Using the DOSE index to predict changes in health status of patients with COPD: a prospective cohort study

BACKGROUND: The severity of chronic obstructive pulmonary disease (COPD) should not be based on the level of airflow limitation alone. A multicomponent index such as the DOSE index (dyspnoea score (D), level of airflow obstruction (O), current smoking status (S), and exacerbations (E)) has the potential to predict important future outcomes in patients with COPD more effectively than the forced expiratory volume in one second. Health status deterioration should be prevented in COPD patients. AIMS: To investigate whether the DOSE index can predict which patients are at risk of a clinically relevant change in health status. METHODS: A prospective cohort study was performed using data from primary and secondary care. The DOSE score was determined at baseline and the 2-year change in the Clinical COPD Questionnaire (CCQ) score was calculated. Linear regression analysis was performed for the effect of a high DOSE score (>/=4) on the change in CCQ score. RESULTS: The study population consisted of 209 patients (112 patients from primary care). Overall, a high DOSE score was a significant predictor of a change in CCQ score after 2 years (0.41, 95% CI 0.13 to 0.70), particularly in primary care patients. CONCLUSIONS: A DOSE score of >/=4 has the ability to identify COPD patients with a greater risk of future worsening in health status.