A cohort study of mortality predictors in patients with acute exacerbation of chronic fibrosing interstitial pneumonia

Abstract

Objectives: To assess clinical, laboratory and radiographic findings associated with outcomes and to clarify more practical ways to predict hospital mortality in patients with acute exacerbation (AE) of chronic fibrosing interstitial pneumonia (CFIP).

Design: Single-centre retrospective cohort study.

Setting: University Hospital in Japan.

Participants: We identified 51 consecutive patients with AE of idiopathic CFIP through multidisciplinary discussion. Patients who had connective tissue disease, drug-induced lung disease, pneumoconiosis, hypersensitivity pneumonitis, sarcoidosis, pulmonary histiocytosis, lymphangioleiomyomatosis and eosinophilic pneumonia were excluded.

Interventions: There were no interventions.

Main outcome measures: The main outcome was determination of in-hospital mortality predictors. Other outcomes included clinical, laboratory and radiographic differences between non-survivors and survivors in patients with AE of CFIP.

Results: The mean age of the patients with AE of CFIP was 71 years. Compared with survivors, non-survivors had a significantly shorter duration of symptoms before admission, lower prevalence of peripheral distribution of ground-glass opacity and centrilobular emphysema (CLE) on thin-section CT, lower peripheral lymphocyte count, higher brain natriuretic peptide titre, lower Pao2:Fio2 (P:F) ratio, higher prevalence of systemic inflammatory response syndrome (SIRS) and higher SIRS score on admission (p=0.0069, 0.0032, 0.015, 0.040, 0.0098, 0.012, 9.9×10(-7) and 5.4×10(-6), respectively). Multivariate analysis revealed SIRS (HR=6.2810, p=0.015), CLE (HR=0.0606, p=3.6×10(-5)) and serum procalcitonin level (HR=2.7110, p=0.022) to be independent predictors of in-hospital mortality. A Kaplan-Meier estimate on the basis of stratification according to the presence or absence of SIRS and CLE demonstrated a distinct survival curve for each subset of patients.

Conclusions: Distinct survival curves documented by stratification according to the presence or absence of SIRS and CLE may provide basic information for a rational management strategy for patients with AE of CFIP on admission.

Keywords: Centrilobular emphysema; Idiopathic pulmonary fibrosis; Systemic inflammatory response syndrome.

Figure 1

Flow diagram of patients with acute exacerbation of chronic fibrosing interstitial pneumonia.

Figure 2

The number of systemic inflammatory response syndrome (SIRS) criteria was positively correlated with the serum procalcitonin concentration (p=0.045). The number of subjects was as follows: 7 (SIRS score 0), 12 (score 1), 11 (score 2), 13 (score 3) and 4 (score 4), respectively. Logistic regression analysis was performed for significance.

Figure 3

A Kaplan-Meier estimate for overall survival. The x axis indicates days after admission.

Figure 4

A Kaplan-Meier estimate for survival according to the thin-section CT classification: define usual interstitial pneumonia (UIP) pattern (black, 28 patients), possible UIP pattern (green, 13 patients) and inconsistent with UIP pattern (red, 10 patients). The x axis indicates days after admission.

Figure 5

The stratification according to the presence or absence of centrilobular emphysema (CLE) and systemic inflammatory response syndrome (SIRS) revealed distinct survival curves of the four groups. Group 1 (green): SIRS− and CLE+ (n=7), group 2 (black): SIRS− and CLE− (n=12), group 3 (blue): SIRS+ and CLE+ (n=11) and group 4 (red): SIRS+ and CLE− (n=21). The x axis indicates days after admission.