This is a retrospective study of patients diagnosed with chronic obstructive pulmonary disease (COPD) with respiratory failure and admitted in West China Hospital during January 2014 to March 2016 by review of medical records. The following variables will be retrospectively studied: age, sex, marriage, height, weight, respiratory rate, PaO2, PaCO2, nutritional risk screening 2002 (NRS 2002) score, ALB, short-term and long-term prognostic outcomes, and so on. The purpose of this study is to compare the predictive power of three widely used nutritional assessment methods (BMI, NRS 2002 and ALB) predicting the prognostic outcomes in a cohort of COPD patients with respiratory failure.

Inclusion Criteria:

• Newly diagnosis of COPD at West China Hospital during January 2014 to March 2016
• Partial pressure of O2 (PaO2) < 60 mmHg and/or partial pressure of CO2 (PaCO2) >50 mmHg
• Age ≥ 18 years
• Respiratory rates > 23 bpm

Exclusion Criteria:

• Pregnancy or during lactation
• Ventilatory dysfunction due to neuromuscular disorders, acute and chronic thromboembolic disease, severe illness in other systems
• Incomplete medical profiles

Patients diagnosed with chronic obstructive pulmonary disease with respiratory failure during January 2014 to March 2016 at West China Hospital by review of medical records.