The quality was variable, with the main reasons for downgrading due to risk of bias being a lack of detail about randomisation/allocation concealment and imprecision due to small study size. Many of the studies had small numbers of patients or events, with large confidence intervals around the effect estimates ranging from a clinically important harm to a clinically important benefit. Quality of life was downgraded for performance bias in all studies, as it was not possible to blind participants. There was also concern that some larger studies stated intent to measure quality of life in the study protocol, but with limited or no results presented, suggesting selective reporting. The committee considered that overall, the evidence was of low quality, often imprecise, and noted that even the direction of effect was inconsistent between outcomes and between studies. The numbers of hospitalisation and deaths in many of the studies was less than might be expected, and that this may represent selection bias towards healthier patients in these trials. Therefore, there may be problems generalising the evidence to the current heart failure population in the UK. In addition, many of the studies were over twenty years old, and most not in the context of current NHS practice, further restricting their applicability. The committee considered whether further research in this area would improve recommendations in this area. While the current evaluation is hampered by heterogeneous small trials, there were some larger trials such as COACH and NorthStar, which have given some moderate and high quality findings. It was not felt to be worthwhile to prioritise research that aimed to add to or improve on these at the current time. 