[Translated article] Spanish COPD guidelines (GesEPOC) 2021: Updated pharmacological treatment of stable COPD

Proteomic Blood Profiles Obtained by Totally Blind Biological Clustering in Stable and Exacerbated COPD Patients

Although Chronic Obstructive Pulmonary Disease (COPD) is highly prevalent, it is often underdiagnosed. One of the main characteristics of this heterogeneous disease is the presence of periods of acute clinical impairment (exacerbations). Obtaining blood biomarkers for either COPD as a chronic entity or its exacerbations (AECOPD) will be particularly useful for the clinical management of patients. However, most of the earlier studies have been characterized by potential biases derived from pre-existing hypotheses in one or more of their analysis steps: some studies have only targeted molecules already suggested by pre-existing knowledge, and others had initially carried out a blind search but later compared the detected biomarkers among well-predefined clinical groups. We hypothesized that a clinically blind cluster analysis on the results of a non-hypothesis-driven wide proteomic search would determine an unbiased grouping of patients, potentially reflecting their endotypes and/or clinical characteristics. To check this hypothesis, we included the plasma samples from 24 clinically stable COPD patients, 10 additional patients with AECOPD, and 10 healthy controls. The samples were analyzed through label-free liquid chromatography/tandem mass spectrometry. Subsequently, the Scikit-learn machine learning module and K-means were used for clustering the individuals based solely on their proteomic profiles. The obtained clusters were confronted with clinical groups only at the end of the entire procedure. Although our clusters were unable to differentiate stable COPD patients from healthy individuals, they segregated those patients with AECOPD from the patients in stable conditions (sensitivity 80%, specificity 79%, and global accuracy, 79.4%). Moreover, the proteins involved in the blind grouping process to identify AECOPD were associated with five biological processes: inflammation, humoral immune response, blood coagulation, modulation of lipid metabolism, and complement system pathways. Even though the present results merit an external validation, our results suggest that the present blinded approach may be useful to segregate AECOPD from stability in both the clinical setting and trials, favoring more personalized medicine and clinical research.

Influence of Diabetes Mellitus and Nutritional Parameters on Clinical and Functional Aspects and Quality of Life in Patients Hospitalized Due to Exacerbation of Chronic Obstructive Pulmonary Disease

Patients with chronic obstructive pulmonary disease (COPD) may experience exacerbations. During severe exacerbations, nutritional and endocrinological comorbidities can play an important role in the clinical and functional aspects of these patients. The aim of this study was to analyse the influence of the presence of diabetes mellitus (DM) and nutritional parameters on the deterioration of symptoms and quality of life during a severe exacerbation in patients with COPD. An observational study was conducted on COPD patients admitted due to an exacerbation. The COPD Assessment Test (CAT) questionnaire was administered, and clinical and functional parameters were compared based on the presence of nutritional and endocrinological alterations. A total of 50 patients were included, of whom 30 (60%) were male. The mean age was 70.5 years (standard deviation (SD) 9.6). The median CAT score during exacerbation was 25 (interquartile range (IQR) 17.5-30), and the baseline score was 13.5 (IQR 7-19), which represented a statistically significant difference (p < 0.001). Patients with iron deficiencies had a lower total CAT score (p = 0.041), specifically for items related to daily activity (p = 0.009) and energy (p = 0.007). Diabetic patients exhibited a greater decline in pulmonary function during exacerbation (p = 0.016), while patients with high thyroid-stimulating hormone (TSH) levels had a shorter hospital stay (p = 0.016). For COPD patients admitted due to an exacerbation, the metabolic assessment is useful and relevant in the clinical set-up, as endocrinological comorbidities negatively affect clinical and functional aspects of these patients.

Systemic Corticosteroids for Treating Respiratory Diseases: Less Is Better, but… When and How Is It Possible in Real Life?

Systemic corticosteroids (CSs), a keystone in pulmonology, are drugs with strong antiinflammatory activity. They are cheap, easily available, and accessible, but with common and serious side effects. Moreover, the use of exogenous CSs may suppress the hypothalamic-pituitary-adrenal (HPA) axis, predisposing to adrenal insufficiency. Safe CS treatment is a challenge of pharmacological research. This narrative review examined the indications of CSs in some respiratory diseases, analyzing what types, dosages, and length of treatment are required as the dosage and duration of CS treatments need to be minimized. Chronic maintenance treatments with CSs are associated with poor prognosis, but they are still prescribed in patients with severe asthma, Chronic obstructive pulmonary disease (COPD), and interstitial lung diseases. When CS discontinuation is not possible, all efforts should be made to achieve clinically meaningful reductions. Guidelines suggest the use of methylprednisolone at a dose of 20-40 mg/day or equivalent for up to 10 days in subjects with COVID-19 pneumonia (but not other respiratory viral diseases) and respiratory failure, exacerbations of asthma, and COPD. Some guidelines suggest that CS treatment shorter than 10-14 days can be abruptly stopped, strictly monitoring subjects with unexplained symptoms after CS withdrawal, who should promptly be tested for adrenal insufficiency (AI) and eventually treated. CSs are often used in severe community-acquired pneumonia associated with markedly increased serum inflammation markers, in acute respiratory distress syndrome (ARDS), in septic shock unresponsive to hydro-saline replenishment and vasopressors, and acute exacerbations of interstitial lung diseases. As these cases often require higher doses and longer duration of CS treatment, CS tapering should be gradual and, when useful, supported by an evaluation of HPA axis function.

Circulating levels of mitochondrial oxidative stress-related peptides MOTS-c and Romo1 in stable COPD: A cross-sectional study

Background

MOTS-c and Romo1 are mitochondrial peptides that are modulated by oxidative stress. No previous studies have explored circulating levels of MOTS-c in patients with chronic obstructive pulmonary disease (COPD).

Methods

We enrolled 142 patients with stable COPD and 47 smokers with normal lung function in an observational cross-sectional study. We assessed serum levels of both MOTS-c and Romo1 and associated these findings with clinical characteristics of COPD.

Results

Compared with smokers with normal lung function, patients with COPD had lower levels of MOTS-c (p = 0.02) and higher levels of Romo1 (p = 0.01). A multivariate logistic regression analysis revealed that above-median MOTS-c levels were positively associated with Romo1 levels (OR 1.075, 95% CI 1.005-1.150, p = 0.036), but no association was found with other COPD characteristics. Below-median levels of circulating MOTS-c were associated with oxygen desaturation (OR 3.25 95% CI 1.456-8.522, p = 0.005) and walking <350 meters (OR 3.246 95% CI 1.229-8.577, p = 0.018) in six-minute walk test. Above-median levels of Romo1 were positively associated with current smoking (OR 2.756, 95% CI 1.133-6.704, p = 0.025) and negatively associated with baseline oxygen saturation (OR 0.776 95% CI 0.641-0.939, p = 0.009).

Conclusions

Reduced levels of circulating MOTS-c and increased levels of Romo1 were detected in patients diagnosed with COPD. Low levels of MOTS-c were associated with oxygen desaturation and poorer exercise capacity using 6 min walk test. Romo1 was associated with current smoking and baseline oxygen saturation.

Trial registration

www.clinicaltrials.gov; No.: NCT04449419; URL: www.clinicaltrials.gov. Date of registration: June 26, 2020.

Bacterial Patterns and Empiric Antibiotic Use in COPD Patients With Community-Acquired Pneumonia

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is strongly associated with the development of community-acquired pneumonia (CAP). Limited data are available on risk factors for difficult to manage bacteria such as Pseudomonas aeruginosa in COPD patients with CAP. Our objective was to assess the microbiological patterns associated with risk factors that determine empiric antibiotic therapy in hospitalized COPD patients with CAP.

METHODS

We performed a secondary data analysis of an international, multicenter, observational, point-prevalence study involving hospitalized COPD patients with CAP from March to June 2015. After identifying the risk factors associated with different microorganisms, we developed a scoring system to guide decision-making about empiric anti-pseudomonal antibiotic therapy in this population.

RESULTS

We enrolled 689 hospitalized COPD patients with CAP with documented microbiological testing. The most frequent microorganisms isolated were Streptococcus pneumoniae (8%) and Gram-negative bacteria (8%), P. aeruginosa (7%) and Haemophilus influenzae (3%). We developed a scoring system incorporating the variables independently associated with P. aeruginosa that include a previous P. aeruginosa isolation or infection (OR 14.2 [95%CI 5.7-35.2]), hospitalization in the past 12 months (OR 3.7 [1.5-9.2]), and bronchiectasis (OR 3.2 [1.4-7.2]). Empiric anti-pseudomonal antibiotics were overutilized in COPD patients with CAP. The new scoring system has the potential to reduce empiric anti-pseudomonal antibiotic use from 54.1% to 6.2%.

CONCLUSIONS

COPD patients with CAP present different microbiological profiles associated with unique risk factors. Anti-pseudomonal treatment is a critical decision when selecting empiric antibiotic therapy. We developed a COPD scoring system to guide decision-making about empiric anti-pseudomonal antibiotic therapy.

Incidence and medical costs of chronic obstructive respiratory disease in Spanish hospitals: a retrospective database analysis

OBJECTIVE

This study aimed to assess the comorbidity profile, use of health care resources and medical costs of patients with chronic obstructive pulmonary disease (COPD) treated at the hospital level in Spain.

METHODS

Admission records of patients with COPD and at least two admissions registered between January 2016 and December 2020 were obtained from a Spanish hospital discharge database and analyzed in a retrospective multicenter study.

RESULTS

95,140 patients met the inclusion criteria; 69.1% were males with a median age of 75 years. Mean Charlson comorbidity index (CCI) was 1.9 in the index admission, increasing to 2.1 during the follow-up period. An acute exacerbation of COPD was registered in 93.6% of patients in the index admission; other secondary diagnoses included respiratory failure (56.8%), essential hypertension (36.9%), hypercholesterolemia (26.7%) and diabetes (26.3%). The age-adjusted incidence rate of COPD was 22.6 per 10,000 persons over the study period, decreasing significantly in the year 2020. Mortality rate was 4.1% for COPD patients, increasing to 6.6% in the year 2020. The year 2020, 191 patients registered a COVID-19 infection, with a mortality rate of 23.0%. Length of hospital stay, and intensive care unit (ICU) stay increased in the follow-up period versus the index admission, similar to admission costs. Mean admission cost was €3212 in the index admission, with cost increases being associated with age, length of stay, ICU stay and CCI.

CONCLUSIONS

Patients' condition worsened significantly over the follow-up period, in terms of comorbidity and dependence on respirator, with an increased mortality rate and higher admission costs.

LABA/LAMA as First-Line Therapy for COPD: A Summary of the Evidence and Guideline Recommendations

Inhaled bronchodilators (alone or in combination) are the cornerstone of treatment for symptomatic patients with COPD, either as initial/first-line treatment or for second-line/treatment escalation in patients who experience persistent symptoms or exacerbations on monotherapy. The Global Initiative for Chronic Obstructive Lung Disease 2022 report recommends initial pharmacological treatment with a long-acting muscarinic antagonist (LAMA) or a long-acting β₂-agonist (LABA) as monotherapy for most patients, or dual bronchodilator therapy (LABA/LAMA) in patients with more severe symptoms, regardless of exacerbation history. The recommendations for LABA/LAMA are broader in the American Thoracic Society treatment guidelines, which strongly recommend LABA/LAMA combination therapy over LAMA or LABA monotherapy in patients with COPD and dyspnea or exercise intolerance. However, despite consistent guideline recommendations, real-world prescribing data indicate that LAMA and/or LABA without an inhaled corticosteroid are not the most widely prescribed therapies in COPD. This article reviews global and regional/national guideline recommendations for the use of LABA/LAMA in COPD, examines the evidence for the effectiveness and safety of LABA/LAMA versus other therapies and offers a practical guide for clinicians to help ensure appropriate use of LABA/LAMA therapy.

Intravenous Iron Replacement Improves Exercise Tolerance in COPD: A Single-Blind Randomized Trial

INTRODUCTION

Iron deficiency affects exercise capacity because of the critical role iron plays in the optimal functioning of skeletal muscle metabolism. We hypothesized that intravenous iron may improve exercise tolerance, quality of life (QoL), and daily physical activity (DPA) in patients with chronic obstructive pulmonary disease (COPD).

METHODS

This was a placebo-controlled, single-blind, parallel-group, randomized clinical trial. Iron deficiency was defined as a ferritin level<100ng/mL or a ferritin level between 100 and 299ng/mL with a transferrin saturation<20%, with or without mild anaemia. Patients were randomized at a 2:1 ratio to receive intravenous ferric carboxymaltose or placebo. The primary objective was to investigate whether intravenous iron replacement improved endurance time from baseline by at least 33%. The secondary objectives were to evaluate impact on QoL using the COPD Assessment Test (CAT) and on DPA by accelerometry.

RESULTS

We included 66 patients, 44 (66.7%) in the intervention group and 22 (33.3%) in the placebo group. Among patients receiving ferric carboxymaltose, 23 (52.3%) achieved the primary endpoint compared to 4 (18.2%) in the placebo group [p=0.009; relative risk 3.12, (95% CI, 1.19-8.12)]. CAT score decreased -3 (-6.0-1.3) points from baseline in the intervention group (p=0.007), in contrast to placebo group [-1 (-4.0-2.3) points, p=0.236] with no differences in DPA and adverse events in both groups.

CONCLUSIONS

Iron replacement improved exercise capacity and QoL in stable COPD patients with iron deficiency. The treatment was well tolerated.

CLINICAL TRIAL REGISTRATION

EudraCT 2016-001238-89.

Respiratory symptoms and their determinants in the general Spanish population: changes over 20 years

Background

Few large epidemiological studies have analysed the prevalence of respiratory symptoms and their determinants in the general adult population. We investigated the prevalence and determinants of respiratory symptoms and compared their prevalence with that of two previous studies conducted in 1999 and 2009.

Method

EPISCAN II was a multicentre, cross-sectional, population-based epidemiological study in individuals older than 40 years.

Results

A total of 9092 individuals were included. Up to 47.5% reported at least one respiratory symptom, being more frequent in women than in men (49.4% versus 45.5%, p=0.0002) and with wheezing being the most frequent (33.7%) followed by dyspnoea (26.8%). The presence of any symptom was associated with female sex, higher body mass index (BMI), lower forced expiratory volume in 1 s (FEV₁ % pred), reduced physical activity, a higher Charlson index and the presence of anxiety and depression. Smoking was also significantly associated with having at least one respiratory symptom in a dose–response fashion (OR: 1.415, 1.916, 2.192 and 2.987 for 0–10, 10–20, 20–30 and >30 pack-years, respectively, all p<0.0001). The prevalence of symptoms remained quite similar over the last 20 years (wheezing 40%, 36% and 33.7% and dyspnoea 10.4%, 9.9% and 13.1% in 1999, 2009 and 2019, respectively).

Conclusions

Approximately half of the adult Spanish population have respiratory symptoms and this prevalence has remained quite stable over the last 20 years. Smoking remains the main factor associated with respiratory symptoms, but female sex, comorbidities, high BMI and low FEV₁ and low physical activity are also significantly associated with respiratory symptoms.

Approximately half of the adult Spanish population has some respiratory symptoms and this prevalence has remained quite stable over the last 20 yearshttps://bit.ly/37uGRT7

Frequency and Associated Factors of Suicidal Ideation in Patients with Chronic Obstructive Pulmonary Disease

We aimed to examine the prevalence of suicidal ideation in patients with chronic obstructive pulmonary disease (COPD) and the association between demographic and clinical variables and the occurrence of suicidal thoughts. This was a cross-sectional study. Sociodemographic and clinical data were recorded, and questionnaires were used to assess depressive symptoms (Beck Depression Inventory), comorbidities (Charlson Index), cognitive performance (Mini Mental State Examination), and quality of life (EuroQoL-5 dimensions and CAT). Specific questions about suicide-related behavior were included. Multivariate logistic regression analysis identified the significant factors associated with previous suicidal ideation and suicide attempts. The analysis included 1190 subjects. The prevalence of suicidal ideation and suicide attempts were 12.1% and 2.5%, respectively. Severely depressed patients had the highest prevalence of suicide-related behavior. The adjusted logistic model identified factors significantly associated with suicidal ideation: sex (odds ratio (OR) for women vs. men = 2.722 (95% confidence interval (CI) = 1.771–4.183)), depression score (OR = 1.163 (95% IC = 1.127–1.200)), and Charlson Index (OR 1.228 (95% IC 1.082–1.394)). Suicidal ideation is common in COPD patients, especially in women. While addressing suicidal ideation and suicide prevention, clinicians should first consider the management of depressive symptomatology and the improvement of coping strategies.

Biomarkers, Clinical Course, and Individual Needs in COPD Patients in Primary Care: The Study Protocol of the Stockholm COPD Inflammation Cohort (SCOPIC)

Background

To facilitate effective personalized medicine, primary health care needs better methods of assessing and monitoring chronic obstructive pulmonary disease (COPD).

Aim

This cohort study aims to investigate how biomarkers relate to clinical characteristics and COPD patients' subjective needs over time.

Methods

Patients (n=750) in different COPD severity according to the GOLD criteria and age- and sex-matched controls (n=750) will be recruited over a period of 5 years from 15 primary health care centers in Region Stockholm, Sweden, and followed for 10 years in the first instance. Data on patients' subjective needs will be collected via telephone/email, data on clinical/physiological variables (eg, symptoms, exacerbations, comorbidities, medications, smoking habits, lung function) from existing databases that are based on medical records, and data on biomarkers via repeated blood sampling. Quantitative and qualitative methods will be used. Initial results are expected after 2 years (feasibility test), and a larger body of evidence after 5 years.

Discussion

The study is expected to provide definitive and clinically useful scientific evidence about how biomarkers relate to clinical variables and patients' subjective needs. This new evidence will facilitate accurate, and personalized COPD management by the use of valid biomarkers. It will provide useful tools for primary care professionals and may facilitate optimal self-management.

Diaphragmatic Movement at Rest and After Exertion: A Non-Invasive and Easy to Obtain Prognostic Marker in COPD

Introduction

Diaphragmatic dysfunction is common in patients with chronic obstructive pulmonary disease (COPD). This study aimed to assess the prognostic significance of impaired diaphragmatic movement at rest and after exercise.

Methods

This was a prospective study of patients with stable COPD. Diaphragmatic movements were examined at rest and after a 6-minute walking test (6MWT) with a convex transducer with a frequency of 3.5-5-7.5 MHz. Maximal movement of the diaphragm was measured in both right and left diaphragm, and the side with higher amplitude was selected for further analysis. Measurements obtained were evaluated for their prognostic value for a composite endpoint of moderate and severe COPD exacerbations and death in 1 year time period was assessed. In addition, postbronchodilator spirometry, symptoms, quality of life, and demographic and clinical information were collected.

Results

A total of 96 patients were analyzed (62.5% male, mean age 65.1 years (standard deviation (SD): 8.1), mean FEV1 (% predicted): 55.8%, SD: 18.3%, mean CAT: 15.6 units, SD: 9.2). Sixty-four patients (67%) presented the composite endpoint. In the multivariate Cox analysis, FVC (HR = 0.944, p = 0.005), CAT score (HR = 1.133, p = 0.011), previous severe exacerbations (HR = 5.446, p = 0.004) and diaphragmatic movement at rest (HR = 0.932, p = 0.033) were found to be predictors of the composite endpoint. This model correctly classified 86.5% (83/96) of the patients.

Conclusion

Non-invasive assessment of diaphragmatic movement by ultrasound measurement both at rest and after exercise could contribute to the assessment of disease severity and prognosis of COPD.

Impact of anxiety and depression on the prognosis of copd exacerbations

Background

Frequent and highly prevalent as comorbidities in Chronic Obstructive Pulmonary Disease (COPD) patients, both depression and anxiety seem to have an impact on COPD prognosis. However, they are underdiagnosed and rarely treated properly.

Aim

To establish the prevalence of depression and anxiety in patients admitted for Acute Exacerbation of COPD (AECOPD) and determine their influence on COPD prognosis.

Methods

Prospective observational study conducted from October 1, 2016 to October 1, 2018 at the following centers in Galicia, Spain: Salnés County Hospital, Arquitecto Marcide, and Clinic Hospital Complex of Santiago de Compostela. Patients admitted for AECOPD who agreed to participate and completed the anxiety and depression scale (HADS) were included in the study.

Results

288 patients (46.8%) were included, mean age was 73.7 years (SD 10.9), 84.7% were male. 67.7% patients were diagnosed with probable depression, and depression was established in 41.7%; anxiety was probable in 68.2% and established in 35.4%. 60.4% of all patients showed symptoms of both anxiety and depression. Multivariate analysis relates established depression with a higher risk of late readmission (OR 2.06, 95% CI 1.28; 3.31) and a lower risk of mortality at 18 months (OR 0.57, 95% CI 0.37; 0.90).

Conclusion

The prevalence of anxiety and depression in COPD patients is high. Depression seems to be an independent factor for AECOPD, so early detection and a multidisciplinary approach could improve the prognosis of both entities. The study was approved by the Ethical Committee of Galicia (code 2016/460).

Time Trends (2012-2020), Sex Differences and Predictors for Influenza Vaccination Uptake among Individuals with Chronic Obstructive Pulmonary Disease in Spain

(1) Background: To analyze time trends, sex differences, and factors associated with influenza vaccination uptake among individuals with COPD in Spain, 2012−2020. (2) Methods: A cross-sectional study based on data from the European Health Surveys for Spain, 2020 (EHSS2020) and 2014 and from the Spanish National Health Interview Surveys for 2017 and 2012. (3) Results: The study included 65,447 participants. Prevalence of COPD was 5.9% (n = 3855). Overall, the influenza vaccination uptake among COPD patients was 57.8% versus 28.6% for those without COPD (p < 0.001). Men with COPD reported higher uptake than women in all the surveys studied. Neither the crude nor the multivariable analysis showed a significant variation change overtime for people with COPD. However, among those aged <65 years, crude uptake decreased from 2012 to 2020 (39.4% vs. 33.3%; p = 0.039). Over the entire period, men were vaccinated significantly more than women (OR 1.28; 95% CI 1.12−1.47). Among COPD participants, included in the EHSS2020, independent predictors of vaccine uptake included being male, higher age, reporting no current smoking and suffering cancer or heart disease. (4) Conclusions: In COPD patients, the influenza vaccination uptake is below desirable levels and did not improve from 2012 to 2020. Sex differences are found, with consistent and constant lower uptake among women with COPD. The observed lower uptake among COPD women and patients with unhealthy lifestyle requires increased attention.

Inhaled corticosteroid dose is associated with Pseudomonas aeruginosa infection in severe COPD

INTRODUCTION

Patients with chronic obstructive pulmonary disease (COPD) with frequent exacerbations (ExCOPD) are commonly treated with inhaled corticosteroids (ICS) and are at risk of infections caused by potential pathogenic bacteria (PPB) including Pseudomonas aeruginosa (PsA).

OBJECTIVES

To investigate the association between the use of ICS and PsA infection among ExCOPD.

METHODS

Case-control study with longitudinal follow-up that recruited ExCOPD after a hospitalisation due to exacerbation between 2012 and 2020. Patients with isolation of PsA (COPD-PsA) in sputum either during admission or follow-up were compared with those with other or no PPB. Clinical, functional characteristics, DDD, use of ICS and survival were evaluated. Cox regression analysis was performed to evaluate the risk factors associated to PsA infection and mortality.

RESULTS

358 patients (78% male, mean age 73±9 years) were enrolled and followed up for a median of 4 years (IQR=3-8). 173 patients (48.3%) had at least a positive culture for PsA. COPD-PsA had more frequent exacerbations, more severe airflow limitation and higher mortality (69.4% vs 46.5%, p<0.001). There were no differences in the use of ICS between groups but the dose of ICS was significantly higher among COPD-PsA (median of 500 µg fluticasone propionate equivalents (IQR=250-1000) vs 400 µg (IQR=200-1000), p=0.007). Blood eosinophil count (BEC) was not different between ICS users and non-users. In multivariate analysis, the dose of ICS was an independent risk factor for PsA infection and mortality but not ICS use.

CONCLUSIONS

ICS dose, but not its use, could be a risk factor for PsA infection in patients with severe COPD regardless of BEC.

[COPD inhaled therapy narrative review]

Inhaled therapy with long-acting bronchodilators is the base of pharmacological treatment in COPD. In order to find out those that offer better control, a search was carried out in Medline (Pubmed). Comparative studies of inhaler therapy in COPD patients were analyzed. The comparison between the fixed combination LABA/LAMA versus LABA/CI in non-exacerbating patients, revealed a better control with LABA/LAMA. Within the LABA/CI combinations, budesonide/formoterol combination offered better control. LAMA inhalers revealed no great differences, but when compared to LABA, it offered a better control. Regarding triple therapy in a single device, was superior to double therapy and to triple therapy in two devices, with no relevant differences among the available combinations.