Does previous asbestos exposure increase the risk of a post coronary artery bypass graft (CABG) pleural effusion - a routine data study?

Our plain-English summary of Does previous asbestos exposure increase the risk of a post coronary artery bypass graft (CABG) pleural effusion - a routine data study?, by H. Welch, J. Harris, M. Pufulete, et al (BMC Pulmonary Medicine, 2023).

The study

• Authors: H. Welch, J. Harris, M. Pufulete, A. Dimagli, U. Benedetto, N. Maskell
• Journal: BMC Pulmonary Medicine
• Published: 2023;23(1):307
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Development of pleural effusion (PE) following CABG is common. Post-CABG PE are divided into early- (within 30 days of surgery) and delayed-onset (30 days-1 year) which are likely due to distinct pathological processes. Some experts suggest asbestos exposure may confer an independent risk for late-onset post-CABG PE, however no large studies have explored this potential association.

Research Question: To explore possible association between asbestos exposure and post-CABG PE using routine data.

Methods: All patients who underwent CABG 01/04/2013-31/03/2018 were identified from the Hospital Episode Statistics (HES) Database. This England-wide population was evaluated for evidence of asbestos exposure, pleural plaques or asbestosis and a diagnosis of PE or PE-related procedure from 30 days to 1 year post-CABG. Patients with evidence of PE three months prior to CABG were excluded, as were patients with a new mesothelioma diagnosis.

Results: 68,150 patients were identified, of whom 1,003 (1%) were asbestos exposed and 2,377 (3%) developed late-onset PE. After adjusting for demographic data, Index of Multiple Deprivation and Charlson Co-morbidity Index, asbestos exposed patients had increased odds of PE diagnosis or related procedure such as thoracentesis or drainage (OR 1.35, 95% CI 1.03-1.76, p = 0.04). In those with evidence of PE requiring procedure alone, the adjusted OR was 1.66 (95% CI 1.14-2.40, p = 0.01). Additional subgroup analysis of the 518 patients coded for pleural plaques and asbestosis alone revealed an adjusted OR of post-CABG PE requiring a procedure of 2.16 (95% CI 1.38-3.37, p = 0.002).

Interpretation: This large-scale study demonstrates prior asbestos exposure is associated with modestly increased risk of post-CABG PE development. The risk association appears higher in patients with assigned clinical codes indicative of radiological evidence of asbestos exposure (pleural plaques or asbestosis). This association may fit with a possible inflammatory co-pathogenesis, with asbestos exposure 'priming' the pleura resulting in greater propensity for PE evolution following the physiological insult of CABG surgery. Further work, including prospective studies and clinicopathological correlation are suggested to explore this further.

© 2023. BioMed Central Ltd., part of Springer Nature.

In plain English

This retrospective population-based cohort study used England's Hospital Episode Statistics database. It asked whether patients whose hospital records suggested past asbestos exposure were more likely to develop a pleural effusion (fluid around the lung) between 30 days and one year after coronary artery bypass graft (CABG) surgery. Exposure was identified from diagnosis codes recorded in the three years before surgery. These included asbestos pneumoconiosis, pleural plaques and occupational exposure to dust. Of 68,150 eligible patients, 1,003 were coded as asbestos exposed and 2,377 had a later effusion diagnosis or procedure. After adjusting for age, sex, deprivation, other illnesses and surgery type, exposed patients had higher odds of any effusion record (odds ratio 1.35, 95% CI 1.03–1.76) and of an effusion needing a procedure (1.66, 1.14–2.40). Among 518 patients coded only for asbestos pneumoconiosis or pleural plaque with asbestos, the adjusted odds ratio for an effusion needing a procedure was 2.16 (1.38–3.37). The authors concluded there was a modest association. They noted that their design shows association, not causation, that coding likely under-records asbestos exposure, and that smoking was not assessed.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective population-based cohort study using routine hospital data (Hospital Episode Statistics, England)
• Who was studied: Adult patients in England's NHS hospitals who underwent CABG, with or without concurrent heart valve repair or replacement. Surgery was performed between April 2013 and March 2018 according to the abstract and tables. 68,150 eligible patients remained after excluding those with a pleural effusion diagnosis or procedure in the 3 months before CABG, one record with missing deprivation data, and two mesothelioma cases.
• Exposure: Asbestos exposure as recorded in hospital diagnosis codes in the three years before CABG. The codes were J61 (pneumoconiosis due to asbestos and other mineral fibres), J92.0 (pleural plaque with presence of asbestos), and in some analyses Z57.2 (occupational exposure to dust) and J92.9 (pleural plaque without asbestos). No fiber types, jobs or doses were recorded. 1,003 patients were classed as exposed; 518 when only J61 and J92.0 were used.
• Main results:
  • Of 68,150 patients, 1,003 were classed as asbestos exposed. 2,377 patients had a pleural effusion diagnosis or procedure from 30 days to one year after CABG, including 962 with a procedure alone.
  • Outcome 1 (effusion diagnosis or procedure), asbestos-exposed versus unexposed: crude odds ratio 1.78 (95% CI 1.37–2.32, p less than 0.001); adjusted odds ratio 1.35 (95% CI 1.03–1.76, p = 0.04).
  • Outcome 2 (effusion needing a procedure), asbestos-exposed versus unexposed: crude odds ratio 2.19 (1.51–3.17, p less than 0.001); adjusted odds ratio 1.66 (1.14–2.40, p = 0.01).
  • Subgroup of 518 patients identified only by codes J61 and J92.0: adjusted odds ratio for an effusion needing a procedure 2.16 (1.38–3.37, p = 0.002). The adjusted odds ratio for any effusion diagnosis or procedure was 1.63 (1.17–2.28, p = 0.01).
  • A sensitivity analysis excluded patients with no hospital admissions in the three years before CABG. Results were similar. Outcome 1 had an adjusted odds ratio of 1.35 (1.03–1.77, p = 0.03). Outcome 2 had a crude odds ratio of 2.12 (1.47–3.08) and an adjusted odds ratio of 1.65 (1.14–2.40, p = 0.01).
  • Asbestos-exposed patients were on average five years older and more often male (97% vs. 81%) than unexposed patients.
  • The monthly timing of effusions was similar in exposed and unexposed patients, with most occurring in the first 6 months after surgery.
• The authors' conclusion: The authors concluded there is a modest association between asbestos exposure and post-CABG pleural effusion. They found the association stronger in patients coded for pleural plaques or asbestosis. They raised the possibility of a shared inflammatory process and called for prospective studies with detailed exposure, chest X-ray and pleural fluid data.
• Limitations the authors state:
  • As a retrospective analysis, the study can only describe associations, not causation.
  • Relatively low patient numbers and a modest effect size.
  • The hospital dataset is likely to under-report asbestos exposure and may under-report effusions requiring intervention.
  • No clinical information such as pleural fluid tests or imaging findings was available.
  • Effusion size and cause were not recorded, so not all effusions can be confirmed as caused by the surgery.
  • Smoking status was not evaluated.
  • The sensitivity analysis approach may overestimate the true rate of asbestos exposure.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Pleural Effusion, Pleural Plaques, Mesothelioma, Thoracentesis, Pleura.

Related studies

• Exposure to insulating materials and risk of coronary artery diseases: a cross-sectional study — S. Moitra, A.F. Tabrizi, et al. (2023)
• The distinction of adenocarcinoma from malignant mesothelioma in cell blocks of effusions: the role of routine mucin histochemistry and immunohistochemical assessment of carcinoembryonic antigen, keratin proteins, epithelial membrane antigen, and milk fat globule-derived antigen — E.S. Cibas, J.M. Corson, et al. (1987)
• A somatic TSHR mutation in a patient with lung adenocarcinoma with bronchioloalveolar carcinoma, coronary artery disease and severe chronic obstructive pulmonary disease — J.W. Kim, S. Lee, et al. (2012)
• A retrospective study on radiological findings of diffuse pleural thickening with benign asbestos pleural effusion in Japanese cases — T. Kishimoto, K. Kato, et al. (2022)
• Gelatinous Pleural Effusion: A Diagnostic Challenge for Pleural Mesothelioma in an 80-Year-Old Man — A.M. Ibnian, O.U. Khan, et al. (2023)
• Impact of induction therapy on postoperative outcome after extrapleural pneumonectomy for malignant pleural mesothelioma: does induction-accelerated hemithoracic radiation increase the surgical risk? — P. Mordant, K. McRae, et al. (2016)

Browse more research in BMC Pulmonary Medicine, or return to medical research.