Blood transcriptomic signature in type-2 biomarker-low severe asthma and asthma control.

BACKGROUND: Patients with type-2 (T2) cytokine-low severe asthma often have persistent symptoms despite suppression of T2 inflammation with corticosteroids. OBJECTIVES: We sought to analyze whole blood transcriptome from 738 samples in T2-biomarker-high/-low patients with severe asthma to relate transcriptomic signatures to T2 biomarkers and asthma symptom scores. METHODS: Bulk RNA-seq data were generated for blood samples (baseline, week 24, week 48) from 301 participants recruited to a randomized clinical trial of corticosteroid optimization in severe asthma. Unsupervised clustering, differential gene expression analysis, and pathway analysis were performed. Patients were grouped by T2-biomarker status and symptoms. Associations between clinical characteristics and differentially expressed genes (DEGs) associated with biomarker and symptom levels were investigated. RESULTS: Unsupervised clustering identified 2 clusters; cluster 2 patients were blood eosinophil-low/symptom-high and more likely to be receiving oral corticosteroids (OCSs). Differential gene expression analysis of these clusters, with and without stratification for OCSs, identified 2960 and 4162 DEGs, respectively. Six hundred twenty-seven of 2960 genes remained after adjusting for OCSs by subtracting OCS signature genes. Pathway analysis identified dolichyl-diphosphooligosaccharide biosynthesis and assembly of RNA polymerase I complex as significantly enriched pathways. No stable DEGs were associated with high symptoms in T2-biomarker-low patients, but numerous associated with elevated T2 biomarkers, including 15 that were upregulated at all time points irrespective of symptom level. CONCLUSIONS: OCSs have a considerable effect on whole blood transcriptome. Differential gene expression analysis demonstrates a clear T2-biomarker transcriptomic signature, but no signature was found in association with T2-biomarker-low patients, including those with a high symptom burden.

Analysis of exhaled breath to identify critically ill patients with ventilator-associated pneumonia.

Ventilator-associated pneumonia commonly occurs in critically ill patients. Clinical suspicion results in overuse of antibiotics, which in turn promotes antimicrobial resistance. Detection of volatile organic compounds in the exhaled breath of critically ill patients might allow earlier detection of pneumonia and avoid unnecessary antibiotic prescription. We report a proof of concept study for non-invasive diagnosis of ventilator-associated pneumonia in intensive care (the BRAVo study). Mechanically ventilated critically ill patients commenced on antibiotics for clinical suspicion of ventilator-associated pneumonia were recruited within the first 24 h of treatment. Paired exhaled breath and respiratory tract samples were collected. Exhaled breath was captured on sorbent tubes and then analysed using thermal desorption gas chromatography-mass spectrometry to detect volatile organic compounds. Microbiological culture of a pathogenic bacteria in respiratory tract samples provided confirmation of ventilator-associated pneumonia. Univariable and multivariable analyses of volatile organic compounds were performed to identify potential biomarkers for a 'rule-out' test. Ninety-six participants were enrolled in the trial, with exhaled breath available from 92. Of all compounds tested, the four highest performing candidate biomarkers were benzene, cyclohexanone, pentanol and undecanal with area under the receiver operating characteristic curve ranging from 0.67 to 0.77 and negative predictive values from 85% to 88%. Identified volatile organic compounds in the exhaled breath of mechanically ventilated critically ill patients show promise as a useful non-invasive 'rule-out' test for ventilator-associated pneumonia.

No skin off your back: the sampling and extraction of sebum for metabolomics.

INTRODUCTION: Sebum-based metabolomics (a subset of "sebomics") is a developing field that involves the sampling, identification, and quantification of metabolites found in human sebum. Sebum is a lipid-rich oily substance secreted by the sebaceous glands onto the skin surface for skin homeostasis, lubrication, thermoregulation, and environmental protection. Interest in sebomics has grown over the last decade due to its potential for rapid analysis following non-invasive sampling for a range of clinical and environmental applications. OBJECTIVES: To provide an overview of various sebum sampling techniques with their associated challenges. To evaluate applications of sebum for clinical research, drug monitoring, and human biomonitoring. To provide a commentary of the opportunities of using sebum as a diagnostic biofluid in the future. METHODS: Bibliometric analyses of selected keywords regarding skin surface analysis using the Scopus search engine from 1960 to 2022 was performed on 12th January 2023. The published literature was compartmentalised based on what the work contributed to in the following areas: the understanding about sebum, its composition, the analytical technologies used, or the purpose of use of sebum. The findings were summarised in this review. RESULTS: Historically, about 15 methods of sampling have been used for sebum collection. The sample preparation approaches vary depending on the analytes of interest and are summarised. The use of sebum is not limited to just skin diseases or drug monitoring but also demonstrated for other systemic disease. Most of the work carried out for untargeted analysis of metabolites associated with sebum has been in the recent two decades. CONCLUSION: Sebum has a huge potential beyond skin research and understanding how one's physiological state affects or reflects on the skin metabolome via the sebaceous glands itself or by interactions with sebaceous secretion, will open doors for simpler biomonitoring. Sebum acts as a sink to environmental metabolites and has applications awaiting to be explored, such as biosecurity, cross-border migration, localised exposure to harmful substances, and high-throughput population screening. These applications will be possible with rapid advances in volatile headspace and lipidomics method development as well as the ability of the metabolomics community to annotate unknown species better. A key issue with skin surface analysis that remains unsolved is attributing the source of the metabolites found on the skin surface before meaningful biological interpretation.

The peppermint breath test: a benchmarking protocol for breath sampling and analysis using GC-MS.

Exhaled breath contains hundreds of volatile organic compounds (VOCs) which offer the potential for diagnosing and monitoring a wide range of diseases. As the breath research field has grown, sampling and analytical practices have become highly varied between groups. Standardisation would allow meta-analyses of data from multiple studies and greater confidence in published results. Washout of VOCs from ingestion into the blood and subsequently breath could provide data for an initial assessment of inter-group performance. The Peppermint Initiative has been formed to address this task of standardisation. In the current study we aimed to generate initial benchmark values for thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) analysis of breath samples containing peppermint-derived VOCs using data from three independent European research groups. Initially, headspace analysis of peppermint oil capsules was performed to determine compounds of interest. Ten healthy participants were recruited by each three groups across Europe. The standard Peppermint protocol was followed. In brief, each participant provided a baseline breath sample prior to taking a peppermint capsule, with further samples collected at 60, 90, 165, 285 and 360 min following ingestion. Sampling and analytical protocols were different for each group, in line with their usual practice. Samples were analysed by TD-GC-MS and benchmarking values determined for the time taken for detected peppermint VOCs to return to baseline values. Sixteen compounds were identified in the capsule headspace, and all were confirmed in breath following ingestion of the peppermint capsules. Additionally, 2,3-dehydro-1,8-cineole was uniquely found in the breath samples, with a washout profile that suggested it was a product of metabolism of peppermint compounds. Five compounds (α-pinene, ß-pinene, eucalyptol, menthol and menthone) were quantified by all three groups. Differences were observed between the groups, particularly for the recovery of menthone and menthol. The average time taken for VOCs to return to baseline was selected as the benchmark and were 377, 423, 533, 418 and 336 min for α-pinene, ß-pinene, eucalyptol, menthone and menthol respectively. We have presented an initial set of easy-to-measure benchmarking values for assessing the performance of TD-GC-MS systems for the analysis of VOCs in breath. These values will be updated when more groups provide additional data.

Publisher Correction: The poetry of materials.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Sputum proteomic signature of gastro-oesophageal reflux in patients with severe asthma.

Gastro-oesophageal reflux disease (GORD) has long been associated with poor asthma control without an established cause-effect relationship. 610 asthmatics (421 severe/88 mild-moderate) and 101 healthy controls were assessed clinically and a subset of 154 severe asthmatics underwent proteomic analysis of induced sputum using untargeted mass spectrometry, LC-IMS-MSE. Univariate and multiple logistic regression analyses (MLR) were conducted to identify proteins associated with GORD in this cohort. When compared to mild/moderate asthmatics and healthy individuals, respectively, GORD was three- and ten-fold more prevalent in severe asthmatics and was associated with increased asthma symptoms and oral corticosteroid use, poorer quality of life, depression/anxiety, obesity and symptoms of sino-nasal disease. Comparison of sputum proteomes in severe asthmatics with and without active GORD showed five differentially abundant proteins with described roles in anti-microbial defences, systemic inflammation and epithelial integrity. Three of these were associated with active GORD by multiple linear regression analysis: Ig lambda variable 1-47 (p = 0·017) and plasma protease C1 inhibitor (p = 0·043), both in lower concentrations, and lipocalin-1 (p = 0·034) in higher concentrations in active GORD. This study provides evidence which suggests that reflux can cause subtle perturbation of proteins detectable in the airways lining fluid and that severe asthmatics with GORD may represent a distinct phenotype of asthma.

The VCDQ--a Questionnaire for symptom monitoring in vocal cord dysfunction.

BACKGROUND: Vocal cord dysfunction (VCD) typically involves abnormal adduction of the vocal cords during inspiration, mimics the symptoms of asthma and leads to the prescription of ineffective medications. OBJECTIVE: We aimed to develop a clinical tool to monitor symptoms and response to treatment in confirmed VCD. METHODS: We collated symptoms of VCD from focus groups comprising patients and healthcare professionals; phrases describing these symptoms were assessed for face validity and internal correlation and rated for importance. The resultant 12-item questionnaire (VCDQ) rated the impact of each on a 5-point Likert scale (total score range 12-60) and was tested for reliability, concurrent validity and performance in 31 patients with endoscopically confirmed VCD (± asthma), 29 asthmatics with no history of VCD and 14 healthy controls. We assessed response to speech and language therapy and the minimal important difference by measuring the VCDQ pre- and post- therapy in a 20 new patients. RESULTS: The VCDQ had excellent test-retest reliability and differentiated VCD vs. healthy (Mann-Whitney U-test: z = -5.390, P < 0.001) and asthma (z = -5.730, P < 0.001). All patients improved post-therapy, assessed both by a global rating of change score (GRCS) and by the VCDQ [median (IQR) score pre-therapy 50.5 (48.0 - 54.8), post-therapy 35.0 (29.3 - 41.8), P < 0.001]. The minimal important difference in the VCDQ associated with a rating of 'minimally better' on the GRCS was 4 points. CONCLUSIONS AND CLINICAL RELEVANCE: The VCDQ is a valid and responsive tool suitable for measuring changes in symptoms in patients with VCD. It also gives insight into which symptoms are important to patients and could guide future therapy refinements. Future assessments of novel therapies for this condition should use an appropriately validated tool such as the VCDQ to measure response.

Breath metabolomic profiling by nuclear magnetic resonance spectroscopy in asthma.

BACKGROUND: Metabolomic profiling of exhaled breath condensate offers opportunities for the development of noninvasive diagnostics in asthma. We aimed to determine and validate discriminatory metabolomic profiles in adult asthma and to explore profiles in clinically relevant disease phenotypes. METHODS: Nuclear magnetic resonance spectroscopy was used to analyse breath condensate samples from 82 subjects with asthma and 35 healthy volunteers. Multivariate modelling was performed on a 'training set' (70% of the total sample) in order to produce a discriminatory model classifying asthmatics from healthy controls, and the model tested in the remaining subjects. Secondary analyses were performed to determine the models for the identification of asthmatic subgroups based on sputum eosinophilia, neutrophilia, asthma control and inhaled corticosteroid use. RESULTS: A classification model consisting of five discriminating spectral regions was derived using data from the training set with an area under the receiver operating curve (AUROC) of 0.84. In the test set (the remaining 30% of subjects), the AUROC was 0.91, thus providing external validation for the model. The success of the technique for classifying asthma phenotypes was variable, with AUROC for: sputum eosinophilia (3% cut-off) 0.69; neutrophilia (65% cut-off) 0.88; asthma control (cut-off Asthma Control Questionnaire score of 1) 0.63; and inhaled corticosteroid use 0.89. CONCLUSION: Nuclear magnetic resonance spectroscopy of breath condensate successfully differentiates asthmatics from healthy subjects. With identification of the discriminatory compounds, this technique has the potential to provide novel diagnostics and identify novel pathophysiological mechanisms, biomarkers and therapeutic targets.

High volume local infiltration analgesia compared to peripheral nerve block for hip and knee arthroplasty-what is the evidence?

Since being reported in 2008, high volume local infiltration analgesia (HVLIA) has rapidly gained popularity for patients undergoing hip and knee replacement. We undertook this review to investigate whether there was evidence for equivalence of HVLIA compared to peripheral nerve block techniques with respect to early postoperative analgesia and functional recovery, or for other outcomes such as cost and process efficiency, persistent postsurgical pain and arthroplasty revision rate. We found that despite the popularity of HVLIA, supporting evidence for its use is currently limited. HVLIA certainly provides postoperative analgesia, but it is not clear whether it is equivalent to contemporary peripheral nerve block techniques in terms of either analgesia or early or later functional outcome in the context of a modern, comprehensive enhanced recovery program. Nor is it possible to state whether HVLIA provides benefits in terms of persistent postsurgical pain or cost and process efficiency. Well designed trials directly comparing peripheral nerve block with a standardised HVLIA technique are urgently required.

Methodology validation, intra-subject reproducibility and stability of exhaled volatile organic compounds.

Robust methods for breath sampling and analysis are required for potential clinical applications. We have evaluated an improved sampling and experimental design, assessing instrumental and biological variability within and across breath measurements. Calibration curves for selected relevant volatile organic compounds (VOCs) were produced to look at the dynamic range and stability of analysis by gas chromatography/time-of-flight mass spectrometry. Linear responses were observed with R(2) > 95% and limits of detection in mid-range pg/µl. Overall experimental design, visualized by means of principal component analysis, demonstrated good clustering on quality control samples, background air and blanks, with dispersion observed as expected across human breath samples. Serial sampling while breathing VOC-filtered air for up to 30 min demonstrated marked variation in reproducibility of VOCs, with median intraclass correlation coefficient of 0.29 (interquartile range 0.16-0.71), with no apparent effect of disease status. We have shown that we can reliably detect VOCs at very low concentrations in exhaled breath samples, and that the reproducibility depends on (a) compound of interest; (b) length of time breathing VOC-filtered air. These parameters will require investigation in studies of potential breath biomarkers, and must be standardized if tests are to become clinically useful.

Epidural analgesia compared with peripheral nerve blockade after major knee surgery: a systematic review and meta-analysis of randomized trials.

The relative analgesic efficacy and side-effect profile of peripheral nerve blockade (PNB) techniques compared with lumbar epidural analgesia for major knee surgery is unclear. We undertook a systematic review and meta-analysis of all randomized trials comparing epidural analgesia with PNB for major knee surgery. Eight studies were identified that had enrolled a total of 510 patients of whom 464 (91%) had undergone total knee joint replacement. All were small trials and none was blinded (Jadad score 1-3). PNB technique was variable: in addition to a femoral catheter (n=5), femoral single shot (n=2), or lumbar plexus catheter (n=1) techniques, sciatic blockade was performed in three trials. There was no significant difference in pain scores between epidural and PNB at 0-12 or 12-24 h, WMD 0.22 (95% CI: -0.36, 0.81), 0.05 (-1.01, 0.91), respectively, and no clinically significant difference at 24-48 h, WMD -0.35 (-0.64, -0.02). There was also no difference in morphine consumption (mg) at 0-24 h, WMD -6.25 (-18.35, 5.86). Hypotension occurred more frequently among patients who received epidurals [OR 0.19 (0.08, 0.45)], but there was no difference in the incidence of nausea and vomiting. Two studies reported a higher incidence of urinary retention in the epidural group. Patient satisfaction was higher with PNB in two of three studies which measured this, although rehabilitation indices were similar. PNB with a femoral nerve block provides postoperative analgesia which is comparable with that obtained with an epidural technique but with an improved side-effect profile and is less likely to cause a severe neuraxial complication.

Nontuberculous mycobacteria in bronchiectasis: Prevalence and patient characteristics.

The aim of the current study was to investigate the prevalence and clinical associations of nontuberculous mycobacteria (NTM) in a well-characterised cohort of patients with adult-onset bronchiectasis. The sputum of all patients attending a tertiary referral bronchiectasis clinic between April 2002 and August 2003 was examined for mycobacteria as part of an extensive diagnostic work-up. NTM-positive patients subsequently had further sputa examined. A modified bronchiectasis scoring system was applied to all high-resolution computed tomography (HRCT) scans from NTM-positive patients, and a matched cohort without NTM. Out of 98 patients attending the clinic, 10 had NTM in their sputum on first culture; of those, eight provided multiple positive cultures. Three patients were treated for NTM infection. A higher proportion of NTM-positive than -negative patients were subsequently diagnosed with cystic fibrosis (two out of nine versus two out of 75). On HRCT scoring, more patients in the NTM-positive group had peripheral mucus plugging than in the NTM-negative group. In the current prospective study of a large cohort of patients with bronchiectasis, 10% cultured positive for nontuberculous mycobacteria in a random clinic sputum sample. Few clinical parameters were helpful in discriminating between groups, except for a higher prevalence of previously undiagnosed cystic fibrosis and of peripheral mucus plugging on high-resolution computed tomography in the nontuberculous mycobacteria group.

Provision for major obstetric haemorrhage: an Australian and New Zealand survey and review.

Obstetric haemorrhage is a leading cause of maternal death and the most common contributor to serious obstetric morbidity. Maternal mortality audit data suggest that appropriate preparation and good emergency management leads to improved outcome. The aim of this study was to assess facilities relevant to major obstetric haemorrhage management in all units in Australia and New Zealand that offer operative obstetric services. The questionnaire was divided into ten sections: demographics, facilities, staffing, policies and guidelines, drugs, procedures, equipment, point of care testing, availability of O negative blood and free comments. Responses were received from 240 (76.4%) of the 314 hospitals surveyed (187 public and 53 private). One hundred and nine units (45%) had fewer than 500 deliveries per year Distances to referral facilities were frequently very large. Of the 90 hospitals (38.1%) without an onsite blood bank, 12 did not have a supply of blood for emergencies. Half of all units (n=121) had on-site intensive care or high dependency facilities and 72.9% (n=175) had an on-site cardiac arrest team. Only 58.8% of units (n=141) had a written haemorrhage protocol. Findings are presented in the context of other literature, including evidence-based guidelines. Haemorrhage responds well to appropriate treatment, although careful preparation and anticipation of problems is required. In our region geographical factors and different systems of healthcare complicate provision of obstetric services. Where facilities are limited, women should be offered antenatal transfer to a larger centre.

Recurrent atrial tachyarrhythmia triggered by percutaneous balloon rhizotomy of the trigeminal nerve.

Stimulation of sensory branches of the trigeminal nerve is known to cause sudden bradycardia (trigeminocardiac reflex). However we report a case where percutaneous balloon rhizotomy of the trigeminal ganglion provoked atrial tachyarrhythmias during two separate treatments. On both occasions the patient was treated with antiarrhythmic drugs and reverted to sinus rhythm within days. Our case demonstrates that surgery involving the trigeminal nerve may cause variable cardiovascular effects that are often clinically significant. Possible mechanisms and management of arrhythmias in this setting are discussed.

Effects of mediator antagonism on mannitol and adenosine monophosphate challenges.

BACKGROUND: Airway hyper-responsiveness (AHR) to indirect stimuli is a useful non-invasive surrogate inflammatory marker in the evaluation of asthma, while histamine and cysteinyl leukotrienes are important inflammatory mediators. OBJECTIVE: To evaluate AHR to indirect bronchoconstrictor stimuli and time taken to recover following single doses of montelukast 10 mg and desloratadine 5 mg in combination, montelukast 10 mg alone and placebo. METHODS: Fifteen mild-to-moderate persistent asthmatics completed a randomized, double-blind, cross-over study. Patients received encapsulated montelukast 10 mg/desloratadine 5 mg combination, montelukast 10 mg alone and placebo, 10-14 h prior to challenge on two separate occasions. The mannitol threshold dose, AMP threshold concentration and recovery times after challenge were measured along with lung function. RESULTS: Compared to placebo, montelukast/desloratadine conferred improvements (P < 0.05) in adenosine monophosphate (AMP) threshold concentration and mannitol threshold dose: a 3.2-fold (95% CI 2.2-4.6) and 2.4-fold (95% CI 1.7-3.3) difference, respectively, while compared to montelukast this amounted to a 2.0-fold (95% CI 1.2-3.4) and 1.5-fold (95% CI 1.1-2.4) improvement, respectively. Montelukast was not significantly different from placebo. Both montelukast/desloratadine and montelukast compared to placebo, shortened recovery following both challenges (P < 0.05): a 27-min (95% CI 17-37) and 29-min (95% CI 20-36) reduction, respectively, for AMP, and a 27-min (95% CI 17-37) and 26-min (95% CI 17-35) reduction, respectively for mannitol. CONCLUSION: The dissociated effects of single doses of montelukast alone but not montelukast/desloratadine combination on AHR and recovery time, highlights the relative roles of histamine in initiating the bronchoconstrictor response and cysteinyl leukotrienes in sustaining it. Similar improvements in AHR and recovery time were observed following both indirect bronchoconstrictor stimuli.

Airway and systemic effects of hydrofluoroalkane fluticasone and beclomethasone in patients with asthma.

BACKGROUND: With the transition to hydrofluoroalkane-134a propellants in metered dose inhalers, it is important to consider the efficacy and safety profiles of formulations containing inhaled corticosteroids. We examined the airway and systemic effects of hydrofluoroalkane-134a fluticasone propionate (FLU-HFA) and beclomethasone dipropionate (BEC-HFA) at recommended labelled doses. METHODS: Twenty mild to moderate asthmatics were randomised in crossover fashion to receive 6 weeks of 500 micro g/day followed by 1000 micro g/day FLU-HFA and BEC-HFA. Measurements were made at baseline after placebo run in and washout, and after each randomised treatment. The primary airway outcome for benefit was the dose of methacholine provoking a fall in forced expiratory volume in 1 second (FEV(1)) of 20% or more (methacholine PD(20)) and for systemic adverse effects was overnight urinary cortisol/creatinine (OUCC). RESULTS: For mean responses, both doses of BEC-HFA and FLU-HFA produced significant improvements in PD(20) compared with baseline. The improvement was not significantly greater with 1000 micro g/day FLU-HFA versus BEC-HFA, a 1.69 fold difference (95% CI 0.94 to 3.04). Both doses of BEC-HFA but not FLU-HFA caused significant suppression of OUCC compared with baseline, with significantly (p<0.05) lower values at 1000 micro g/day for BEC-HFA versus FLU-HFA (1.97 fold difference (95% CI 1.28 to 3.02)). CONCLUSION: There was no difference in the airway and systemic effects in patients with mild to moderate asthma between FLU-HFA and BEC-HFA at a dose of 500 micro g/day. At 1000 micro g/day there was increased systemic bioactivity with BEC-HFA compared with FLU-HFA, without any gain in airway efficacy.

Evaluation of the importance of head and probe stabilisation in acoustic rhinometry.

As yet there is no established procedure to ensure the repeatability of acoustic rhinometry measurements although anecdotal evidence suggests that instrument fixation improves repeatability. The aim of this study is to validate the methodology of acoustic rhinometry and determine whether instrument fixation and head stabilisation is necessary. Four methods were compared in fifteen healthy volunteers, after nasal decongestion: A) Patient holding the probe (patient-held), B) Probe fixed in a probe stand (probe-stand), C) Probe fixed in stand and head stabilised in head rest (head-rest), D) Examiner holding the probe (examiner-performed). The two minimum cross-sectional areas and volume between 0 and 5 cm were recorded. The examiner-performed and probe-stand methods were consistently less variable than the other methods. With examiner-performed method, this was significant (p < 0.05) versus head-rest and patient-held methods for both measures of minimum cross-sectional area. For nasal volume the examiner-performed method was significantly (p < 0.05) less variable than the head-rest method. In conclusion, examiner-performed acoustic rhinometry is more repeatable than combined head stabilisation and instrument fixation and therefore the use of a head-rest may be unnecessary. Instrument fixation or examiner performed test is also preferable to allowing the patient to position the probe. The repeatability of the probe-stand method was similar to the examiner-performed method.

Dose-response for adrenal suppression with hydrofluoroalkane formulations of fluticasone propionate and beclomethasone dipropionate.

AIMS: With the recent introduction of hydrofluoroalkane (HFA) inhalers it is important to know the relative systemic safety profiles of inhaled corticosteroids. We therefore decided to compare systemic bioavailability of HFA-beclomethasone dipropionate (BDP) vs HFA-fluticasone propionate (FP). METHODS: Sixteen healthy volunteers were randomised in placebo-controlled single blind cross-over fashion to receive 3 weeks with HFA-FP or HFA-BDP, given as 1 week cumulative doubling doses (nominal ex-valve) of 500, 1000 and 2000 microg day(-1), with a 1 week placebo run-in and wash-out. Overnight (22.00 h to 08.00 h) and early morning (08.00 h) urinary cortisol/creatinine excretion and 08.00 h serum cortisol were measured after each placebo and dosing period. All data were log-transformed to normalize their distribution. RESULTS: Urine and serum cortisol were suppressed by 2000 microg FP and BDP vs placebo and by 1000 microg BDP vs placebo for urinary cortisol/creatinine (P < 0.05). Overnight urinary cortisol/creatinine ratio (the primary endpoint) was suppressed more by 1000 microg BDP vs 1000 microg FP (P < 0.05), amounting to a geometric mean fold difference (95% CI) of 1.64 (1.04-2.56). There were also more individual low values less than 3 nmol mmol(-1) with BDP than FP at 1000 microg: n = 8/16 vs n = 2/16 (P < 0.05). CONCLUSIONS: There was dose-related suppression of corrected urinary cortisol/creatinine with the HFA formulations of BDP and FP. Suppression of overnight urinary cortisol/creatinine ratio was significantly greater with HFA-BDP than HFA-FP at 1000 microg. This suggests that the greater glucocorticoid potency of HFA-FP may be offset by the greater lung bioavailability of HFA-BDP.