Moderate dose inhaled corticosteroids plus salmeterol versus higher doses of inhaled corticosteroids in symptomatic asthma

BACKGROUND

There is uncertainty as to the dose of inhaled corticosteroids (ICS) at which to start concomitant long acting beta agonist (LABA) treatment in patients with asthma not adequately controlled by ICS alone.

METHODS

A meta-analysis was carried out of randomised, double blind clinical trials that compared the efficacy of adding salmeterol to moderate doses of ICS (fluticasone propionate 200 mug/day or equivalent) with increasing the ICS dose by at least twofold in symptomatic adult patients with asthma. The main outcome measures were the number of subjects withdrawn from the study due to asthma and the number of subjects with at least one moderate or severe exacerbation.

RESULTS

Twelve studies with a total of 4576 subjects met the inclusion criteria for the analyses. The number of subjects withdrawn due to asthma and with at least one moderate or severe exacerbation was higher in the high dose ICS group (odds ratios 1.58, 95% CI 1.12 to 2.24 and 1.35, 95% CI 1.10 to 1.66, respectively). For the secondary outcome variables (forced expiratory volume in 1 second, morning and evening peak expiratory flow, and daytime beta agonist use) there was significantly greater benefit in the salmeterol group.

CONCLUSIONS

This meta-analysis shows that the addition of salmeterol to moderate doses of ICS (fluticasone 200 mug/day or equivalent) in patients with asthma symptomatic at that dose results in significantly greater clinical benefit than increasing the dose of ICS by twofold or more.

Efficacy of bupropion in the indigenous Maori population in New Zealand

BACKGROUND

Smoking rates are high in indigenous populations and contribute to their poor health. In New Zealand the indigenous Maori population has a high rate of smoking, with around 50% of adults being smokers compared with 20% of the adult European population. A study was undertaken to determine whether bupropion is effective in the treatment of smoking cessation in the indigenous Maori population in New Zealand.

METHODS

A randomised, placebo controlled, double blind, parallel group study was performed in 134 Maori smokers aged 16-70 years who smoked more than 10 cigarettes per day. The main outcome measures were continued abstinence from smoking at 3 and 12 months.

RESULTS

At each time point continued abstinence was better for the subjects allocated to bupropion, with a risk ratio for abstinence over all time points of 2.44 (95% CI 1.22 to 4.88). The rates of continued abstinence in the bupropion and placebo groups at 3 months were 44.3% and 17.4%, respectively, with a risk ratio of 2.54 (95% CI 1.30 to 5.00). The corresponding figures at 12 months were 21.6% and 10.9%, respectively, with a risk ratio of 1.99 (95% CI 0.79 to 5.00).

CONCLUSION

Bupropion is an effective treatment for smoking cessation in the indigenous Maori population in New Zealand.

Systematic review of the dose-response relation of inhaled fluticasone propionate

AIMS

To examine the dose-response relation of inhaled fluticasone for both efficacy and adrenal function in children with asthma.

METHODS

Systematic review of double blind randomised dose-response studies of fluticasone in children of at least 4 weeks duration.

MAIN OUTCOME MEASURES

FEV1, morning peak expiratory flow, night awakenings, beta agonist use, major exacerbations, 12 or 24 hour urinary cortisol, peak plasma cortisol post-stimulation.

RESULTS

Seven studies of 1733 children with asthma met the inclusion criteria for efficacy. The dose-response curve for each efficacy outcome measure suggested that the response began to plateau between 100 and 200 microg per day with additional efficacy at the 400 microg per day dose shown in one study of severe asthmatics. Five studies of 1096 children with asthma met the inclusion criteria for assessment of adrenal function. The largest placebo controlled study of 437 children reported no difference in 24 hour urinary cortisol between placebo and fluticasone at doses of 100 and 200 microg per day. The non-placebo controlled study of 528 children reported significant suppression of overnight urinary cortisol levels with fluticasone at 400 compared with 200 microg per day.

CONCLUSIONS

There is insufficient data to determine the dose-response of fluticasone in children at doses >400 microg per day. The dose-response curve for fluticasone appears to plateau between 100 and 200 microg per day for efficacy. There was additional efficacy at the 400 microg per day dose in children with severe asthma; however there was evidence of adrenal suppression at this dose.

Dose-response relationship of inhaled budesonide in adult asthma: a meta-analysis

The aim of this study was to examine the dose-response relationship of inhaled budesonide in adolescents and adults with asthma. A meta-analysis was carried out on placebo-controlled, randomised clinical trials, presenting data on at least one outcome measure of asthma and using at least two doses of budesonide, delivered by turbuhaler or metered-dose inhaler + spacer twice daily. A total of six studies of 1,435 adolescents and adults, with mild to moderately severe asthma, met the inclusion criteria for the meta-analysis. A negative exponential model indicated that 80% of the benefit at 1,600 micrograms.day-1 was achieved at doses of approximately 200-400 micrograms.day-1 and 90% by 300-600 micrograms.day-1. Meta-regression with a quadratic term in dose showed that the maximum effect was obtained with doses of approximately 1,000 micrograms.day-1. In conclusion, the available published data indicate that, in adolescents and adults with mild to moderate asthma, most of the therapeutic benefit of budesonide delivered by turbuhaler or metered-dose inhaler + spacer is achieved with a dose of approximately 400 micrograms.day-1 and the maximum effect is achieved at approximately 1,000 micrograms.day-1. This conclusion is qualified by the recognition that there is considerable individual variability in the response to inhaled corticosteroids and that the subjects included in this meta-analysis had predominantly mild to moderate asthma.

Clinical dose-response relationship of fluticasone propionate in adults with asthma

BACKGROUND

A study was undertaken to examine the dose-response relation of inhaled fluticasone in adolescents and adults with asthma.

METHODS

A meta-analysis was carried out of randomised clinical trials that presented data on at least one outcome measure of asthma and that used at least two doses of fluticasone given twice daily. The main outcome measures were forced expiratory volume in 1 second (FEV1), morning peak expiratory flow (amPEF), beta agonist use, and withdrawals due to exacerbations of asthma.

RESULTS

Seven studies of 2431 adolescents and adults with moderate to severe asthma met the inclusion criteria for the meta-analysis. Four studies examined a dose of >500 microg/day. For all outcome measures there were no statistically significant differences between a dose of 200 v 500 microg/day, 500 v 1000 microg/day, and 200 v > or =500 microg/day, although the point estimates favoured the higher doses. The mean improvement for FEV1 and amPEF resulting from an increase in dose from 200 to > or =500 microg/day was 0.07 l (95% CI -0.01 to 0.14) and 5.9 l/min (95% CI -3.0 to 15.3), respectively. The odds ratio for withdrawals with 200 microg/day compared with > or =500 microg/day was 1.27 (95% CI 0.78 to 2.07).

CONCLUSIONS

In adolescents and adults with asthma, most of the therapeutic benefit of fluticasone is achieved with a total daily dose of 200 microg/day with minimal further clinical benefit achieved with higher doses. This conclusion is qualified by the recognition that there is considerable individual variability in the response to inhaled corticosteroids in asthma, which would suggest that some patients may obtain a greater clinical benefit at higher doses.

Ovarian cysts in guinea pigs: influence of age and reproductive status on prevalence and size

Forty-three guinea pigs presented as part of a screening programme were divided into six categories on the basis of age and reproductive history. Three age groupings were used: less than one year, one to two years, and over two years. Each age group was further divided into two categories: animals which had had single or multiple pregnancies, and animals which had never bred. Each animal received a clinical examination and was scanned using B-mode ultrasound for the presence of ovarian cysts. Possible relationships between reproductive history and the prevalence of cysts were investigated using Mantel-Haenzel analysis, and between prevalence, cyst size and age using linear regression analysis. Two out of the 43 animals (4.7 per cent) showed symmetrical alopecia. No statistically significant correlation between reproductive history and the prevalence of cysts was detected at the 95 per cent confidence level. A statistically significant relationship was found, however, between cyst size and age (P<0.01) and between cyst prevalence and age (P<0.02).

Strain imaging with intravascular ultrasound array scanners: validation with phantom experiments

Intravascular Ultrasound (IVUS) is routinely used in interventional cardiology for imaging coronary plaque morphology. However, the use of B-mode images for tissue characterization and detection of vulnerable coronary plaques is limited. Strain imaging with ultrasound is a new modality that provides additional information for tissue characterization by imaging differences in tissue stiffness. The aim is to differentiate between vulnerable (soft) plaques and less dangerous calcified (hard) plaques. In this work, the applicability of a time efficient strain imaging algorithm in conjunction with data from IVUS array transducers is evaluated. Unfocused radiofrequency (rf) data from the transducer array is acquired using custom made hardware. Rf line reconstruction is performed offline by synthetic aperture focusing techniques. Vessel mimicking phantoms of different geometries and material stiffness are made from agar and Polyvinyl Alcohol Cryogel (PVA). Experiments are conducted in a water tank and a water column is used for applying intraluminal pressure differences required for strain imaging. The results show that strain images can be calculated with A-lines reconstructed from unfocused rf raw data. Regions of different stiffness can be identified qualitatively by local strain variations. With the used algorithm strains of up to 2% can be imaged without significant decor-relation.

Audit of compliance to adjuvant chemotherapy and radiotherapy guidelines in breast cancer in a cancer network

The North Trent Cancer Network Breast Group in the United Kingdom revised its adjuvant treatment guidelines in breast cancer management in 1998. We aimed to check the compliance to the guidelines, 8 months after their introduction. Data were collected, retrospectively, from the medical records of patients with invasive breast cancer who underwent definitive surgery (in a 3-month period) in different cancer units and the cancer centre within the North Trent Cancer Network. The overall compliance to treatment guidelines was 82% (90% and 74% for chemotherapy and radiotherapy, respectively), which was similar across the network. In 5% of cases, compliance could not be determined. On case review, 22% of the non-compliant incidents were justified and 16% seemed to be due to variation in guideline interpretation. We discuss the possible reasons for non-compliance and show a need to periodically monitor compliance to adjuvant treatment guidelines.

Determination of the glycaemic index of foods: interlaboratory study

OBJECTIVE

Practical use of the glycaemic index (GI), as recommended by the FAO/WHO, requires an evaluation of the recommended method. Our purpose was to determine the magnitude and sources of variation of the GI values obtained by experienced investigators in different international centres.

DESIGN

GI values of four centrally provided foods (instant potato, rice, spaghetti and barley) and locally obtained white bread were determined in 8-12 subjects in each of seven centres using the method recommended by FAO/WHO. Data analysis was performed centrally.

SETTING

University departments of nutrition.

SUBJECTS

Healthy subjects (28 male, 40 female) were studied.

RESULTS

The GI values of the five foods did not vary significantly in different centres nor was there a significant centrexfood interaction. Within-subject variation from two centres using venous blood was twice that from five centres using capillary blood. The s.d. of centre mean GI values was reduced from 10.6 (range 6.8-12.8) to 9.0 (range 4.8-12.6) by excluding venous blood data. GI values were not significantly related to differences in method of glucose measurement or subject characteristics (age, sex, BMI, ethnicity or absolute glycaemic response). GI values for locally obtained bread were no more variable than those for centrally provided foods.

CONCLUSIONS

The GI values of foods are more precisely determined using capillary than venous blood sampling, with mean between-laboratory s.d. of approximately 9.0. Finding ways to reduce within-subject variation of glycaemic responses may be the most effective strategy to improve the precision of measurement of GI values.

Endothelin is an important determinant of renal function in a rat model of acute liver and renal failure

BACKGROUND AND AIMS

Renal failure occurs in approximately 55% of patients with acute liver failure. We have previously shown that plasma endothelin 1 concentrations are elevated in patients with acute liver failure and the hepatorenal syndrome. There are few reported satisfactory animal models of liver failure together with functional renal failure. In this study, a rat model of acute liver failure induced by galactosamine that also develops renal failure was first characterised. This model was used to investigate the hypothesis that endothelin 1 is an important mediator involved in the pathogenesis of renal impairment that occurs in acute liver failure.

METHODS

Acute liver failure was induced in male Sprague-Dawley rats by intraperitoneal injection of galactosamine together with treatment with the endothelin receptor antagonist Bosentan. Twenty four hour urine collections were made using a metabolic cage. Renal blood flow was measured in anaesthetised animals.

RESULTS

This model developed renal failure and liver failure in the absence of any significant renal pathology, and with an accompanying fall in renal blood flow. Plasma concentrations of endothelin 1 were increased twofold following the onset of liver and renal failure (p<0.05), and there was significant upregulation of the endothelin receptor A (ET(A)) in the renal cortex (p<0.05). Administration of Bosentan prevented the development of renal failure when given before or 24 hours after the onset of liver injury (p<0.05) but had no effect on liver injury itself, or on renal blood flow.

CONCLUSIONS

This study demonstrates that this animal model has many of the features needed to be regarded as a model of renal failure that occurs in acute liver failure. The observation that plasma levels of endothelin 1 and ET(A) receptors are increased and upregulated, and that renal failure is prevented by an endothelin antagonist supports the hypothesis originally put forward that ET(A) is important in the pathogenesis of renal failure that occurs in patients with acute liver failure.

Dose-response relation of inhaled fluticasone propionate in adolescents and adults with asthma: meta-analysis

OBJECTIVE

To examine the dose-response relation of inhaled fluticasone propionate in adolescents and adults with asthma.

DESIGN

Meta-analysis of placebo controlled, randomised clinical trials that presented data on at least one outcome measure of asthma and that used at least two different doses of fluticasone.

SETTING

Medline, Embase, and GlaxoWellcome's internal clinical study registers.

MAIN OUTCOME MEASURES

FEV(1), morning and evening peak expiratory flow, night awakenings, beta agonist use, and major exacerbations.

RESULTS

Eight studies, with 2324 adolescents and adults with asthma, met the inclusion criteria. Data on doses of >500 microg/day were limited. The dose-response curve for the raw data began to reach a plateau at around 100-200 microg/day and peaked by 500 microg/day. A negative exponential model for the data, without meta-analysis, indicated that 80% of the benefit at 1000 microg/day was achieved at doses of 70-170 microg/day and 90% by 100-250 microg/day. A quadratic meta-regression showed that the maximum achievable efficacy was obtained by doses of around 500 microg/day. The odds ratio for patients remaining in a study at a dose of 200 microg/day, compared with higher doses, was 0.73 (95% confidence interval 0.49 to 1.08). Comparison of the standardised difference in FEV(1 )for an inhaled dose of 200 microg/day against higher doses showed a difference in FEV(1) of 0.13 of a standard deviation (-0.02 to 0.29).

CONCLUSIONS

In adolescent and adult patients with asthma, most of the therapeutic benefit of inhaled fluticasone is achieved with a total daily dose of 100-250 microg, and the maximum effect is achieved with a dose of around 500 microg/day. However, these findings were limited by the lack of data on individual patients and by the paucity of dose-response studies that included doses of >500 microg/day.

Control of vancomycin-resistant enterococcus in health care facilities in a region

BACKGROUND

In late 1996, vancomycin-resistant enterococci were first detected in the Siouxland region of Iowa, Nebraska, and South Dakota. A task force was created, and in 1997 the assistance of the Centers for Disease Control and Prevention was sought in assessing the prevalence of vancomycin-resistant enterococci in the region's facilities and implementing recommendations for screening, infection control, and education at all 32 health care facilities in the region.

METHODS

The infection-control intervention was evaluated in October 1998 and October 1999. We performed point-prevalence surveys, conducted a case-control study of gastrointestinal colonization with vancomycin-resistant enterococci, and compared infection-control practices and screening policies for vancomycin-resistant enterococci at the acute care and long-term care facilities in the Siouxland region.

RESULTS

Perianal-swab samples were obtained from 1954 of 2196 eligible patients (89 percent) in 1998 and 1820 of 2049 eligible patients (89 percent) in 1999. The overall prevalence of vancomycin-resistant enterococci at 30 facilities that participated in all three years of the study decreased from 2.2 percent in 1997 to 1.4 percent in 1998 and to 0.5 percent in 1999 (P<0.001 by chi-square test for trend). The number of facilities that had had at least one patient with vancomycin-resistant enterococci declined from 15 in 1997 to 10 in 1998 to only 5 in 1999. At both acute care and long-term care facilities, the risk factors for colonization with vancomycin-resistant enterococci were prior hospitalization and treatment with antimicrobial agents. Most of the long-term care facilities screened for vancomycin-resistant enterococci (26 of 28 in 1998 [93 percent] and 23 of 25 in 1999 [92 percent]) and had infection-control policies to prevent the transmission of vancomycin-resistant enterococci (22 of 25 [88 percent] in 1999). All four acute care facilities had screening and infection-control policies for vancomycin-resistant enterococci in 1998 and 1999.

CONCLUSIONS

An active infection-control intervention, which includes the obtaining of surveillance cultures and the isolation of infected patients, can reduce or eliminate the transmission of vancomycin-resistant enterococci in the health care facilities of a region.

Can the presence of equinus contracture be established by physical exam alone?

The condition in which ankle dorsiflexion is restricted is known as equinus contracture (EC). Equinus contracture is purported to be associated with a number of clinical conditions. However, there are no data to support or refute a clinician's ability to diagnose EC by clinical exam. We prospectively evaluated the maximum ankle dorsiflexion with the knee fully extended in 68 people (34 patients with isolated fore- or midfoot pain and 34 asymptomatic subjects) both by clinical exam and by a custom-designed ankle goniometer. We compared the likelihood of agreement of the clinical impression (equinus, no equinus) to the maximum ankle dorsiflexion measured with the instrument at two different numerical definitions of EC (< or =5 degrees and < or =10 degrees of maximum dorsiflexion). When all subjects were included and equinus defined as < or =5 degrees of ankle dorsiflexion, a clinician's ability to detect the equinus when it is truly present is 77.8%. If equinus is defined as < or =10 degrees, this ability increases to 97.2%. Alternatively, if equinus is not present, as defined by < or =5 degrees, then a clinician's ability to correctly diagnose no equinus is 93.8%. If equinus is defined to < or =10 degrees, this ability decreases to 68.8%.

Trends in case-mix-adjusted use of radiology resources at an urban level 1 trauma center

OBJECTIVE

The objective of our study was to determine the utilization rates of diagnostic radiology services at an urban level 1 trauma center.

MATERIALS AND METHODS

This was an observational study of imaging use patterns from 1993 to 1998. Data were segregated by patient type and imaging procedure. Annual hospital admissions were adjusted for severity of illness using the Health Care Financing Administration's case-mix index. Per-patient imaging trends for the emergency department and outpatients were assessed using a ratio of the total number of procedures to the number of patient visits. Linear regression models were used to assess the strength of associations between resource use, measured as relative value units (RVUs), and independent variables (calendar year, patient type, and examination type).

RESULTS

The RVUs for all imaging increased 53% for inpatients, 69% for outpatients, and 85% in the emergency department. No significant trend for use was found for the aggregate of inpatient imaging. There was a significant increase in the inpatient MR imaging RVUs (p = 0.04). No significant trend was found for the aggregated outpatient imaging RVUs. The trends were significant for angiography (p = 0.006), MR imaging (p = 0.002), and sonography (p = 0.04). The aggregated emergency room imaging RVUs showed a significant increase over time (p < 0.03).

CONCLUSION

The number of imaging procedures increased during the study period. There was no overall trend toward increasing use of imaging in inpatients once an adjustment for severity of illness was made. Increases in patient visit-adjusted emergency department use of CT, sonography, and nuclear medicine procedures resulted from changes in practice patterns. For emergency department and outpatient settings, adjusting for the number of patient visits explains a significant portion of the increase in utilization.

The accuracy of references in Australian and New Zealand Medical Journals

AIMS

Previous studies have found high error rates in references in biomedical journals. The aim of this paper was to assess the accuracy of references in three Australian and New Zealand general medical journals.

METHODS

References from the August 1999 issues of the Medical Journal of Australia, the New Zealand Medical Journal and the Australian and New Zealand Journal of Medicine were assessed for accuracy using PubMed of the National Library of Medicine.

RESULTS

This study found a high rate of reference errors in Australian and New Zealand medical journals. The reference error rate ranged from 33.5 to 48.8%. The most frequent errors were in the author's names and in the title.

CONCLUSIONS

The reference error rate in Australia and New Zealand medical journals is high and is preventable. Authors should be more diligent and preferably verify cited references against the original article.

Passive resistance of hamstring muscles in children with severe multiple disabilities?

The purposes of this study were to evaluate whether resistance to stretch could be measured in a reproducible manner from day to day in children with severe multiple disabilities, and whether 6 weeks of daily activity, including one daily stretch, would modify passive resistance to stretch. Passive resistance to stretch was measured in six children using an established model that synchronously and continuously measured knee flexion moment (Nm) and EMG activity of the hamstring, while the velocity and angle of a static stretch was controlled. Resistance to stretch was evaluated in the absence of EMG activity. Measurements were taken on two separate occasions with a 2-week hiatus, and before and after a 6-week activity period which included a daily 1-minute static stretch. There was no significant change in resistance to stretch when tested 2 weeks apart (test 1, 8.6 +/- 1.2 Nm; test 2, 8.3 +/- 1.2 Nm, p>0.05) which yielded a strong correlation coefficient (Spearman r=1.0, p<0.01; Pearson r=0.953, p<0.01). Similarly, there was no difference in resistance to stretch before and after the 6-week period (mean difference 0.22 +/- 0.75 Nm, p>0.05). Data from this study demonstrate that resistance to stretch of the hamstring muscle group could be measured in a reproducible manner from day to day in children with multiple disabilities. Further, resistance to stretch was unchanged after 6 weeks of daily activity, including a daily 1-minute static stretch.