We wanted to discover whether using the SiT was better or worse than alternatives, such as receiving two separate inhalers for regular treatment and relief of symptoms.
What did we do?
We reviewed the clinical trials that looked at SiT against inhaled steroids and reliever medication given as two separate inhalers (sometimes called current best practice).
What did we find out?
We found 13 trials on 13,152 adults and one trial also included 224 children, up to February 2013. The trials were all sponsored by the manufacturer of the single inhaler.
When compared with current best practice or higher doses of inhaled steroid, we found that SiT probably reduces the number of flare-ups that will need treatment with an oral steroid in adults but we are uncertain whether the number of adults admitted to hospital would be reduced. When compared with high doses of inhaled steroids, we found that fewer people experienced a flare-up that needed treatment with an oral steroid.
The results for death (1 per 1000 people given either treatment), or life threatening problems (just under 50 per 1000 people given either treatment), were too imprecise to enable us to rule out either treatment being more harmful than the other. More adults left the trial early because they experienced adverse effects in the group taking single inhalers. There was only one small trial in children, so we are unable to make any firm conclusions in children.
The studies were generally well-designed, although in the studies which compared SiT against current best practice people knew which treatment they were getting, and this could have affected the reliability of the results. The studies comparing SiT against inhaled steroids were designed differently and were more reliable. Overall, we think that more evidence from future trials might change the strength of the conclusions for the question of whether SiT is better than current best practice. We believe that there is good quality evidence that SiT is more effective than high dose inhaled steroids, although the studies recruited people who were likely to respond.