Long-acting β2-agonists in adult asthma and the pattern of risk of death and severe asthma outcomes: a study using the GPRD

The objective of this study was to describe risks of death and asthma outcomes with prescription of long-acting beta(2)-agonists (LABA), short-acting beta(2)-agonists (SABA) or inhaled corticosteroids (ICS) in general practice. The study population included beta(2)-agonist users aged >= 18 yrs, who were in the UK General Practice Research Database (GPRD), which is linked to the national registry of hospitalisations. The study included 507,966 patients with 5.5 million SABA, 4.0 million ICS and 1.3 million LABA prescriptions. Rates of asthma outcome increased with more severe treatment steps. The mortality rate was increased with least and most severe treatment steps. Higher relative rates (RR) of outcomes were found in recent starters and heavy long-term users with LABA, SABA and ICS. The RRs in heavy long-term users were 1.9 for all-cause mortality and 3.0 for asthma death with SABA, 1.4 and 1.6, respectively, with LABA and 1.7 and 2.2, respectively, with ICS. The RR of death was statistically similar over time between LABA and ICS despite changes in exposure. Risks for death and asthma outcomes varied substantially with exposure characteristics. The statistical power for detecting increases in asthma death was low. The results of this study did not indicate that LABA exposure was associated with an increased risk for all-cause mortality.