| ObjectivesTo evaluate the association of body mass index (BMI) with disease severity of bronchiectasis and investigate the prognostic value of BMI in patients with bronchiectasis.Methods1. In this longitudinal study, patients diagnosed with bronchiectasis as confirmed by high-resolution computed tomography scan of chest were consecutively recruited at 4 general hospitals in Shandong from January,2010 to December,2013 and were followed up until April,2014. General information, BMI and etiology of patients with bronchiectasis were analyzed. Clinical variables expressing disease severity were recorded, including modified Medical Research Council dyspnea scale, pulmonary function tests, arterial blood gas analyses, radiographic extent of bronchiectasis, sputum microbiology, serum C-reactive protein and erythrocyte sedimentation rate. Numbers of acute exacerbations, numbers of hospitalizations and survival time were estimated during follow-ups.2. These patients with bronchiectasis were classified into 4 groups:underweight group (BMI< 18.5 kg/m2), normal weight group (18.5 kg/m2≤ BMI< 25 kg/m2), overweight group (25 kg/m2< BMI< 30 kg/m2) and obese group (BMI> 30 kg/m2). Differences in clinical variables expressing disease severity, numbers of acute exacerbations and survival time were compared across 4 groups.3. Multivariate regression analyses were used to study the determinants of numbers of hospitalizations.4. Cox proportional hazard model analyses were performed to test the predictive factors of mortality.Results1. In total,339 patients with bronchiectasis were enrolled in the study. There were more women than man (197 cases vs 142 cases). Patients with bronchiectasis had an average age of 56.0 ± 13.5 years old. The mean BMI was 21.9 ±4.1 kg/m2. Idiopathic was the most common reason (204 cases,60.2%). Pulmonary function abnormalities were identified in 240 patients (70.8%) and the most common pattern was obstructive ventilatory dysfunction (136 cases,56.7%).118 patients’ (34.8%) arterial blood gas analyses met the diagnostic criteria for respiratory failure. Sputum specimens were cultured positive in 179 patients (52.8%), in which Pseudomonas aeruginosa was the most common isolated pathogen (138 cases,77.1%).2. Patients with bronchiectasis had an average of 1.7 ± 1.5 acute exacerbations each year. During the follow-ups,43 cases (12.7%) died. One-,2-,3-and 4-year cumulative survivals of bronchiectasis patients were 94%,86%,81% and 73%, respectively.3. The percentages of 4 groups were listed as followed:underweight group (97 cases, 28.6%), normal weight group (173 cases,51.1%), overweight group (55 cases, 16.2%), and obese group (14 cases,4.1%). Forced vital capacity, the ratio between forced expiratory volume in one second and forced expiratory volume, and inspiratory capacity of the underweight group patients were significantly lower than the other 3 groups (all P＜0.05); while numbers of acute exacerbations, radiographic extent of bronchiectasis, serum C-reactive protein and serum erythrocyte sedimentation rate of the underweight group patients were significantly higher than the other 3 groups (all P<0.05). The underweight group patients had a higher frequency of isolation rate of Pseudomonas aeruginosa (P＜0.05). Cumulative survival curves were statistically different among 4 groups (X2=31.67, P＜0.001), and mortality of the underweight group patients was the lowest (χ2=35.16, P＜0.001).4. Modified Medical Research Council dyspnea scale, BMI, serum erythrocyte sedimentation rate, serum C-reactive protein and total symptom duration in years appeared as independent predictors of hospitalizations of bronchiectasis patients in the multivariate regression analyses (coefficient of determination of the optimal standard regression equation R2=0.58). BMI negatively correlated with numbers of hospitalizations (standard regression coefficient b’=-0.26,.P<0.001); while modified Medical Research Council dyspnea scale (b’-0.44, P＜0.001), serum erythrocyte sedimentation rate (b’=0.15, P=0.007), serum C-reactive protein (b’=0.14, P=0.014) and total symptom duration in years (b’=0.08, P=0.039) positively correlated with the number of hospitalizations.5. Five parameters were independently associated with the survival of bronchiectasis patients in Cox proportional hazard model analyses:arterial carbon dioxide partial pressure, inspiratory capacity, age, BMI and predicted percentage of forced expiratory volume in one second. The higher arterial carbon dioxide partial pressure (≥50 mmHg) [relative risk (RR)=2.13,95% confidence interval (CI): 0.99-4.59], the higher mortality; the lower inspiratory capacity (RR=0.1%,95% CI: 0.05-0.65), the higher mortality; the older age (>55 years old) (RR=7.70,95%CI: 1.79-33.26), the higher mortality; the lower BMI (BMI< 18.5 kg/m2) (RR=0.48, 95% CI:0.27-0.85), the higher mortality; and the lower predicted percentage of forced expiratory volume in one second (RR=0.96,95% CI:0.93-0.99), the higher mortality.ConclusionsUnderweight was highly prevalent in patients with bronchiectasis (28.6%). Bronchiectasis patients with lower BMI were prone to suffer from deteriorated pulmonary function. Bronchiectasis patients with lower BMI had a higher frequency of isolation rate of Pseudomonas aeruginosa. Bronchiectasis patients with lower BMI had a higher risk of hospitalization and death. BMI appeared to be one of the major predictors of numbers of hospitalizations and mortality of bronchiectasis patients.ObjectiveBronchiectasis is a chronic respiratory disease with diverse causes that may differ in clinical features and treatment options. However, few large-scale studies on the etiology of bronchiectasis are currently available. This study aims to determine the etiology and clinical features of bronchiectasis in a Chinese Han population in Shandong Province.MethodsThis prospective study enrolled adult patients diagnosed with bronchiectasis as confirmed by high-resolution computed tomography scan of chest at 4 general hospitals in Shandong from January 2010 to August 2014. Causes of bronchiectasis were screened by the analysis of clinical history and auxiliary examinations (including serum immunoglobulin determination, Aspergillus skin prick test, saccharin test, autoantibody detection, and electronic bronchoscopy). Differences in clinical features across diverse causes were also compared.Results1. A total of 476 adult patients with bronchiectasis were included and all patients were of Chinese Han ethnicity. Idiopathic (314 cases,66.0%) was the most common cause of bronchiectasis, followed by post-tuberculosis bronchiectasis (76 cases,16.0%). Other uncommon causes included post-infective bronchiectasis (18 cases,3.8%), immunodeficiency (18 cases,3.8%), allergic bronchopulmonary aspergillosis (19 cases,4.0%), rheumatic diseases (21 cases,4.4%), primary ciliary dyskinesia (4 cases,0.9%), ulcerative colitis (2 cases,0.4%), gastroesophageal reflux disease (1 case,0.2%), foreign body airway obstruction (1 case,0.2%), pulmonary sequestration (1 case,0.2%) and pulmonary hypoplasia (1 case,0.2%).2. Allergic bronchopulmonary aspergillosis patients was associated with younger age (P＜0.05). No association was found between gender and etiology (P>0.05).3. The most vulnerable lobe of bronchiectasis was left lower lobe (318 cases,66.8%). Patients with post-tuberculosis bronchiectasis had a higher frequency of upper lobe involvement (P<0.05). Cylindrical bronchiectasis was the most common type of all causes, with varicose bronchiectasis occurring more frequently in post-tuberculosis bronchiectasis and allergic bronchopulmonary aspergillosis (P＜0.05).4. Patients with different causes did not differ in lung function or sputum isolation rate of Pseudomonas aeruginosa (all P>0.05). The differences of courses of antibiotics in previous year, hospitalizations in previous year and Bronchiectasis Severity Index scores among diverse causes were not statistically significant (all P>0.05).ConclusionsIn a Chinese Han population in Shandong, idiopathic bronchiectasis is the most common form of bronchiectasis followed by post-tuberculosis bronchiectasis, while post-infective bronchiectasis and immunodeficiency are uncommon reasons. Patients with different causes differ in distribution and pattern of bronchiectasis on high-resolution computed tomography scan of chest. However, there are no significant difference in lung function, isolation rate of Pseudomonas aeruginosa and disease severity among diverse causes. |
