Survival After Acute Flares of Interstitial Lung Disease Varies by Fibrosis Type, Study Says

Survival following an acute exacerbation (AE) for patients with idiopathic pulmonary fibrosis (IPF) and other fibrosing interstitial lung disease (FILD) varied depending on the underlying ILD, according to a paper published in BMJ Open Respiratory Research.

Investigators from Finland examined retrospective data from 128 patients with IPF and other FILD with a history of AE in order to compare the clinical characteristics, causes of death, and factors impacting on the prognosis of this population. The investigators compared survival data of IPF and non-IPF cases and gathered information about the underlying and immediate causes of death from death certificates, they explained.

The study authors wrote that estimates show between 5% and 15% of patients with IPF experience an AE every year, which are normally treated based on clinical practices at each hospital. That usually involves administration of corticosteroids, though there are few randomized controlled studies that investigate this topic, the study authors said.

Most of the patients in the analysis had IPF, the study authors said, and the most common subgroup was CTD-ILD. The study authors determined that 11 patients had an asbestosis-related AE. The study authors did not identify any AE triggers, they said.

Additionally, 56% of the treatment periods took place in the respiratory ward, rather than in the intensive or immediate care units and did not require invasive or non-invasive mechanical ventilation, the study authors said. Only 16 patients required mechanical ventilation and 6 survived hospital treatment.

After AE-IPF hospitalization, the median survival was 2.6 months, the study authors determined. Patients with some other FILD had longer median survival at 21 months. The study authors wrote that patients with IPF or asbestosis had the shortest survival compared to other FILDs, while non-specific interstitial pneumonia (NSIP) was the subgroup with the most favorable prognosis, they said.

Pulmonary fibrosis was the most common underlying and immediate cause of death, the investigators said; it accounted for 84% and 45% of deaths with IPF and non-IPF, respectively.

Previous studies into AEs in patients with IPF have not detected an explicit survival rate post-hospitalization, the study authors said. Their findings are more unique, they said, as they were able to discern differences between subgroups of FILD, such as IPF, NSIP, RA-ILD, asbestosis, and other FILD.

The study authors also compared results from 3 papers published from the United States to their findings. The US studies found 1-year mortality rates of more than 50% among patients with non-IPF, which was much higher than their own study. However, the US studies did not use updated AE-IPF criteria in their analysis and 1 of the studies included patients treated in the ICU (a known risk factor for death among IPF patients), the study authors noted.

“Altogether, it can be stated that the earlier publications focusing on acute respiratory worsening or AE of IPF or non-IPF FILDs have consisted of small and heterogenic study populations with variable inclusion criteria, which complicate making comparisons between the investigations,” the study authors concluded. “Our results showing a remarkable difference in survival time between patients with IPF and non-IPF after AE suggested that AE-FILD and AE-IPF cannot be considered as completely identical disease entities, and furthermore, even subtypes of non-IPF FILDs may have a variable prognosis after an AE.”

The study authors also said that corticosteroid treatment preceding the hospitalization was also a risk factor for shortened survival in IPF patients. It was rare that a patient was administered nintedanib or pirfenidone in their study, they said, as most hospitalizations were done when no antifibrotic medications were available in Finland. The study authors said they were unable to show any benefit of antifibrotic drugs in 7 patients that received nintedanib or pirfenidone.

Reference

Prognosis and causes of death of patients with acute exacerbation of fibrosing interstitial lung diseases. Salonen J, Purokivi M, Bloigu R, Kaarteenaho R. BMJ Open Resp Res 2020;7:e000563. doi:10.1136/ bmjresp-2020-000563.