Exertional breathlessness related to medical conditions in middle-aged people: the population-based SCAPIS study of more than 25,000 men and women.

BACKGROUND: Breathlessness is common in the population and can be related to a range of medical conditions. We aimed to evaluate the burden of breathlessness related to different medical conditions in a middle-aged population. METHODS: Cross-sectional analysis of the population-based Swedish CArdioPulmonary bioImage Study of adults aged 50-64 years. Breathlessness (modified Medical Research Council [mMRC] ≥ 2) was evaluated in relation to self-reported symptoms, stress, depression; physician-diagnosed conditions; measured body mass index (BMI), spirometry, venous haemoglobin concentration, coronary artery calcification and stenosis [computer tomography (CT) angiography], and pulmonary emphysema (high-resolution CT). For each condition, the prevalence and breathlessness population attributable fraction (PAF) were calculated, overall and by sex, smoking history, and presence/absence of self-reported cardiorespiratory disease. RESULTS: We included 25,948 people aged 57.5 ± [SD] 4.4; 51% women; 37% former and 12% current smokers; 43% overweight (BMI 25.0-29.9), 21% obese (BMI ≥ 30); 25% with respiratory disease, 14% depression, 9% cardiac disease, and 3% anemia. Breathlessness was present in 3.7%. Medical conditions most strongly related to the breathlessness prevalence were (PAF 95%CI): overweight and obesity (59.6-66.0%), stress (31.6-76.8%), respiratory disease (20.1-37.1%), depression (17.1-26.6%), cardiac disease (6.3-12.7%), anemia (0.8-3.3%), and peripheral arterial disease (0.3-0.8%). Stress was the main factor in women and current smokers. CONCLUSION: Breathlessness mainly relates to overweight/obesity and stress and to a lesser extent to comorbidities like respiratory, depressive, and cardiac disorders among middle-aged people in a high-income setting-supporting the importance of lifestyle interventions to reduce the burden of breathlessness in the population.

Comparing recalled versus experienced symptoms of breathlessness ratings: An ecological assessment study using mobile phone technology.

BACKGROUND AND OBJECTIVE: Recall of breathlessness is important for clinical care but might differ from the experienced (momentary) symptoms. This study aimed to characterize the relationship between momentary breathlessness ratings and the recall of the experience. It is hypothesized that recall is influenced by the peak (worst) and end (most recent) ratings of momentary breathlessness (peak-end rule). METHODS: This study used mobile ecological momentary assessment (mEMA) for assessing breathlessness in daily life through an application installed on participants' mobile phones. Breathlessness ratings (0-10 numerical rating scale) were recorded throughout the day and recalled each night and at the end of the week. Analyses were performed using regular and mixed linear regression. RESULTS: Eighty-four people participated. Their mean age was 64.4 years, 60% were female and 98% had modified Medical Research Council (mMRC) ≥ 1. The mean number of momentary ratings of breathlessness provided was 7.7 ratings/participant/day. Recalled breathlessness was associated with the mean, peak and end values of the day. The mean was most closely associated with the daily recall. Associations were strong for weekly values: peak breathlessness (beta = 0.95, r2  = 0.57); mean (beta = 0.91, r2  = 0.53); and end (beta = 0.67, r2  = 0.48); p < 0.001 for all. Multivariate analysis showed that peak breathlessness had the strongest influence on the breathlessness recalled at the end of the week. CONCLUSION: Over 1 week, recalled breathlessness is most strongly influenced by the peak breathlessness; over 1 day, it is mean breathlessness that participants most readily recalled.

Prevalence, severity and impacts of breathlessness in Indian adults: An exploratory, nationally representative, cross-sectional online survey.

There are no known estimates of the prevalence, severity and impacts from breathlessness in low- and middle-income countries. This study aimed to explore the prevalence, severity, self-attributed underlying conditions and impacts of breathlessness limiting exertion in community-dwelling adults in India. This exploratory, population-based online survey recruited a pre-planned sample of 3,000 adult respondents stratified by age, sex and rurality (quotas as per the 2011 Indian National Census). Measures included: demographics; breathlessness limiting exertion (modified Medical Research [mMRC] scale); health-related quality of life (EQ-5D-5L); and disability (World Health Organisation's Disability Assessment Schedule 2.0 12-item questionnaire [WHODAS-12]). Respondents (n = 3,046) had a mean age of 38 years (SD 15); 57% were male, 59% lived in rural areas and 33% had completed 12th grade. Breathlessness limiting exertion (mMRC ≥1) was reported by 44%, mostly attributed to poor nutrition (28%), lung conditions excluding tuberculosis (17%) or anaemia (13%). Compared to those without breathlessness, a higher proportion of people with breathlessness (mMRC ≥1) reported problems across all EQ-5D-5L dimensions. Most people reporting breathlessness (81%) indicated the symptom had adversely affected their normal activities. Disability scores (WHODAS-12 total and individual domains) increased as breathlessness worsened. To conclude, in India, conservative estimates indicate 626 million people live with breathlessness of whom 52 million people live with severe breathlessness. The symptom is associated with poorer health-related quality of life and marked disability, including reduced ability to perform daily activities.

Factors most strongly associated with breathlessness in a population aged 50-64 years.

Background: Breathlessness is a troublesome and prevalent symptom in the population, but knowledge of related factors is scarce. The aim of this study was to identify the factors most strongly associated with breathlessness in the general population and to describe the shapes of the associations between the main factors and breathlessness. Methods: A cross-sectional analysis was carried out of the multicentre population-based Swedish CArdioPulmonary bioImage Study (SCAPIS) of adults aged 50 to 64 years. Breathlessness was defined as a modified Medical Research Council breathlessness rating ≥2. The machine learning algorithm extreme gradient boosting (XGBoost) was used to classify participants as either breathless or nonbreathless using 449 factors, including physiological measurements, blood samples, computed tomography cardiac and lung measurements, lifestyle, health conditions and socioeconomics. The strength of the associations between the factors and breathlessness were measured by SHapley Additive exPlanations (SHAP), with higher scores reflecting stronger associations. Results: A total of 28 730 participants (52% women) were included in the study. The strongest associated factors for breathlessness were (in order of magnitude): body mass index ( SHAP score 0.39), forced expiratory volume in 1 s (0.32), physical activity measured by accelerometery (0.27), sleep apnoea (0.22), diffusing lung capacity for carbon monoxide (0.21), self-reported physical activity (0.17), chest pain when hurrying (0.17), high-sensitivity C-reactive protein (0.17), recent weight change (0.14) and cough (0.13). Conclusion: This large population-based study of men and women aged 50-64 years identified the main factors related to breathlessness that may be prevented or amenable to public health interventions.

Which breathlessness dimensions associate most strongly with fatigue?-The population-based VASCOL study of elderly men.

BACKGROUND: Breathlessness and fatigue are common symptoms in older people. We aimed to evaluate how different breathlessness dimensions (overall intensity, unpleasantness, sensory descriptors, emotional responses) were associated with fatigue in elderly men. METHODS: This was a cross-sectional analysis of the population-based VAScular disease and Chronic Obstructive Lung Disease (VASCOL) study of 73-year old men. Breathlessness dimensions were assessed using the Dyspnoea-12 (D-12), Multidimensional Dyspnoea Profile (MDP), and the modified Medical Research Council (mMRC) scale. Fatigue was assessed using the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) questionnaire. Clinically relevant fatigue was defined as FACIT-F≤ 30 units. Scores were compared standardized as z-scores and analysed using linear regression, adjusted for body mass index, smoking, depression, cancer, sleep apnoea, prior cardiac surgery, respiratory and cardiovascular disease. RESULTS: Of 677 participants, 11.7% had clinically relevant fatigue. Higher breathlessness scores were associated with having worse fatigue; for D-12 total, -0.35 ([95% CI] -0.41 to -0.30) and for MDP A1, -0.24 (-0.30 to -0.18). Associations were similar across all the evaluated breathlessness dimensions even when adjusting for the potential confounders. CONCLUSION: Breathlessness assessed using D-12 and MDP was associated with worse fatigue in elderly men, similarly across different breathlessness dimensions.

Factors important for health-related quality of life in men and women: The population based SCAPIS study.

INTRODUCTION: Health-related quality of life (HRQoL) is essential for human wellbeing, influenced by a complex interplay of factors, and is reported lower in women than men. We aimed to evaluate which factors were the most important for HRQoL in a middle-aged general population. METHODS: This was a cross-sectional, multi-centre study of 29,212 men (48%) and women (52%) aged 50-64 in the general population in Sweden. Physical and mental HRQoL (0-100) was assessed using the Short Form 12 questionnaire, and association was evaluated for 356 variables including demographics, lifestyle, symptoms, physiological measurements, and health conditions. Using machine learning, each variable´s importance for HRQoL was measured by an importance score, comparable to effect size, and summarised in 54 factors, in men and women separately. RESULTS: Men and women had similar mean and standard deviation (SD) scores for physical HRQoL (53.4 [SD 8.1] vs 51.4 [9.7]) and mental HRQoL (37.1 [5.0] vs 37.3 [5.4]). The most important factors for physical HRQoL were (importance score) physical activity (40), employment (36), pain (33), sleep (33), and sense of control (26). The most important factors for mental HRQoL were sense of control (18), physical activity (12), depression (12), pain (6), and employment (5). CONCLUSIONS: The factors important for HRQoL identified by this study are likely to be amenable to interventions, and our findings can support prioritising interventions. The identified factors need to be a target even before middle-age to lay the foundation for long and happy lives.

Prevalence and severity of differing dimensions of breathlessness among elderly males in the population.

Breathlessness is common in the general population. Existing data were obtained primarily with the uni-dimensional modified Medical Research Council breathlessness scale (mMRC) that does not assess intensities of unpleasantness nor physical, emotional and affective dimensions. The aim of this research was to determine the prevalence and intensity of these dimensions of breathlessness in elderly males and any associations with their duration, change over time and mMRC grade. We conducted a population-based, cross-sectional study of 73-year-old males in a county in southern Sweden. Breathlessness was self-reported at one time point using a postal survey including the Dyspnea-12 (D-12), the Multidimensional Dyspnea Profile (MDP) and the mMRC. Presence of an increased dimension score was defined as a score ≥minimal clinically important difference for each dimension scale. Association with the mMRC, recalled change since age 65, and duration of breathlessness were analysed with linear regression. Among 907 men, an increased dimension score was present in 17% (D-12 total score), 33% (MDP A1 unpleasantness), 19% (D-12 physical), 17% (MDP immediate perception), 10% (D-12 affective) and 17% (MDP emotional response). The unpleasantness and affective dimensions were strongly associated with mMRC≥3. Higher MDP and D-12 scores were associated with worsening of breathlessness since age 65, and higher MDP A1 unpleasantness was associated with breathlessness of less than 1 year duration. Increased scores of several dimensions of breathlessness are prevalent in 73-year-old males and are positively correlated with mMRC scores, worsening of breathlessness after age 65, and duration of less than 1 year.

Agreement of the modified Medical Research Council and New York Heart Association scales for assessing the impact of self-rated breathlessness in cardiopulmonary disease.

BACKGROUND: The functional impact of breathlessness is assessed using the modified Medical Research Council (mMRC) scale for chronic respiratory disease and with the New York Heart Association Functional Classification (NYHA) scale for heart failure. We evaluated agreement between the scales and their concurrent validity with other clinically relevant patient-reported outcomes in cardiorespiratory disease. METHODS: Outpatients with stable chronic respiratory disease or heart failure were recruited. Agreement between the mMRC and NYHA scales was analysed using Cramér's V and Kendall's tau B tests. Concurrent validity was evaluated using correlations with clinically relevant measures of breathlessness, anxiety, depression, and health-related quality of life. Analyses were conducted for all participants and separately in chronic obstructive pulmonary disease (COPD) and heart failure. RESULTS: In a total of 182 participants with cardiorespiratory disease, the agreement between the mMRC and NYHA scales was moderate (Cramér's V: 0.46; Kendall's tau B: 0.57) with similar results for COPD (Cramér's V: 0.46; Kendall's tau B: 0.66) and heart failure (Cramér's V: 0.46; Kendall's tau B: 0.67). In the total population, the scales correlated in similar ways to other patient-reported outcomes. CONCLUSION: In outpatients with cardiorespiratory disease, the mMRC and NYHA scales show moderate to strong correlations and similar associations with other patient-reported outcomes. This supports that the scales are comparable when assessing the impact of breathlessness on function and patient-reported outcomes.

Underlying conditions contributing to breathlessness in the population.

PURPOSE OF REVIEW: Assessment of underlying conditions that contribute to breathlessness is fundamental for symptom management. This review aims to summarize the knowledge from the past two years on the most common underlying conditions among individuals with breathlessness in the general population and to identify research gaps. RECENT FINDINGS: Nine studies from the last two years were included in the review; two studies systematically assessed underlying conditions among breathless individuals in the general population. The modified Medical Research Council (mMRC) scale was used in eight of nine studies. Respiratory diseases were the main underlying condition (40-57%), of which asthma was the most common (approx. 25%), and chronic obstructive pulmonary disease was particularly strongly associated with breathlessness. Other conditions prevalent among breathless individuals included heart diseases, anxiety, depression, and obesity, and several conditions often co-existed. SUMMARY: Breathlessness in the general population is common and associated with several underlying conditions. Respiratory disease is the most commonly reported underlying condition. Refined methods such as machine learning could be useful to study the complex interplay between multiple underlying causes of breathlessness and impact on outcomes such as quality of life and survival.

Breathlessness dimensions association with physical and mental quality of life: the population based VASCOL study of elderly men.

BACKGROUND: Breathlessness is a multidimensional symptom prevalent in elderly affecting many aspects of life. We aimed to determine how different dimensions of breathlessness are associated with physical and mental quality of life (QoL) in elderly men. METHODS: This was a cross-sectional, population-based analysis of 672 men aged 73 years in a Swedish county. Breathlessness was assessed using Dyspnoea-12 (D-12) and Multidimensional Dyspnoea Profile (MDP), and QoL using the Short Form 12 physical and mental scores. Scores were compared as z-scores across scales and analysed using multivariable linear regression, adjusted for smoking, body mass index and the presence of respiratory and cardiovascular disease. RESULTS: Worse breathlessness was related to worse physical and mental QoL across all the D-12 and MDP dimension scores. Physical QoL was most strongly associated with perceptional breathlessness scores, D-12 total and physical scores (95% CI -0.45 to -0.30). Mental QoL was more strongly influenced by affective responses, MDP emotional response score (95% CI -0.61 to -0.48). Head-to-head comparison of the instruments confirmed that D-12 total and physical scores most influenced physical QoL, while mental QoL was mostly influenced by the emotional responses captured by the MDP. CONCLUSION: Breathlessness dimensions and QoL measures are associated differently. Physical QoL was most closely associated with sensory and perceptual breathlessness dimensions, while emotional responses were most strongly associated with mental QoL in elderly men. D-12 and MDP contribute complimentary information, where affective and emotional responses may be related to function, deconditioning and QoL.

VAScular and Chronic Obstructive Lung disease (VASCOL): a longitudinal study on morbidity, symptoms and quality of life among older men in Blekinge county, Sweden.

PURPOSE: Despite data showing breathlessness to be more prevalent in older adults, we have little detail about the severity or multidimensional characteristics of breathlessness and other self-reported measures (such as quality of life and other cardiorespiratory-related symptoms) in this group at the population level. We also know little about the relationship between multidimensional breathlessness, other symptoms, comorbidities and future clinical outcomes such as quality of life, hospitalisation and mortality. This paper reports the design and descriptive findings from the first two waves of a longitudinal prospective cohort study in older adults. PARTICIPANTS: Between 2010 and 2011, 1900 men in a region in southern Sweden aged 65 years were invited to attend for VAScular and Chronic Obstructive Lung disease (VASCOL) baseline (Wave 1) assessments which included physiological measurements, blood sampling and a self-report survey of lifestyle and previous medical conditions. In 2019, follow-up postal survey data (Wave 2) were collected with additional self-report measures for breathlessness, other symptoms and quality of life. At each wave, data are cross-linked with nationwide Swedish registry data of diseases, treatment, hospitalisation and cause of death. FINDINGS TO DATE: 1302/1900 (68%) of invited men participated in Wave 1, which include 56% of all 65-year-old men in the region. 5% reported asthma, 2% chronic obstructive pulmonary disease, 56% hypertension, 10% diabetes and 19% had airflow limitation. The VASCOL cohort had comparable characteristics to those of similarly aged men in Sweden. By 2019, 109/1302 (8.4%) had died. 907/1193 (76%) of the remainder participated in Wave 2. Internal data completeness of 95% or more was achieved for most Wave 2 measures. FUTURE PLANS: A third wave will be conducted within 4 years, and the cohort will be followed through repeated follow-ups planned every fourth year, as well as national registry data of diagnosis, treatments and cause of death.

A common model for the breathlessness experience across cardiorespiratory disease.

Chronic breathlessness occurs across many different conditions, often independently of disease severity. Yet, despite being strongly linked to adverse outcomes, the consideration of chronic breathlessness as a stand-alone therapeutic target remains limited. Here we use data-driven techniques to identify and confirm the stability of underlying features (factors) driving breathlessness across different cardiorespiratory diseases. Questionnaire data on 182 participants with main diagnoses of asthma (21.4%), COPD (24.7%), heart failure (19.2%), idiopathic pulmonary fibrosis (18.7%), other interstitial lung disease (2.7%), and "other diagnoses" (13.2%) were entered into an exploratory factor analysis (EFA). Participants were stratified based on their EFA factor scores. We then examined model stability using 6-month follow-up data and established the most compact set of measures describing the breathlessness experience. In this dataset, we have identified four stable factors that underlie the experience of breathlessness. These factors were assigned the following descriptive labels: 1) body burden, 2) affect/mood, 3) breathing burden and 4) anger/frustration. Stratifying patients by their scores across the four factors revealed two groups corresponding to high and low burden. These two groups were not related to the primary disease diagnosis and remained stable after 6 months. In this work, we identified and confirmed the stability of underlying features of breathlessness. Previous work in this domain has been largely limited to single-diagnosis patient groups without subsequent re-testing of model stability. This work provides further evidence supporting disease independent approaches to assess breathlessness.

Underlying contributing conditions to breathlessness among middle-aged individuals in the general population: a cross-sectional study.

INTRODUCTION: Breathlessness is common in the general population and associated with poorer health. Prevalence, frequencies and overlap of underlying contributing conditions among individuals reporting breathlessness in the general population is unclear. The aim was to evaluate which conditions that were prevalent, overlapping and associated with breathlessness in a middle-aged general population. METHOD: Cross-sectional analysis of individuals aged 50-65 years in the Swedish CArdioPulmonary bioImage Study pilot. Data from questionnaire, spirometry testing and fitness testing were used to identify underlying contributing conditions among participants reporting breathlessness (a modified Medical Research Scale (mMRC) score ≥1). Multivariate logistic regression was used to identify independent associations with breathlessness. RESULTS: 1097 participants were included; mean age 57.5 years, 50% women and 9.8% (n=108) reported breathlessness (mMRC ≥1). Main underlying contributing conditions were respiratory disease (57%), anxiety or depression (52%), obesity (43%) and heart disease or chest pain (35%). At least one contributing condition was found in 99.6% of all participants reporting breathlessness, while two or more conditions were present in 66%. CONCLUSION: In a middle-aged general population, the main underlying contributing conditions to breathlessness were respiratory disease, anxiety or depression, obesity and heart disease or chest pain with a high level of overlap.

Minimal Clinically Important Differences and Feasibility of Dyspnea-12 and the Multidimensional Dyspnea Profile in Cardiorespiratory Disease.

CONTEXT: Breathlessness is a cardinal symptom in cardiorespiratory disease and consists of multiple dimensions that can be measured using the instruments Dyspnea-12 (D12) and the Multidimensional Dyspnea Profile (MDP). OBJECTIVES: The objective of the study is to determine the minimal clinically important differences (MCIDs) of all D12 and MDP summary and subdomain scores as well as the instruments' feasibility in patients with cardiorespiratory disease. METHODS: Prospective multicenter cohort study of outpatients with diagnosed cardiorespiratory disease and breathlessness in daily life. D12 and MDP were assessed at baseline, after 30-90 minutes and two weeks. MCIDs were calculated using anchor-based and distributional methods for summary and subdomain scores. Feasibility was assessed as rate of missing data, help required, self-reported difficulty, and completion time. RESULTS: A total 182 outpatients (53.3% women) were included; main diagnoses were chronic obstructive pulmonary disease (COPD; 25%), asthma (21%), heart failure (19%), and idiopathic pulmonary fibrosis (19%). Anchor-based MCIDs were for D12 total score 2.83 (95% CI 1.99-3.66); D12 physical 1.81 (1.29-2.34); D12 affective 1.07 (0.64-1.49); MDP A1 unpleasantness 0.82 (0.56-1.08); MDP perception 4.63 (3.21-6.05), and MDP emotional score 2.37 (1.10-3.64). The estimates were consistent with small-to-moderate effect sizes using distributional analysis, and MCIDs were similar between COPD and non-COPD patients. The instruments were generally feasible and quick to use. CONCLUSION: D12 and MDP are responsive to change and feasible for use for assessing multidimensional breathlessness in outpatients with cardiorespiratory disease. MCIDs were determined for use as endpoints in clinical trials.

No gender-related bias in COPD diagnosis and treatment in Sweden: a randomised, controlled, case-based trial.

INTRODUCTION: COPD is a major cause of morbidity and mortality. The prevalence, morbidity and mortality of COPD among females have increased. Previous studies indicate a possible gender bias in the diagnosis and management of COPD. The present study aims to determine if there is gender bias in the management of COPD in Sweden. METHODS: This was a double-blind, randomised (1:1), controlled, parallel-group, web-based trial using the hypothetical case scenario of a former smoker (40 pack-years and quit smoking 3 years ago) who was male or female. The participants were blind to the randomisation and the purpose of the trial. The case progressively revealed more information with associated questions on how the physician would manage the patient. Study participants chose from a list of tests and treatments at each step of the case scenario. RESULTS: In total, 134 physicians were randomised to a male (n=62) or a female (n=72) case. There was no difference in initial diagnosis (61 (98%) male cases and 70 (97%) female cases diagnosed with COPD) and planned diagnostic procedures between the male and female cases. Spirometry was chosen by all the physicians as one of the requested diagnostic tests. The management of the hypothetical COPD case did not differ by sex of the responding physician. CONCLUSION: In Sweden, diagnosis and management of a hypothetical patient with COPD did not differ by the gender of the patient or physician.

Differences between experienced and recalled breathlessness: a review.

PURPOSE OF REVIEW: Experienced breathlessness and recalled breathlessness are two different entities, which may be associated with different factors and might have different impacts on function for the individual. The aim was to review the knowledge from the last 2 years concerning experienced breathlessness and recalled breathlessness and related factors. RECENT FINDINGS: Experienced breathlessness was most often induced or measured during exercise testing in a lab environment using a modified Borg scale. It was associated with both psychological factors, such as social rejection, presence of others, psychosocial stress and prenatal exposure to stress, as well as physical factors, such as hypoxia and frequent exacerbations.Recalled breathlessness was most often measured in epidemiological studies, most commonly using the modified Medical Research Council scale. It was associated with lung volumes, overweight, exercise training, frailty, smoking, personality traits, behavior and marital and occupational status. SUMMARY: No studies during the review period had directly compared experienced breathlessness and recalled breathlessness. Several factors were related to either experienced breathlessness or recalled breathlessness but no clear differences between factors were found in this review. There is a need for comparative studies using the same measurement methods and in the same settings in order to examine their relation.

Breathlessness and incidence of COPD, cardiac events and all-cause mortality: A 44-year follow-up from middle age throughout life.

BACKGROUND: Breathlessness is prevalent in the general population and may be associated with adverse health outcomes. This study aimed to evaluate the association of breathlessness with Chronic Obstructive Pulmonary Disease (COPD) events, cardiac events and all-cause mortality from middle-age throughout life. METHODS: Breathlessness was measured in 699, 55-year old men residing in Malmö, Sweden using modified Medical Research Council (mMRC). COPD events (hospitalisation, death or diagnosis) cardiac events and all-cause mortality was assessed using The Swedish Causes of Death Register and Hospital Discharge Register. Data was analyzed using Cox- and competing risks (Fine-Gray) regression analysis. RESULTS: 695 (99%) of 699 participants died and four emigrated during follow up. Eighty-seven (12%) had mMRC = 1 and 19 (3%) had mMRC≥2. Breathlessness was associated with COPD events; adjusted Sub-Hazard Ratio 2.1 (95% CI, 1.2-3.6) for mMRC = 1 and 7.5 (2.6-21.7) for mMRC ≥ 2 but not associated with cardiac events when adjusting for competing events and confounding. Breathlessness was associated increased all- cause mortality (Hazard Ratios of 1.4 (1.1-1.7) (mMRC = 1) and 3.4 (2.1-5.6) (mMRC ≥ 2)). CONCLUSION: Breathlessness is associated with increased risk of COPD events and increase in all-cause mortality from age 55 until death.

Clinical validation of the Swedish version of Dyspnoea-12 instrument in outpatients with cardiorespiratory disease.

Introduction: Breathlessness is the cardinal symptom in both cardiac and respiratory diseases, and includes multiple dimensions. The multidimensional instrument Dyspnoea-12 has been developed to assess both physical and affective components of breathlessness. This study aimed to perform a clinical validation of the Swedish version of Dyspnoea-12 in outpatients with cardiorespiratory disease. Methods: Stable outpatients with cardiorespiratory disease and self-reported breathlessness in daily life were recruited from five Swedish centres. Assessments of Dyspnoea-12 were performed at baseline, after 30-90 min and after 2 weeks. Factor structure was tested using confirmatory factor analysis and internal consistency using Cronbach's alpha. Test-retest reliability was analysed using intraclass correlation coefficients (ICCs). Concurrent validity at baseline was evaluated by examining correlations with lung function and several instruments for the assessment of symptoms and health status. Results: In total, 182 patients were included: with the mean age of 69 years and 53% women. The main causes of breathlessness were chronic obstructive pulmonary disease (COPD; 25%), asthma (21%), heart failure (19%) and idiopathic pulmonary fibrosis (19%). Factor analysis confirmed the expected underlying two-component structure with two subdomains. The Dyspnoea-12 total score, physical subdomain score and affective subdomain scores showed high internal consistency (Cronbach's alpha 0.94, 0.84 and 0.80, respectively) and acceptable reliability after 2 weeks (ICC total scores 0.81, 0.79 and 0.73). Dyspnoea-12 showed concurrent validity with the instruments modified Medical Research Council scale, COPD Assessment Test, European Quality of Life-Five Dimensions-Five levels, the Functional Assessment of Chronic Illness Therapy-Fatigue, the Hospital Anxiety and Depression Scale, and with forced expiratory volume in 1 s in percentage of predicted value. The results were consistent across different cardiorespiratory conditions. Conclusion: The Dyspnoea-12 is a valid instrument for multidimensional assessment of breathlessness in Swedish patients with cardiorespiratory diseases.