A Three-year Follow-up Observational Study On Lung Function And Quality Of Life In Patients With COPD

Background and Objectives:Chronic obstructive pulmonary disease(COPD)is a heterogeneous disease with high prevalence,high mortality,which often took heavy social and economic burden to their families and society.According to the prediction of WHO,the prevalence and mortality of it will keep a high level for a long time in the future[1].Early studies showed that the lung function of patients with COPD progressively decreased[2-3],but in recent years,the studies had found that there was heterogeneity in changes of the lung function[4-7].As well known,Smoking is one of the most important risk factors for COPD[3].Study found that smoking related with respiratory symptoms,FEV1 decline and all-cause mortality of patientswith COPD[8-10];Smoking during pregnancy not only affects the development of fetal lung organs,but also affects the development of the immune system and the development of th e lung function in the fetus[1].In addition,there are reports about correlation between low body mass index,air pollution,social economic status,comorbidities and other risk factors with impairment of lung function of patients with COPD [4,7].So there is of great significance to study the risk factors of pulmonary function damage,which will contribute to the prevention and treatment of COPD.Health related quality of life(HRQo L)is a multi-dimensional concept,which mainly means satisfaction and happiness in the relationship of health and the individual survival in the process of life,including physical function,psychological and social function and so on.It can reflect the subjective experience of the disease and medical treatment by the way of the scale,so it is an important supplement to the clinical objective examination index.Some studies showed that there was a decreased tendency in the quality of life for most COPD patients with longer follow-up period,but there were also some reports,of which forced expiratory volume in one second(FEV1),symptoms,and the HRQo L of COPD patients could be improved by effective intervention measures.Therefore,it is of great significance to deeply understand the characteristics of COPD disease for the aims of the prevention and treatment of COPD.However,as a result of longitudinal study always means long observation time,the compliance of domestic COPD patients is generally not high,draw out of the subjects during interviews times and so on,the domestic longitudinal study on COPD is so little.This retrospective longitudinal study intends to investigate the characteristics and the risk factors of pulmonary function and HRQo L changed obviously in patients with COPD with 3-year follow-up.To some extent,it will be helpful to provide a theoretical basis for the prevention and individual management of COPD patients in clinical work.Methods:Objects came from “The center of chronic respiratory disease management” of XINQIAO Hospital,who had been diagnosed with COPD,finished registration and follow-up at least for 3 years from September 2009 ~June 2012.At registration,all patients informed consent and been collected their general information(including: age,gender,occupation,smoking history,medication history,etc.)and arrange next visit.In the after interviews,they would be collected data including illness changes,finished pulmonary function tests,symptom assessment questionnaire and/or six minute walk test according to the visit plan.The recommendation of treatment be established by a repiratory doctor according to the "Global initiative for chronic obstructive lung disease(GOLD)".According to the annual decline in FEV1,subjects were divided into stable group(-5% < FEV1 fell at an annual rate of < 5%)and change group(FEV1 decline in rate?5% or ?-5%);according to the value variation of the SGRQ total score over baseline,subjects were divided for HRQ o L stability / improvement group(< 4 units)and HRQo L worsening group(?4 units).To calculate the rate of decline in FEV1 by linear regression model,and to detect the risk factors of lung function change and HRQo L by binary logistic regression model.Results:1.General information: a total of 60 cases were included in this study,including 58 males and 2 females,age(65.67 ±6.83)years old,smoking index(33.22±15.12)pack years.Both at baseline and follow-up after 3 years,the proportion of grade GOLD3 was the most than any other grades.The proportion of Grade 1,2 reduced,increased in GOLD4 compared to the previous;Compared with baseline values,FEV1,FEV1%predicted,6MWT all decreased and the BODE index increased(P < 0.05).Medication: The proportion of patients using two drugs(ICS+LABA or LAMA,LABA+LAMA)in the treatment was the most both at baseline and after follow-up 3 years(56.7%~63.3%),the proportion of ones using neither inhaled steroids nor long-acting bronchodilator agent reduced,the number of using three drug combination treatment(ICS+LABA+LAMA)was increased significantly(P < 0.05).2.FEV1 decline in the population distribution: an average annual decline rate in FEV1 was(3.74 ±6.18)%,the average value of FEV1 decreased(31.61± 62.11)ml/year.In 60 cases of COPD patients,47 cases with FEV1 decreased(78.3%),of whom 0~39ml 19 cases(31.7%),40~79ml 16 cases(26.7%),80~119ml 11 cases(18.3%),and ?120ml 1 case(1.7%);FEV1 increased in 13 cases(21.7%),including 5 cases of 0~39ml(8.3%),3 cases of 40~79ml(5.0%),4 cases of 80~119ml(6.7%),?120ml 1 case(1.7%).3.The decline of FEV1 and FEV1%pred in the GOLD grades: FEV1,FEV1%pred declined fastest in GOLD 2 than other grades(P < 0.05),and the proportion in GOLD4 had the slowest decline.4.Correlation and regression analysis of FEV1 changes: correlation analysis showed that the rate of decline in FEV1 was positively correlated with the initial FEV1,FEV1%pred,and the number of acute exacerbation(r=0.298,0.361,0.273,P<0.05).Univariate logistic regression results showed FEV1 changed apparently related with the reversibility of airway,initial FEV1 level.Multiple stepwise regression analysis showed that positive result of the bronchialdilation test,the initial FEV1 high level were independent risk factors for the effects of changes in FEV1(OR=5.54,95% CI=1.55~19.73;OR=8.28,95% CI=1.42~48.32).5.The SGRQ score and BODE index were followed up for 3 years: there was no significant difference between the total score and three domain scores compared with the baseline values,while the BODE index was significantly higher than the baseline value(P < 0.05).6.The distribution of population of SGRQ total score in BODE index score:after 3 years of follow-up,the number of level I in BODE index significantly reduced,while the level III,level IV were significantly increased compared with the baseline values.7.Implications of regression analysis for HRQo L decreased:Univariate Logistic regression showed that baseline BODE index,number of acute exacerbation(including: the number of total acute exacerbation in three years,the number of total severe acute exacerbation in three years,the number of severe acute exacerbation inthe last year)may be the risk factors of HRQo L deterition.Multiple Logistic regression confirmed that the baseline BODE index was one independent risk factor of it(OR=1.686,95% CI=1.100~2.585).And the number of acute severe exacerbations in the last year might also have prediction value for the decline of HRQo L(OR=3.316,95% CI=0.989~11.123).Conclusion:1.In real world,although most of patients used intervention including inhaled corticosteroids combined with a long-acting bronchodilator agent,after 3 years of follow-up,the majority of the patients with lung function decreased significantly,but the quality of life in overall objects can be kept no significantly descend;2.There is correlation in lung function decreased with initial airway obstruction degree and bronchodilator reversibility.The rate of decline in FEV1 of those patients in milder degree of obstruction and with positive bronchodilation test decreased faster than those in serious degree and those with negative bronchodilation test.3.BODE index is one of independent risk factors for health related quality of life decreased.The severe acute exacerbation may also have an impact on the role of deterioration of quality of life related to COPD.