A delay in diagnosis of idiopathic pulmonary fibrosis (IPF) of ≥1year was associated with poor progression-free survival, quality of life, and hospitalization rates, according to findings from an ongoing cohort published in BMJ Open Respiratory Research.
Investigators, led by Saher Burnham Shaker, MD, PhD, of the department of respiratory medicine, Herlev and Gentofte University Hospital, Copenhagen, Denmark, report that outcomes tended to be worse among patients who had mild disease vs more severe disease at the time of diagnosis.
The study authors cite a median interval between onset of symptoms and an IPF diagnosis between 0.6 and 2.3 years, based on patient surveys and registries. Current data are both sparse and conflicting on the impact of diagnostic delay and, authors add, studies were conducted before the approval of antifibrotic treatments. Patients with early and advanced disease show similar rates of disease progression “supporting early initiation of antifibrotic treatment," they write. Data also are consistent showing significant efficacy of the treatments in patients with less advance disease.
The results are based on recent data from the ongoing Pulmonary Fibrosis Biomarker Cohort ([PFBIO] ClinicalTrials.gov Identifier: NCT02755441), which includes incident patients diagnosed with IPF according to international guidelines. Patients are recruited immediately after their diagnosis but before beginning antifibrotic treatment and are followed for up to 5 years with visits at baseline, 6 and 12 months, and annually thereafter.
Participants completed the St George’s Respiratory Questionnaire (SGRQ) and the chronic obstructive pulmonary disease assessment test (CAT) at each visit. A validated IPF-specific version of the SGRQ (SGRQ-Ider) and 2 symptom-specific scores for self-reported dyspnea also were used.
From April 2016 to June 2021, there were 264 incident patients with IPF included in the PFBIO cohort. Mean age was 73 years and 75% of the cohort were men. Among them 78 experienced a diagnostic delay of <1 year and 186 a delay of >1 year. For the study, diagnostic delay was defined as the time between the first occurrence of any IPF-related symptom and the date of IPF diagnosis.
Shaker et al report that among participants with disease identified as mild at diagnosis (forced vital capacity [FVC] >80% predicted), a long delay before diagnosis was associated with lower FVC, higher SGRQ total score, higher SGRQ-Ider total score, and higher scores for self-reported dyspnea. None of these associations were seen among patients with moderate-to-severe disease at diagnosis (FVC ≤80% predicted).
The research team found overall, in multivariate analysis, that a delay of >1 year vs <1 year was associated with worse progression-free survival (hazard ratio [HR] 1.70; 95% CI, 1.18-2.46, P =.004). More specifically, however, a long diagnostic delay was associated with worse progression-free survival in patients with mild disease (HR 2.43; 95% CI, 1.45-4.01, P <.001) but not for patients with moderate-to-severe disease (HR 0.91; 95% CI, 0.51-1.62, P =.76).
Using multivariate negative binomial regression analysis, Shaker and colleagues found that patients who had a long diagnostic delay had higher all-cause hospital admission rates during the first year after diagnosis (incidence rate ratio [IRR] 3.28; 95% CI, 1.35-8.55; P =.01) and during full follow-up (IRR 1.74; 95% CI, 1.01-3.02; P =.04).
Rates for respiratory hospital admission also were increased during the first year after diagnosis but not for the entire follow-up period. When subgroups were analyzed, the results remained consistent among patients with mild disease at diagnosis but not with moderate-to-severe disease.
Among the study limitations the authors cite are the observational design and use of FVC to stratify disease severity.
“We report a consistent negative impact of a diagnostic delay of more than 1 year on progression-free survival, quality of life, and hospitalization rates in patients with IPF,” stated the researchers. “These findings were most pronounced in patients with mild disease (FVC >80% predicted) at the time of diagnosis highlighting the importance and potential benefit of an early diagnosis for proper management of IPF patients.”
Reference: Hoyer N, Prior TS, Bendstrup E, Shaker SB. Diagnostic delay in IPF impacts progression-free survival, quality of life and hospitalisation rates. BMJ Open Resp Res. 2022;9:e001276. doi:10.1136/ bmjresp-2022-001276