Factors Affecting Survival Of Hospitalized Patients With Acute Exacerbation Of COPD And Clinicians' Knowledge Of Guidelines For The Management Of COPD In Secondary General Hospitals

BackgroudChronic obstructive pulmonary diseases(COPD) is a chronic disease of a great number of patients all over the world and high fatality rate, leading to heavy social financial burden. COPD is complicated by recurrent acute exacerbations (Acute exacerbations of COPD, AECOPD), which are associated with enormous health care expenditures and high morbidity. AECOPD is defined as"an event in the natural course of the disease characterized by a change in the patient's baseline dyspnea, cough, and/or sputumand beyond normal day-to-day variations, which is acute in onset and may warrant a change in regular medication in a patient with underlying COPD".According to current epidemiological investigations, fatality rate of COPD will get a further rise within the next ten years. Recently many researches are focusing on prognosis of COPD patients and factors of fatality rate prediction to reverse the trend. In all of these researches, studies of prognositic factors of AECOPD are very important. Nowadays, factors that determine the short- and long-term outcomes of patients with COPD are not yet precisely understood. Identification of the factors that may influence survival in patients with COPD may enable clinicians to better assess life expectancy. This is extremely important, in that it may help offset the social and economic burden of COPD through the implementation of more individualised and effective treatment strategies, as well as better mobilising healthcare resources.Inpatients of current prognosis researches are mainly from teaching hospitals, large general hospitals or respiratory hospitals. Domestic relative researches are mostly retrospective cases, barely prospective ones. This survey took COPD inpatients of AECOPD in three secondary general hospitals, and did prospective cohort study on prognostic factors of COPD inpatients, providing reference of judging prognosis of COPD inpatients to clinicians.In recent 20 years, many countries are actively doing epidemiological investigation and experimental study, and renewing guidelines for management of COPD according to the study results. Understanding and correct use of these guidelines will greatly help clinicians to make acute diagnosis of COPD, prevent COPD at early stage and give effective managment. At the time some researches indicate that general population and medical practitioners are lack of the knowlege of COPD, leading to high rate of missed diagnose and treatment. As there is a high incidence of COPD and the disease lasts a long course, the patients usually choose to see a doctor or be hospitalized in general hospitals. Therefor the awareness and treatment principles of clinicians in general hospitals may directly effect the early diagnosis and treatment and prognosis of most patients. Our research carried out a questionnaire survey among three secondary general hospitals, in order to get the knowledge of how well clinicians know about and use the guidlines for management of COPD.Objective1. To assess the prognostic factors related to in-hospital fatality rate and 1-year survival after hospitalisation of patients with AECOPD.2. To get the knowledge of how well clinicians know about and use the guidlines for management of COPD.Methods1. Factors affecting survival of hospitalized patients with acute exacerbation of COPDWe investigated prospectively the in-hospital and 1-year fatality rate and potential determinants of fatality rate for all patients with AECOPD admitted to the three secondary general hospitals in one of the cities in Sichuan Province between February 1, 2007 and February 1, 2008. Patients who were hospitalized for COPD acute exacerbation during the period were recruited in this study. Clinical and epidemiological parameters on admission in patients were prospectively assessed. Patients were followed-up for 1 year. Patients'survival status was assessed by reviewing patient records, and by telephone calls. Each patient was assessed at 6 month and 1year after discharge. All-cause death was the event of the study.Factors hypothesized to be associated with in-hospital fatality rate were analyzed with chi-square test in univariate analysis and Logistic regression model in multivariate analysis. If the outcome was in-hospital death, the dependent variable Y=1, else Y=0. OR and 95% CI of factors were calculated. Goodness of fit of models was analyzed with Pearson test.Survival curve for the cohort was estimated by the Kaplan-Meier product limit method. Factors hypothesized to be associated with the 1-year survival were analyzed with univariate and multivariate Cox proportional hazard regression model analysis. All-cause death was the failure event. If the patient died in one year, the dependent variable Y=1 and the time variable equaled the duration between the date of death and the admission date. If the patient lost contact or suvived through the year, that was censor, the dependent variable Y=0, and the time variable equaled the duration between the last date of follow-up and the admission date. HR and 95% CI of prognostic factors were calculated. Goodness of fit of models was analyzed with logarithm of likelihood function.A two-sided P-value<0.05 was considered to be statistically significant.2. Clinicians'knowledge of guidelines for the management of COPD in secondary general hospitalsBetween February, 1, 2007 and April 30, 2007, we completed a questionnaire survey on COPD of all the clinicians in the three secondary general hospitals in one of the cities in Sichuan Province. We used the same questionnaire to investigate how well they know about and use guidelines for management of COPD by face-to-face interview. We assorted the clinicians surveyed by their working years and majors, and use chi-square test to compare the differences of awareness of COPD diagnose standards and whether they treat COPD according to the guidelines among clinicians, and use adjusted significant level method to test pair comparison among multiple groups. A two-sided P-value<0.05(or P-value<α′while testing pair comparison among multiple groups)was considered to be statistically significant. Results1. Factors affecting survival of hospitalized patients with acute exacerbation of COPDBetween February 1, 2007 and February 1, 2008, 257 AECOPD inpatients were recruited into the follow-up cohort. In total, 15 patients died in hospital and 17 patients died after discharge during the 1-year follow-up. The in-hospital fatality rate was 5.84%. The overall 6-month fatality rate and 1-year fatality rate rate was 8.95% and 12.45%, respectively. The number of patients who couldn't be contacted for the reason of unavailable calls and address changes was 28, wich accounted for 10.89% of the total number of the survey. The rest 197 patients survived through the whole year.In univariate analysis, in-hospital fatality rate was significantly associated with age, FEV1% predicted, arterial oxygen tension (PaO2), arterial oxygen saturation (SaO2), PH, Charlson's complication index. In multivariate Logistic regression model, lower arterial oxygen tension (OR, 4.775; 95%CI, 1.545~14.757; P=0.007) and higher Charlson's complication index (OR, 4.608; 95%CI, 1.330~15.966; P=0.016) were significantly associated with in-hospital fatality rate, after adjustment for age.In the univariable Cox regression model, age, exacerbation frequency, FEV1% predicted, PaO2, albumin, Charlson's complication index, BODE, 6 minutes walk distance and BMI were significantly associated with 1-year death. In the Cox proportional hazard model, exacerbation frequency≥3 times in one year(HR, 2.431; 95%CI, 1.164~5.078; P=0.018), albumin<2.5 g/dl(HR, 1.546; 95%CI, 1.082~5.587; P=0.045), Charlson's index≥3(HR, 3.846; 95%CI, 1.130~8.924; P=0.036), BMI<21kg/m2(HR, 4.143; 95%CI, 1.479~11.604; P=0.007) were independent significantly associated with 1-year death, after adjustment for age.2. Clinicians'knowledge of guidelines for the management of COPD in secondary general hospitals298 clinicians got surveyed and 258 clinicians responded, with the overall response rate of 86.58%. Among the respondents, there were only 20.93 %( n=54) could tell the accurate definition of COPD. Clinicians'diagnosis of COPD is mainly based on symptoms. Only 36.82 %( n=95) of surveyed clinicians reported use of spirometry to diagnose COPD but only 13.95 %( n=36) clinicians said they would arrange spirometry to diagnose or evaluate the severity of COPD. 87.21% of them thought current clinical treatment had no effect on progress of COPD. Among the physicians and emergency department doctors(n=113), only 15.93%(n=18) chose guidelines for the management of COPD as the basis of treatment for COPD.The clinicians of respiratory major compared to the other two groups had a higher rate on whether to diagnose COPD based on lung function(83.33% Vs. 44.16% Vs. 21.38%) and whether arranging spirometry(41.67%Vs. 11.69%% Vs. 8.28% ), P<0.001. the physicians excepted for respiratory major and emergency department doctors had a higher rate (44.16%) on whether to diagnose COPD based on lung function than those clinicians excepted for physicians (21.38%), P<0.001, while there were no differences on whether arranging spirometry between the two goups clinicians, P>0.017(α′). The rate of choosing lung function as the most important diagnostic basis and arranging spirometry had no differences between the clinicians with different work years, p>0.05.There were no differences in the basis of choosing treating methods of COPD among clinicians of different majors, P>0.05. The clinicians who worked for over 10 years preferred personal clinical experience as the basis of treatment for COPD, while the youger clinicians preferred medicine textbooks.The medicine that physicians and emergency department doctors (n=113) mostly chose was: antibiotic (99.12%, n=112), mucolytic (95.57%, n=108), oralβ2-agonist (53.98 %, n=61), theophylline (29.20%, n=33), short-actingβ2-agonist inhalation (23.01%, n=26). Long-acting bronchoilators, systemic glucocorticosteroids during acute exacerbation and nonpharmacologic treatments are seldom chosen.Conclusion1. This survey indicated that, for the inpatients with AECOPD, PaO2 and Charlson's complication index were independent risk factors associated with in-hospital fatality rate. Exacerbation frequency, albumin, Charlson's index, BMI could be identified as risk factors associated with 1-year fatality rate. Physicians should incorporate these factors in their decision-making process.2. There were still gaps between the guidelines and clinicians'knowledge of COPD in secondary general hospitals. The continuing education for clinicians in general hospitals should be strengthen to realize that clinicians will hold a more active attitude, choose reasonable treating plan and run a standardized treatment to decrease misdiagnosis, mistreaatment and fatality rate of COPD.