Meta-methodology: conducting and reporting meta-analyses

Clinical efficacy of inhaled corticosteroids in equine asthma: A meta-analysis and number needed to treat

Equine asthma, a prevalent chronic inflammatory condition affecting the equine population, significantly compromises the performance and quality of life in affected horses. Inhaled corticosteroids (ICS) are often the first-line pharmacological intervention due to their potent anti-inflammatory properties. This meta-analysis investigates the clinical efficacy of ICS in treating equine asthma, emphasizing the number needed to treat (NNT) and the likelihood of achieving a clinical response. A comprehensive literature search identified relevant studies comparing ICS with placebo (PCB) controlled treatments. Data were synthesized from four clinical trials involving 252 asthmatic horses. Results indicate an overall NNT of 3.2 (95 % CI 2.3-4.7), meaning that approximately three horses must be treated with ICS for one to achieve a significant clinical response. Additionally, the relative risk of achieving clinical improvement with ICS versus PCB was 1.73 (95 % CI 1.47-2.02), demonstrating a marked increase in therapeutic effectiveness. Subgroup analysis revealed an NNT of 3.0 for severe cases, underscoring the efficacy of ICS across different severity levels. Despite potential biases noted in some studies, sensitivity analyses confirmed the robustness of these findings. The GRADE assessment rated the quality of evidence as high. These results highlight the therapeutic value of ICS in managing equine asthma, providing evidence-based recommendations for their clinical use. Future research should explore long-term outcomes and potential synergistic effects of ICS combined with other treatments to enhance clinical efficacy in managing equine asthma.

Strength of association between comorbidities and asthma: a meta-analysis

BACKGROUND

The strength of association between comorbidities and asthma has never been ranked in relation to the prevalence of the comorbidity in the nonasthma population. We investigated the strength of association between comorbidities and asthma.

METHODS

A comprehensive literature search was performed for observational studies reporting data on comorbidities in asthma and nonasthma populations. A pairwise meta-analysis was performed and the strength of association calculated by anchoring odds ratios and 95% confidence intervals with the rate of comorbidities in nonasthma populations via Cohen's d method. Cohen's d=0.2, 0.5 and 0.8 were cut-off values for small, medium and large effect sizes, respectively; very large effect size resulted for Cohen's d >0.8. The review was registered in the PROSPERO database; identifier number CRD42022295657.

RESULTS

Data from 5 493 776 subjects were analysed. Allergic rhinitis (OR 4.24, 95% CI 3.82-4.71), allergic conjunctivitis (OR 2.63, 95% CI 2.22-3.11), bronchiectasis (OR 4.89, 95% CI 4.48-5.34), hypertensive cardiomyopathy (OR 4.24, 95% CI 2.06-8.90) and nasal congestion (OR 3.30, 95% CI 2.96-3.67) were strongly associated with asthma (Cohen's d >0.5 and ≤0.8); COPD (OR 6.23, 95% CI 4.43-8.77) and other chronic respiratory diseases (OR 12.85, 95% CI 10.14-16.29) were very strongly associated with asthma (Cohen's d >0.8). Stronger associations were detected between comorbidities and severe asthma. No bias resulted according to funnel plots and Egger's test.

CONCLUSION

This meta-analysis supports the relevance of individualised strategies for disease management that look beyond asthma. A multidimensional approach should be used to assess whether poor symptom control is related to uncontrolled asthma or to uncontrolled underlying comorbidities.

Impact of Sex on Proper Use of Inhaler Devices in Asthma and COPD: A Systematic Review and Meta-Analysis

Despite females being more often affected by asthma than males and the prevalence of COPD rising in females, conflicting evidence exists as to whether sex may modulate the correct inhaler technique. The aim of this study was to assess the impact of sex on the proper use of inhaler devices in asthma and COPD. A pairwise meta-analysis was performed on studies enrolling adult males and females with asthma or COPD and reporting data of patients making at least one error by inhaler device type (DPI, MDI, and SMI). The data of 6,571 patients with asthma or COPD were extracted from 12 studies. A moderate quality of evidence (GRADE +++) indicated that sex may influence the correct use of inhaler device in both asthma and COPD. The critical error rate was higher in females with asthma (OR 1.31, 95%CI 1.14−1.50) and COPD (OR 1.80, 95%CI 1.22−2.67) using DPI vs. males (p < 0.01). In addition, the use of SMI in COPD was associated with a greater rate of critical errors in females vs. males (OR 5.36, 95%CI 1.48−19.32; p < 0.05). No significant difference resulted for MDI. In conclusion, choosing the right inhaler device in agreement with sex may optimize the pharmacological treatment of asthma and COPD.

Stem Cell-Based Regenerative Therapy and Derived Products in COPD: A Systematic Review and Meta-Analysis

COPD is an incurable disorder, characterized by a progressive alveolar tissue destruction and defective mechanisms of repair and defense leading to emphysema. Currently, treatment for COPD is exclusively symptomatic; therefore, stem cell-based therapies represent a promising therapeutic approach to regenerate damaged structures of the respiratory system and restore lung function. The aim of this study was to provide a quantitative synthesis of the efficacy profile of stem cell-based regenerative therapies and derived products in COPD patients. A systematic review and meta-analysis was performed according to PRISMA-P. Data from 371 COPD patients were extracted from 11 studies. Active treatments elicited a strong tendency towards significance in FEV1 improvement (+71 mL 95% CI -2−145; p = 0.056) and significantly increased 6MWT (52 m 95% CI 18−87; p < 0.05) vs. baseline or control. Active treatments did not reduce the risk of hospitalization due to acute exacerbations (RR 0.77 95% CI 0.40−1.49; p > 0.05). This study suggests that stem cell-based regenerative therapies and derived products may be effective to treat COPD patients, but the current evidence comes from small clinical trials. Large and well-designed randomized controlled trials are needed to really quantify the beneficial impact of stem cell-based regenerative therapy and derived products in COPD.

Adding a Second Bronchodilator in COPD: A Meta-Analysis on the Risk of Specific Cardiovascular Serious Adverse Events of Tiotropium/Olodaterol Fixed-Dose Combination

Dual bronchodilation therapy represents the cornerstone for the treatment of COPD. A large retrospective study reports that adding a second long-acting bronchodilator in patients with COPD significantly increases the risk of heart failure. Nevertheless, retrospective studies are characterized by limitations including misdiagnosis and inaccuracy of recordkeeping. This study aimed to ascertain whether tiotropium/olodaterol (T/O) 5/5 μg fixed-dose combination (FDC) may modulate the risk of main cardiovascular outcomes in COPD patients enrolled in randomized controlled trials (RCTs). A meta-analysis (CRD42017070100) was performed by selecting RCTs reporting raw data from the ClinicalTrials.gov database concerning the impact of T/O 5/5 µg FDC vs. monocomponents on the occurrence of specific cardiovascular serious adverse events: arrhythmia, heart failure, myocardial infarction, and stroke. Data were reported as relative risk and 95% Confidence Interval, and the risk of publication bias assessed via Egger's test. Eighty six full text articles were identified, and 10 RCTs published in 7 studies between 2015 and 2018 were included into the analysis. Data obtained from 12,690 COPD patients (44.47% T/O FDC, 55.53% monocomponents) were extracted. T/O 5/5 μg FDCs did not significantly modulate (p-value > 0.05) the risk of arrhythmia (1.02, 0.55 - 1.92), heart failure (0.88, 0.41 - 1.92), myocardial infarction (1.15, 0.70 - 1.87), and stroke (0.98, 0.44 - 2.16) vs. monocomponents. No significant publication bias affected the effect estimates of this meta-analysis. The results of this quantitative synthesis indicate that dual bronchodilation with T/O 5/5 μg FDC is characterized by an acceptable cardiovascular safety profile in COPD patients.

Age does not affect the efficacy of anti-IL-5/IL-5R in severe asthmatics

Background

Healthcare decisions made on the basis of insufficient evidence may potentially have ineffective or even harmful consequences. The proportion of older ages (over 65 years) in randomized controlled trials (RCTs) for severe asthma is not enough to establish whether anti-IL-5/IL-5R therapies are equally effective in the elderly as in younger subjects.

Methods

In order to assess the relationship between age and the efficacy of anti-IL-5 monoclonal antibodies (mABs) with respect to the risk of exacerbations and changes in FEV₁, a meta-regression analysis via random-effect method was carried out by plotting the effect estimates (outcome variables) resulting from the pairwise meta-analysis with the age of asthmatic subjects (explanatory variable). A comprehensive literature search was performed for pivotal RCTs on the effects of anti-IL-5/IL-5R in severe asthma, with the following keywords: "asthma and mepolizumab", "asthma and reslizumab" and "asthma and benralizumab". The study was restricted to "clinical trials", "age over 65" and "humans". Data were checked for age, exacerbation rates, changes from baseline in FEV₁, and blood eosinophil (Eos) count. Secondary outcomes included inhaled and oral medication use, clinical scores and quality of life.

Results

A total of 10 studies were analysed. Age did not modulate the efficacy of anti-IL-5/IL-5R treatment against the risk of exacerbation neither in the overall population (coefficient -0.007, P = 0.89), nor in patients with high blood Eos count (coefficient 0.075, P = 0.30). The blood Eos level drove the efficacy of anti-IL-5/IL-5R mABs against the risk of exacerbation regardless of age (coefficient -0.27, P < 0.001). Age did not significantly affect the efficacy of anti-IL-5/IL-5R mABs with respect to the change in FEV₁ (coefficient -7.15, P = 0.190); however, in high Eos subjects this improvement tended to be less evident in the more advanced age ranges (coefficient -15.18, P = 0.087). In addition, anti-IL-5/IL-5R mABs reduced ACQ score (P < 0.001 vs. placebo), SGRQ score (P < 0.001 vs. placebo), Total Asthma Symptom Score (P < 0.05 vs. placebo), and the use of oral glucocorticoids (P < 0.001 vs. placebo).

Conclusions

Age does not negatively affect the efficacy of anti-IL-5/IL-5R mABs. These findings support the use of anti-IL-5/IL-5R mABs in asthmatics of different age ranges.

Clinical efficacy of bronchodilators in equine asthma: Looking for minimal important difference

BACKGROUND

Airway obstruction is the main trait of severe equine asthma that affects respiratory function and elicits detrimental effects on clinical presentation. Only few and underpowered clinical studies have investigated the impact of improvement in lung function induced by bronchodilators on the clinical signs of asthma-affected horses.

OBJECTIVES

To identify the minimal important difference (MID) in lung function elicited by bronchodilator leading to a meaningful improvement in clinical signs.

STUDY DESIGN

Pairwise meta-analysis and meta-regression analysis.

METHODS

Literature searches were performed for studies that investigated the effect of bronchodilator therapy on lung function and clinical condition of asthmatic horses. The relationship between the change in lung function variables and clinical score was analysed via random-effect meta-regression. One-point change of the Improved clinically Detectable Equine Asthma Scoring System (IDEASS) score was used to identify the MID.

RESULTS

A significant (P<0.05) relationship was found between the changes in IDEASS score and maximum change in transpulmonary pressure (ΔPpl_max ) or pulmonary resistance (R_L ). Since only the model resulting for R_L passed through the origin (Y-intercept when X = 0: -0.31, 95% CI -0.75 to 0.14), this variable was used to identify the MID correlated with a meaningful improvement in clinical signs. The resulting MID value was a change in R_L of 0.63 cm H₂ O/L/s (95% CI 0.33-0.94), representing the slope of meta-regression model (high quality of evidence).

MAIN LIMITATIONS

No long-term studies investigated the effect of bronchodilator agents on both lung function and clinical signs in asthmatic horses.

CONCLUSIONS

In conclusion, bronchodilator pharmacotherapy in equine asthma elicits clinically meaningful effect when R_L increases ≥1 cm H₂ O/L/s, a value indicating the MID. Assessing the MID based on change in R_L may improve the quality of evidence and the scientific impact of future clinical trials as it extends beyond the simple, and limiting, evaluation of statistical significance.

Clinical effect of corticosteroids in asthma-affected horses: A quantitative synthesis

BACKGROUND

There are limited findings from low-powered studies based on few number of subjects with equine asthma. Furthermore, no studies have been performed to assess a meaningful clinically detectable impact of corticosteroids in equine asthma.

OBJECTIVES

To assess and compare the clinical effect of inhaled and systemic corticosteroids in equine asthma and identify a quantitative clinical score suitable to assess the Minimal Important Difference (MID), expressed as the Minimally Clinically Detectable Difference (MCDD).

STUDY DESIGN

Pair-wise and network meta-analysis.

METHODS

Literature searches for studies on corticosteroid therapy in equine asthma were performed. The risk of publication bias was assessed by Funnel plots and Egger's test. The effect on changes in clinical scores vs. control was analysed via random-effects models and Bayesian networks.

RESULTS

Corticosteroids significantly improved the clinical condition (Standardised Mean Difference: -1.52, 95% CrI -2.07 to -0.98; P<0.001 vs. control). No difference was detected between inhaled and systemic corticosteroids with regard to the changes in clinical scores (Relative Effect: 0.08, 95% CrI -1.45 to 1.32; P = 0.8). An Improved clinically Detectable Equine Asthma Scoring System (IDEASS) indicated that corticosteroids improved the clinical condition of asthmatic horses by 30% compared with controls (IDEASS value: -2.36, 95% CI -3.39 to -1.33; P<0.001). A one-point change in IDEASS represented the MCDD in equine asthma.

MAIN LIMITATIONS

Moderate quality of evidence for systemic corticosteroids.

CONCLUSIONS

Inhaled corticosteroids are effective in improving the clinical condition of horses with equine asthma and prevent exacerbations. Systemic corticosteroids should be used only in selected cases with symptomatic airway hyperresponsiveness during exacerbation. IDEASS requires further validation but may represent a suitable approach to rank the level of asthma severity and assess the clinical effect of pharmacotherapy in horses with equine asthma.

The impact of dual bronchodilation on cardiovascular serious adverse events and mortality in COPD: a quantitative synthesis

Objective

Long-acting β₂-agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) are burdened by the potential risk of inducing cardiovascular serious adverse events (SAEs) in COPD patients. Since the risk of combining a LABA with a LAMA could be greater, we have carried out a quantitative synthesis to investigate the cardiovascular safety profile of LABA/LAMA fixed-dose combinations (FDCs).

Methods

A pair-wise and network meta-analysis was performed by using the data of the repository database ClinicalTrials.gov concerning the impact of approved LABA/LAMA FDCs versus monocomponents and/or placebo on cardiovascular SAEs in COPD.

Results

Overall, LABA/LAMA FDCs did not significantly (P>0.05) modulate the risk of cardiovascular SAEs versus monocomponents. However, the network meta-analysis indicated that aclidinium/formoterol 400/12 µg and tiotropium/olodaterol 5/5 µg were the safest FDCs, followed by umeclidinium/vilanterol 62.5/25 µg which was as safe as placebo, whereas glycopyrronium/formoterol 14.9/9.6, glycopyrronium/indacaterol 15.6/27.5 µg, and glycopyrronium/indacaterol 50/110 µg were the least safe FDCs. No impact on mortality was detected for each specific FDC.

Conclusion

This meta-analysis indicates that LABA/LAMA FDC therapy is characterized by an excellent cardiovascular safety profile in COPD patients. However, the findings of this quantitative synthesis have been obtained from populations that participated in randomized clinical trials, and were devoid of major cardiovascular diseases. Thus, post-marketing surveillance and observational studies may help to better define the real impact of specific FDCs with regard to the cardiovascular risk.

LABA/LAMA combination in COPD: a meta-analysis on the duration of treatment

When there are no randomised clinical trials directly comparing all relevant treatment options, an indirect treatment comparison via meta-analysis of the available clinical evidence is an acceptable alternative. However, meta-analyses may be very misleading if not adequately performed. Here, we propose and validate a simple and effective approach to meta-analysis for exploring the effectiveness of long-acting β2-agonist (LABA)/long-acting muscarinic antagonist (LAMA) fixed-dose combinations in chronic obstructive pulmonary disease.14 articles with 20 329 patients (combinations n=9292; monocomponents n=11 037) were included in this study. LABA/LAMA combinations were always more effective than the monocomponents in terms of the improvement in trough forced expiratory volume in 1 s, transition dyspnoea index and St George's Respiratory Questionnaire scores after 3, 6 and 12 months of treatment. No significant publication bias was identified. Significant discrepancies with previous network meta-analyses have been found, with overall differences ranging from 26.7% to 43.3%.Results from previous network meta-analyses were misleading because no adequate attention was given to formulating the review question, specifying eligibility criteria, correctly identifying studies, collecting appropriate information and deciding what it would be pharmacologically relevant to analyse. The real gradient of effectiveness of LABA/LAMA fixed-dose combinations remains an unmet medical need; however, it can be investigated indirectly using a high-quality meta-analytic approach.

Pirfenidone, nintedanib and N-acetylcysteine for the treatment of idiopathic pulmonary fibrosis: A systematic review and meta-analysis

BACKGROUND

The prevalence of idiopathic pulmonary fibrosis (IPF) is increasing every year. Pirfenidone and nintedanib were approved for treatment of IPF in 2014, but they received only a conditional recommendation for use and, thus, to date no drugs are strongly recommended for IPF. The aim of this study was to assess the effectiveness and safety of the currently approved drugs for IPF and N-acetylcysteine (NAC), the most debated drug in the last update of guidelines for IPF treatment.

METHODS

RCTs in IPF were identified searching from databases of published and unpublished studies. The influence of pirfenidone, nintedanib and NAC on clinical outcomes, safety, and mortality was assessed via pair-wise meta-analysis.

RESULTS

Ten papers (3847 IPF patients; 2254 treated; 1593 placebo) were included in this study. Our results showed that both pirfenidone and nintedanib, but not NAC, were significantly effective in reducing FVC decline and the risk of FVC ≥10% decline in percent predicted over 12 months. Nintenadib significantly protected against the risk of acute exacerbation and mortality. Pirfenidone and nintedanib showed a similar and good safety profile, whereas NAC provided a signal for increased adverse events.

CONCLUSIONS

The rank of effectiveness emerging from this meta-analysis represents an indirect indicator of potential differences between currently approved doses of pirfenidone and nintedanib. Direct comparisons are necessary to assess this matter, and well designed bench-to-bedside studies would permit to understand the potential of combined, sequential, or adjunctive treatment regimens in which perhaps NAC may have a role for specific clusters of IPF patients.

Influence of N-acetylcysteine on chronic bronchitis or COPD exacerbations: a meta-analysis

In order to clarify the possible role of N-acetylcysteine (NAC) in the treatment of patients with chronic bronchitis and chronic obstructive pulmonary disease (COPD), we have carried out a meta-analysis testing the available evidence that NAC treatment may be effective in preventing exacerbations of chronic bronchitis or COPD and evaluating whether there is a substantial difference between the responses induced by low (≤ 600 mg per day) and high (> 600 mg per day) doses of NAC. The results of the present meta-analysis (13 studies, 4155 COPD patients, NAC n = 1933; placebo or controls n = 2222) showed that patients treated with NAC had significantly and consistently fewer exacerbations of chronic bronchitis or COPD (relative risk 0.75, 95% CI 0.66-0.84; p < 0.01), although this protective effect was more apparent in patients without evidence of airway obstruction. However, high doses of NAC were also effective in patients suffering from COPD diagnosed using spirometric criteria (relative risk 0.75, 95% CI 0.68-0.82; p = 0.04). NAC was well tolerated and the risk of adverse reactions was not dose-dependent (low doses relative risk 0.93, 95% CI 0.89-0.97; p = 0.40; high doses relative risk 1.11, 95% CI 0.89-1.39; p = 0.58). The strong signal that comes from this meta-analysis leads us to state that if a patient suffering from chronic bronchitis presents a documented airway obstruction, NAC should be administered at a dose of ≥ 1200 mg per day to prevent exacerbations, while if a patient suffers from chronic bronchitis, but is without airway obstruction, a regular treatment of 600 mg per day seems to be sufficient.

Cardiovascular Safety Outcome Trials: A meeting report from the Cardiac Safety Research Consortium

This White Paper provides a summary of presentations and discussions at a Cardiovascular Safety Outcome Trials Think Tank cosponsored by the Cardiac Safety Research Consortium, the US Food and Drug Administration, and the American College of Cardiology, held at American College of Cardiology's Heart House, Washington, DC, on February 19, 2014. Studies to assess cardiovascular (CV) risk of a new drug are sometimes requested by regulators to resolve ambiguous safety signals seen during its development or among other members of its class. Think Tank participants thought that important considerations in undertaking such studies were as follows: (1) plausibility-how likely it is that a possible signal indicating risk is real, based on strength of evidence, and/or whether a plausible mechanism of action for potential CV harm has been identified; (2) relevance-what relative and absolute CV risk would need to be excluded to determine that the drug had an acceptable benefit-to-risk balance for its use in the intended patient population; and (3) how plausibility and relevance influence the timing and approach to further safety assessment.