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

The ADO score (age, dyspnoea, airflow obstruction) 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 4,804 UK COPD patients with ≥3 ADO measurements from The Health Improvement Network (2005 to 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 association 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 per one unit increase in ADO per year; 95% CI: 1.59 to 2.52). More rapid ADO score worsening was seen among current (rate difference= 0.059; 95% CI: 0.031 to 0.087; P=0.001) and former smokers (0.028; 0.003 to 0.054; P=0.032) and patients with depression (0.038; 0.005 to 0.071; P=0.022) while overweight (-0.0347; -0.0544 to -0.0150; P=0.001) and obese (-0.0412; -0.0625 to -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 BMI. Keywords Chronic obstructive pulmonary disease, multivariate analysis, serial assessment, epidemiology, prognosis