A Study On Correlation Of Diaphragm Thickening Fraction And Clinical Characteristics In Elderly Patients With Stable Chronic Obstructive Pulmonary Disease

Objective:To investigate the relationship between diaphragm thickening fraction(DTF)and disease severity and clinical characteristics in elderly patients with stable chronic obstructive pulmonary disease(COPD).The purpose was to study the value of DTF in evaluating the severity of disease,symptom severity and exercise ability in COPD.Methods:We conducted a descriptive cross-sectional study.Stable COPD patients over 60 years old and healthy controls were collected from the outpatients of Respiratory Department and Geriatrics Department of Sichuan Provincial people's Hospital from March 2019 to December 2019.Demographic and clinical data(age,sex,body mass index(BMI),years of smoking,duration of COPD,number of acute exacerbations in the last year,mMRC symptom score,GOLD pulmonary function grade and grouping)were recorded.The dominant arm circumference,triceps skinfold thickness,dominant hand grip strength,lung function test,diaphragm thickness at functional residual capacity(TdiFRC)),diaphragm thickness at total lung capacity(TdiTLC),maximum mouth inspiratory pressure((PImax)and 6-minute walk test(6MWT)were measured simultaneously.Calculating DTF as(TdiTLC-TdiFRC)/TdiFRC,and correlation analysis was made.Results:A total of 30 patients with elderly COPD and 20 healthy controls were collected,including 14 males and 16 females in COPD group with an average age of 75.9±7.6 years,the healthy control group including 8 males and 12 females with an average age of 73.4±6.2 years.DTF,PImax and 6-minute walking distance(6MWD)in elderly COPD group were significantly lower than those in control group.But there was no significant difference in TdiFRC and TdiLTC between the elderly COPD group and the control group.DTF in elderly COPD group was negatively correlated with age,but not correlated with BMI,number of acute exacerbations in the last year,duration of COPD,mMRC symptom score,GOLD grade of pulmonary function,FEV1,FEV1%pred,FEV1/FVC,PEF,dominant arm circumference,triceps skinfold thickness,dominant hand grip strength,PImax,TdiFRC,and 6MWD.PImax was positively correlated with FEV1,FEV1%pred,FEV1/FVC,PEF,dominant hand grip strength and 6MWD,but not correlated with age,BMI,dominant arm circumference and triceps skinfold thickness.Patients with elderly COPD were divided into two groups according to the duration of COPD,mMRC symptom score,GOLD grade of pulmonary function and grouping,but there was no significant difference in DTF between the two groups.Conclusions:1.DTF,PImax and 6MWD in elderly patients with COPD were lower than those in the control group.2.DTF in elderly COPD was not correlated with the number of acute exacerbations in the last year,mMRC symptom score,GOLD grade of pulmonary function,PImax and 6MWD.3.It was suggested that there may be diaphragm dysfunction in elderly patients with COPD.Ultrasound-based DTF in subjects with elderly COPD seemed to be unable to identify those at high risk for symptoms and exacerbations as defined by GOLD composite disease index.