Patients with idiopathic pulmonary fibrosis (IPF) who experience more than a year of diagnostic delay after symptom onset have shorter progression-free survival (PFS), lower quality of life, and higher hospitalization rates, according to a study recently published in BMJ Open Respiratory Research.

Antifibrotic treatment is proven to slow disease progression in IPF. However, it cannot reverse already established fibrosis or its effects on pulmonary function. Therefore, the authors hypothesized that a significant delay in diagnosis after the onset of symptoms could negatively affect patient outcomes.

Unfortunately, studies regarding the consequences of delayed IPF diagnosis show conflicting results, and most of them were made before antifibrotic treatment was commonly used.

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The authors aimed to demonstrate the importance of early IPF diagnosis in a population of more than 260 patients recruited from 2 centers specializing in interstitial lung disease, Herlev and Gentofte University Hospital in Copenhagen, Denmark and Aarhus University Hospital in Aarhus, Denmark.

All patients included in the study had a multidisciplinary team diagnosis. The only exclusion criterion was the inability to consent. Diagnostic delay was defined as the time between symptom onset and diagnosis.

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Forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLCO) were used as markers of disease severity and progression. Although there is currently no standardized staging method for IPF, researchers defined PFS as the time between symptom onset and a 10% decline in the predicted FVC or a 15% decline in the predicted DLCO. Quality of life was assessed using 2 standardized questionaries. Patients with an FVC higher than 80% were considered to have mild disease.

After performing a multivariate analysis, the authors noted a median diagnostic delay of 2 years. Interestingly, at the time of diagnosis, symptoms and baseline characteristics were similar in patients with a diagnostic delay of less than 12 months (short diagnostic delay) and those with a diagnostic delay of more than 12 months (long diagnostic delay).

Nonetheless, PFS did vary significantly between the groups, with patients in the short delay group having a PFS of over 35 months years compared to 15 months in the long delay group. This difference was only observed in patients with mild disease at the time of diagnosis.

Patients in the short delay group with mild disease at the time of diagnosis also scored higher on quality of life assessment and tended to have lower hospitalization rates. 

“We have demonstrated a clinically relevant negative impact of a diagnostic delay on progression-free survival, quality of life and hospitalization rates in a large real-life and well-characterized cohort of patients with IPF,” the authors concluded.


Hoyer N, Prior TS, Bendstrup E, Shaker SB. Diagnostic delay in IPF impacts progression-free survival, quality of life and hospitalisation rates. BMJ Open Respir Res. 2022;9:e001276. doi:10.1136/bmjresp-2022-001276