Age-related smoking status in patients with Chronic Obstructive Pulmonary Disease (COPD) stratified by severity of airflow obstruction: an observational cohort study using the Hampshire Health Record Analytical database (HHRA).
Smoking is known to accelerate the deterioration in lung function experienced by patients with chronic obstructive pulmonary disease (COPD), as shown by the decline in forced expiratory volume in one second (FEV1), a measure of airflow obstruction and disease severity in these patients. Recent evidence has shown that smoking cessation in the earlier stages of the disease leads to a more marked reduction in the rate of loss of FEV1 than in those with more severe disease. Smoking cessation is therefore especially important and likely to be most effective in younger patients and those with earlier disease. Our aim was to quantify differences in current smoking status in patients diagnosed with COPD stratified by age and severity of AFO (%predicted FEV1) in a UK General Practice population.
We performed a retrospective observational cohort study, using individual patient-anonymised routine data held in the Hampshire Health Record (HHRA, an electronic NHS database holding coded clinical data for over one million patients living in Hampshire, UK). Read codes (a coded classification of clinical terms used in UK primary care to record information electronically) were used to identify a prevalent cohort with a practice diagnosis of COPD as at 31/12/2010 and to assess smoking status and FEV1 %predicted.
The total cohort consisted of 16,185 patients (male 54.5%) mean (SD) age 70.9 yrs (11.4). FEV1 %predicted values were available in 50% of patients: median (IQR) 59 (45-72). Smoking status was recorded in 96.2% of patients: 37% current smokers, 57% ex-smokers and 3% never smokers. In patients aged <65 years, 57% (n=2521) were current smokers, compared to 29% (n=3411) of those aged >65 years (p<0.0001). In those patients with FEV1 ?50%, the proportion of currently active smokers was highest in the youngest patients: 72.7% (n=341) in those aged <55 years and 55.4% (n=572) in those aged 55-64 years, whereas in the older patients only a minority were active smokers: 38.8% (n=698) in those aged 65-74 years and 24.8% (n=476) in those aged >75 years.
: While smoking cessation is important in all patients with COPD, evidence suggests that we have been largely unsuccessful in helping younger patients and those with better preserved lung function. Support should be maximised early in the disease when there is the greatest scope for improving the prognosis.
- Lynn Josephs, NIHR CLAHRC Wessex Methodological Hub, University of Southampton, Southampton, UK
- Matthew Johnson, NIHR Biomedical Research Unit, University of Southampton, Southampton, UK
- Rosanna Orlando, NIHR Biomedical Research Unit, University of Southampton, Southampton, UK
- David Culliford, NIHR Biomedical Research Unit, University of Southampton, Southampton, UK
- Paul Roderick, NIHR CLAHRC Wessex Methodological Hub, University of Southampton, Southampton, UK
- Mike Thomas, NIHR CLAHRC Wessex Methodological Hub, University of Southampton, Southampton, UK