Precipitating causes and outcomes of chronic obstructive pulmonary disease exacerbation at a tertiary care center in northeast Thailand

Background: Acute exacerbation of chronic obstructive pulmonary disease (COPD) is a leading cause of hospitalization and economic burden. Frequent exacerbations impair quality of life and effect decline of lung function.

Objective: We evaluated characteristics of COPD patients with frequent exacerbations. The precipitating causes, outcomes, hospital stay, and cost of admission were also determined.

Methods: The study population included COPD patients admitted because of acute COPD exacerbation at Srinagarind Hospital between 1 January 2006 and 31 December 2010.

Results: Over the 5-year period, 183 patients were admitted. Their mean age was 74.9 (SD 9.28) years and the male to female ratio was 170:13. Most patients (144; 79%) had one exacerbation per year and 39 (21%) had more than one per year. The group with more exacerbations, had a higher stage of the disease than those with only one exacerbation (p = 0.023), but there was no significant difference in the mortality rate (18% vs 14%, p = 0.53). A total of 245 episodes of acute exacerbation of COPD occurred in 183 patients. The mean duration of symptoms was 4.1 (SD 3.46) days. Forty-seven percent presented with Anthonisen type III, 42.4% with Anthonisen type II, and 10.6% with Anthonisen type I exacerbations. For 44 exacerbations (18%), the precipitating causes were not determined. The most common precipitating cause was pneumonia, which occurred in 90 episodes (36.7%). The second common was bronchitis (27.8%); followed by heart failure (8.2%), infected bronchiectasis (5.3%), diarrhea (1.2%), acute urinary retention (0.8%), unstable angina (0.4%), pneumothorax (0.4%), urinary tract infection (0.4%), atrial fibrillation (0.4%) and drug induced cough (0.4%). The organisms responsible for respiratory tract infection were identified in 31% cases of pneumonia and 18% of bronchitis cases. The top three common pathogens for pneumonia were Pseudomonas aeruginosa (9%), Acinetobacter baumannii (8%), and Klebsiella pneumoniae (8%). The top three common pathogens for bronchitis were P aeruginosa (7%), Haemophilus influenza (6%), and K pneumoniae (4%). About one quarter (25.3%) of acute exacerbations were complicated by respiratory failure. The mean duration of admission was 17.3 days (range 1-682 days). The mean cost of admission per exacerbation was 80,010 Thai baht (US $2,666) (range, 2,779-3,433,108 baht). The total cost for 245 exacerbations was 19.6 million baht ($653,000).

Conclusion: Respiratory tract infections were common causes of COPD exacerbation and one quarter of which developed respiratory failure. Preventive measures such as vaccination, smoking cessation, lung rehabilitation, and appropriate drug use are helpful.