Diagnostic accuracy of chest X-ray screening for silicosis: a systematic review, meta-analysis and modelling study

TL;DR

This study evaluates how well chest X-rays detect silicosis compared to other methods and finds that X-rays miss a significant number of cases, especially in less severe disease.

Contribution

The study models how CXR sensitivity changes with disease severity and prevalence, offering insights into diagnostic limitations.

Findings

CXR has moderate sensitivity (0.76) and high specificity (0.89) compared to HRCT for silicosis diagnosis.

CXR sensitivity increases with higher severity cut-offs of the reference test.

Missed silicosis cases increase with lower prevalence and less severe disease in screening scenarios.

Abstract

Chest X-ray (CXR) is widely used for silicosis diagnosis, despite concerns regarding sensitivity. We investigated the diagnostic accuracy of CXR for silicosis screening compared with CT, high-resolution CT (HRCT) and autopsy, and modelled the relationship between CXR sensitivity and disease severity.

Medline, Embase, Scopus and Web of Science databases were searched on 2 July 2024 (PROSPERO registration: CRD42024513830). Meta-analyses were performed by reference standard and at increasing reference test severity cut-offs. The Quality Assessment of Diagnostic Accuracy Studies-2 tool assessed risk of bias. In scenarios of fixed and relative sensitivity, according to disease severity, we estimated missed silicosis cases and the number needed to screen (NNS) in hypothetical populations of low (5%), medium (15%) and high (30%) silicosis prevalence.

Twenty studies included 2156 participants and 1105 silicosis cases. CXR had moderate sensitivity (0.76; 95% CI 0.63 to 0.86, I2=84%) and high specificity (0.89, 95% CI 0.77 to 0.95, I2=57%) compared with HRCT in 12 studies, and low sensitivity (0.50, 95% CI 0.45 to 0.55, I2=0%) and high specificity (0.91, 95% CI 0.87 to 0.93, I2=20%) compared with autopsy in two studies. CXR sensitivity increased with higher reference test severity cut-offs. Clinically relevant numbers of cases were missed in fixed and relative sensitivity scenarios; increased prevalence and less severe disease resulted in more missed cases and a lower NNS.

Silicosis severity and reference test type both plausibly influence CXR sensitivity. Assuming either fixed or relative sensitivity results in missed silicosis cases. Judicious HRCT screening is likely to improve case detection.

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