Sex Appears to Influence IPF Diagnosis, Test of Doctors Worldwide Finds

Joana Carvalho, PhD avatar

by Joana Carvalho, PhD |

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A person’s sex appears to affect whether or not they are diagnosed with idiopathic pulmonary fibrosis (IPF), according to a study that tested respiratory physicians worldwide.

Women are less likely to be given an IPF diagnosis, and men may be overdiagnosed, its results suggests.

Investigators also noted that the influence of a patient’s sex on an IPF diagnosis is particularly evident in the absence of clear radiological findings indicative of the disease.

“In our study only about 10% of cases with female patients were given a first-choice diagnosis of IPF, which is substantially lower than expected, and supports the hypothesis that an IPF diagnosis is missed in female patients,” the researchers wrote. “In registry and real-life data, males comprise between 67% and 77% of all patients diagnosed with IPF,” and “between 78% and 82%” of clinical trial populations.

The study, “Patient gender bias on the diagnosis of idiopathic pulmonary fibrosis,” was published in the journal Thorax.

Biological sex is important to consider when it comes to the diagnosis and prognosis of interstitial lung diseases (ILDs). In the specific case of IPF, being male is considered to heighten a risk of death. The overall prevalence of IPF is also much higher among men than women.

“However, it is not known if biases pertaining to biological sex or gender exist when it comes to establishing a diagnosis of ILD on an individual patient basis, assuming equal age, exposures and comorbidities, or if patient gender impacts a physician’s diagnostic confidence for the diagnosis of ILD and IPF specifically,” the researchers wrote.

Researchers in Canada, in collaboration with colleagues in the U.K., conducted a study in which they asked a group of 404 respiratory physicians from 76 countries to diagnose 60 patients suspected of having ILD based on their medical records.

Physicians, most with specialized training in ILDs, were also asked to rate the confidence of their decision. Each doctor could provide up to five diagnoses per patient. All procedures were performed via a web-based application.

Patient data was collected at the ILD Unit of the Royal Brompton and Harefield NHS Foundation Trust, in London, between January and October 2010.

Statistical analyses were then used to calculate the odds of a person being diagnosed with IPF based on their sex.

Of the 60 patients whose records were analyzed, 34 (57%) were male. Compared to males, female patients tended to be younger and were less likely to have classical, definite radiological findings indicative of IPF on their computed tomography (CT) scans.

Physicians selected IPF as their first-option diagnosis more frequently in men than women (37.8% versus 10.6% in women). The degree of confidence in their decision was also much higher when they diagnosed men as opposed to women.

“The odds of a male patient receiving a first-choice diagnosis of IPF were three times that of a female patient, after adjusting for age, smoking history, environmental or occupational exposures, and presence of autoantibodies or serum precipitins,” the investigators wrote.

This was even more striking in cases where patient scans did not show an obvious pattern of usual interstitial pneumonia (UIP), one of the telltale clinical signs of IPF.

In general, the risk of mortality was higher among patients who had been diagnosed with IPF, compared to those diagnosed with another ILD. However, women who were diagnosed with IPF had a higher risk of death compared to men (2.21 versus 1.26).

This difference in mortality between female and male patients was even stronger when the IPF diagnosis had been performed by a subgroup of physicians who were considered experts in the field (4.16 versus 1.32).

According to the team, the lower risk of mortality seen in men diagnosed with IPF may indicate that male patients are being misdiagnosed with the disease more frequently than women.

“Our results suggest that physicians place great emphasis on patient gender in making a clinical diagnosis of IPF, especially in cases where the CT scan is not definitive for a UIP pattern, and that overall, female patients are likely to be underdiagnosed with IPF, whereas male patients are overdiagnosed with IPF,” the researchers wrote.

“Overall, the ILD research and clinical community need to carefully ensure that female patients with IPF are diagnosed and managed appropriately. Moreover, IPF treatment trials should ensure that enrolled cohorts accurately reflect the proportions of male and female patients with IPF in unselected populations,” they added.

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