Impact of sleep-related hypoventilation in patients with pleuroparenchymal fibroelastosis

Abstract

Background Pleuroparenchymal fibroelastosis (PPFE) is a rare fibrosing lung disease with a predilection for the upper lobe and its progression causes hypoventilation, resulting in hypercapnia. Even though the association between sleep-related hypoventilation (SRH) and chronic obstructive pulmonary disease was well documented, its impact in patients with PPFE was not evaluated. The aim of this study is to clarify the impact of SRH on prognosis in PPFE. Methods A retrospective review of the medical records of 52 patients with PPFE who underwent transcutaneous carbon dioxide monitoring during sleep was done. Patients were stratified into SRH (n = 28) and non-SRH (n = 24) groups based on American Academy of Sleep Medicine criteria. The impact of SRH on the prognosis of PPFE, as well as the clinical factors and comorbidities of PPFE associated with SRH, were evaluated. Results Forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), total lung capacity (TLC), and carbon monoxide diffusing capacity (DLco) in the SRH group were significantly lower than the non-SRH group (P < .01). Chronic pulmonary aspergillosis (CPA) was found at a higher rate in the SRH group (P = .02). The median survival time for SRH patients was 330 days, whereas roughly 80% of non-SRH patients were alive during the 3-year observation period (P < .01). Body mass index was a significant prognostic factor in PPFE patients with SRH (HR .78; 95% CI; .64–.94; P < .01). Home oxygen therapy (HOT) during the day and noninvasive positive pressure ventilation (NPPV) at night while sleeping tended to improve prognosis in the SRH group, as indicated by HR of .25 (P = .07). Conclusions SRH may be a poor prognostic factor for PPFE. Additionally, SRH may modify susceptibility to Aspergillosis in patients with PPFE. HOT plus NPPV may improve the disease outcomes in patients with SRH.

Proposed Clinical Algorithm for Pleuroparenchymal Fibroelastosis (PPFE)

“…Although there does not appear to be sufficient evidence, several previous studies showed that poor prognostic factors in PPFE patients include lower FVC and DL CO values, deterioration in FVC during follow-up, hypercapnia (PaCO 2 ≥ 50 Torr), elevated Krebs von den Lungen-6 (KL-6) (≥600 U/mL), standardized upper-lobe volume by 3D-CT (<30%), lower-lobe lung lesions (lower-lobe UIP), lower Geriatric Nutritional Risk Index (GNRI) (major malnutrition-related risk: GNRI < 82), decrease in GNRI during follow-up, body weight loss (≥−5%/year) during follow-up, development of pneumothorax, dyspnea grade ≥ 2 on the mMRC (Modified Medical Research Council) dyspnea scale, pulmonary hypertension, sleep-related hypoventilation, and higher peripheral neutrophil-lymphocyte ratio (NLR) (≥2.775) [7,8,14,23,25,50,51,[54][55][56][57][58][59].…”

“…Median survival times of patients following subgroup analysis based on the presence or absence of poor prognostic factors were as follows: pneumothorax (1.5 vs. 2.8 years), PaCO 2 ≥ 50 Torr (0.97 vs. 1.96 years), sleep-related hypoventilation (0.9 vs. not calculated), KL-6 ≥ 600 U/mL (2 vs. 5.1 years), lower-lobe UIP (1 vs. 5.2 years), pulmonary hypertension (1.3 vs. 4.2 years), and upper-lobe volume by 3D-CT < 30% (2.5 vs. 6.1 years) (Table 1) [7,16,23,25,50,58]. The three major causes of death were chronic progression (26.3-84.6%), acute exacerbation (AE) of ILD (3.6-36.4%), and pulmonary infection (0-52.6%) (Figure 4) [7,8,50,54,55,60,61].…”