and concordance with prescribing criteria based on specified drugs for five classes of commonly prescribed drugs were derived.

RESULTS

Non-steroidal anti-inflammatory drugs (NSAIDs): GP concordance was higher with a non-specified personal formulary (any five NSAIDs) than with a list of specified drugs (five NSAIDs of 'low' or 'medium' risk of gastrointestinal toxicity), and concordance with both increased over time. In 1997, around 70% of GPs used five or fewer NSAIDs for 90% of their prescribing; 47% of GPs had 90% of prescribing from five selected agents. Angiotensin converting enzyme inhibitors/angiotensin-II receptor antagonists: The introduction of new agents appeared to increase the size of the GPs' personal formularies, and concordance with defined standards decreased over time. Antibacterial agents: Concordance with a specified drug standard (nine drugs listed in the Australian Antibiotic Guidelines) increased substantially over time but was largely due to increased prescribing of two heavily promoted drugs. Beta-blocking agents: Over time, GPs restricted most prescribing to two agents, atenolol and metoprolol. Calcium channel blockers: GPs did not appear to restrict prescribing of these drugs; most GPs prescribed all five agents available.

CONCLUSIONS

Australian GPs use 'personal formularies'. Formulary size varies with the drug class, can change over time as new agents become available, and its contents can be influenced by promotional activities. Prescribing standards based on numbers of drugs used may not always reflect rational prescribing choices. Criteria based on specified drugs provide more rigorous prescribing standards, but may give a misleading picture of prescribing quality in the absence of information on patients and the indications for treatment. Personal formulary measures are potentially useful prescribing indicators but need to be carefully defined and interpreted. GPs should be encouraged to identify their personal formularies and review the drugs included in them.

Factors influencing the uptake of technologies to minimize perioperative allogeneic blood transfusion: an interview study of national and institutional stakeholders

BACKGROUND

Alternatives to allogeneic blood transfusion exist and are being used to varying extents in Australian hospitals. Evidence on effectiveness and cost-effectiveness is generally inconclusive and provides a suboptimal basis for policy development.

AIM

To describe the influences on uptake of transfusion technologies as perceived by national and institutional stakeholders.

METHODS

Qualitative interview study. Interview transcripts were coded and analysed independently by at least two researchers. Participants had opportunity to comment on their transcript and the manuscript.

RESULTS

A total of 71 interviews were conducted with representatives of the media, specialist medical societies, consumer special interest groups, the Australian Red Cross Blood Service (ARCBS), government, private health insurers, technology manufacturers, prominent clinicians in the area and a sample of clinicians drawn from hospitals with variable use of blood-saving technologies. Technical advances and acceptance of lower transfusion triggers were identified as the main influences on the decrease in use of allogeneic blood transfusion in the past decade. Participants indicated that patients were most aware and supportive of autologous predonation. Participants noted that 'enthusiasts' were involved in educating about the need for alternatives, negotiating resourcing and maintaining the use of a technology. Funding mechanisms were seen as main barriers to use of alternatives. A discrepancy was noted in the rigour of evaluation and regulation of pharmaceuticals and devices/procedures.

CONCLUSIONS

Uptake of blood transfusion technologies by institutions was dependent mostly on funding arrangements and the presence of an 'enthusiast'. Critical review of the evidence for effectiveness or cost-effectiveness of these technologies was rarely mentioned. Opportunities exist for evidence-based medicine principles to play a greater role in policy decisions in this area.

Phenotypic methods for determining genomovar status of the Burkholderia cepacia complex

Recent taxonomic advances have demonstrated that Burkholderia cepacia is a cluster of at least seven closely related genomic species (or genomovars) collectively referred to as the B. cepacia complex, all of which may cause infections among cystic fibrosis patients and other vulnerable individuals. Thus, it is important for clinical microbiologists to be able to differentiate genomovars. Prior to this study, 361 B. cepacia complex isolates and 51 isolates easily confused with B. cepacia complex previously had been identified using a polyphasic approach, and in this study, a comparison of phenotypic and biochemical tests was carried out. It was determined that Burkholderia multivorans and Burkholderia stabilis could reliably be separated from other members of the B. cepacia complex by phenotypic methods. A combination of phenotypic and molecular tests such as recA PCR and 16S rRNA RFLP are recommended for differentiation among the genomovars of the B. cepacia complex. A biochemical reaction scheme for the identification of B. gladioli, Pandoraea species, and Ralstonia pickettii and the differentiation of these species from the B. cepacia complex is also presented.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have prompted re-consideration of the use of allogeneic (blood from an unrelated donor) blood transfusion.

OBJECTIVES

To assess the effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid, and epsilon aminocaproic acid, on peri-operative red blood cell (RBC) transfusion.

SEARCH STRATEGY

We searched MEDLINE (to May 1998), EMBASE (to December 1997), web sites of international health technology assessment agencies (to May 1998). References in identified trials and review articles were checked and authors contacted to identify any additional studies.

SELECTION CRITERIA

Randomised controlled trials of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

We found 61 trials of aprotinin (7027 participants). Aprotinin reduced the rate of RBC transfusion by a relative 30% (RR=0.70: 95%CI: 0.64 to 0.76). The average absolute risk reduction (ARR) was 20.4% (95%CI: 15.6% to 25.3%). On average, aprotinin use saved 1.1 units of RBC (95%CI: 0.69 to 1.47) in those requiring transfusion. Aprotinin also significantly reduced the need for re-operation due to bleeding (RR=0.40: 95%CI: 0.25 to 0.66). We found 18 trials of tranexamic acid (TXA) (1,342 participants). TXA reduced the rate of RBC transfusion by a relative 34% (RR=0.66: 95%CI: 0.54 to 0.81). This represented an ARR of 17.2% (95%CI: 8.7% to 25.7%). TXA use resulted in a saving of 1.03 units of RBC (95%CI: 0.67 to 1.39) in those requiring transfusion. We found four trials of epsilon aminocaproic acid (EACA) (208 participants). EACA use resulted in a statistically non-significant reduction in RBC transfusion (RR=0.48: 95%CI: 0.19 to 1.19). Comparisons between agents Eight trials made 'head-to-head' comparisons between TXA and aprotinin. There was no significant difference between the two drugs in the rate of RBC transfusion: RR=1.21 (95%CI: 0.83 to 1.76) for TXA compared to aprotinin. Adverse Effects Aprotinin did not seem to be associated with an excess risk of adverse effects, including thrombo-embolic events (thrombosis RR=0.64: 95%CI: 0.31 to 1.31) and renal failure (RR=1.19: 95%CI: 0.79 to 1.79). Fewer data were available for TXA and EACA.

REVIEWER'S CONCLUSIONS

From this review it appears that aprotinin reduces the need for red cell transfusion, and the need for re-operation due to bleeding, without serious adverse effects. However, there was significant heterogeneity in trial outcomes, and some evidence of publication bias. Similar trends were seen with TXA and EACA, although the data were rather sparse. The poor evaluation of these latter drugs is unfortunate as results suggest they may be equally as effective as aprotinin, but are significantly cheaper. The evidence reviewed here supports the use of aprotinin in cardiac surgery. Further small trials of this drug are not warranted. Future trials should be large enough to compare the efficacy and cost-effectiveness of aprotinin with that of TXA and EACA.

Desmopressin for minimising perioperative allogeneic blood transfusion

BACKGROUND

Public concerns regarding the safety of transfused blood have prompted re-consideration of the use of allogeneic (from an unrelated donor) red blood cell (RBC) transfusion, and a range of techniques designed to minimise transfusion requirements.

OBJECTIVES

To examine the evidence for the efficacy of desmopressin (1-deamino-8-D-arginine-vasopressin), in reducing perioperative blood loss and the need for red cell transfusion in patients who do not have congenital bleeding disorders.

SEARCH STRATEGY

Articles were identified by: computer searches of OVID MEDLINE, EMBASE, and Current Contents (to August 2000) and web sites of international health technology assessment agencies (to May 1998). References in the identified trials and review articles were checked and authors contacted to identify additional studies.

SELECTION CRITERIA

Randomised controlled parallel group trials in which adult patients, scheduled for non-urgent surgery, were randomised to DDAVP, or to a control group, who did not receive the intervention.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed using criteria proposed by Schulz et al. (1995) and Jadad et al. (1996). The principal outcomes were: the number of patients exposed to red cells, and the amount of blood transfused. Other clinical outcomes are detailed in the review.

MAIN RESULTS

Fourteen trials of DDAVP (N=1034) reported data on the proportion of patients exposed to allogeneic RBC transfusion. In subjects treated with DDAVP the relative risk of exposure to peri-operative allogeneic blood transfusion was 0.98 (95%CI: 0.88 to 1.10) compared with control. In DDAVP-treated patients the relative risk of requiring re-operation due to bleeding was 0.56 (95%CI: 0.18 to 1.73). There was no statistically significant effect overall for mortality and non-fatal myocardial infarction in DDAVP-treated patients compared with control (RR=1.53: 95%CI: 0.58 to 4.05) and (RR=1.52: 95%CI: 0.67 to 3.49) respectively.

REVIEWER'S CONCLUSIONS

There is no convincing evidence that desmopressin minimises perioperative allogeneic RBC transfusion in patients who do not have congenital bleeding disorders. These data suggest that there is no benefit of using DDAVP as a means of minimising perioperative allogeneic RBC transfusion. This meta-analysis had 90% power to detect a relative risk reduction of at least 17% for receiving a red cell transfusion at alpha = 0.05 (two-sided).

Imaging in the new millennium

The last few decades of the 20th century were marked by tremendous advances in diagnostic imaging and related therapeutic procedures. The new millennium holds great promise for more spectacular advances. Continuing evolution of computer technology coupled with existing and evolving digital imaging platforms will serve as a catalyst for significant developments in virtually all areas of imaging. This report surveys the potential of these advances in areas relevant to critical care.

Problems with the interpretation of pharmacoeconomic analyses: a review of submissions to the Australian Pharmaceutical Benefits Scheme

CONTEXT

Pharmacoeconomic analyses are being used increasingly as the basis for reimbursement of the costs of new drugs. Reports of these analyses are often published in peer-reviewed journals. However, the analyses are complex and difficult to evaluate.

OBJECTIVE

To describe the nature of problems encountered in the evaluation and interpretation of pharmacoeconomic analyses used as a basis for reimbursement decisions.

DATA SOURCES

All major submissions to the Department of Health and Aged Care (DHAC) by the pharmaceutical industry for funding made under the Australian Pharmaceutical Benefits Scheme. Specifically, the DHAC's database of submissions that were received between January 1994 and December 1997 were reviewed.

STUDY SELECTION

Of a total of 326 submissions, 218 had serious problems of interpretation and were included in the analysis. The nature of the serious problems reviewed were classified as estimates of comparative clinical efficacy, comparator issues, modeling issues, and calculation errors.

DATA EXTRACTION

All submissions in the DHAC's database were reviewed and data were extracted if both the DHAC evaluators and technical subcommittee considered problems to have a significant bearing on the decisions of the parent committee.

DATA SYNTHESIS

Of a total of 326 submissions, 218 (67%) had significant problems and 31 had more than 1 problem. Of the 249 problems identified, 154 (62%) related to uncertainty in the estimates of comparative clinical efficacy, and 71 (28.5%) related to modeling issues, which included clinical assumptions or cost estimates, used in the construction of the economic models. There were 15 instances of disagreement over the choice of comparator, and serious calculation errors were found on 9 occasions. Overall, 159 problems (64%) were considered to be avoidable.

CONCLUSIONS

Significant problems were identified in these pharmacoeconomic analyses. The intensive evaluation process used in the Australian Pharmaceutical Benefits Scheme allowed for identification and correction of pharmacoecomomic analysis problems, but the resources that are required may be beyond the capacity of many organizations, including peer-reviewed journals.

Use of interventions to minimise perioperative allogeneic blood transfusion in Australia. A survey by the International Study of Perioperative Transfusion (ISPOT) Study Group

OBJECTIVE

To investigate use of interventions to minimise need for perioperative transfusion of allogeneic blood in surgical units in Australia.

DESIGN

Two questionnaire-based surveys of practice.

SETTING

All hospitals in Australia, 1996-1997.

PARTICIPANTS

Survey 1: all Australian hospitals that have at least 50 beds and undertake surgery; Survey 2: surgical units identified as using the interventions.

MAIN OUTCOME MEASURES

Reported rates of use of the various interventions (preoperative autologous donation, acute normovolaemic haemodilution [ANH], cell salvage, and drugs); use of guidelines; and perceptions about the appropriateness of current levels of use.

RESULTS

Survey 1 was returned by 349 of 400 hospitals (87%) and Survey 2 by 324 of 578 surgical units (56%). Preoperative autologous donation was most widely used (70% of hospitals), most commonly in units performing orthopaedic or vascular surgery (65% and 37%, respectively). Cell salvage and ANH were used by 27% and 24% of hospitals, respectively, most often in units performing cardiothoracic (40% and 44%, respectively) and vascular surgery (29% and 15%, respectively). These three interventions were used significantly more in private than in public hospitals (P < 0.05). Use of printed guidelines was uncommon. Respondents considered that autologous transfusion techniques should be used more widely because of their perceived efficacy and concerns about safety of allogeneic blood. Perceived barriers to greater use included lack of surgeon or physician interest, uncertain scheduling of surgery in public hospitals and cost (cell salvage). Drugs to minimise blood loss were used by fewer than 10% of hospitals.

CONCLUSIONS

Interventions to minimise the need for perioperative allogeneic blood transfusion (apart from drugs) are widely used in Australia. However, enthusiasm for intraoperative techniques of re-infusing autologous blood needs to be assessed against the evidence of their efficacy and cost-effectiveness.

Multiple combination bactericidal antibiotic testing for patients with cystic fibrosis infected with Burkholderia cepacia

Most Burkholderia cepacia strains are resistant to many, or all, of the antibacterial agents commonly used in cystic fibrosis (CF), and selection of appropriate antibiotics for treatment of pulmonary exacerbations is therefore difficult. We developed a technique for rapid in vitro testing of multiple antibiotic combinations for B. cepacia isolates. For each of 119 multi-drug-resistant isolates of B. cepacia, our multiple combination bactericidal test (MCBT) studied the bactericidal activity of 10 to 15 antimicrobial agents using 225 +/- 97 single, double, and triple antibiotic combinations. Of the 119 isolates, 50% were resistant to all single antibiotics tested, 8% were resistant to all two-drug antibiotic combinations, but all were inhibited by at least one bactericidal triple-drug combination. When used alone, meropenem, ceftazidime and high-dose tobramycin (200 microg/ml) were bactericidal against only 47, 15, and 14% of in vitro isolates, respectively. Using a double antibiotic combination improved bactericidal activity; meropenem-minocycline, meropenem-amikacin, and meropenem-ceftazidime combinations were bactericidal against 76, 73, and 73% of isolates, respectively. However, 47% of isolates demonstrated antagonism (growth of an organism when a second antibiotic was added to a bactericidal single antibiotic). Triple antibiotic combinations that contained tobramycin, meropenem, and an additional antibiotic were most effective, and were bactericidal against 81 to 93% of isolates. We conclude that triple-antibiotic combinations are more likely than double and single antibiotic combinations to be bactericidal against B. cepacia in vitro. MCBT testing is a useful technique to help clinicians decide on appropriate nonantagonistic combination antibiotic therapy for patients with CF infected with B. cepacia.

Vitamin D and vitamin D analogues for preventing fractures associated with involutional and post-menopausal osteoporosis

BACKGROUND

Due to their known effects on bone metabolism, Vitamin D and related compounds have been proposed for the prevention of osteoporosis and fractures.

OBJECTIVES

To determine the effects of supplementation with Vitamin D or a Vitamin D analogue in the prevention of fractures of the axial and appendicular skeleton in elderly men or women with involutional or post-menopausal osteoporosis.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, BIOSIS, CINAHL, HealthPLAN, Dissertation Abstracts, Index to UK Theses, Current Contents, and bibliographies of identified trials and reviews. Trials were also obtained from the Cochrane Musculoskeletal Injuries Group trials register. Date of the most recent search: December 1995.

SELECTION CRITERIA

Any randomised or quasi-randomised trial which compared Vitamin D or a Vitamin D analogue, either alone or in combination with calcium supplementation, with a placebo, no intervention, or the administration of calcium supplements, with fracture as an outcome, in elderly men or women with involutional or post-menopausal osteoporosis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality, by use of a seven item scale, and extracted data. Additional information was sought from trialists. Where possible the data were pooled.

MAIN RESULTS

Fourteen trials recording 13 different comparisons were included. In the only trial of Vitamin D alone, protection against hip fracture was not confirmed. Two regimens, each represented by one large trial, which showed limited evidence of efficacy in reducing the incidence of hip or other appendicular skeleton fractures were: 1) Oral Vitamin D when accompanied by calcium supplementation. 2) 1,25 dihydroxy Vitamin D (calcitriol). This appeared more effective than calcium in a direct comparison. Regimens showing limited evidence of efficacy in reducing the incidence of vertebral deformity were: 1) 1,25 dihydroxy Vitamin D (calcitriol), which appeared more effective than calcium in one large trial, and more effective than placebo from pooled results of two small trials. 2) Oral 1-alpha hydroxy Vitamin D (alfacalcidol), when administered with calcium supplements (two small trials, which lacked power to confirm a possible effect). Hypercalcaemia and gastro-intestinal symptoms, reported in less than 5% of participants, were slightly more common when Vitamin D analogues were taken. However, the risk of death was marginally less.

REVIEWER'S CONCLUSIONS

Uncertainty remains about the efficacy of regimens which include Vitamin D or its analogues in fracture prevention. Particularly if co-supplementation of calcium is required, significant cost differences are likely to exist between regimens. Further randomised trials with economic evaluation are desirable before community fracture prevention programmes employing Vitamin D supplementation can be confidently introduced.

Assessing new health technologies: lessons to be learned from drugs

Balancing the interests of producers, consumers and purchasers (governments) increases the complexity of evidence-based evaluation of non-drug health technologies.

Effects of information framing on the intentions of family physicians to prescribe long-term hormone replacement therapy

OBJECTIVE

To determine whether the way in which information on benefits and harms of long-term hormone replacement therapy (HRT) is presented influences family physicians' intentions to prescribe this treatment.

DESIGN

Family physicians were randomized to receive information on treatment outcomes expressed in relative terms, or as the number needing to be treated (NNT) with HRT to prevent or cause an event. A control group received no information.

SETTING

Primary care.

PARTICIPANTS

Family physicians practicing in the Hunter Valley, New South Wales, Australia.

INTERVENTION

Estimates of the impact of long-term HRT on risk of coronary events, hip fractures, and breast cancer were summarized as relative (proportional) decreases or increases in risk, or as NNT.

MEASUREMENTS AND MAIN RESULTS

Intention to prescribe HRT for seven hypothetical patients was measured on Likert scales. Of 389 family physicians working in the Hunter Valley, 243 completed the baseline survey and 215 participated in the randomized trial. Baseline intention to prescribe varied across patients-it was highest in the presence of risk factors for hip fracture, but coexisting risk factors for breast cancer had a strong negative influence. Overall, a larger proportion of subjects receiving information expressed as NNT had reduced intentions, and a smaller proportion had increased intentions to prescribe HRT than those receiving the information expressed in relative terms, or the control group. However, the differences were small and only reached statistical significance for three hypothetical patients. Framing effects were minimal when the hypothetical patient had coexisting risk factors for breast cancer.

CONCLUSIONS

Information framing had some effect on family physicians' intentions to prescribe HRT, but the effects were smaller than those previously reported, and they were modified by the presence of serious potential adverse treatment effects.

Management and outcomes of congestive heart failure: a prospective study of hospitalised patients

OBJECTIVES

To characterise the morbidity, mortality and patterns of care for patients hospitalised with congestive heart failure (CHF).

DESIGN

Prospective cohort study with one-year follow-up.

PATIENTS

409 patients aged 60 years and over admitted to hospital with congestive heart failure between 1 May and 30 November 1993.

SETTING

John Hunter Hospital (tertiary referral for cardiology) and Mater Hospital (non-tertiary referral for cardiology), Newcastle, New South Wales.

OUTCOME MEASURES

Length of hospital stay (LOS); unplanned readmissions; mortality at 28 days and one year; and relationship between outcomes and patient and disease characteristics determined by multivariate analysis.

RESULTS

Annual hospitalisation rate for CHF in the 60 years and over age group was 783/100,000, with CHF accounting for 10.9% of patients in this age group. Median LOS was eight days, and varied significantly between hospitals. ACE inhibitors were being taken by 66% of subjects at discharge. Rate of unplanned readmissions within 28 days was 20%. Mortality was 12.5% at 28 days and 33% at one year. For a first admission for CHF, 28-day mortality was lower than for readmissions (odds ratio, 0.25; 95% confidence interval, 0.1-0.62), and average LOS was 17% lower. Increasing age and renal impairment were significantly associated with higher one-year mortality. Greater comorbidity was associated significantly with longer LOS and non-significantly with higher 28-day and one-year mortality.

CONCLUSIONS

CHF is a common reason for admission, often results in unplanned readmissions, and has a high mortality. Undertreatment with ACE inhibitors continues. The importance of avoiding recurrent admissions was clear. A program of intensive case management may reduce the burden attributable to CHF.

Identification of Burkholderia cepacia isolates from patients with cystic fibrosis and use of a simple new selective medium

We evaluated 819 isolates referred to us as "Burkholderia cepacia" from cystic fibrosis (CF) clinics and research laboratories from five countries; 28 (3.4%) were not B. cepacia. A further 12 (1.5%) organisms appeared to be other Burkholderia species, but identification could not be confirmed by conventional means. The most prevalently misidentified organisms were Stenotrophomonas maltophilia, Alcaligenes xylosoxidans, and Comamonas acidovorans. Many of these organisms grew on oxidation-fermentation polymyxin-bacitracin-lactose (OFPBL) and Pseudomonas cepacia agars, selective media currently used for B. cepacia isolation. We developed a new medium, B. cepacia selective agar (BCSA), which is more enriched for the growth of B. cepacia yet which is more selective against other organisms than currently available selective agars. A total of 190 of 191 (99.5%) isolates of B. cepacia from patients with CF grew on BCSA without vancomycin, whereas 100% grew on OFPBL agar and 179 (94.2%) grew on P. cepacia agar. Of 189 other gram-negative and gram-positive organisms tested, 10 (5.3%) grew on BCSA without vancomycin. The addition of vancomycin to BCSA lowered the false positivity rate to 3.7% without further inhibition of B. cepacia. The false positivity rates for OFPBL and P. cepacia agars were 19.6 and 13.8%, respectively. Isolates of B. cepacia from CF patients grew most quickly on BCSA, with 201 of 205 (98.0%) being readily visible within 24 h, whereas 182 (88.8%) grew on OFPBL agar and 162 (79.0%) grew on P. cepacia agar within 24 h. We propose that the use of BCSA will allow investigators to overcome many of the difficulties associated with the identification of B. cepacia and should be considered for use as a primary isolation agar for specimens from patients with CF.

Epidemiology of Burkholderia cepacia infection in patients with cystic fibrosis: analysis by randomly amplified polymorphic DNA fingerprinting

We fingerprinted a collection of 627 Burkholderia cepacia isolates from 255 patients with cystic fibrosis (CF) and 43 patients without CF and from the environment, by a PCR-based randomly amplified polymorphic DNA (RAPD) method with primers selected for their ability to produce discriminatory polymorphisms. The RAPD typing method was found to be reproducible and discriminatory, more sensitive than PCR ribotyping, and able to group epidemiologically related B. cepacia strains previously typed by both pulsed-field gel electrophoresis and conventional ribotyping. Seven strain types infecting multiple CF patients were found at several different CF treatment centers in Canada, the United States, the United Kingdom, France, and Australia, indicating the presence of epidemic strain types. Most CF patients were each colonized with a single strain type, and several patients harbored the same strain type for 5 or more years. B. cepacia isolates recovered from other clinical sources (44 isolates examined) and from the environment (58 isolates examined) possessed RAPD fingerprints that were generally distinct from CF-associated strain types (525 isolates examined). RAPD is a versatile fingerprinting method for studying the epidemiology of B. cepacia.

Mediastinitis following median sternotomy: CT findings

PURPOSE

To evaluate the usefulness of computed tomography (CT) in the diagnosis of mediastinitis following median sternotomy.

MATERIALS AND METHODS

Fifty patients aged 6 weeks to 80 years (31 male, 19 female) who underwent CT for clinically suspected mediastinitis following median sternotomy were retrospectively identified. CT scans were evaluated for primary findings (localized mediastinal fluid, pneumomediastinum, or both) versus secondary or other findings (mediastinal edema, adenopathy, pleural effusion, or a sternal or lung abnormality). Patients were divided into three groups on the basis of the CT findings and final clinical diagnosis: those with primary CT signs and a final diagnosis of mediastinitis, those with primary CT signs of mediastinitis and a different final diagnosis, and those with neither primary CT findings nor a final diagnosis of mediastinitis.

RESULTS

All patients with clinical mediastinitis had primary CT findings. These patients under went CT an average of 24 days after surgery. Patients with primary CT findings and a final clinical diagnosis of something other than mediastinitis underwent CT an average of 9 days following following surgery. Through postoperative day 14, CT had a sensitivity of 100% for clinical mediastinitis but a specificity of 33%; after postoperative day 14, the sensitivity was 100% and the specificity was 100%.

CONCLUSION

Primary CT findings are not specific for mediastinitis through postoperative day 14; after day 14, they are highly indicative of mediastinitis.

Development of hematopoietic cancers after implantation of total joint replacement

The evidence from the 4 epidemiologic studies published before mid 1995, which have investigated the incidence of cancers in patients who have undergone joint implants, is conflicting. The results of the 2 earlier studies suggested a sustained increase in the risk of lymphoma and leukemia after total hip arthroplasty. The results of the 2 more recent studies have not confirmed this, although in 1 study an increased risk was observed in the first year after implantation. The heterogeneity may be statistical in origin, but could also have a biologic explanation in the greater proportion of metal on metal prostheses used before 1973. All 4 studies used national data as the comparison. Here, are presented the results of 2 matched cohort studies and a case control study set in North America and Scotland, and an overview of the 4 previous studies. Neither the results of the matched studies of patients operated on after 1973 nor the results of the latter 2 published studies suggest an increased risk of lymphoma or leukemia. If metal on metal articulations are reintroduced, careful surveillance is essential.

Pattern of non-steroidal anti-inflammatory drug use in Australia 1990-1994. A report from the Drug Utilization Sub-Committee of the Pharmaceutical Benefits Advisory Committee

OBJECTIVE

To determine the pattern of use of non-steroidal anti-inflammatory drugs (NSAIDs) in the Australian community, 1990-1994.

DESIGN

Data from the national drug utilisation database were expressed in defined daily doses per 1000 population per day (DDDs/1000 population per day). Temporal trends were assessed and comparisons were made with NSAID use in other countries. Epidemiological data were used to estimate the likely impact of changing NSAID use on peptic ulcer hospitalisation rates.

SETTING

Australian community (excluding hospitals).

MAIN OUTCOME MEASURES

Estimated consumption of prescription NSAIDs, expressed in DDDs/1000 population per day.

RESULTS

NSAID use in the Australian community fell from 50.1 DDDs/1000 population per day in 1990 to 34.6 DDDs/1000 population per day in 1994 (down 31%). From this reduced exposure we estimated that the number of admissions for NSAID-related upper gastrointestinal complications will have fallen by about 400 per year. Market research data for this period show a lower percentage use of NSAIDs for osteoarthritis and a decrease in the proportion of use in age groups over 50 years.

CONCLUSIONS

The level of use of non-steroidal anti-inflammatory drugs in Australia has been high in comparison with other countries, but in recent years has fallen markedly. This fall occurred in conjunction with regulatory interventions, educational campaigns and increased concern in the medical and lay press regarding the risks associated with the use of NSAIDs.

"Black blood" T2-weighted inversion-recovery MR imaging of the heart

PURPOSE

To develop a short-inversion-time inversion-recovery (STIR) magnetic resonance imaging pulse sequence for evaluating the myocardium that is relatively free of flow and motion artifact.

MATERIALS AND METHODS

The authors implemented a breath-hold, cardiac-triggered STIR sequence with preparatory radio-frequency pulses to eliminate signal from flowing blood. A segmented rapid acquisition with relaxation enhancement (turbo spin echo) readout was used, with the inversion-recovery delay adjusted to null fat. The sequence was implemented at 1.0 and 1.5 T and tested in phantoms, five healthy volunteers, and three patients.

RESULTS

Phantom studies confirmed the expected behavior of the sequence. In the volunteers, fat-suppressed images of the heart with STIR contrast were generated in a breath-hold period. Blood in the heart chambers was uniformly nulled, and motion artifacts were effectively suppressed. Focal high signal intensity consistent with edema was seen in two patients with acute myocardial infarction; in a third patient, a paracardiac mass was visualized and sharply demarcated relative to normal myocardium.

CONCLUSION

Fast STIR imaging of the heart with effective suppression of flow and motion artifacts was implemented. The approach has much potential for high-contrast imaging in a variety of diseases affecting the heart and mediastinum.

Radiologic evaluation of the patient after cardiac surgery

The chest radiograph traditionally has played a central role in the preoperative and postoperative care of cardiac surgery patients. Familiarity with the preoperative evaluation, the basics of the process of cardiopulmonary bypass, and the nuances of care in the postoperative period enables the radiologist to provide a more meaningful radiologic consultation.

Measurement of the shear and tensile fracture properties of leaves of pasture grasses

The shear fracture properties of leaves of pasture grasses were measured using a shearing device consisting of 2 blades at fixed angles. The mechanics of the shearing process were examined with both paper and leaves of Festuca arundinacea. The investigations indicated that the intrinsic strength of the material being cut is best represented as force exerted during the cut divided by the length of the cutting blade in contact with the material. Tensile fracture properties of leaves of 5 pasture grasses were also measured, and the relationship between tensile and shear properties was examined. Intrinsic shear strength was weakly negatively correlated with tensile strength.

Normal and abnormal vascular structures that simulate neoplasms on chest radiographs: clues to the diagnosis

Despite increased use of and reliance on cross-sectional imaging techniques in the thorax, conventional chest radiography remains the most commonly performed imaging examination. However, conventional radiographic appearances of normal and abnormal vascular structures can be misinterpreted as representing neoplasms or soft-tissue masses and lead to inappropriate diagnostic procedures. Vascular structures that can simulate neoplasms include normal structures such as the subclavian artery and left brachiocephalic, azygos, and pulmonary veins and abnormal structures such as congenital and acquired anomalies of the thoracic aorta and its branches, pulmonary arteries and veins, superior and inferior venae cavae, and azygos and hemiazygos veins. Other entities such as postoperative changes, massive pulmonary embolism, false ventricular aneurysm, and esophageal varices can also be misinterpreted. Important radiographic features that help distinguish these vascular structures from true neoplasms include proximity to known vascular structures, smooth margination, mural calcification, round or oval configuration, poor or nonvisualization in one of two orthogonal views, and absence or altered position of normal vascular structures. Knowledge of patient history and a detailed understanding of normal mediastinal anatomic structures and common variants help in making the correct diagnosis. Familiarity with these entities will result in the proper, most cost-efficient evaluation.