What are the possible sources of bias in the studies included in the NICE 2018 recommendation for chronic heart failure monitoring?
An assessment of possible sources of bias showed that the randomisation and allocation concealment was either unclear or inadequate in many studies. The level of missing data was also not clear for some of the included studies, and there was limited detail in the existing meta-analyses on how the authors minimised the effects of missing data. Together these factors led to a high risk of bias assessment for many of the outcomes, including the mortality and quality of life evidence.