Combined corticosteroid and longacting beta-agonist in one inhaler for chronic obstructive pulmonary disease

Anti-inflammatory effects of the novel inhaled phosphodiesterase type 4 inhibitor CHF6001 on virus-inducible cytokines

Respiratory virus infections precipitate asthma and chronic obstructive pulmonary disease (COPD) exacerbations, with most exacerbations due to rhinovirus infection. Both asthma and COPD exacerbations are not well controlled by steroid therapies, and there is a much research interest in finding improved therapies or combinations of therapies for controlling exacerbations. CHF6001 is a new, inhaled highly potent and selective phosphodiesterase type 4 (PDE4) inhibitor. Using in vitro human bronchial epithelial cells (BEAS‐2B), we investigated the potential anti‐inflammatory effects of CHF6001 on rhinovirus (RV1B)‐induced cytokines. Cytokine mRNA was measured by real‐time PCR, while protein release was measured by ELISA. CHF6001 was used in a 7‐point dose–response curve (1000–0.001 nmol/L) as a 1.5‐h pretreatment prior to infection in comparison with roflumilast. Both roflumilast and CHF6001 reduced RV1B‐induced IL‐8, IL‐29, IP‐10, and RANTES mRNA and protein in a concentration‐dependent manner. Generally, CHF6001 was 13‐ to 16‐fold more potent (subnanomolar EC₅₀ values) than roflumilast at reducing IL‐8, IL‐29, IP‐10, and RANTES mRNA and protein release, but had similar efficacies. In combination with the steroid fluticasone propionate (1 nmol/L), CHF6001 had additive effects, significantly reducing RV‐induced cytokines when compared with steroid or CHF6001 alone. Combined low‐dose steroid and low‐dose CHF6001 had a similar efficacy as high‐dose steroid or CHF6001 alone, indicating the combination had steroid and PDE4 inhibitor sparing effects. Overall results indicate that PDE4 inhibitors have anti‐inflammatory activity against virus‐induced inflammatory mediators and that CHF6001 is more potent than roflumilast.

Long-acting inhaled therapy (beta-agonists, anticholinergics and steroids) for COPD: a network meta-analysis

BACKGROUND

Pharmacological therapy for chronic obstructive pulmonary disease (COPD) is aimed at relieving symptoms, improving quality of life and preventing or treating exacerbations.Treatment tends to begin with one inhaler, and additional therapies are introduced as necessary. For persistent or worsening symptoms, long-acting inhaled therapies taken once or twice daily are preferred over short-acting inhalers. Several Cochrane reviews have looked at the risks and benefits of specific long-acting inhaled therapies compared with placebo or other treatments. However for patients and clinicians, it is important to understand the merits of these treatments relative to each other, and whether a particular class of inhaled therapies is more beneficial than the others.

OBJECTIVES

To assess the efficacy of treatment options for patients whose chronic obstructive pulmonary disease cannot be controlled by short-acting therapies alone. The review will not look at combination therapies usually considered later in the course of the disease.As part of this network meta-analysis, we will address the following issues.1. How does long-term efficacy compare between different pharmacological treatments for COPD?2. Are there limitations in the current evidence base that may compromise the conclusions drawn by this network meta-analysis? If so, what are the implications for future research?

SEARCH METHODS

We identified randomised controlled trials (RCTs) in existing Cochrane reviews by searching the Cochrane Database of Systematic Reviews (CDSR). In addition, we ran a comprehensive citation search on the Cochrane Airways Group Register of trials (CAGR) and checked manufacturer websites and reference lists of other reviews. The most recent searches were conducted in September 2013.

SELECTION CRITERIA

We included parallel-group RCTs of at least 6 months' duration recruiting people with COPD. Studies were included if they compared any of the following treatments versus any other: long-acting beta2-agonists (LABAs; formoterol, indacaterol, salmeterol); long-acting muscarinic antagonists (LAMAs; aclidinium, glycopyrronium, tiotropium); inhaled corticosteroids (ICSs; budesonide, fluticasone, mometasone); combination long-acting beta2-agonist (LABA) and inhaled corticosteroid (LABA/ICS) (formoterol/budesonide, formoterol/mometasone, salmeterol/fluticasone); and placebo.

DATA COLLECTION AND ANALYSIS

We conducted a network meta-analysis using Markov chain Monte Carlo methods for two efficacy outcomes: St George's Respiratory Questionnaire (SGRQ) total score and trough forced expiratory volume in one second (FEV1). We modelled the relative effectiveness of any two treatments as a function of each treatment relative to the reference treatment (placebo). We assumed that treatment effects were similar within treatment classes (LAMA, LABA, ICS, LABA/ICS). We present estimates of class effects, variability between treatments within each class and individual treatment effects compared with every other.To justify the analyses, we assessed the trials for clinical and methodological transitivity across comparisons. We tested the robustness of our analyses by performing sensitivity analyses for lack of blinding and by considering six- and 12-month data separately.

MAIN RESULTS

We identified 71 RCTs randomly assigning 73,062 people with COPD to 184 treatment arms of interest. Trials were similar with regards to methodology, inclusion and exclusion criteria and key baseline characteristics. Participants were more often male, aged in their mid sixties, with FEV1 predicted normal between 40% and 50% and with substantial smoking histories (40+ pack-years). The risk of bias was generally low, although missing information made it hard to judge risk of selection bias and selective outcome reporting. Fixed effects were used for SGRQ analyses, and random effects for Trough FEV1 analyses, based on model fit statistics and deviance information criteria (DIC). SGRQ SGRQ data were available in 42 studies (n = 54,613). At six months, 39 pairwise comparisons were made between 18 treatments in 25 studies (n = 27,024). Combination LABA/ICS was the highest ranked intervention, with a mean improvement over placebo of -3.89 units at six months (95% credible interval (CrI) -4.70 to -2.97) and -3.60 at 12 months (95% CrI -4.63 to -2.34). LAMAs and LABAs were ranked second and third at six months, with mean differences of -2.63 (95% CrI -3.53 to -1.97) and -2.29 (95% CrI -3.18 to -1.53), respectively. Inhaled corticosteroids were ranked fourth (MD -2.00, 95% CrI -3.06 to -0.87). Class differences between LABA, LAMA and ICS were less prominent at 12 months. Indacaterol and aclidinium were ranked somewhat higher than other members of their classes, and formoterol 12 mcg, budesonide 400 mcg and formoterol/mometasone combination were ranked lower within their classes. There was considerable overlap in credible intervals and rankings for both classes and individual treatments. Trough FEV1 Trough FEV1 data were available in 46 studies (n = 47,409). At six months, 41 pairwise comparisons were made between 20 treatments in 31 studies (n = 29,271). As for SGRQ, combination LABA/ICS was the highest ranked class, with a mean improvement over placebo of 133.3 mL at six months (95% CrI 100.6 to 164.0) and slightly less at 12 months (mean difference (MD) 100, 95% CrI 55.5 to 140.1). LAMAs (MD 103.5, 95% CrI 81.8 to 124.9) and LABAs (MD 99.4, 95% CrI 72.0 to 127.8) showed roughly equivalent results at six months, and ICSs were the fourth ranked class (MD 65.4, 95% CrI 33.1 to 96.9). As with SGRQ, initial differences between classes were not so prominent at 12 months. Indacaterol and salmeterol/fluticasone were ranked slightly better than others in their class, and formoterol 12, aclidinium, budesonide and formoterol/budesonide combination were ranked lower within their classes. All credible intervals for individual rankings were wide.

AUTHORS' CONCLUSIONS

This network meta-analysis compares four different classes of long-acting inhalers for people with COPD who need more than short-acting bronchodilators. Quality of life and lung function were improved most on combination inhalers (LABA and ICS) and least on ICS alone at 6 and at 12 months. Overall LAMA and LABA inhalers had similar effects, particularly at 12 months. The network has demonstrated the benefit of ICS when added to LABA for these outcomes in participants who largely had an FEV1 that was less than 50% predicted, but the additional expense of combination inhalers and any potential for increased adverse events (which has been established by other reviews) require consideration. Our findings are in keeping with current National Institute for Health and Care Excellence (NICE) guidelines.

Combined corticosteroid and long-acting beta(2)-agonist in one inhaler versus inhaled corticosteroids alone for chronic obstructive pulmonary disease

BACKGROUND

Both long-acting beta(2)-agonists and inhaled corticosteroids have been recommended in guidelines for the treatment of chronic obstructive pulmonary disease (COPD). Their co-administration in a combined inhaler is intended to facilitate adherence to medication regimens and to improve efficacy. Three preparations are currently available: fluticasone propionate/salmeterol (FPS). budesonide/formoterol (BDF) and mometasone furoate/formoterol (MF/F).

OBJECTIVES

To assess the efficacy and safety of combined long-acting beta2-agonist and inhaled corticosteroid (LABA/ICS) preparations, as measured by clinical endpoints and pulmonary function testing, compared with inhaled corticosteroids (ICS) alone, in the treatment of adults with chronic obstructive pulmonary disease (COPD).

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials, which is compiled from systematic searches of multiple literature databases. The search was conducted in June 2013. In addition, we checked the reference lists of included studies and contacted the relevant manufacturers.

SELECTION CRITERIA

Studies were included if they were randomised and double-blind. Compared studies combined LABA/ICS with the ICS component.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. The primary outcomes were exacerbations, mortality and pneumonia. Health-related quality of life (as measured by validated scales), lung function and side effects were secondary outcomes. Dichotomous data were analysed as fixed-effect odds ratios with 95% confidence intervals (CIs), and continuous data as mean differences or rate ratios and 95% CIs.

MAIN RESULTS

A total of 15 studies of good methodological quality met the inclusion criteria by randomly assigning 7814 participants with predominantly poorly reversible, severe COPD. Data were most plentiful for the FPS combination. Exacerbation rates were significantly reduced with combination therapies (rate ratio 0.87, 95% CI 0.80 to 0.94, 6 studies, N = 5601) compared with ICS alone. The mean exacerbation rate in the control (ICS) arms of the six included studies was 1.21 exacerbations per participant per year (range 0.88 to 1.60), and we would expect this to be reduced to a rate of 1.05 (95% CI 0.97 to 1.14) among those given combination therapy. Mortality was also lower with the combination (odds ratio (OR) 0.78, 95% CI 0.64 to 0.94, 12 studies, N = 7518) than with ICS alone, but this was heavily weighted by a three-year study of FPS. When this study was removed, no significant mortality difference was noted. The reduction in exacerbations did not translate into significantly reduced rates of hospitalisation due to COPD exacerbation (OR 0.93, 95% CI 0.80 to 1.07, 10 studies, N = 7060). Lung function data favoured combination treatment in the FPS, BDF and MF/F trials, but the improvement was small. Small improvements in health-related quality of life were measured on the St George's Respiratory Questionnaire (SGRQ) with FPS or BDF compared with ICS, but this was well below the minimum clinically important difference. Adverse event profiles were similar between the two treatments arms, and rates of pneumonia when it was diagnosed by chest x-ray (CXR) were lower than those reported in earlier trials.

AUTHORS' CONCLUSIONS

Combination ICS and LABA offer some clinical benefits in COPD compared with ICS alone, especially for reduction in exacerbations. This review does not support the use of ICS alone when LABAs are available. Adverse events were not significantly different between treatments. Further long-term assessments using practical outcomes of current and new 24-hour LABAs will help determine their efficacy and safety. For robust comparisons as to their relative effects, long-term head-to-head comparisons are needed.

Combined corticosteroid and long-acting beta(2)-agonist in one inhaler versus long-acting beta(2)-agonists for chronic obstructive pulmonary disease

BACKGROUND

Both inhaled steroids (ICS) and long-acting beta(2)-agonists (LABA) are used in the management of chronic obstructive pulmonary disease (COPD). This updated review compared compound LABA plus ICS therapy (LABA/ICS) with the LABA component drug given alone.

OBJECTIVES

To assess the efficacy of ICS and LABA in a single inhaler with mono-component LABA alone in adults with COPD.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials. The date of the most recent search was November 2011.

SELECTION CRITERIA

We included randomised, double-blind controlled trials. We included trials comparing compound ICS and LABA preparations with their component LABA preparations in people with COPD.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study risk of bias and extracted data. The primary outcomes were exacerbations, mortality and pneumonia, while secondary outcomes were health-related quality of life (measured by validated scales), lung function, withdrawals due to lack of efficacy, withdrawals due to adverse events and side-effects. Dichotomous data were analysed as random-effects model odds ratios or rate ratios with 95% confidence intervals (CIs), and continuous data as mean differences and 95% CIs. We rated the quality of evidence for exacerbations, mortality and pneumonia according to recommendations made by the GRADE working group.

MAIN RESULTS

Fourteen studies met the inclusion criteria, randomising 11,794 people with severe COPD. We looked at any LABA plus ICS inhaler (LABA/ICS) versus the same LABA component alone, and then we looked at the 10 studies which assessed fluticasone plus salmeterol (FPS) and the four studies assessing budesonide plus formoterol (BDF) separately. The studies were well-designed with low risk of bias for randomisation and blinding but they had high rates of attrition, which reduced our confidence in the results for outcomes other than mortality.Primary outcomes There was low quality evidence that exacerbation rates in people using LABA/ICS inhalers were lower in comparison to those with LABA alone, from nine studies which randomised 9921 participants (rate ratio 0.76; 95% CI 0.68 to 0.84). This corresponds to one exacerbation per person per year on LABA and 0.76 exacerbations per person per year on ICS/LABA. Our confidence in this effect was limited by statistical heterogeneity between the results of the studies (I(2) = 68%) and a risk of bias from the high withdrawal rates across the studies. When analysed as the number of people experiencing one or more exacerbations over the course of the study, FPS lowered the odds of an exacerbation with an odds ratio (OR) of 0.83 (95% CI 0.70 to 0.98, 6 studies, 3357 participants). With a risk of an exacerbation of 47% in the LABA group over one year, 42% of people treated with LABA/ICS would be expected to experience an exacerbation. Concerns over the effect of reporting biases led us to downgrade the quality of evidence for this effect from high to moderate.There was no significant difference in the rate of hospitalisations (rate ratio 0.79; 95% CI 0.55 to 1.13, very low quality evidence due to risk of bias, statistical imprecision and inconsistency). There was no significant difference in mortality between people on combined inhalers and those on LABA, from 10 studies on 10,680 participants (OR 0.92; 95% CI 0.76 to 1.11, downgraded to moderate quality evidence due to statistical imprecision). Pneumonia occurred more commonly in people randomised to combined inhalers, from 12 studies with 11,076 participants (OR 1.55; 95% CI 1.20 to 2.01, moderate quality evidence due to risk of bias in relation to attrition) with an annual risk of around 3% on LABA alone compared to 4% on combination treatment. There were no significant differences between the results for either exacerbations or pneumonia from trials adding different doses or types of inhaled corticosteroid.Secondary outcomes ICS/LABA was more effective than LABA alone in improving health-related quality of life measured by the St George's Respiratory Questionnaire (1.58 units lower with FPS; 2.69 units lower with BDF), dyspnoea (0.09 units lower with FPS), symptoms (0.07 units lower with BDF), rescue medication (0.38 puffs per day fewer with FPS, 0.33 puffs per day fewer with BDF), and forced expiratory volume in one second (FEV(1)) (70 mL higher with FPS, 50 mL higher with BDF). Candidiasis (OR 3.75) and upper respiratory infection (OR 1.32) occurred more frequently with FPS than SAL. We did not combine adverse event data relating to candidiasis for BDF studies as the results were very inconsistent.

AUTHORS' CONCLUSIONS

Concerns over the analysis and availability of data from the studies bring into question the superiority of ICS/LABA over LABA alone in preventing exacerbations. The effects on hospitalisations were inconsistent and require further exploration. There was moderate quality evidence of an increased risk of pneumonia with ICS/LABA. There was moderate quality evidence that treatments had similar effects on mortality. Quality of life, symptoms score, rescue medication use and FEV(1) improved more on ICS/LABA than on LABA, but the average differences were probably not clinically significant for these outcomes. To an individual patient the increased risk of pneumonia needs to be balanced against the possible reduction in exacerbations.More information would be useful on the relative benefits and adverse event rates with combination inhalers using different doses of inhaled corticosteroids. Evidence from head-to-head comparisons is needed to assess the comparative risks and benefits of the different combination inhalers.

Medical therapy for chronic obstructive pulmonary disease in 2007

Medical treatment for patients with stable chronic obstructive pulmonary disease (COPD) has evolved significantly over the past 2 decades. Current World Health Organization recommendations suggest a stepwise approach to therapy depending upon disease severity. As-needed use of short-acting bronchodilators is recommended for patients with mild disease. Scheduled dosing of bronchodilators is recommended for patients with more advanced disease. Inhaled beta-agonists and anti-cholinergic agents in combination have proved to be more effective than either agent alone. Long-acting preparations are associated with better disease control and have not been associated with tachyphylaxis. Inhaled corticosteroids are useful for reducing the frequency of exacerbations in patients who experience one or more episodes per year. Oxygen therapy is clearly beneficial in patients with advanced COPD and chronic respiratory failure, and its potential benefits in less severe disease are currently being studied. Pulmonary rehabilitation benefits patients with mild-to-severe disease, although the greatest benefits have been demonstrated in those with moderate COPD. New ultra-long-acting inhaled bronchodilators, phosphodiesterase inhibitors, protease inhibitors, and retinoids intended to promote tissue regeneration are currently being evaluated in clinical trials as future therapeutic agents.

Traitement de l'inflammation bronchique dans la mucoviscidose

Cystic fibrosis airway inflammation is characterized by neutrophilic efflux and high levels of proinflammatory cytokines such as IL-8 and IL-6. Inhaled corticosteroids are widely used despite lack of evidence of efficacity. Despite evidence of efficacity of ibuprofen, many clinicians have chosen not to use this therapy because of concerns regarding potential side effects. Azithromycin has antiinflammatory properties and is effective in cystic fibrosis (CF) patients. Deoxyribonuclease (rhDNase) has been shown to improve lung function in patients with cystic fibrosis and may also have a positive effect on inflammation. Other antiinflammatory drugs are in the process of validation.

Combined corticosteroid and long-acting beta-agonist in one inhaler versus long-acting beta-agonists for chronic obstructive pulmonary disease

BACKGROUND

The co-administration of inhaled corticosteroids and long-acting beta-agonists in a combined inhaler is intended to facilitate adherence to medication regimens, and to improve efficacy in COPD. In this review they are compared with mono component long-acting beta-agonists.

OBJECTIVES

To assess the efficacy of combined inhaled corticosteroids and long-acting beta-agonists preparations with mono component long-acting beta-agonists in adults with chronic obstructive pulmonary disease.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register of trials. The date of the most recent search is April 2007.

SELECTION CRITERIA

Studies were included if they were randomised and double-blind. Studies could compare a combined inhaled corticosteroids and long-acting beta-agonist preparation with component long-acting beta-agonist preparation.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. The primary outcomes were exacerbations, mortality and pneumonia, with health-related quality of life (measured by validated scales), lung function and side-effects as secondary outcomes. Dichotomous data were analysed as fixed effect odds ratios (OR), and continuous data as mean differences and 95% confidence intervals (CI). Sensitivity analysis was performed by combining data with a random effects model.

MAIN RESULTS

Ten studies of good methodological quality met the inclusion criteria, randomising 7598 participants with severe chronic obstructive pulmonary disease. Eight studies assessed fluticasone/salmeterol, and two studies budesonide/formoterol. The exacerbation rates with combined inhalers were reduced in comparison to long-acting beta-agonists alone (Rate Ratio 0.82, 95% CI 0.78 to 0.88). There was no significant difference in mortality between combined inhalers and long-acting beta-agonists alone. Pneumonia occurred more commonly with combined inhalers (OR 1.62; 95% CI 1.35 to 1.94). There was no significant difference in terms of hospitalisations, although the two studies contributing data to this outcome may have been drawn from differing populations. Combination was more effective than LABA in improving quality of life measured by the St George Respiratory Questionnaire, and the Chronic Respiratory Questionnaire, and predose and post dose FEV1.

AUTHORS' CONCLUSIONS

Combination therapy was more effective than long-acting beta-agonists in reducing exacerbation rates, although the evidence for the effects on hospitalisations was mixed, and requires further exploration. No significant impact on mortality was found even with additional information from the TORCH trial. The superiority of combination inhalers should be viewed against the increased risk of side-effects, particularly pneumonia. Additional studies on BDF are required and more information would be useful of the relative benefits and adverse event rates with different doses of inhaled corticosteroids.

Combined corticosteroid and long-acting beta-agonist in one inhaler versus placebo for chronic obstructive pulmonary disease

BACKGROUND

Long-acting beta-agonists and inhaled corticosteroids have both been recommended in guidelines for the treatment of chronic obstructive pulmonary disease. Their co-administration in a combined inhaler may facilitate adherence to medication regimens, and improve efficacy.

OBJECTIVES

To assess the efficacy of combined inhaled corticosteroid and long-acting beta-agonist preparations, compared to placebo, in the treatment of adults with chronic obstructive pulmonary disease.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register of trials. The date of the most recent search is April 2007.

SELECTION CRITERIA

Studies were included if they were randomised and double-blind. Studies could compare any combined inhaled corticosteroids and long-acting beta-agonist preparation with placebo.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. One author entered the data.

MAIN RESULTS

Eleven studies met the inclusion criteria (6427 participants randomised). Two different combination preparations (fluticasone/salmeterol and budesonide/formoterol) were used. Study quality was good. Fluticasone/salmeterol and budesonide/formoterol both reduced the rate of exacerbations. Pooled analysis of both combination therapies indicated that exacerbations were less frequent when compared with placebo, Rate Ratio: 0.74 (95% CI 0.7 to 0.8). The clinical impact of this effect depends on the frequency of exacerbations experienced by patients. The patients included in these trials had on average 1-2 exacerbations per year which means that treatment with combination therapy would lead to a reduction of one exacerbation every two to four years in these individuals. There is an overall reduction in mortality, but this outcome is dominated by the results of TORCH and further studies on budesonide/formoterol are required. The three year number needed to treat to prevent one extra death is 36 (95% CI 21 to 258), using a baseline risk of 15.2% from the placebo arm of TORCH. Both treatments led to statistically significant improvement in health status measurements, although the clinical importance of the differences observed is open to interpretation. Symptoms and lung function assessments favoured combination treatments. There was an increase in the risk of pneumonia with combined inhalers. The three year number needed to treat for one extra case of pneumonia is 13 (95% CI 9 to 20), using a baseline risk of 12.3% from the placebo arm of TORCH. Fewer participants withdrew from studies assessing combined inhalers due to adverse events and lack of efficacy.

AUTHORS' CONCLUSIONS

Compared with placebo, combination therapy led to a significant reduction of a quarter in exacerbation rates. There was a significant reduction in all-cause mortality with the addition of data from the TORCH trial. The increased risk of pneumonia is a concern, and better reporting of this outcome in future studies would be helpful. In order to draw firmer conclusions about the effects of combination therapy in a single inhaler more data are necessary, particularly in relation to the profile of adverse events and benefits in relation to different doses of inhaled corticosteroids.

Combined corticosteroid and long-acting beta-agonist in one inhaler versus inhaled steroids for chronic obstructive pulmonary disease

BACKGROUND

Long-acting beta-agonists and inhaled corticosteroids have both been recommended in guidelines for the treatment of chronic obstructive pulmonary disease. Their co-administration in a combined inhaler is intended to facilitate adherence to medication regimens, and to improve efficacy. Two preparations are currently available, fluticasone/salmeterol (FPS) and budesonide/formoterol (BDF).

OBJECTIVES

To assess the efficacy of combined inhaled corticosteroid and long-acting beta-agonist preparations, compared to inhaled corticosteroids, in the treatment of adults with chronic obstructive pulmonary disease.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register of trials. The date of the most recent search is April 2007.

SELECTION CRITERIA

Studies were included if they were randomised and double-blind. Studies compared combined inhaled corticosteroids and long-acting beta-agonist preparations with the inhaled corticosteroid component.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. The primary outcome were exacerbations, mortality and pneumonia. Health-related quality of life (measured by validated scales), lung function and side-effects were secondary outcomes. Dichotomous data were analysed as fixed effect odds ratios (OR), and continuous data as mean differences and 95% confidence intervals (CI).

MAIN RESULTS

Seven studies of good methodological quality met the inclusion criteria randomising 5708 participants with predominantly poorly reversible, severe COPD. Exacerbation rates were significantly reduced with combination therapies (Rate ratio 0.91; 95% confidence interval 0.85 to 0.97, P = 0.0008). Data from two FPS studies indicated that exacerbations requiring oral steroids were reduced with combination therapy. Data from one large study suggest that there is no significant difference in the rate of hospitalisations. Mortality was also lower with combined treatment (odds ratio 0.77; 95% confidence interval 0.63 to 0.94). Quality of life, lung function and withdrawals due to lack of efficacy favoured combination treatment. Adverse event profiles were similar between the two treatments. No significant differences were found between FPS and BDP in the primary outcomes, but the confidence intervals for the BDP results were wide as smaller numbers of patients have been studied.

AUTHORS' CONCLUSIONS

Combination ICS and LABA significantly reduces morbidity and mortality in COPD when compared with mono component steroid. Adverse events were not significantly different between treatments, although evidence from other sources indicates that inhaled corticosteroids are associated with increased risk of pneumonia. Assessment of BDF in larger, long-term trials is required. Dose response data would provide valuable evidence on whether efficacy and safety outcomes are affected by different steroid loads.

Meta-analytic methods for pooling rates when follow-up duration varies: a case study

BACKGROUND

Meta-analysis can be used to pool rate measures across studies, but challenges arise when follow-up duration varies. Our objective was to compare different statistical approaches for pooling count data of varying follow-up times in terms of estimates of effect, precision, and clinical interpretability.

METHODS

We examined data from a published Cochrane Review of asthma self-management education in children. We selected two rate measures with the largest number of contributing studies: school absences and emergency room (ER) visits. We estimated fixed- and random-effects standardized weighted mean differences (SMD), stratified incidence rate differences (IRD), and stratified incidence rate ratios (IRR). We also fit Poisson regression models, which allowed for further adjustment for clustering by study.

RESULTS

For both outcomes, all methods gave qualitatively similar estimates of effect in favor of the intervention. For school absences, SMD showed modest results in favor of the intervention (SMD -0.14, 95% CI -0.23 to -0.04). IRD implied that the intervention reduced school absences by 1.8 days per year (IRD -0.15 days/child-month, 95% CI -0.19 to -0.11), while IRR suggested a 14% reduction in absences (IRR 0.86, 95% CI 0.83 to 0.90). For ER visits, SMD showed a modest benefit in favor of the intervention (SMD -0.27, 95% CI: -0.45 to -0.09). IRD implied that the intervention reduced ER visits by 1 visit every 2 years (IRD -0.04 visits/child-month, 95% CI: -0.05 to -0.03), while IRR suggested a 34% reduction in ER visits (IRR 0.66, 95% CI 0.59 to 0.74). In Poisson models, adjustment for clustering lowered the precision of the estimates relative to stratified IRR results. For ER visits but not school absences, failure to incorporate study indicators resulted in a different estimate of effect (unadjusted IRR 0.77, 95% CI 0.59 to 0.99).

CONCLUSIONS

Choice of method among the ones presented had little effect on inference but affected the clinical interpretability of the findings. Incidence rate methods gave more clinically interpretable results than SMD. Poisson regression allowed for further adjustment for heterogeneity across studies. These data suggest that analysts who want to improve the clinical interpretability of their findings should consider incidence rate methods.