Health Status Instruments Add Prognostic Value in Predicting COPD Exacerbations: Insights from the TIE Cohort Study.

AIM: Identifying patients at risk for acute exacerbations of COPD (AECOPDs) is crucial to improve outcomes. We aimed to evaluate the ability of three health status instruments to predict AECOPDs in subjects with and without previous AECOPDs.

METHODS

A prospective cohort study of COPD patients from primary and outpatient care in three Swedish regions. AECOPDs were retrieved from medical records. The modified Medical Research Council Dyspnoea scale (mMRC), the COPD Assessment Test (CAT), and the Clinical COPD Questionnaire (CCQ) were evaluated. Thresholds for AECOPD prediction were estimated using receiver operator characteristic (ROC) curves. Predictive values were assessed using crude and multivariable Cox regression models.

RESULTS

We included 572 patients (59% women, age 69 ± 8 years, FEV1 57 ± 18% of predicted) in 2014-2016. All three instruments independently predicted future AECOPDs within three years (adjusted hazard ratio [aHR] 1.5-1.8) using thresholds mMRC ≥ 2, CAT ≥13, and CCQ ≥ 1.6. Patients without prior-year AECOPDs but high scores on all instruments had a similar AECOPD risk as those with prior AECOPDs but scores below threshold (aHR 2.4-2.5). Among patients with ≥1 AECOPD the year before inclusion and at least one of the three health status instruments above threshold, the aHR for future AECOPD during the study period ranged from 4.6 to 5.7.

CONCLUSIONS

mMRC, CAT, and CCQ were independently associated with AECOPDs over the following three-year period. The health status instruments provided additional predictive value for future AECOPDS in patients both with and without previous AECOPDs.

ABBREVIATIONS: aHR: Adjusted Hazard Ratio; AECOPD: Acute Exacerbations of Chronic Obstructive Pulmonary Disease; AUC: Area Under Curve; BMI: Body Mass Index; CAT: COPD Assessment Test; CCQ: Clinical COPD Questionnaire; COPD: Chronic Obstructive Pulmonary Disease; DAG: Directed Acyclic Graphs; FEV1: Forced Expiratory Volume in 1 Second; FVC: Forced Vital Capacity; GOLD: Global Initiative for Obstructive Lung Disease; HR: Hazard Ratio; IHD: Ischaemic Heart Disease; ICS: Inhaled Corticosteroids; IQR: Interquartile Range; mMRC: Modified Medical Research Council Dyspnoea Scale; ROC: Receiver Operator Characteristic; SD: Standard Deviation; TIE: Tools for Identifying Exacerbations.