Tiotropium treatment for bronchiectasis: a randomised, placebo-controlled, crossover trial

Tiotropium via HandiHaler® is an established long-acting, anticholinergic bronchodilator that prevents exacerbations and improves lung function in patients with COPD. We hypothesized that tiotropium would reduce pulmonary exacerbations and improve lung function in patients with stable bronchiectasis and airflow limitation, and assessed the effect of tiotropium on these outcomes. In a randomised, double-blind, 2-period crossover trial, we recruited adult patients from 3 hospitals in New Zealand. Patients were excluded if they had a smoking history of more than 20 pack years. Patients were assigned to either the tiotropium-placebo or placebo-tiotropium sequence in a 1:1 ratio, using randomly permuted blocks stratified by centre. Participants and investigators were masked to treatment allocation. Eligible patients received tiotropium 18mcg via the HandiHaler® device daily for 6 months followed by 6 months of placebo, or vice versa, with a washout period of 4 weeks. The primary endpoint was rate of event-based exacerbations during the 6-month period. Primary analyses were carried out in an intention-to-treat set. Ninety patients were randomly assigned and 85 completed both treatment cycles. The rate of exacerbations under the tiotropium treatment was 2.17 y^-1 and 2.27 y^-1 under placebo (rate ratio 0.96, 95% CI 0.72-1.27; p=0.77). Tiotropium, as compared with placebo, improved FEV₁ by 58 mL (95% CI 23-92; p=0.002). Adverse events were similar under both treatments. Tiotropium via HandiHaler® over 6 months significantly improved lung function but not frequency of exacerbations. Further research is required to understand the clinical context and significance of these findings.

Dispersal of Mycobacterium tuberculosis Driven by Historical European Trade in the South Pacific

Mycobacterium tuberculosis (Mtb) is a globally distributed bacterial pathogen whose population structure has largely been shaped by the activities of its obligate human host. Oceania was the last major global region to be reached by Europeans and is the last region for which the dispersal and evolution of Mtb remains largely unexplored. Here, we investigated the evolutionary history of the Euro-American L4.4 sublineage and its dispersal to the South Pacific. Using a phylodynamics approach and a dataset of 236 global Mtb L4.4 genomes we have traced the origins and dispersal of L4.4 strains to New Zealand. These strains are predominantly found in indigenous Māori and Pacific people and we identify a clade of European, likely French, origin that is prevalent in indigenous populations in both New Zealand and Canada. Molecular dating suggests the expansion of European trade networks in the early 19th century drove the dispersal of this clade to the South Pacific. We also identify historical and social factors within the region that have contributed to the local spread and expansion of these strains, including recent Pacific migrations to New Zealand and the rapid urbanization of Māori in the 20th century. Our results offer new insight into the expansion and dispersal of Mtb in the South Pacific and provide a striking example of the role of historical European migrations in the global dispersal of Mtb.

Whole genome sequencing of Mycobacterium tuberculosis reveals slow growth and low mutation rates during latent infections in humans

Very little is known about the growth and mutation rates of Mycobacterium tuberculosis during latent infection in humans. However, studies in rhesus macaques have suggested that latent infections have mutation rates that are higher than that observed during active tuberculosis disease. Elevated mutation rates are presumed risk factors for the development of drug resistance. Therefore, the investigation of mutation rates during human latency is of high importance. We performed whole genome mutation analysis of M. tuberculosis isolates from a multi-decade tuberculosis outbreak of the New Zealand Rangipo strain. We used epidemiological and phylogenetic analysis to identify four cases of tuberculosis acquired from the same index case. Two of the tuberculosis cases occurred within two years of exposure and were classified as recently transmitted tuberculosis. Two other cases occurred more than 20 years after exposure and were classified as reactivation of latent M. tuberculosis infections. Mutation rates were compared between the two recently transmitted pairs versus the two latent pairs. Mean mutation rates assuming 20 hour generation times were 5.5X10⁻¹⁰ mutations/bp/generation for recently transmitted tuberculosis and 7.3X10⁻¹¹ mutations/bp/generation for latent tuberculosis. Generation time versus mutation rate curves were also significantly higher for recently transmitted tuberculosis across all replication rates (p = 0.006). Assuming identical replication and mutation rates among all isolates in the final two years before disease reactivation, the u20hr mutation rate attributable to the remaining latent period was 1.6×10⁻¹¹ mutations/bp/generation, or approximately 30 fold less than that calculated during the two years immediately before disease. Mutations attributable to oxidative stress as might be caused by bacterial exposure to the host immune system were not increased in latent infections. In conclusion, we did not find any evidence to suggest elevated mutation rates during tuberculosis latency in humans, unlike the situation in rhesus macaques.

Azithromycin for prevention of exacerbations in non-cystic fibrosis bronchiectasis (EMBRACE): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Azithromycin is a macrolide antibiotic with anti-inflammatory and immunomodulatory properties. We tested the hypothesis that azithromycin would decrease the frequency of exacerbations, increase lung function, and improve health-related quality of life in patients with non-cystic fibrosis bronchiectasis.

METHODS

We undertook a randomised, double-blind, placebo-controlled trial at three centres in New Zealand. Between Feb 12, 2008, and Oct 15, 2009, we enrolled patients who were 18 years or older, had had at least one pulmonary exacerbation requiring antibiotic treatment in the past year, and had a diagnosis of bronchiectasis defined by high-resolution CT scan. We randomly assigned patients to receive 500 mg azithromycin or placebo three times a week for 6 months in a 1:1 ratio, with a permuted block size of six and sequential assignment stratified by centre. Participants, research assistants, and investigators were masked to treatment allocation. The coprimary endpoints were rate of event-based exacerbations in the 6-month treatment period, change in forced expiratory volume in 1 s (FEV(1)) before bronchodilation, and change in total score on St George's respiratory questionnaire (SGRQ). Analyses were by intention to treat. This study is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12607000641493.

FINDINGS

71 patients were in the azithromycin group and 70 in the placebo group. The rate of event-based exacerbations was 0·59 per patient in the azithromycin group and 1·57 per patient in the placebo group in the 6-month treatment period (rate ratio 0·38, 95% CI 0·26-0·54; p<0·0001). Prebronchodilator FEV(1) did not change from baseline in the azithromycin group and decreased by 0·04 L in the placebo group, but the difference was not significant (0·04 L, 95% CI -0·03 to 0·12; p=0·251). Additionally, change in SGRQ total score did not differ between the azithromycin (-5·17 units) and placebo groups (-1·92 units; difference -3·25, 95% CI -7·21 to 0·72; p=0·108).

INTERPRETATION

Azithromycin is a new option for prevention of exacerbations in patients with non-cystic fibrosis bronchiectasis with a history of at least one exacerbation in the past year.

FUNDING

Health Research Council of New Zealand and Auckland District Health Board Charitable Trust.

Vitamin D, innate immunity and outcomes in community acquired pneumonia

BACKGROUND AND OBJECTIVE

Vitamin D regulates the production of the antimicrobial peptides cathelicidin and beta-defensin-2, which play an important role in the innate immune response to infection. We hypothesized that vitamin D deficiency would be associated with lower levels of these peptides and worse outcomes in patients admitted to hospital with community acquired pneumonia.

METHODS

Associations between mortality and serum levels of 25-hydroxyvitamin D, cathelicidin and beta-defensin-2 were investigated in a prospective cohort of 112 patients admitted with community acquired pneumonia during winter.

RESULTS

Severe 25-hydroxyvitamin D deficiency (<30nmol/L) was common in this population (15%) and was associated with a higher 30-day mortality compared with patients with sufficient 25-hydroxyvitamin D (>50nmol/L) (odds ratio 12.7, 95% confidence interval: 2.2-73.3, P=0.004). These associations were not explained by differences in age, comorbidities, or the severity of the acute illness. Neither cathelicidin nor beta-defensin-2 levels predicted mortality, although there was a trend towards increased mortality with lower cathelicidin (P=0.053). Neither cathelicidin nor beta-defensin-2 levels correlated with 25-hydroxyvitamin D.

CONCLUSIONS

25-hydroxyvitamin D deficiency is associated with increased mortality in patients admitted to hospital with community acquired pneumonia during winter. Contrary to our hypothesis, 25-hydroxyvitamin D levels were not associated with levels of cathelicidin or beta-defensin-2.

The Geneva prognostic score and mortality in patients diagnosed with pulmonary embolism by CT pulmonary angiogram

This study prospectively evaluates whether a previously established adverse outcome score (the Geneva prognostic score) predicts 3 and 12-month overall mortality among the patients diagnosed with pulmonary embolism (PE) by a CT pulmonary angiogram (CTPA). Five hundred twenty-three consecutive patients who had CTPA for suspected PE were recruited prospectively from March 2003 to October 2004. The Geneva prognostic score was calculated for all patients. Twelve-month follow up was completed in all patients in December 2005. There were 105 patients diagnosed with PE. The mean score was 2.71 (standard deviation (SD) 1.25) for those patients who had died (n = 7) and 1.14 (SD 1.19) for those patients who were alive (n = 98) at 3-month follow up (P < 0.001). The mean scores were 2.69 (SD 0.95) for those who had died (n = 13) and 1.04 (SD 1.15) for those patients who were alive (n = 92) at 12-month follow up (P < 0.001). At 3-month follow up, among the 88 patients with a score of 2 or less, three patients (3.4%) died and among 17 patients with a score of greater than 2, four patients (23.5%) died (P = 0.01). At 12-month follow up, five patients (5.7%) with a score of 2 or less died and eight patients (47.1%) with a score of three or more died (P < 0.0001). The Geneva prognostic score stratifies patients with low and high risk for overall mortality at 3 and 12 months among patients diagnosed with PE by CTPA.

Withholding anticoagulation after a negative computed tomography pulmonary angiogram as a stand-alone imaging investigation: a prospective management study

BACKGROUND

Accurate diagnosis of pulmonary embolism (PE) is essential and it is not clear whether a computed tomography pulmonary angiogram (CTPA) could be used as a stand-alone imaging investigation. The aim of the study was to test the accuracy of the clinical outcome of a negative CTPA as a stand-alone imaging investigation to exclude PE.

METHODS

Five hundred and thirty-four consecutive patients who had a CTPA for diagnosis or exclusion of PE were recruited from March 2003 to October 2004. Four hundred and ninety-four patients had a helical CTPA as a stand-alone imaging investigation for diagnosis or exclusion of PE. A 3-month post-CTPA follow up was carried out in all patients to establish the clinical outcome accuracy of a negative CTPA as a stand-alone imaging investigation.

RESULTS

There were 387 (78.3%) negative and 107 (21.7%) positive CTPA examinations. The average age of the patients was 57.16 years (standard deviation 18.57). Among those with a negative CTPA who survived, one patient had deep vein thrombosis and 342 patients had no evidence of an episode of venous thromboembolism or PE at the 3-month follow up. Thirty-eight patients died within the 3-month follow-up period and one patient's death was attributed to suspected PE. The negative predictive value of a CTPA is 99.5% (95% confidence interval 98.1-99.9%).

CONCLUSION

Helical negative CTPA examination excludes clinically significant PE as a stand-alone imaging investigation. Where concurrent deep vein thrombosis is suspected, lower limb needs to be imaged by ultrasound if the CTPA is negative.

Pulmonary embolism: accuracy and safety of a negative CT pulmonary angiogram and value of a negative D-dimer assay to exclude CT pulmonary angiogram-detectable pulmonary embolism

This is a retrospective study to determine the accuracy and safety of a negative CT pulmonary angiogram (CTPA) based on clinical outcome and to determine the usefulness of a negative D-dimer assay before CTPA. A total of 483 patients with a negative CTPA study were followed up for 3 months, with the aim of detecting episodes of venous thromboembolism and mortality. Three hundred and forty-nine patients had an immunochromatographic D-dimer assay called 'Simplify', carried out before a CTPA examination. Seventy-eight patients had a negative D-dimer assay and a negative CTPA. Three patients had a negative D-dimer assay and a positive CTPA. All three patients had a moderate pretest clinical probability. Of the 483 patients who had a negative CTPA and a 3-month follow up, 444 (92%) were alive and 39 (8%) had died. Of the 444 patients who were alive, none had any further suspected episode of thromboembolism or had received anticoagulation therapy within the follow-up period. Of those who died, none of the deaths was thought to be as a result of pulmonary embolism (PE). Single-detector helical CT can be used safely as the primary diagnostic test to evaluate PE. Negative Simplify D-dimer assay and low pretest clinical probability exclude CTPA-detectable PE, and a CTPA is unnecessary in this cohort of patients.

Computed tomography pulmonary angiogram diagnosis of pulmonary embolism

Over the last decade, contrast-enhanced spiral CT has been established as a non-invasive alternative to catheter angiography and is now regarded as the first-line imaging investigation for the diagnosis of pulmonary embolism (PE). The reported sensitivities for the diagnosis of PE of spiral CT vary from 45 to 100% and the specificities vary from 78 to 100%. Prospective outcome studies have shown a high negative predictive value for a single-detector spiral CT for PE. Patients' outcomes were not adversely affected in these studies when anticoagulation was withheld after a negative CT pulmonary angiogram. The main limitation of single-detector spiral CT has been its limited ability to detect isolated subsegmental PE. However, multidetector spiral CT allows evaluation of pulmonary vessels down to sixth-order branches and significantly increases the rate of detection of PE in segmental and subsegmental levels. The interobserver correlations for diagnosis of subsegmental PE with multidetector spiral CT exceed the reproducibility of selective pulmonary angiography. If appropriate equipment is available (multidetector CT), then CT pulmonary angiogram is safe to be used as the first-line imaging investigation for the diagnosis of PE.

Māori have a much higher incidence of community-acquired pneumonia and pneumococcal pneumonia than non-Māori: findings from two New Zealand hospitals

To determine the incidence rates of community-acquired pneumonia and pneumococcal pneumonia requiring hospitalisation among Maori and non-Maori, an observational study was conducted in Christchurch and Hamilton. Self-reported data were collected using an interviewer-administered questionnaire. Routine clinical, radiological, and microbiological techniques were used apart from the BinaxNow pneumococcal antigen test for diagnosis of this infection. Census data was used to determine the denominator for statistical analyses. The pneumonia rate overall was 3.03 times higher among Maori than non-Maori (p<0.001). Differences were significant for each 10-year age group from age 45-74 years (p<0.05). The rate of pneumococcal pneumonia was 3.23 fold higher for Maori than non-Maori (p<0.001), but it did not reach statistical significance in the age-related comparisons. These ethnic disparities are of major concern, and policy planners should consider further interventions to improve the efficacy of current anti-smoking campaigns and to undertake studies of conjugate pneumococcal vaccines for Maori.

Community-acquired pneumonia: influence of management practices on length of hospital stay

AIMS

To identify variation in the management of -community-acquired pneumonia between two New Zealand hospitals and the factors that may account for any differences.

METHODS

A 12-month, prospective two-centre study was conducted. Between July 1999 and July 2000, 474 adult patients with community-acquired pneumonia were enrolled: 304 in Christchurch Hospital and 170 in Waikato Hospital. The patients were similar in age, sex, prior antibiotic use and comorbidity. There was no significant difference in the clinical outcomes for the patients at the two centres.

RESULTS

The mean duration of i.v. antibiotic therapy was 1.7 versus 3.0 days (P < 0.001) and length of stay (LOS) was 3.0 versus 5.9 days (P < 0.001) for Waikato and Christchurch Hospitals, respectively. Using multivariate analysis, we could account for 61% of the observed variation in LOS. Duration of i.v. antibiotic therapy independently accounted for 16% of variation in LOS compared with age (2%), chronic obstructive pulmonary disease, duration of fever, intensive care unit admission and centre of admission (all <1%). For the duration of i.v. antibiotics, centre of admission, largely reflecting clinician practice at each centre, independently accounted for 13% of variation, compared with duration of fever (5%), admission to the Intensive Care Unit (4%), Pneumonia Severity Index score (3%) and bacteraemia (3%).

CONCLUSION

Of the identifiable factors, variations in clinician behaviour outweighed the influence of patient factors on the duration of i.v. antibiotic therapy, which in turn was the major determinant of LOS for patients hospitalised with community-acquired pneumonia. An early switch from i.v. to oral antibiotic therapy in conjunction with early discharge planning may significantly reduce LOS without compromising patient outcomes.

Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study

BACKGROUND

In the assessment of severity in community acquired pneumonia (CAP), the modified British Thoracic Society (mBTS) rule identifies patients with severe pneumonia but not patients who might be suitable for home management. A multicentre study was conducted to derive and validate a practical severity assessment model for stratifying adults hospitalised with CAP into different management groups.

METHODS

Data from three prospective studies of CAP conducted in the UK, New Zealand, and the Netherlands were combined. A derivation cohort comprising 80% of the data was used to develop the model. Prognostic variables were identified using multiple logistic regression with 30 day mortality as the outcome measure. The final model was tested against the validation cohort.

RESULTS

1068 patients were studied (mean age 64 years, 51.5% male, 30 day mortality 9%). Age >/=65 years (OR 3.5, 95% CI 1.6 to 8.0) and albumin <30 g/dl (OR 4.7, 95% CI 2.5 to 8.7) were independently associated with mortality over and above the mBTS rule (OR 5.2, 95% CI 2.7 to 10). A six point score, one point for each of Confusion, Urea >7 mmol/l, Respiratory rate >/=30/min, low systolic(<90 mm Hg) or diastolic (</=60 mm Hg) Blood pressure), age >/=65 years (CURB-65 score) based on information available at initial hospital assessment, enabled patients to be stratified according to increasing risk of mortality: score 0, 0.7%; score 1, 3.2%; score 2, 3%; score 3, 17%; score 4, 41.5% and score 5, 57%. The validation cohort confirmed a similar pattern.

CONCLUSIONS

A simple six point score based on confusion, urea, respiratory rate, blood pressure, and age can be used to stratify patients with CAP into different management groups.

Community-acquired pneumonia in Christchurch and Waikato 1999-2000: microbiology and epidemiology

AIMS

To prospectively record current epidemiology and microbiology of community-acquired pneumonia in two New Zealand centres.

METHODS

Between July 1999 and 2000 all adults admitted to Christchurch and Waikato Hospitals with community-acquired pneumonia were screened for study inclusion. All those enrolled had their medical history, clinical variables, inpatient management and clinical outcomes recorded and standardised microbial diagnostic testing carried out.

RESULTS

474 participants were enrolled with a mean age of 64 years and a microbial diagnosis was made in 197 cases (42%). Streptococcus pneumoniae (14%), Haemophilus influenzae (10%) and Influenza A virus (7%), Legionella spp (4%) and Mycoplasma pneumoniae (3%) were the most commonly isolated organisms. An 'atypical' organism was diagnosed in 8% of cases compared to 30% and 23% in previous Christchurch and Waikato studies respectively. Fourteen of the 67 S pneumoniae isolates (21%) had reduced susceptibility to penicillin, all with a MIC < or = 2 microg/mL, a level of reduced susceptibility not associated with worse patient outcomes. Clinical outcome included a mean hospital stay of 6.7 days and a 6 week mortality of 6%.

CONCLUSION

Although S pneumoniae was the most commonly isolated organism in this study there have been significant changes in the prevalence of atypical organisms since previous surveys. Ongoing surveillance of antibiotic resistance and variations in the prevalence of organisms causing community-acquired pneumonia is required to guide clinicians' empiric antibiotic use.

Tuberculosis in immigrants and visitors

Immigrants and visitors are a significant factor in the epidemiology of tuberculosis (TB) in New Zealand, accounting for an increasing proportion of notifications in recent years. At present screening of immigrants from countries with a high incidence of TB is inadequate. There are deficiencies in procedures, inadequate screening coverage, ineffectual coordination between the Ministry of Health and New Zealand Immigration Service, incomplete follow-up on those at risk of TB, confusion over financial responsibility, inadequate data to describe the problems and monitor interventions, and a lack of commitment to assistance with TB control in neighbouring countries from which some of our TB arises. We make recommendations in all of these areas. Timely screening of high-risk immigrants should be seen as health protection for ethnic minorities.