Incidental diagnosis of IPF common, still portends poor survival outcomes

Almost one-third of patients with idiopathic pulmonary fibrosis had an incidental diagnosis, with survival outcomes still comparably poor to those diagnosed non-incidentally, according to a study published in Respiratory Medicine.

“The Japanese government recommends an annual physical examination for adults [older than] 40 years of age. Thus, some patients are incidentally diagnosed with IPF during annual checkups in Japan,” Ryo Yamazaki, MD, of the department of respiratory medicine and allergology at Kindai University, Osakasayama, Osaka, Japan, and colleagues wrote. “These patients are often asymptomatic and might be in early-stage disease considering that most patients with IPF have symptoms, such as cough and/or dyspnea on exertion, at the time of diagnosis. However, whether this incidentally diagnosed or latent type of IPF corresponds to the earliest stage of the disease or is inherently different from the IPF of symptomatic patients is unknown.”

Researchers retrospectively reviewed the files of 107 consecutive patients with newly diagnosed IPF between January 2008 and August 2017 at Kindai University in Japan to identify diagnosis methods and outcomes. Researchers categorized patients as being diagnosed with IPF incidentally due to suspicious findings during their annual health checkup or other examinations, or non-incidentally following presentation with respiratory symptoms.

Overall, 35 patients (32.7%; mean age, 73.9 ± 5.3 years; four women; BMI, 22.7 ± 3 kg/m²) were diagnosed with IPF incidentally — including 18 during annual health checkups and 17 during assessment for other medical issues — whereas 72 patients (67.2%; mean age, 74 ± 6.9 years; 16 women; BMI, 21.9 ± 3.3 kg/m²) were not diagnosed incidentally.

Seven of the 35 patients diagnosed incidentally had respiratory symptoms including cough (n = 4; 11.4%) and dyspnea on exertion (n = 3; 8.6%).

A comparable proportion of the incidentally vs. non-incidentally diagnosed groups received antifibrotic agents for at least 6 months (37.1% vs. 37.3%). Both groups also showed comparable annual (–181 mL/year vs. –125 mL/year) and absolute (–5.4% vs. –4%) changes in FVC values 12 months after diagnosis.

“The annual changes in FVC after the diagnosis of IPF were comparable between

the two groups, indicating that even if a patient was diagnosed with IPF and had little or no symptoms, the disease was still progressive,” the researchers wrote.

From diagnosis, patients who were diagnosed incidentally vs. non-incidentally had a median survival of 4.9 years vs. 3.9 years, which did not represent a significant difference.

Researchers observed decreased BMI as the sole independent predictor of survival among patients who were diagnosed with IPF incidentally (HR = 0.78; 95% CI, 0.65-0.93). After adjusting for age, sex, FVC percent predicted and antifibrotic therapy, BMI remained the sole independent predictor of survival in the multivariate proportional hazards regression analysis (adjusted HR = 0.8; 95% CI, 0.65-0.99).

“Identifying patients, particularly those with a low BMI, during the earliest stage of IPF might be important, because such patients would then have a chance to be treated by antifibrotic agents,” the researchers wrote.