The Clinical Characteristics And Prognosis Of Patients With Acute Exacerbation In Idiopathic Pulmonary Fibrosis

Objectives:Idiopathic pulmonary fibrosis(IPF)is defined as a specific form of chronic,progressive fibrosing interstitial pneumonia,occurring primarily in older adults.The 5-year survival rate of IPF is only 20%.Acute exacerbation of IPF(AE-IPF)is an acute,clinically significant respiratory deterioration characterized by evidence of new widespread alveolar abnormality.AE-IPF has a poor prognosis with a high mortality.In current study,we reviewed the clinical data of 107 patients with AE-IPF,and compared the clinical data between patients with UIP pattern and those with possible UIP pattern,clarified the clinical characteristics and prognosis of patients with AE-IPF in China.Materials and methods:We retrospectively reviewed the clinical data,laboratory and imaging findings of overall 107 AE-IPF patients,who admitted to the Nanjing Drum Tower Hospital,Nanjing University Medical School from January 2010 to December 2016.Patients who did not die in hospital were followed up by telephone,and those who were loss to follow-up were excluded.The diagnosis of IPF was based on the 2013 ATS/ERS guidelines,mainly according to the clinical data and chest high resolution computed tomography(HRCT)findings.The determination of acute exacerbation was based on the updated 2016 international guidelines.The patients were divided into UIP pattern and possible UIP pattern group according to chest imaging,and the chest CT score was evaluated.Chi square and t-test were used to compare the baseline clinical characteristics between the UIP pattern group and possible UIP group pattern.Bivariate correlation analysis was used to analyze the collection between clinical characteristics and survival time after AE in the two groups.Kaplan-Meier was used to draw a survival curve to compare the differences in survival between the two groups.Cox regression was used for a multivariate analysis of prognosis.Results:The 107 cases of AE-IPF contained 81 males and 26 females.The mean age was 68.52±9.87years old.The mean CT score was 7.25±0.92.The medium survival time was 33±118.2 days.There were 86 patients(80.4%)in the UIP pattern group.Male patients with UIP pattern were significantly more than more those with possible UIP pattern Patients in UIP pattern were older than those with possible UIP pattern.N-acetylcysteine use before AE,and white blood cell(WBC)counts,IgG and mean pulmonary arterial pressure(mPAP)at AE were higher in UIP pattern group compared with possible UIP pattern group.The differences were significant(p<0.05).In all 107 patients,AE incidences of 3m,6m,1y,2y,3y after initial diagnosis of IPF were 53.3%,66.4%,77.6%,85.0%and 93.5%,respectively.Smoking and corticosteroid reduction or discontinuation before AE were the two insignificantly risk factors for AE occurrence after initial diagnosis of AIPF for 6m(95%CI:1.009-2.651,p=0.046 and 95%CI:0.327-0.958,p=0.034,respectively).In UIP group,the survival time after AE had a positive correlation with PaO2/FiO2(r=0.234,p=0.030),and negative correlation with CT score,WBC counts,C reactive protein(CRP);lactate dehydrogenase(LDH),the maximum dose of Methylprednisolone and the use of mechanical ventilation(MV)(r=-0.445,p=0.000;r=-0.260,p=0.015;r=-0.296,p=0.006;r=-0.235,p=0.029;r=-0.024,p=0.038andr=-0.231,p=0.032,respectively).In possible UIP group,the survival time after AE was only negatively correlated to the D-dimmer(r=-0.519,p=0.023).Kaplan-Meier survival analysis showed that there was no significant difference in overall survival between UIP and possible UIP pattern groups,but patients in UIP group had a better survival in 30-day after AE than those in possible UIP pattern group significantly(p=0.019).The Cox regression analysis shows that CT score,WBC count and PaO2/FiO2 were the independent predictors for the prognosis in UIP patients(95%Cl:1.253-2.171,p=0.000;95%CI:1.027-1.114,p=0.001and95%CI:0.986-0.997,p=0.002).However,none of these clinical variates can predict the survival in possible UIP group.Conclusion:AE occurrences among patients with AE-IPF within 6 months after initial diagnosis of IPF were about 2/3.Although there was no significant difference in overall survival between the two groups of UIP pattern and possible UIP pattern,the short-term prognosis of patients with possible UIP pattern may be worse than those with UIP pattern.Increased peripheral white blood cell count,high chest CT score,low oxygen index were independent predictors for the prognosis of patients with UIP pattern on chest HRCT.