Prognostic Analysis of Pneumocystis Jirovecii Pneumonia in Interstitial Lung Disease Patients: A Retrospective Clinical Study

Abstract

(1) Background: The clinical characteristics and the prognostic factors of HIV-negative Pneumocystis jirovecii pneumonia (PJP) patients (non-HIV-PJP) with interstitial lung disease (ILD) remain unclear. Our objectives were to describe the clinical characteristics and to explore the prognostic factors of non-HIV-ILD-PJP patients. (2) Methods: The enrolled patients in this retrospective study were stratified based on the presence or absence of ILD and fibrotic ILD (FILD). The log-rank test and Cox regression models were used to analyze the prognostic factors. (3) Results: Among 378 non-HIV-PJP patients, there were 133 patients with ILD-PJP, and 70 patients were classified as having FILD-PJP. The all-cause mortality rate for the ILD-PJP group is higher than that of the ILD-PJP group (57.9% vs. 38.4%, p < 0.001). However, the all-cause mortality is similar between the FILD-PJP group and non-FILD-PJP group. Preexisting ILD (HR: 2.156, p = 0.003) and honeycomb appearance on the chest HRCT (HR = 16.3, p < 0.001) are independent survival risk factors for ILD-PJP. Non-invasive ventilation is an independent survival risk factor for ILD-PJP patients (HR = 928.56, p < 0.01) and FILD-PJP patients (HR = 33.86, p < 0.001). (4) Conclusions: Pre-existing ILD and honeycomb appearance on the chest HRCT are independent survival risk factors for PJP patients. Non-invasive ventilation is associated with poor survival for both ILD-PJP and FILD-PJP patients.

Keywords: Pneumocystis jirovecii pneumonia; human immunodeficiency virus negative; interstitial lung disease; prognosis.

Figure 1

Chest CT scanning of Pneumocystis jirovecii pneumonia (PJP) with different underlying pulmonary diseases: (1) (A1,A2) A 52 year old female nephrotic syndrome patient without underlying pulmonary disease suffered from PJP 3 months later. (A1) Chest CT scan (16 April 2019) shows normal lung parenchymal before the administration of prednisone and mycophenolate mofetil. (A2) Chest CT scan (11 July 2019) obtained 3 months later showing diffuse ground-glass opacities (GGOs) and multiple traction bronchiectasis. She suffered from fever and dyspnea on July 2, 2019. She was diagnosed with PJP on 12 July 2019. (2) (B1,B2) A 36 year old female eosinophilic granulomatosis with polyangiitis patients with non-fibrosing interstitial lung disease was complicated with PJP 2 months later. (B1) Chest CT scan (8 March 2017) show diffused GGOs throughout the bilateral lungs before the administration of prednisone and iv. cyclophosphamide. (B2) Chest CT scan (5 May 2017) obtained 2 months later shows relapsing diffused GGOs in the right upper lobe and local GGOs in the left upper lobe. She complained of fever and dyspnea on 1 May 2017. She was diagnosed with PJP on 9 May 2017. (3) (C1,C2) A 60 year old male rheumatoid arthritis patients with fibrotic interstitial lung disease (FILD) was complicated with PJP 3 months later. (C1) Chest CT scan (11 May 2019) shows bilateral subpleural with basal predominance of the reticulation, interlobular septal thickening, and scattered honeycombs before the administration of Tofacitinib. (C2) Chest CT scan (8 August 2019) obtained 3 months later shows diffused GGOs and multiple traction bronchiectasis in the background of FILD. He had suffered from exaggerated dyspnea since August 3, 2019. He was diagnosed with PJP on 11 August 2019.

Figure 2

The study flow chart.

Figure 3

Kaplan–Meier survival analysis for all enrolled PJP patients. The all-cause mortality rate for the PJP in interstitial lung disease (ILD-PJP) group is higher than that of the non-ILD-PJP group (log-rank = 12.2, p < 0.001).

Figure 4

Kaplan–Meier survival analysis for all enrolled ILD-PJP patients. The all-cause mortality is similar between the FILD-PJP patients and the non-FILD-PJP patients (log-rank = 0.03, p > 0.5).