A case-control study of asthma outcomes in general practice patients with a history of opiate misuse: preliminary findings from the Lung-Heath of opiate users (L-Hop) project

Problem

Opiate misusers are encouraged to smoke rather than inject drugs in order to reduce the risk of fatal overdose and blood borne virus transmission. However, it is known that inhalation of opiates can lead to progressive lung disease and trigger acute severe exaserbations. The 2014 National UK report ‘Why asthma still kills’ identified substance misuse as a factor in 6% of deaths and also highlighted excessive prescribing of inhaled beta-agonists and under-prescribing of corticosteriod inhalers as important factors.The present study is concerned with exploring the effect of opiate misuse on asthma. Is there evidence that it is associated with measures of poorer asthma control and suboptimal inhaler use? Is there evidence of excess progression to COPD?

Approach

This is a case-control study using English primary care data. The study population are general practice patients aged 16-59 years. Those with a co-morbid diagnosis of asthma and opiate use (cases) will be compared to a group of matched asthma controls. Data comes from anonymised electronic patient records currently held on the TPP SystmOne clinical system. The primary outcome measure is the proportion of patients who have had greater than 12 issued prescriptions for an inhaled beta-agonist in the previous 12 months. Secondary outcomes include whether there is a co-existing diagnosis of COPD and the proportion of issues of preventer inhalers. Conditional logistic regression, matching on age, gender, smoking status and socioeconomic status will be used.

Findings

Findings from this important large scale study into lung health of opiate users will be presented.

Consequences

The results of this study with form the basis of further work to develop innovative interventions to improve access to healthcare and long-term health outcomes for this vulnerable group.