Pleural thickening: its significance and relationship to asbestos dust exposure

Our plain-English summary of Pleural thickening: its significance and relationship to asbestos dust exposure, by T. Rodman, M.S. Rodman (The American Review of Respiratory Disease, 1983).

The study

• Authors: T. Rodman, M.S. Rodman
• Journal: The American Review of Respiratory Disease
• Published: 1983;127(5):656-7
• Type of article: Letter
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M nos. 001702, 002739).

In plain English

This letter to the editor reanalyzed data from an earlier report by Albelda and associates on patients at the Hospital of the University of Pennsylvania; it was not a new study. The authors built 2-by-2 tables, scaled to 1,000 patients, treating bilateral pleural thickening on chest X-ray as a test for a history of asbestos exposure. By their calculations, its sensitivity and specificity were 0.117 and 0.967 for "possible" exposure, and 0.143 and 0.955 for "probable" exposure. They used a 36% prevalence of possible exposure taken from the earlier report. With it, they calculated that a positive X-ray raised the probability of a known exposure history to 67%, or to 29% had prevalence been 10%. They said the 67% figure applied only to a patient about whom not even age or sex was known. The authors concluded that studies should report sensitivity and specificity and measure prevalence in well-defined groups. In a published reply, Albelda and Epstein called these calculations invalid. They said the letter wrongly assumed that screened patients without pleural thickening had no exposure history, and that the actual prevalence of exposure was unknown.

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: Letter to the editor (correspondence) reanalyzing data published in another study (Albelda et al. 1982); no new patients were studied
• Who was studied: Patients at the Hospital of the University of Pennsylvania reported in the earlier Albelda study; for illustration the letter writers extrapolated the data to 1,000 patients
• Exposure: A history of "possible" (Groups 1, 2 and 3) or "probable" (Groups 1 and 2) occupational exposure to asbestos, compared with bilateral pleural thickening seen on chest X-ray; no fiber types or doses given
• Main results:
  • For a history of "possible" asbestos exposure, the letter writers calculated that bilateral pleural thickening on X-ray had a sensitivity of 0.117 and specificity of 0.967 (predictive value positive 42/63 = 0.667), in the table extrapolated to 1,000 patients
  • For a history of "probable" asbestos exposure, the letter writers calculated a sensitivity of 0.143 and a specificity of 0.955
  • Using the 36% prevalence of possible exposure they took from the earlier report, the letter writers calculated a predictive value of 0.67 (67%) for a positive X-ray. Had the prevalence been 10%, they calculated it would have been 0.29 (29%), making a positive finding twice as likely to be a false positive as a true positive
  • The letter writers argued that pooling data across a heterogeneous group (men and women, older and younger) produced a predictive value not applicable to any individual patient
  • In their published reply, Albelda and Epstein stated that the letter's calculations rested on the incorrect assumption that screened patients without pleural thickening had no exposure history; the true prevalence of exposure was unknown
• The authors' conclusion: The letter writers concluded that authors should report sensitivity and specificity, which they described as independent of the population studied, and should study prevalence in well-defined groups, combining the two to calculate predictive value
• Limitations the authors state:
  • The letter writers stated that their probability figures applied only to a Hospital of the University of Pennsylvania patient about whom nothing, not even age or sex, is known, and so had no relevance to evaluating an individual case

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Pleural Thickening.

Related studies

• Pleural thickening: its significance and relationship to asbestos dust exposure — S.M. Albelda, D.M. Epstein, et al. (1982)
• Diffusing capacity and forced vital capacity in 5,003 asbestos-exposed workers: relationships to interstitial fibrosis (ILO profusion score) and pleural thickening — A. Miller, R. Warshaw, et al. (2013)
• Thickening of pulmonary interlobar fissures: exposure-response relationship in crocidolite and amosite miners — A. Solomon, L.M. Irwig, et al. (1979)
• Diffuse thickening superimposed on circumscribed pleural thickening related to asbestos exposure — A. Miller, J.A. Miller (1993)
• Low levels of exposure to libby amphibole asbestos and localized pleural thickening — K.Y. Christensen, T.F. Bateson, et al. (2013)
• Risk and significance of chest radiograph and pulmonary function abnormalities in an elderly cohort of former nuclear weapons workers — M.A. Mikulski, P.G. Hartley, et al. (2011)

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