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Background: Daily sublingual immunotherapy (SLIT) for 3 years reduces symptoms of allergic disease and induces tolerance. Real-life data from children with asthma receiving SLIT are scarce.

Objective: We used population-based data to describe characteristics, SLIT duration, and changes in morbidity in children with asthma prescribed SLIT.

Methods: The study included children (5-17 years) with asthma who were prescribed SLIT, and who were registered in the Swedish National Airway Register (SNAR) before SLIT initiation (N = 1,514), of whom 782 had post-SLIT recordings in the SNAR. Age, sex, Asthma Control Test score (≤19 denotes uncontrolled asthma), spirometry data, number of SLIT tablets dispensed, and socioeconomic background were extracted from the SNAR and other national registers. SLIT duration was classified as <4, ≥4, >12, or >24 months.

Results: SLIT was more common in boys (69%) and adolescents (71%). Most children had parents with higher education (70%), and 25% had uncontrolled asthma. SLIT duration of ≥4, >12, and >24 months was identified in 86%, 50%, and 30%, respectively. Parents with higher education were associated with SLIT duration of ≥4 months (odds ratio = 3.69; 95% confidence interval 2.75-4.96). SLIT duration of >12 months was associated with lower risk of post-SLIT uncontrolled asthma (adjusted odds ratio = 0.49; 95% confidence interval, 0.25-0.99). No associations were found between SLIT duration of ≥4, >12, or >24 months and changes in spirometry.

Conclusion: Longer SLIT duration was associated with higher education in parents and lower risk of uncontrolled asthma. Measures to improve persistence in SLIT in children with asthma may have important clinical implications.

Background: Severity of airflow obstruction in patients with asthma can be influenced by features beyond lung function impairment. The aim of this study was to assess the severity of obstruction according to the 2022 European Respiratory Society/American Thoracic Society standards, and its associations with perinatal factors, as well as potential interactions with background and clinical factors.

Methods: The study population consisted of 44,394 patients with asthma, aged 7–49 years, with at least one measurement of forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) recorded in the Swedish National Airway Register in 2014–2022, who were included in the Medical Birth Register between 1973 and 2015 with data on gestational age (GA) and birthweight. Airflow obstruction was defined as pre-bronchodilator FEV1/FVC < lower limit of normal and categorized as mild, moderate, or severe based on FEV1z-score. Normal FEV1served as the reference category.

Results: Among 7873 (17.7 %) patients with airflow obstruction, the prevalence of severe obstruction pre-bronchodilator was 6.1 %. Patients born extremely-to-very preterm or small for GA (SGA) had increased relative risk ratios for severe obstruction pre-bronchodilator (RRRadj2.34, 95 % CI 1.24–4.41, and 2.03, 1.38–2.98) compared with those born at term and appropriate for GA, respectively, with obstruction and normal FEV1. For GA and birthweight, there were non-significant interactions with background or clinical factors.

Conclusions: Severe obstruction was prevalent in children and adults with asthma. Patients born extremely-to-very preterm or SGA exhibited a significant association with severe obstruction pre-bronchodilator, regardless of background and clinical factors.

Rationale: Few studies have identified risk sets for perinatal factors and airflow obstruction into middle adulthood.

Objectives: To investigate associations between gestational age (GA), GA-adjusted birthweight, and mode of delivery and persistent airflow obstruction among patients 7-49 years old with obstructive lung diseases.

Methods: The study population encompassed 44,778 individuals with asthma or chronic obstructive pulmonary disease (COPD) and one or more registration of post-bronchodilator values of forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) recorded in the Swedish National Airway Register in 2014-2022 and with both GA and birthweight data in the Medical Birth Register between 1973-2015. Persistent airflow obstruction was defined as a FEV1/FVC z-score below the lower limit of normal. Analyses were done separately for children, young adults, and middle-aged adults.

Results: Subjects who were extremely, very, moderate, and late preterm-born all had increased odds ratios (ORs) of persistent airflow obstruction up to age 49 years compared with those term-born. Middle-aged adults born small for GA had increased OR of persistent airflow obstruction compared with those appropriate for GA (OR, 1.49; 95% confidence interval, 1.23-1.81). In the risk sets, GA was the most significant covariate for persistent airflow obstruction. GA-adjusted birthweight was an additional covariate for those born late preterm, term, or postterm. Mode of delivery did not contribute.

Conclusions: GA was an independent covariate of persistent airflow obstruction and, in the risk sets, proved to be the most important covariate in patients of all ages with either asthma or COPD. GA-adjusted birthweight further improved the prediction.

Background: Airway obstruction is a characteristic spirometric finding in asthma but the clinical significance of other abnormal spirometric patterns is less well described. We aimed to explore pre-and post-bronchodilator (BD) prevalences and clinical characteristics of preserved ratio impaired spirometry (PRISm), dysanapsis and airflow obstruction with low forced expiratory volume in 1 s (FEV₁) in children diagnosed with asthma.

Methods: We extracted specialist care data (clinical and spirometry) from the Swedish National Airway Register (n=3301, age 5–17 years). Normal spirometry was defined as FEV₁⩾ lower limit of normal (LLN) and FEV₁/forced vital capacity (FVC)⩾LLN. PRISm was defined as forced FEV₁< LLN and FEV₁/FVC⩾LLN, dysanapsis as FEV₁/FVC<LLN and FEV₁⩾LLN, and airflow obstruction with reduced FEV₁ as FEV₁/FVC<LLN and FEV₁<LLN. The BD response (BDR) was calculated as ((post-BD(L)−pre-BD(L))/predicted (L))×100. Values >10% were considered positive (BDRpos). Groups were compared using parametric tests and associations were explored using logistic regression analysis.

Results: Pre-/post-BD PRISm, dysanapsis and obstruction with low FEV₁ were identified in 9%/7%, 10%/4% and 8%/2%, respectively. Compared with normal spirometry, all three groups were associated with older age and BDRpos in pre-BD analyses. Furthermore, dysanapsis was associated with overweight/ obesity and obstruction with low FEV1 with uncontrolled asthma and more treatment.

Interpretation: In this paediatric asthma cohort, PRISm and dysanapsis were associated with BDRpos and they were at least as common as airflow obstruction with reduced FEV₁. These spirometric phenotypes should be addressed in the management of childhood asthma and testing of BDR should be considered also in children with PRISm and dysanapsis.

Background: COPD is largely underdiagnosed. Active identification of cases is crucial to establish preventive measures before manifestation of clinical disease. The significance of different spirometric patterns preceding COPD, especially preserved ratio impaired spirometry (PRISm), has been highlighted but remains unclear.

Research Question: Which clinical characteristics, smoking habits, and spirometric patterns, with primary focus on PRISm findings, precede the development of airway obstruction (AO)?

Study Design and Methods: The OLIN COPD Study was established from 2002 through 2004. After re-examination of population-based cohorts, individuals with AO (n = 993; FEV1 to VC ratio < 0.70) were identified together with control participants without AO (n = 993; FEV1 to VC ratio ≥ 0.70). Most of these people had participated in examinations during the 1980s or 1990s, and in total, 902 cases and 819 control participants had previous clinical data. Logistic regression was performed with case status as outcome and spirometric patterns, age, sex, smoking habits, and BMI at first examination as covariates.

Results: The mean (SD) person-years between first examination and inclusion in the OLIN COPD Study was 10.5 (4.0) years. At first examination, the prevalence of PRISm was higher in cases (18.6%) vs control participants (13.4%). Current smoking was more common in cases (45.1% vs 18.2%), whereas former smoking was similar (31.8% vs 34.9%). Cases reported more respiratory symptoms (78.0% vs 44.3%) than control participants. At first examination, PRISm, current smoking, and former smoking were strongly associated with becoming a case when adjusted for confounders, with adjusted OR (aOR) of 3.5, 4.1, and 1.5, respectively. When stratifying for smoking habits, aORs for PRISm in those with current smoking, former smoking, and nonsmoking status were 2.9, 3.8 and 3.7, respectively.

Interpretation: In this study, PRISm was associated with transition into AO corresponding to COPD within 1 decade, independent of smoking habits and with similar strength of association among those who have never smoked, who formerly smoked, and who currently smoke.

Background: Physician diagnosed COPD with normal spirometry (dnsCOPD) (sometimes labeled pre-COPD) and Preserved Ratio Impaired Spirometry (PRISm) has been studied in population-based cohorts, but not in physician diagnosed COPD (dCOPD) patients from routine clinical practice. The Swedish National Airway Register (SNAR) is a large nationwide register including data from dCOPD patients from over 1000 clinics across all regions of Sweden and is representative of the COPD care in Sweden. We aimed to identify and characterize patients with dnsCOPD, PRISm and spirometrically confirmed COPD (sCOPD) from dCOPD patients in SNAR, stratify them further according to symptoms and exacerbations risk using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) A/B/E classification, and assess differences in risk for exacerbations, cause-specific hospitalisations and mortality.

Methods: We enrolled patients aged ≥30 years with dCOPD in the SNAR from 1 January 2014 to 30 June 2022 with complete spirometry i.e., postbronchodilator values for both forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) (index date). Patients with concomitant asthma were excluded. Patients were stratified into dnsCOPD (FEV1/FVC ≥0.7 and FEV1 ≥80% predicted), PRISm (FEV1/FVC ≥0.7 and FEV1 <80% predicted) and sCOPD (FEV1/FVC <0.7). Further substratification was based on GOLD A/B/E (A: COPD assessment test (CAT) score <10 points and <2 moderate, 0 severe exacerbations within 1 year before the index date, B: CAT-score ≥10 points and <2 moderate, 0 severe exacerbations, E: ≥2 moderate or ≥1 severe exacerbation(s)). Patients were followed until 31 November 2022. Competing risk regression was used to calculate subdistribution hazard ratios (SHR)s with 95% confidence intervals (CIs) for exacerbation, hospitalisation and mortality.

Findings: Of 45,653 patients with dCOPD, 5.4% had dnsCOPD, 11.4% had PRISm and 83.3% had sCOPD. Smoking history was similar between groups (ever smoker: dnsCOPD: 79% PRISm: 82% sCOPD: 86%) and inhalation therapy was common in all groups (any inhaler: 75%, 80% and 80%, triple combination: 22%, 28% and 35%). Patients with PRISm had a high prevalence of obesity (dnsCOPD: 30%, PRISm: 43%, COPD: 22%), cardiovascular disease (dnsCOPD: 39%, PRISm: 48%, COPD: 41%) and diabetes (dnsCOPD: 10%, PRISm: 17%, COPD: 9%). Baseline GOLD group B or E were highly prevalent in dnsCOPD (B: 54%, E: 11%), PRISm (B: 59%, E: 14%), as well as in COPD (B: 54%, E: 17%). DnsCOPD and PRISm patients had lower risk of exacerbations (SHR 0.69, 95%CI 0.64–0.74 and 0.85, 95%CI 0.81–0.89), respiratory hospitalisation (0.40, 95%CI 0.34–0.46 and 0.68, 95%CI 0.62–0.73), and respiratory mortality (0.22, 95%CI 0.13–0.37 and 0.60, 95%CI 0.48–0.75) compared to sCOPD. Cardiovascular mortality was lower in dnsCOPD (0.41, 95%CI 0.19–0.86), but similar in PRISm (0.73, 95%CI 0.49–1.08) compared to sCOPD. The A/B/E classification was predictive for all outcomes in dnsCOPD and PRISm. DnsCOPD and PRISm group E patients had higher risks for all outcomes than sCOPD group A or B.

Interpretation: DnsCOPD and PRISm are prevalent in a real-life cohort of patients with a physician diagnosis of COPD. These patients are symptomatic, might suffer from exacerbations and are commonly treated with inhaled therapy, equally to sCOPD. Patients with PRISm had a high prevalence of obesity, diabetes and cardiovascular disease. DnsCOPD and PRISm had generally lower overall risks of exacerbation or respiratory events, although PRISm patients showed similar cardiovascular risk to sCOPD. The A/B/E classification predicted future events, even in dnsCOPD and PRISm patients.

Funding: This study is performed with support from The Swedish Heart-Lung Foundation ( 20200150) and the Swedish government and country council ALF grant ( ALFGBG-824371).

Purpose: There is an association between low socioeconomic status and chronic obstructive pulmonary disease (COPD), but it is not known whether this impacts on drug prescription for COPD treatment. The aim of the study was to explore whether drug prescription differs between COPD patients with low and high socioeconomic status.

Patients and methods: Data from patients with incident and prevalent COPD (age>40 years), without an asthma diagnosis, visiting primary care in 2021–2022 were extracted from The Swedish National Airway Register (SNAR) and linked to Swedish National Health registries. Socioeconomic status was assessed by educational level and annual income. Statistical analyses were conducted by means of chi square tests, together with post-hoc test.

Results: In total, 38692 patients (mean age 73.6 years, 55.5% women, FEV1 59.5% of predicted value) were included. Subdivision into GOLD group A, B and E was possible in 29128 patients. Triple therapy (long-acting antimuscarinic antagonists, LAMA + long-acting beta-2-agonist, LABA + inhaled steroids, ICS), was more often prescribed in the low education group (observed/expected ratio 1.09; p<0.0001) and low income group (ratio 1.05; p<0.05) and less often in the high education group (ratio 0.87; p<0.0001) and high income group (ratio 0.88; p<0.0001). Monotherapy (LAMA) was more often prescribed in patients with high income (ratio 1.09; p<0.0001) and less often in patients with low income (ratio 0.93; p=0.0004). Differences between high and low education and income were driven by differences in group B.

Conclusion: Prescription patterns were associated with small, statistically significant differences, between COPD patients with low and high socioeconomic status. Triple therapy was more often prescribed to patients with low socioeconomic status, and monotherapy with LAMA more often to patients with high. The reason for this is not clear but may be caused by differences in exacerbation rate between the socioeconomic groups.

Objective: To study whether worsening asthma at school was related to generic health-related quality of life (HRQoL) and asthma-related impact and worry among 15-year-olds with current asthma in Sweden. In addition, we studied the association between worsening asthma at school at age 15 and the change in the degree to which asthma interfered with daily activities between ages 15 and 19 years.

Methods: Within the Obstructive Lung Disease in Northern Sweden (OLIN) studies, a cohort of schoolchildren has been followed from age 8 years until 19 years of age. In the current study, the sample included 266 adolescents with physician-diagnosed asthma, and either wheeze or use of asthma medication during the last 12 months at age 15 years.

Results: At age 15, HRQoL scores were lower among those who reported worsening asthma at school (standardised beta (β) = −0.18, p = 0.003), they had more asthma-related worries (β = −0.33, p < 0.001) and asthma impacted their life during activities more (β = −0.46, p < 0.001) than those whose asthma did not worsen. Furthermore, the more adolescents reported that asthma worsened at school at age 15, the more it was associated with the increase in the degree to which asthma interfered with their activities between 15 and 19 years (β = 0.14, p = 0.038).

Conclusions: Worsening asthma at school was associated with lower generic health-related quality of life, higher asthma-related worry and impact on daily activities among teenagers with asthma.