The stability of the ADO score among UK COPD patients from The Health Improvement Network

Abstract

The ADO (age, dyspnoea, airflow obstruction) score predicts 3-year overall mortality among chronic obstructive pulmonary disease (COPD) patients. Information on the changes in COPD prognostic scores is sparse and it is unclear if the ADO score should be measured serially. We followed 4804 UK COPD patients with three or more ADO measurements from The Health Improvement Network (2005-2014) in a retrospective open cohort design. Patient's ADO scores were calculated once per year unless an obstruction or dyspnoea measurement was missing. Cox regression models assessed the independent role of serial ADO scores on mortality. The associations between baseline patient characteristics and long-term change in ADO scores were assessed using linear mixed effect models. Fewer than 7% of patients had worsened (i.e. increased) by ≥1 point per year after a median follow-up of 4.4 years. There was strong evidence that patients with more rapid worsening in ADO scores had increased mortality (hazard ratio 2.00 (95% CI 1.59-2.52) per 1 point increase in ADO per year). More rapid ADO score worsening was seen among current smokers (rate difference 0.059 (95% CI 0.031-0.087); p=0.001) and ex-smokers (0.028 (95% CI 0.003-0.054); p=0.032) and patients with depression (0.038 (95% CI 0.005-0.071); p=0.022), while overweight (-0.0347 (95% CI -0.0544- -0.0150); p=0.001) and obese (-0.0412 (95% CI -0.0625- -0.0198); p<0.001) patients had a less rapid ADO score worsening. Serial assessment of the ADO score can identify patients with worsening disease and update their prognosis, especially for patients who smoke, are depressed or have lower body mass index.