Intermittent fasting in Type 2 diabetes mellitus and the risk of hypoglycaemia: a randomized controlled trial

AIMS

To establish whether the risk of hypoglycaemia is greater with 2 consecutive days of very-low-calorie diet compared with 2 non-consecutive days of very-low-calorie diet in people with Type 2 diabetes.

METHODS

This was a non-blinded randomized parallel group interventional trial of intermittent fasting in adults. The participants had a BMI of 30-45 kg/m² , Type 2 diabetes treated with metformin and/or hypoglycaemic medications and an HbA_1c concentration of 50-86 mmol/mol (6.7-10%). The participants followed a 2092-2510-kJ diet on 2 days per week for 12 weeks. A total of 41 participants were randomized 1:1 to consecutive (n=19) or non-consecutive (n=22) day fasts, of whom 37 (n=18 and n=19, respectively) were included in the final analysis. The primary outcome was difference in the rate of hypoglycaemia between the two study arms. Secondary outcomes included change in diet, quality of life, weight, lipid, glucose and HbA_1c levels, and liver function.

RESULTS

The mean hypoglycaemia rate was 1.4 events over 12 weeks. Fasting increased the rate of hypoglycaemia despite medication reduction (RR 2.05, 95% CI 1.17 to 3.52). There was no difference between fasting on consecutive days and fasting on non-consecutive days (RR 1.54, 95% CI 0.35 to 6.11). Improvements in weight, HbA_1c , fasting glucose and quality of life were experienced by participants in both arms.

CONCLUSIONS

In individuals with Type 2 diabetes on hypoglycaemic medications, fasting of any type increased the rate of hypoglycaemia. With education and medication reduction, fewer than expected hypoglycaemic events occurred. Although it was not possible to determine whether fasting on consecutive days increased the risk of hypoglycaemia, an acceptable rate was observed in both arms.

A Two Centre Observational Study of Simultaneous Pulse Oximetry and Arterial Oxygen Saturation Recordings in Intensive Care Unit Patients

The influence of variables that might affect the accuracy of pulse oximetry (SpO2) recordings in critically ill patients is not well established. We sought to describe the relationship between paired SpO2/SaO2 (oxygen saturation via arterial blood gas analysis) in adult intensive care unit (ICU) patients and to describe the diagnostic performance of SpO2 in detecting low SaO2 and PaO2. A paired SpO2/SaO2 measurement was obtained from 404 adults in ICU. Measurements were used to calculate bias, precision, and limits of agreement. Associations between bias and variables including vasopressor and inotrope use, capillary refill time, hand temperature, pulse pressure, body temperature, oximeter model, and skin colour were estimated. There was no overall statistically significant bias in paired SpO2/SaO2 measurements; observed limits of agreement were +/-4.4%. However, body temperature, oximeter model, and skin colour, were statistically significantly associated with the degree of bias. SpO2 <89% had a sensitivity of 3/7 (42.9%; 95% confidence intervals, CI, 9.9% to 81.6%) and a specificity of 344/384 (89.6%; 95% CI 86.1% to 92.5%) for detecting SaO2 <89%. The absence of statistically significant bias in paired SpO2/SaO2 in adult ICU patients provides support for the use of pulse oximetry to titrate oxygen therapy. However, SpO2 recordings alone should be used cautiously when SaO2 recordings of 4.4% higher or lower than the observed SpO2 would be of concern. A range of variables relevant to the critically ill had little or no effect on bias.

Weight-based carbohydrate treatment of hypoglycaemia in people with Type 1 diabetes using insulin pump therapy: a randomized crossover clinical trial

AIM

To test whether weight-based treatment is more effective than usual care in people with Type 1 diabetes receiving continuous subcutaneous insulin infusion therapy with regard to both hypoglycaemia and avoiding excessive rebound hyperglycaemia.

METHODS

Children and adults on continuous subcutaneous insulin infusion were enrolled into a study with a crossover design. Each episode of hypoglycaemia (defined as capillary glucose <4.0 mmol/l) was randomly assigned one of two treatment protocols using glucose tablets: either 0.3 g/kg body weight or usual treatment with 15 g (adults) or 10 g (children) for capillary glucose levels 3-3.9 mmol/l or twice these doses for capillary glucose levels <3 mmol/l. All participants received each treatment in random order for up to 10 hypoglycaemic episodes. Glucose levels were re-tested 10 min after treatment, with a repeat dose if still <4 mmol/l.

RESULTS

Of the 37 participants enrolled, 35 (aged 6-68 years) completed the study. Twenty-four participants completed all treatment episodes, while 10 participants had <10 hypoglycaemic episodes and two withdrew without data. The mean glucose difference between weight-based and usual treatment after 10 min was 0.33 mmol/l (95% CI 0.005 to 0.66; P=0.047) in adults and 0.45 (95% CI 0.18 to 0.72; P=0.001) in children. The odds ratios for resolution of hypoglycaemia at 10 min with a single treatment using weight-based compared with usual treatment were 3.12 (95% CI 1.38 to 7.02; P=0.0070) in adults and 2.61 (95% CI 1.19 to 5.74; P=0.017) in children.

CONCLUSIONS

Weight-based treatment using 0.3 g/kg glucose was more effective for symptomatic hypoglycaemia in children and adults with Type 1 diabetes who were using continuous subcutaneous insulin infusion than treatment based on current international recommendations.

Reference ranges for serum periostin in a population without asthma or chronic obstructive pulmonary disease

BACKGROUND

The clinical utility of serum periostin as a type 2 biomarker in asthma is limited by lack of reference range values derived from a population without respiratory disease.

OBJECTIVE

To derive age- and sex-related reference intervals for serum periostin from an adult population without asthma or COPD.

METHODS

Serum periostin levels were measured in 480 individuals, comprising 60 female and 60 male adults in each of the 18- to 30-year, 31- to 45-year, 46- to 60-year and 61- to 75-year age groups. Key exclusion criteria included a doctor's diagnosis of asthma, chronic bronchitis or COPD, and a history of wheezing or use of respiratory inhalers in the last 12 months. The distribution of periostin and logarithm-transformed periostin levels was derived, and 90% confidence intervals for an individual prediction were calculated.

RESULTS

The distribution of serum periostin was right skewed with a mean (SD) periostin of 51.2 (11.9) ng/mL, median (IQR) 50.1 (43.1 to 56.9) ng/mL and range 28.1 to 136.4 ng/mL. There was no association between logarithm periostin and age or sex, although levels were low in current smokers. The 90% confidence limits for periostin were 35.0 and 71.1 ng/mL.

CONCLUSIONS AND CLINICAL RELEVANCE

Serum periostin levels in adults without asthma or COPD are similar to those in adults with asthma. Serum periostin measurements do not need to be adjusted to take account of a patient's age or sex, although levels are lower in current smokers. Reference values for serum periostin levels in adults without asthma or COPD are provided.

Venous thromboembolism rates in patients with lower limb immobilization after Achilles tendon injury are unchanged after the introduction of prophylactic aspirin: audit

ESSENTIALS: We audited venous thromboembolism (VTE) in Achilles injuries after the use of prophylactic aspirin. We audited 218 patients with Achilles injury requiring lower limb immobilization for ≥ 1 week. Fourteen patients (6.4%, 95% CI 3.6% to 10.5%) developed symptomatic and confirmed VTE. The incidence was similar to the 6.3% identified in the same patient group prior to the use of aspirin.

BACKGROUND/OBJECTIVE

We report a follow-up audit of the incidence of venous thromboembolism (VTE) in patients requiring lower limb immobilization because of Achilles tendon injury, since the introduction of a policy to routinely prescribe 100 mg of aspirin daily.

PATIENTS/METHODS

We studied 218 patients aged 18-65 years who attended the Orthopaedic Assessment Unit at Wellington Hospital between January 2013 and December 2014 with Achilles tendon injury requiring lower limb immobilization for ≥ 1 week. Information on assessment of VTE risk, prescription of aspirin and symptomatic VTE occurring within 70 days of immobilization was obtained and compared with the same information collected with the same method in the same patient group between January 2006 and December 2007, before the policy to routinely prescribe aspirin was introduced.

RESULTS

A total of 189 of 218 (93%) patients were prescribed aspirin, as compared with 0.5% previously. Fourteen patients (6.4%, 95% confidence interval 3.6-10.5%) developed symptomatic radiologically confirmed VTE (10 distal deep vein thromboses [DVTs], two proximal DVTs, one pulmonary embolism [PE], and one PE with distal DVT). Aspirin was prescribed to all patients who subsequently developed a VTE; in one of 14, a recognized risk factor was documented. The VTE incidence was similar to the 6.3% identified in the previous audit.

CONCLUSION

Lower limb immobilization following Achilles tendon injury confers a high risk of VTE even with aspirin prophylaxis. Consideration should be given to prophylaxis with low molecular weight heparin during lower limb immobilization following Achilles tendon injury, as this has proven efficacy in this clinical situation.

Randomized controlled trial of asthma risk with paracetamol use in infancy--a feasibility study

BACKGROUND

There is non-experimental evidence that paracetamol (acetaminophen) use may increase the risk of developing asthma. However, numerous methodological issues need to be resolved before undertaking a randomized controlled trial to investigate this hypothesis.

OBJECTIVE

To establish the feasibility of a randomized controlled trial of liberal paracetamol as usually given by parents/guardians vs. a comparator (restricted paracetamol in accordance with WHO guidelines, ibuprofen or placebo), and childhood asthma risk.

METHODS

Questionnaires were completed by parents/guardians of infants admitted to Wellington Hospital with bronchiolitis to assess views about comparator treatments. Subsequently, infants of parents/guardians who provided informed consent were randomized to restricted or liberal paracetamol use for 3 months with paracetamol use recorded.

RESULTS

Of 120 eligible participants, 72 (60%) parents/guardians completed the questionnaire. Ibuprofen, restricted paracetamol and placebo were acceptable to 42 (58%), 29 (40%) and 9 (12%) parents/guardians, respectively. 36 (30%) infants were randomized to restricted or liberal paracetamol. Paracetamol use was greater for the liberal vs. restricted group for reported [Hodges-Lehmann estimator of difference 0.94 mg/kg/day (95% CI 0.2-3.52), P = 0.02] and measured use [Hodges-Lehmann estimator of difference 2.11 mg/kg/day (95% CI 0.9-4.18), P = 0.004]. The median reported and measured use of paracetamol was 2.0-fold and 3.5-fold greater in the liberal vs. restricted group.

CONCLUSIONS AND CLINICAL RELEVANCE

Although separation in paracetamol dosing is likely to be achieved with a liberal vs. restricted paracetamol regime, ibuprofen is the preferred comparator treatment in the proposed RCT of paracetamol use and risk of asthma in childhood.

The association between paracetamol use and asthma: causation or coincidence?

A better understanding of the causation of asthma and allergic disorders could potentially lead to intervention strategies that reduce their prevalence and severity. One potential causative factor is the use of paracetamol. Most of the evidence for the link with asthma is from non-experimental studies of paracetamol exposure in utero, infancy, childhood and adult life; however, it has been difficult to rule out confounding and bias in the associations observed. The two randomized clinical trials of the effect of paracetamol in patients with asthma have been difficult to interpret, due to methodological issues. There have been no randomized controlled trials of paracetamol use and the development of asthma. Both asthma and paracetamol use are common, and so even if there is a relatively small effect of paracetamol exposure on the development of asthma or its severity, then such an effect would be of major public health significance. It is proposed that randomized controlled trials of the effect of paracetamol on the development of asthma and its severity are a high research priority.

Weight-based hypoglycaemia treatment protocol for adults with Type 1 diabetes: a randomized crossover clinical trial

AIM

To determine whether a weight-based hypoglycaemia treatment using 0.3 g/kg (or 0.2 g/kg) glucose effectively treats adults with Type 1 diabetes mellitus compared with an internationally recommended 15-g treatment.

METHODS

Patients with frequent hypoglycaemia were recruited from hospital-based diabetes clinics. The treatment for each hypoglycaemic episode, defined as capillary glucose <4.0 mmol/l, was randomly assigned to one of three protocols: 0.2 g/kg, 0.3 g/kg, or 15 g, using Dextro(TM) glucose tablets (Dextro Energy, Krefeld, Germany). Each participant received each treatment in random order for up to 15 hypoglycaemic episodes. Capillary glucose was re-tested 10 min after treatment, with a repeat dose if still < 4 mmol/l.

RESULTS

The study recruited 34 participants aged 22-71 years, whose mean (sd) BMI was 25.2 (3.1) kg/m(2) and HbA1c 63 (10.4) mmol/mol [7.9 (0.9)%]. Two people withdrew because they did not like the taste of the Dextro tablets and one was excluded because they used their own glucose preparation. Unadjusted for clustering within participants, the mean (sd) capillary glucose after 10 min was 4.67 (1.25) mmol/l for 0.3 g/kg (141 episodes), 4.29 (0.94) mmol/l for 0.2 g/kg (132 episodes), and 4.37(0.99) mmol/l for 15 g (136 episodes). Capillary glucose, adjusted for clusters and baseline, was higher after 10 min for 0.3 g/kg glucose compared with 15 g glucose; a difference of 0.26 (95% CI 0.04-0.48) mmol/l (P = 0.02), but not for 0.2 g/kg; -0.07 (95% CI -0.29-0.16) mmol/l (P = 0.56). Capillary glucose for only three hypoglycaemic episodes rose above 8 mmol/l.

CONCLUSIONS

A weight-based protocol of 0.3 g/kg glucose appears more effective for treating symptomatic hypoglycaemia in adults with Type 1 diabetes than either the most common current recommendation of 15 g glucose or a 0.2 g/kg glucose dose.

Refeeding syndrome is uncommon in alcoholics admitted to a hospital detoxification unit

The refeeding syndrome is increasingly recognised. It is a serious change in electrolytes when nutrition is reintroduced to malnourished patients. Alcohol dependence is a risk factor for the refeeding syndrome. We report a prospective cohort study of 36 alcoholics hospitalised for withdrawal management. We found no evidence of refeeding syndrome in any patient after 3 days of hospitalisation, despite hypomagnesaemia, a risk factor for the refeeding syndrome being prevalent (44% of subjects). Low thiamine levels were infrequent affecting 3/29 (10%). We recommend that in alcoholics admitted for managed withdrawal, risk of refeeding syndrome appears to be low, and routine testing of repeat electrolytes appears unnecessary.

The impact of haemodilution and bypass pump flow on cerebral oxygen desaturation during cardiopulmonary bypass--A comparison of two systems of cardiopulmonary bypass

OBJECTIVE

To determine the influence of haemodilution, bypass flow rates and calculated oxygen delivery during cardiopulmonary bypass (CPB) with either a conventional CPB (C-CPB) circuit or a miniaturised (Mini-CPB) circuit on cerebral oxygen desaturation. The effect of minimal haemodilution with a Mini-CPB was investigated.

PARTICIPANTS

Eighty patients scheduled for elective cardiac surgery.

INTERVENTION

Oxygenated haemoglobin (O2Hb) and tissue oxygenation index (TOI) were measured with near-infrared spectroscopy (NIRS).

RESULTS

The average indexed bypass pump flow was significantly lower with Mini-CPB. When combined with haemoglobin concentration, the average oxygen delivery was the same between groups. Patients in the C-CPB group had a greater duration and severity of cerebral desaturation to a level <20% below baseline values, but none reached the depth and duration of the cerebral desaturation associated with poor outcome. Cerebral oxygen desaturation with C-CPB was significantly associated with low flows during bypass, whereas desaturation with Mini-CPB was associated with low perioperative haemoglobin concentration.

Metrics of salbutamol use as predictors of future adverse outcomes in asthma

BACKGROUND

Beta-agonist overuse is associated with adverse outcomes in asthma, however, the relationships between different metrics of salbutamol use and future risk are uncertain.

OBJECTIVE

To investigate the relationship between metrics of salbutamol use and adverse outcome.

METHODS

In a 24-week randomized controlled trial of 303 asthma patients at risk of severe exacerbations which compared the efficacy and safety of combination budesonide/formoterol inhaler according to a single inhaler regimen (SMART) with a fixed-dose regimen with salbutamol as reliever ('Standard'), actual medication use was measured by electronic monitoring (Australian New Zealand Clinical Trials Registry Number ACTRN12610000515099). A nested cohort study explored the relationship between metrics of baseline salbutamol use over 2 weeks and future severe asthma exacerbations, poor asthma control (ACQ-5 ≥ 1.5) or 'extreme' salbutamol overuse (> 32 salbutamol actuations/24-h period).

RESULTS

Higher mean daily salbutamol use (per two actuations/day) [Odds ratio (OR) (95% CI) 1.24 (1.06-1.46)], higher days of salbutamol use (per 2 days in 2 weeks) [OR 1.15 (1.00-1.31)] and higher maximal 24-h use (per two actuations/day) [OR 1.09 (1.02-1.16)] were associated with future severe exacerbations. Higher mean daily salbutamol use was associated with future poor asthma control [OR 1.13 (1.02-1.26)]. Higher mean daily salbutamol use [OR 2.73 (1.84-4.07)], number of days of use [OR 1.46 (1.24-1.71)], and maximal daily use [OR 1.57 (1.31-1.89)] were associated with an increased risk of future extreme salbutamol overuse.

CONCLUSION AND CLINICAL RELEVANCE

Electronically recorded frequency of current salbutamol use is a strong predictor of risk of future adverse outcomes in asthma, with average daily use performing the best. These findings provide new information for clinicians considering metrics of salbutamol as predictors of future adverse outcomes in asthma.

The Antidotal Activity of Some Dithiols and Acetyldithiols in Mice Poisoned with Oxophenarsine

The toxicity in mice has been studied of oxophenarsine, the oxophenarsine-dimercaprol compound, 15 dithiols and 10 acetyl dithiols. The LD50 of oxophenarsine given intramuscularly was about 0&#x006d;̇14 mM/kg. Significant differences in mortality were not observed when oxophenarsine was given intraperitoneally. Death occurred more rapidly after large than after small doses of oxophenarsine. The lungs of mice dying of oxophenarsine poisoning were heavier than normal, particularly when the doses were small and the time of survival long. The LD50 of the oxophenarsine-dimercaprol compound given intramuscularly was about 0&#x006d;̇06 mM/kg. and given intraperitoneally was about 0&#x006d;̇30 mM/kg. Death occurred more rapidly than in oxophenarsine poisoning and the lungs were much heavier than either normally or in oxophenarsine poisoning. The LD50 of dimercaprol glucoside was found to depend on the iodine titre of the solution used. Estimated on this basis, the least toxic samples examined had an LD50 of about 4&#x006d;̇5 mM/kg. Dimercaprol glucoside was effective against larger doses of oxophenarsine than was dimercaprol when the thiols were given immediately after oxophenarsine. The glucoside was less effective than dimercaprol when the thiols were given more than about 20 minutes after oxophenarsine. Approximately equimolar mixtures of oxophenarsine and dimercaprol glucoside were not more toxic than oxophenarsine alone. No other dithiols examined had as good a combination of low toxicity and high activity against oxophenarsine as dimercaprol glucoside. The nearest approach was made by other dimercaprol sugar ethers. Acetylated dithiols of low molecular weight had quite good anti-arsenical activity, but were not more active relative to their toxicity than free dithiols. Acetylated dithiols with a molecular weight greater than about 300 had very low toxicity and little or no activity against oxophenarsine. Three substances (diacetyl dimercaprol, 1:4-dithioerythritol and particularly 1:4-dithiothreitol) accelerated death and increased the mortality in mice poisoned with oxophenarsine. The dimercaprol used in these experiments was a sample of water-purified BAL kindly presented by Professor R. A. Peters. Some of the dimercaprol glucoside was prepared by Dr. L. N. Owen, some was provided by the Ministry of Supply, and one sample was provided by Boots Pure Drug Co., Ltd. The other dithiols and all the acetylated dithiols were prepared by Dr. L. N. Owen and his associates. Oxophenarsine (mapharside, not diluted with sucrose as in commercial preparations) was generously presented by Dr. J. S. White, of Parke Davis and Co., Ltd. The oxophenarsine-dimercaprol compound was synthesised and kindly presented by Dr. L. A. Stocken. I am most grateful for all these gifts. I am much indebted also to Dr. L. N. Owen for numerous helpful discussions, to Mr. Leslie Angus, Miss Jean Tulloch and Miss Irene Munro for technical assistance, to Mrs. J. A. C. Weatherall for performing certain of the toxicity tests, and particularly to Professor J. H. Gaddum for his advice and criticism. The work was initiated during the tenure of a personal grant from the Medical Research Council and was supported by a grant for expenses from the Council.

Paracetamol in pregnancy and the risk of wheezing in offspring: a systematic review and meta-analysis

BACKGROUND

There is evidence to suggest that the risk of asthma might be increased with exposure to paracetamol in the intrauterine environment, infancy, later childhood and adult life.

OBJECTIVE

To review the evidence from studies investigating the association between paracetamol use in pregnancy and childhood asthma.

METHODS

A systematic review and meta-analysis was undertaken of studies reporting the association between paracetamol use in pregnancy and subsequent asthma in childhood. The primary outcome variable was wheeze in the last 12 months. For tabulated raw data, not adjusted for confounders, random effects odds ratios (OR) were pooled by the inverse variance weighted method.

RESULTS

There were six studies identified that were included in the meta-analysis. The age of children studied ranged from 30 to 84 months. The pooled random effects OR for the risk of current wheeze in the children of women who were exposed to any paracetamol during any stage of pregnancy was 1.21 (95% confidence interval 1.02-1.44). Features of the studies variably included an association with paracetamol use during all trimesters of pregnancy and an association with persistent asthma, severe asthma, and with atopy.

CONCLUSION AND CLINICAL RELEVANCE

The use of paracetamol during pregnancy is associated with an increased risk of childhood asthma. More research is urgently required to determine the impact of paracetamol during pregnancy on the risk of wheezing in offspring so that appropriate public health recommendations can be made.

Effectiveness of the 2009 seasonal influenza vaccine against pandemic influenza A(H1N1)2009 in healthcare workers in New Zealand, June-August 2009

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Effectiveness of the 2009 seasonal influenza vaccine against pandemic influenza A(H1N1)2009 in healthcare workers in New Zealand, June-August 2009

There is uncertainty whether the 2009 seasonal influenza vaccination influences the risk of infection with the 2009 pandemic influenza A(H1N1) virus. This issue was investigated in 548 healthcare workers from Capital and Coast District Health Board, Wellington, New Zealand, presenting with influenza-like illness during the influenza pandemic between June and August 2009. All workers completed an assessment sheet and had a nasopharyngeal swab tested by real-time RT-PCR. The risk of pandemic influenza A(H1N1) infection associated with the 2009 seasonal inactivated trivalent influenza vaccine was determined by logistic regression, with adjustment for potential confounding variables. In 96 workers pandemic influenza A(H1N1) RNA was detected and 452 tested negative. The multivariate analysis did not show any effect of vaccination on PCR-confirmed influenza A(H1N1)2009 infection (odds ratio 1.2, 95% confidence interval 0.7–1.9, p=0.48). We conclude that 2009 seasonal influenza vaccination had no protective effect against influenza A(H1N1)2009 infection amongst healthcare workers. To protect against further waves of the current pandemic influenza or future pandemics in which the influenza virus is antigenically distinct from contemporary seasonal influenza viruses, it would be necessary to vaccinate with a specific pandemic influenza vaccine, or a seasonal influenza vaccine that includes the pandemic influenza serotype.

Randomised double-blind, placebo-controlled trial of the effects of the 'party pills' BZP/TFMPP alone and in combination with alcohol

The objective of this study was to determine the clinical effects of party pills containing benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) when taken alone and in combination with alcohol. The study was a randomised, double-blind, placebo-controlled trial conducted in a hospital-based clinic in Wellington, New Zealand. Thirty-five volunteers who had previously used party pills containing BZP were included in this trial. Participants received one of the following four treatments: 300 mg/74 mg BZP/TFMPP and placebo, 300 mg/74 mg BZP/TFMPP and 57.6 g (6 units) alcohol, placebo and 57.6 g (6 units) alcohol and double placebo. The primary outcome variable was a measure of driving performance, the standard deviation of lateral position (SDLP) measured at 6.5 h. Secondary measures included adverse events, cardiovascular effects, psychological function and delayed effects on sleep. The study was stopped early, after 35 of the planned 64 subjects had undertaken testing, because of severe adverse events that occurred in four of 10 BZP/TFMPP-only subjects, three of seven combined BZP/TFMPP and alcohol subjects, none of the 6 placebo subjects, and none of the 12 alcohol-only subjects. The overall rate of severe adverse events (defined as causing considerable interference with usual activity and/or rated by subject as severe) in those receiving BZP/TFMPP was seven of 17 (41.2%, 95% CI 18.4-67.1). The severe events included agitation, anxiety, hallucinations, vomiting, insomnia and migraine. BZP/TFMPP significantly improved the driving performance, decreasing SDLP at -4.2 cm (95% CI -6.8 to -1.6, P = 0.002). The effect of alcohol was to increase SDLP: 2.3 cm (95% CI -0.3 to 4.9, P = 0.08). BZP/TFMPP also resulted in increased heart rate and blood pressure and in difficulty in getting to sleep. BZP/TFMPP alone or with alcohol carries a significant risk of severe adverse events when taken in similar doses to those recommended by manufacturers.

The role of paracetamol in the pathogenesis of asthma

Paracetamol use represents a putative risk factor for the development of asthma. There is convincing epidemiological evidence that the risk of asthma may be increased with exposure to paracetamol in the intrauterine environment, infancy, later childhood and adult life. A dose-dependent association has also been observed in these different age groups in different populations world-wide. An association has also been shown between paracetamol use in both rhinoconjunctivitis and eczema. There is biological plausibility with paracetamol use leading to decreased glutathione levels resulting in increased oxidant-induced inflammation and potentially enhanced T-helper type 2 responses. At the population level, patterns of paracetamol use might explain, to some extent, the world-wide variation in the prevalence of asthma and related disorders, particularly the high rates in English-speaking countries, which have high per capita prescription and over-the-counter use of paracetamol. A temporal association also exists between the international trends of increasing paracetamol use and increasing prevalence of asthma over recent decades. Further research is urgently required, in particular randomized-controlled trials (RCTs) into the long-term effects of frequent paracetamol use in childhood, to determine the magnitude and characteristics of any such risk. Importantly, RCTs will also enable evidence-based guidelines for the recommended use of paracetamol to be developed.

Venous thromboembolism following prolonged cast immobilisation for injury to the tendo Achillis

We report an audit of 208 patients with a mean age of 39 years (16 to 65) attending the Orthopaedic Assessment Unit at the Wellington Hospital between January 2006 and December 2007 with an injury of the tendo Achillis requiring immobilisation in a cast. Information on assessment of venous thromboembolism (VTE) risk, prophylactic measures and VTE events for all patients was obtained from the medical records. A VTE risk factor was documented in the records of three (1%) patients. One of the 208 patients received aspirin prophylaxis; none received low molecular weight heparin. In all, 13 patients (6.3%, 95% confidence interval 3.4 to 10.5) developed symptomatic VTE during immobilisation in a cast, including six with a distal deep-vein thrombosis (DVT), four with a proximal DVT, and three with a confirmed pulmonary embolus. This incidence of symptomatic VTE is similar to that reported following elective hip replacement. We propose that consideration is given to VTE prophylaxis during prolonged immobilisation of the lower limbs in a cast, to ensure that the same level of protection is provided as for patients undergoing elective hip replacement.

Meta-analysis of the risk of mortality with salmeterol and the effect of concomitant inhaled corticosteroid therapy

BACKGROUND

There is concern that long-acting beta agonist (LABA) drugs may increase the risk of asthma mortality.

METHODS

A meta-analysis was conducted of asthma deaths in randomised controlled clinical trials from the GlaxoSmithKline database that compared salmeterol with a non-LABA comparator treatment in asthma. The Peto one-step method was used to determine the risk overall (all studies) and in derived datasets based on inhaled corticosteroid (ICS) use.

RESULTS

There were 35 asthma deaths in 215 studies with 106,575 subjects. Two studies (SMART and SNS) contributed 30/35 (86%) asthma deaths, the overall findings largely reflecting the characteristics of these studies. The odds ratio for risk of asthma mortality with salmeterol was 2.7 (95% CI 1.4 to 5.3). In 54 placebo controlled studies the risk of death from asthma in patients not prescribed ICS was 7.3 (95% CI 1.8 to 29.4). In 127 studies in which patients were prescribed ICS, the risk of asthma death was 2.1 (95% CI 0.6 to 7.9). In 63 studies in which patients were randomised to receive the combination salmeterol/fluticasone propionate inhaler or ICS, there were no asthma deaths among 22,600 patients.

CONCLUSIONS

Salmeterol monotherapy in asthma increases the risk of asthma mortality and this risk is reduced with concomitant ICS therapy. There is no evidence that combination salmeterol/fluticasone propionate therapy is associated with an increased risk of asthma mortality, although this interpretation is limited by the low statistical power of available studies.

Childhood asthma and GOLD-defined chronic obstructive pulmonary disease

BACKGROUND

Current understanding of chronic obstructive pulmonary disease (COPD) is that it results from an interaction of genetic and environmental factors. This study aimed to investigate the strength of association of various known risk factors for COPD.

METHODS

Detailed written questionnaires, full pulmonary function tests and atopy testing were completed in 749 people, aged 25-75 years, recruited from a random population sample. COPD was defined, using Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines, as a post-bronchodilator forced expiratory volume in 1 s/forced vital capacity (FEV(1) /FVC) ratio <0.7.

RESULTS

The prevalence of COPD was higher in men (OR 1.7 (95% CI 1.1-2.7)) and increased with increasing age (OR per decade older 2.1 (95% CI 1.7-2.7)). COPD was more frequent in current and ex-smokers and increased with increasing pack years (OR per 10 pack years 1.3 (95% CI 1.1-1.5)). On a logit scale, a diagnosis of asthma as a child conferred a similar risk as an increase in age of 22 years or 62 pack years of cigarette smoking.

CONCLUSION

Childhood asthma emerged with the strongest association for GOLD-defined COPD. Possible explanations for this are suggested, including limitations of the current GOLD spirometric definition of COPD, a chance observation because of the high prevalence of both disorders in this population, or alternatively childhood asthma is a risk factor for COPD.

Pre-hospital oxygen therapy in acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

High concentration oxygen is commonly administered during acute exacerbations of chronic obstructive pulmonary disease (AECOPD). The aim of this study was to determine the association between oxygen, severity markers and poor outcomes in AECOPD.

METHODS

In an audit of patients with AECOPD arriving by ambulance to the Emergency Department of Wellington Hospital, details of oxygen administration, clinical outcomes and severity markers were documented. The main outcome measure was a composite of death, assisted ventilation, or respiratory failure. Associations between oxygen therapy, severity markers and poor clinical outcomes were assessed by logistic regression.

RESULTS

Of 250 patients 77 (31%) died, required assisted ventilation or were in respiratory failure. Increased oxygen flow was associated with increasing risk of death, assisted ventilation or respiratory failure with an odds ratio (OR) of 1.2 (95% CI 1.0-1.4) per 1 L/min oxygen flow. Increasing PaO(2) was associated with a greater risk of a poor outcome with an OR of 1.1 (95% CI 1.0-1.3) per 10 mmHg higher PaO(2). Home oxygen (OR 2.8, 95% CI 1.5-5.1), previous respiratory failure (OR 2.6, 95% CI 1.5-4.6), previous ventilation (OR 3.2, 95% CI 1.7-5.9) and home nebulizer use (OR 2.4, 95% CI 1.4-4.3) were associated with an increased risk of a poor outcome.

CONCLUSION

In AECOPD high flow oxygen in the ambulance is associated with poor clinical outcomes. A number of easily identified markers of chronic disease severity indicate an increased risk of a poor clinical outcome.

Assessing PaCO2 in acute respiratory disease: accuracy of a transcutaneous carbon dioxide device

BACKGROUND

Pulse oximetry non-invasively assesses the arterial oxygen saturation of patients with acute respiratory disease; however, measurement of the arterial partial pressure of carbon dioxide (PaCO(2)) requires an arterial blood gas. The transcutaneous partial pressure of carbon dioxide (PtCO(2) ) has been used in other settings with variable accuracy. We investigated the accuracy of a PtCO(2) device in the assessment of PaCO(2) in patients with asthma and suspected pneumonia attending the emergency department.

METHODS

Patients with severe asthma (FEV(1) < 50% predicted) or suspected pneumonia (fever, cough and respiratory rate >18/min) were enrolled. Subjects were excluded if they had a history of chronic obstructive pulmonary disease or other conditions associated with respiratory failure. Arterial blood gases were taken at the discretion of the investigator according to clinical need, and paired with a simultaneous reading from the PtCO(2) probe.

RESULTS

Twenty-five patients were studied with one set of data excluded because of poor PtCO(2) signal quality. The remaining 24 paired samples comprised 12 asthma and 12 pneumonia patients. The range of PaCO(2) was 19-64 mmHg with a median of 36.5 mmHg. Bland-Altman analysis showed a mean (SD) PaCO(2) - PtCO(2) difference of -0.13 (1.9) mmHg with limits of agreement of plus or minus 3.8 mmHg (-3.9 to +3.7).

CONCLUSION

A PtCO(2) device was accurate in the assessment of PaCO(2) in patients with acute severe asthma and suspected pneumonia when compared with an arterial blood gas. These bedside monitors have the potential to improve patient care by non-invasively monitoring patients with acute respiratory disease at risk of hypercapnia.

Risk of mortality associated with formoterol: a systematic review and meta-analysis

There is concern long-acting beta-agonist (LABA) drugs may increase the risk of asthma mortality. We undertook a systematic review which included the AstraZeneca Formoterol Clinical Trial Safety Database and Novartis Food and Drug Administration Formoterol Briefing Document. Randomised controlled clinical trials of duration > or = 4 weeks that compared formoterol with a non-LABA comparator treatment in asthma were included in a meta-analysis of the risk of all-cause mortality and asthma death. Simple contingency tables, Peto's one-step method and a Bayesian analysis were used. There were 42 deaths (nine from asthma) recorded in 62 studies with 49,327 subjects. The simple contingency table odds ratio for risk of all-cause mortality with formoterol was 1.1 (95% CI 0.6-2.2) and for asthma death was 2.7 (95% CI 0.5-26.7). Analyses by the other methods using both "as randomised" and "as exposed" classifications of treatment gave similar risk estimates with wide confidence and credible intervals. We conclude that there was insufficient power to determine whether formoterol increases the risk of mortality. However, the point estimates of a 2.0- to 3.2-fold increased risk of asthma death are not reassuring and add weight to evidence that LABA use in certain circumstances may increase the risk of asthma mortality.

Distinct clinical phenotypes of airways disease defined by cluster analysis

Airways disease is currently classified using diagnostic labels such as asthma, chronic bronchitis and emphysema. The current definitions of these classifications may not reflect the phenotypes of airways disease in the community, which may have differing disease processes, clinical features or responses to treatment. The aim of the present study was to use cluster analysis to explore clinical phenotypes in a community population with airways disease. A random population sample of 25-75-yr-old adults underwent detailed investigation, including a clinical questionnaire, pulmonary function tests, nitric oxide measurements, blood tests and chest computed tomography. Cluster analysis was performed on the subgroup with current respiratory symptoms or obstructive spirometric results. Subjects with a complete dataset (n = 175) were included in the cluster analysis. Five clusters were identified with the following characteristics: cluster 1: severe and markedly variable airflow obstruction with features of atopic asthma, chronic bronchitis and emphysema; cluster 2: features of emphysema alone; cluster 3: atopic asthma with eosinophilic airways inflammation; cluster 4: mild airflow obstruction without other dominant phenotypic features; and cluster 5: chronic bronchitis in nonsmokers. Five distinct clinical phenotypes of airflow obstruction were identified. If confirmed in other populations, these findings may form the basis of a modified taxonomy for the disorders of airways obstruction.

Quality of life measured by the St George's Respiratory Questionnaire and spirometry

The present authors aimed to determine if the criteria for the diagnosis of chronic obstructive pulmonary disease (COPD) and its classification by severity as recommended by the Global Initiative for Chronic Obstructive Lung Disease are supported by measurements of respiratory health-related quality of life. A community-based sample of adults aged 25-75 yrs had pre- and post-bronchodilator spirometry and completed the St George's Respiratory Questionnaire (SGRQ). Loess scatter plot smoothers of the SGRQ versus post-bronchodilator forced expiratory volume in one second (FEV(1))/forced vital capacity (FVC) ratio and post-bronchodilator FEV(1) % predicted together with receiver operating characteristic (ROC) curve analysis were used to determine the relationship between spirometric variables and clinically important differences in the SGRQ score. The scatter plot smoother and ROC curve analyses supported the value of 0.7 for post-bronchodilator FEV(1)/FVC ratio, which was approximately 4 units higher than the nadir of the SGRQ. To represent a distance of 8 units on the SGRQ, the cut-off points for post-bronchodilator FEV(1) that delimit COPD severity stages were 80, 60 and 40% pred for mild, moderate and severe COPD, respectively. To diagnose chronic obstructive pulmonary disease the use of post-bronchodilator forced expiratory volume in one second/forced vital capacity ratio of 0.7 is supported by health-related quality of life measurements. There may be advantages in using forced expiratory volume in one second cut-off points of 80, 60 and 40% predicted for the classification of mild, moderate and severe chronic obstructive pulmonary disease, respectively, similar to the approach recommended for asthma.

The risk of asthma mortality with inhaled long acting beta-agonists

This article reviews the available evidence as to whether inhaled long acting beta-agonists (LABA) increase the risk of asthma mortality and considers the implications for the use of this treatment in the management of asthma. Randomised controlled trials suggest that LABAs prescribed as monotherapy may increase the risk of asthma death in certain circumstances, such as the unsupervised "off-label" use without concomitant inhaled corticosteroid (ICS) treatment in patients with unstable asthma. However, there is also evidence that the use of LABAs in conjunction with ICS treatment in adult asthma as recommended in current guidelines is not associated with an increased risk of asthma mortality. The only way in which a prescriber can ensure that a patient with asthma takes LABA treatment in conjunction with ICS is through a combination ICS/LABA product, an approach which may have additional therapeutic advantages. We propose that in the management of asthma, a case can now be made to limit the availability of LABAs to combination LABA/ICS therapy.

Prevention of falls and fall-related fractures in community-dwelling older adults: a meta-analysis of estimates of effectiveness based on recent guidelines

BACKGROUND

Two recent falls prevention guidelines have been published but did not include quantitative estimates of effectiveness based on the published reports that were reviewed to support their recommendations.

AIM

To produce quantitative estimates of effectiveness of falls prevention programs from the randomised controlled trials cited in the guidelines together with an updated search of the available published reports to August 2002.

METHODS

A meta-analysis of randomised controlled trials cited in falls guidelines and studies identified by an updated search of the available published reports was carried out. Randomised controlled trials were identified from the falls guidelines and a search, which met the following criteria: trials in community-dwelling older people; 1-year follow up; and outcome measures reported as the number of subjects with at least one fall or the number of subjects with a fracture.

RESULTS

The guidelines identified four studies of 'exercise as a sole intervention', which when combined with one further study identified in a search of the published reports, gave a fixed effects odds ratio (OR) favouring this strategy of 0.81 (95% confidence interval (CI) 0.58-1.14); the number of patients needed to be treated to prevent one person having a fall was 19.5. The guidelines identified seven studies of a 'multiple intervention' strategy that gave a random effects OR favouring this strategy of 0.64 (95% CI 0.47-0.88). Four further studies were identified by the search of the published reports. The updated OR favouring this intervention strategy was 0.65 (95% CI 0.52-0.81); the number of patients needed to be treated to prevent one person having a fall was 9.8. Only two studies had data for fracture and a fixed effects OR favouring falls interventions for fracture prevention was 0.50 (95% CI 0.18-1.40); the number of patients needed to be treated to prevent one person having a fracture was 45.5.

CONCLUSION

Semiquantitative statements of evidence can both understate and overstate the effectiveness of falls prevention strategies. There is moderate evidence of efficacy for falls prevention particularly for multiple intervention strategies.

Proportional classifications of COPD phenotypes

BACKGROUND

Chronic obstructive pulmonary disease (COPD) encompasses a group of disorders characterised by the presence of incompletely reversible airflow obstruction with overlapping subsets of different phenotypes including chronic bronchitis, emphysema or asthma. The aim of this study was to determine the proportion of adult subjects aged >50 years within each phenotypic subgroup of COPD, defined as a post-bronchodilator ratio of forced expiratory volume in 1 s/forced vital capacity (FEV(1)/FVC) <0.7, in accordance with current international guidelines.

METHODS

Adults aged >50 years derived from a random population-based survey undertook detailed questionnaires, pulmonary function tests and chest CT scans. The proportion of subjects in each of 16 distinct phenotypes was determined based on combinations of chronic bronchitis, emphysema and asthma, with and without incompletely reversible airflow obstruction defined by a post-bronchodilator FEV(1)/FVC ratio of 0.7.

RESULTS

A total of 469 subjects completed the investigative modules, 96 of whom (20.5%) had COPD. Diagrams were constructed to demonstrate the relative proportions of the phenotypic subgroups in subjects with and without COPD. 18/96 subjects with COPD (19%) had the classical phenotypes of chronic bronchitis and/or emphysema but no asthma; asthma was the predominant COPD phenotype, being present in 53/96 (55%). When COPD was defined as a post-bronchodilator FEV(1)/FVC less than the lower limit of normal, there were one-third fewer subjects with COPD and a smaller proportion without a defined emphysema, chronic bronchitis or asthma phenotype.

CONCLUSION

This study provides proportional classifications of the phenotypic subgroups of COPD which can be used as the basis for further research into the pathogenesis and treatment of this heterogeneous disorder.

Routine use of oxygen in the treatment of myocardial infarction: systematic review

CONTEXT

International guidelines recommend the routine use of oxygen therapy in the treatment of myocardial infarction (MI).

OBJECTIVE

To undertake a systematic review and meta-analysis of randomised placebo-controlled trials of oxygen therapy in MI.

DATA SOURCES

Medline, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, EMBASE and CINHAL.

STUDY SELECTION

Randomised placebo-controlled trials of oxygen therapy in MI.

DATA EXTRACTION

The primary clinical outcome was mortality.

RESULTS

Two of 51 potential studies met the inclusion criteria. The one study with substantive clinical outcome data reported that in uncomplicated MI, high-flow oxygen was associated with a non-significant increased risk of death (risk ratio 2.9, 95% CI 0.8 to 10.3, p = 0.08) and a greater serum aspartate aminotransferase level (difference 19.2 IU/ml, 95% CI 0 to 38.4, p = 0.05) than room air.

CONCLUSION

The limited evidence that does exist suggests that the routine use of high-flow oxygen in uncomplicated MI may result in a greater infarct size and possibly increase the risk of mortality.

Dose-response relationship for risk of non-vertebral fracture with inhaled corticosteroids

OBJECTIVE

To determine the strength of association between the dose of inhaled corticosteroids (ICS) and risk of non-vertebral fracture in adults.

METHODS

A systematic review and meta-analysis of case-control studies of non-vertebral fractures in adults, in which at least two doses of ICS were reported as the dose of beclomethasone dipropionate (BDP) or equivalent.

RESULTS

Five case-control studies were identified, with a total of 43 783 cases and 259 936 controls. There was an association between the risk of non-vertebral fracture and increasing dose of BDP. The random-effects odds ratio of relative risk for a non-vertebral fracture was 1.12 (95% confidence interval 1.00-1.26) per 1000 microg increase in the daily dose of BDP or equivalent.

CONCLUSION

In older adults, the relative risk of non-vertebral fractures increases by about 12% for each 1000 microg/day increase in the dose of BDP or equivalent. The magnitude of this risk was considerably less than other common risk factors for fracture in the older adult.

Cannabis use and risk of lung cancer: a case-control study

The aim of the present study was to determine the risk of lung cancer associated with cannabis smoking. A case-control study of lung cancer in adults <or=55 yrs of age was conducted in eight district health boards in New Zealand. Cases were identified from the New Zealand Cancer Registry and hospital databases. Controls were randomly selected from the electoral roll, with frequency matching to cases in 5-yr age groups and district health boards. Interviewer-administered questionnaires were used to assess possible risk factors, including cannabis use. The relative risk of lung cancer associated with cannabis smoking was estimated by logistic regression. In total, 79 cases of lung cancer and 324 controls were included in the study. The risk of lung cancer increased 8% (95% confidence interval (CI) 2-15) for each joint-yr of cannabis smoking, after adjustment for confounding variables including cigarette smoking, and 7% (95% CI 5-9) for each pack-yr of cigarette smoking, after adjustment for confounding variables including cannabis smoking. The highest tertile of cannabis use was associated with an increased risk of lung cancer (relative risk 5.7 (95% CI 1.5-21.6)), after adjustment for confounding variables including cigarette smoking. In conclusion, the results of the present study indicate that long-term cannabis use increases the risk of lung cancer in young adults.