The challenges of recruiting never-smokers with chronic obstructive pulmonary disease from the large population-based Swedish CArdiopulmonary bioImage study (SCAPIS) cohort

Pernilla Sönnerfors; Petra Kristina Jacobson; Anders Andersson; Annelie Behndig; Leif Bjermer; Anders Blomberg; Heléne Blomqvist; Jonas Erjefält; Maria Friberg; Kristina Lamberg Lundström; Anna Lundborg; Andrei Malinovschi; Hans Lennart Persson; Ellen Tufvesson; Åsa Wheelock; Christer Janson; Carl Magnus Sköld

doi:10.1080/20018525.2024.2372903

The challenges of recruiting never-smokers with chronic obstructive pulmonary disease from the large population-based Swedish CArdiopulmonary bioImage study (SCAPIS) cohort

Eur Clin Respir J. 2024 Jul 15;11(1):2372903. doi: 10.1080/20018525.2024.2372903. eCollection 2024.

Authors

Pernilla Sönnerfors^{1

2}, Petra Kristina Jacobson³, Anders Andersson^{4

5}, Annelie Behndig⁶, Leif Bjermer⁷, Anders Blomberg⁶, Heléne Blomqvist^{1

8}, Jonas Erjefält⁹, Maria Friberg⁶, Kristina Lamberg Lundström¹⁰, Anna Lundborg⁴, Andrei Malinovschi¹¹, Hans Lennart Persson³, Ellen Tufvesson⁷, Åsa Wheelock^{1

8}, Christer Janson¹⁰, Carl Magnus Sköld^{1

8}

Affiliations

¹ Respiratory Medicine Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.
² Medical Unit Occupational Therapy and Physiotherapy, Women´s Health and Allied Health Professionals Theme, Karolinska University Hospital, Stockholm, Sweden.
³ Department of Respiratory Medicine in Linköping, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.
⁴ COPD Center, Department of Respiratory Medicine and Allergology, Sahlgrenska University Hospital, Gothenburg, Sweden.
⁵ COPD Center Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
⁶ Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden.
⁷ Department of Clinical Sciences, Respiratory medicine, Allergology and Palliative Medicine, Lund University, Lund, Sweden.
⁸ Department of Respiratory Medicine and Allergy, Karolinska University Hospital, Stockholm, Sweden.
⁹ Unit of Airway inflammation, Department of Experimental Medicine Sciences, Lund University, Lund, Sweden.
¹⁰ Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden.
¹¹ Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden.

Abstract

Background: A substantial proportion of individuals with COPD have never smoked, and it is implied to be more common than previously anticipated but poorly studied.

Aim: To describe the process of recruitment of never-smokers with COPD from a population-based cohort (n = 30 154).

Methods: We recruited never-smokers with COPD, aged 50-75 years, from six University Hospitals, based on: 1) post broncho-dilator forced expiratory volume in 1 second/forced vital capacity (FEV₁/FVC) < 0.70 and 2) FEV₁ 50-100% of predicted value and 3) being never-smokers (self-reported). In total 862 SCAPIS participants were identified, of which 652 were reachable and agreed to a first screening by telephone. Altogether 128 (20%) were excluded due to previous smoking or declined participation. We also applied a lower limit of normal (LLN) of FEV₁/FVC (z-score<-1.64) according to the Global Lung Initiative to ensure a stricter definition of airflow obstruction.

Results: Data on respiratory symptoms, health status, and medical history were collected from 492 individuals, since 32 were excluded at a second data review (declined or previous smoking), prior to the first visit. Due to not matching the required lung function criteria at a second spirometry, an additional 334 (68%) were excluded. These exclusions were by reason of: FEV₁/FVC ≥0.7 (49%), FEV₁ > 100% of predicted (26%) or z-score ≥ -1,64 (24%). Finally, 154 never-smokers with COPD were included: 56 (36%) women, (mean) age 60 years, FEV₁ 84% of predicted, FEV₁/FVC: 0.6, z-score: -2.2, Oxygen saturation: 97% and BMI: 26.8 kg/m².

Conclusions: The challenges of a recruitment process of never-smokers with COPD were shown, including the importance of correct spirometry testing and strict inclusion criteria. Our findings highlight the importance of repeated spirometry assessments for improved accuracy in diagnosing COPD.

Keywords: COPD; COPD diagnosis; SCAPIS; never-smokers; population-based; recruitment; spirometry.

Grants and funding

The study was supported by The Swedish Heart and Lung Foundation [grant number 20160090] and through the Regional Agreement on Medical Training and Clinical Research (ALF) between Stockholm County Council and Karolinska Institutet [grant number FoUI-951900, FoUI-971259]. The founders had no role in study design, data collection, or analysis.