A reminder, the automated review system is a proof of concept. Using the example of obesity I’d like to point out problems and explain why they are happening. In part this to acknowledge them but more importantly to give a further insight in to how the system works!

Two evidence blobs stood out, to me, antibiotics and probiotics:

Antibiotics:  The positive, low risk of bias, RCT was “Efficacy of prophylactic antibiotic administration for breast cancer surgery in overweight or obese patients: a randomized controlled trial“.  So, our system has mis-classified this by not picking up the breast cancer.  It’s a similar issue with the two other trials included, both are about surgery in obese patients.

I’m going to see if we can exclude trials where two ‘populations’ (breast cancer and obesity) are mentioned for a given trial. Although I wonder if that causes more problems than it solves!

Probiotics: There was a recent systematic review “Effects of probiotics on body weight, body mass index, fat mass and fat percentage in subjects with overweight or obesity: a systematic review and meta-analysis of randomized controlled trials“, it concludes:

“Administration of probiotics resulted in a significantly larger reduction in body weight (weighted mean difference [95% confidence interval]; -0.60 [-1.19, -0.01] kg, I2 = 49%), BMI (-0.27 [-0.45, -0.08] kg m-2 , I2 = 57%) and fat percentage (-0.60 [-1.20, -0.01] %, I2 = 19%), compared with placebo; however, the effect sizes were small. The effect of probiotics on fat mass was non-significant (-0.42 [-1.08, 0.23] kg, I2 = 84%).”

So, it’s a positive review – albeit it with small effect size. Our system cannot distinguish large or small effect sizes – simply positivity or negativity.  Hence it appears as one of the better interventions!

I’m not sure how to overcome that one…!