The goal of this observational study is to explore current status of diagnosis, treatment and quality of life for patients with idiopathic pulmonary fibrosis. It aims to integrate qualitative and quantitative data to describe the distribution of perspective, experience, patient journey, treatment, expectation and quality of life for patients with idiopathic pulmonary fibrosis.

Participants will be invited to participate the interview, and answer quantitative survey questions about their quality of life.

Idiopathic pulmonary fibrosis (IPF) is a rare, progressive, fibrotic interstitial lung disease of unknown aetiology primarily affecting middle-aged and elderly patients, more men than women. Median survival is 3∼5 years from the time of diagnosis. The prognosis is worse than for most common malignancies. However, patients' experiences, quality of life and needs during the disease course, have not been adequately investigated, which leads a lack of evidence to support the priority of treatment or drug development.

This study plans to conduct an mixed methods research to integrate qualitative and quantitative data to explore the perspective, experience, patient journey, treatment, expectation and quality of life for patients with idiopathic pulmonary fibrosis. For qualitative interview, there are 50 patients with idiopathic pulmonary fibrosis, and 15 physicians will be interviewed. For quantitative survey, there are 245 patients with idiopathic pulmonary fibrosis will be involved.

Inclusion Criteria:

• IPF patients who are diagnosed according to international guidelines.
• Physicians who are clinical experts with extensive experience in the treatment of IPF.

Exclusion Criteria:

- The patient is unable to express his/her opinion clearly.

Under meeting the above inclusion and exclusion criteria, patients will be selected from Peking University Third Hospital, Beijing Chaoyang Hospital, Shenzhen Peking University-Hong Kong University of Science and Technology Medical Center, Zhejiang Chinese medical University, and West China Hospital of Sichuan University. Additionally, to ensure geographic representation of the patients, some participants will be recruited from a patient organization called "Take a Deep Breath for Love". A total of 295 IPF patients and 15 physicians are expected to represent six regions of the country, including Northeast, North China, Northwest, East China, Central South, and Southwest.

This is a deeply exploration study about rare disease in China, which will integrate qualitative and quantitative data to answer the research question. This IPD data could not be shared. If some researchers plan to request IPD data, who could send email to the investigators. the investigators will review the request and send the available data.