Studies have shown that although thickeners may reduce the number of episodes of reflux, they prolong the length of time of the remaining episodes of reflux because thickened fluid does not drain as well from the oesophagus.
In general, thickeners will not cure reflux, just temporarily alleviate the reflux. If you are considering them, please check with your doctor before introduction.
http://www.cryingoverspiltmilk.co.nz/food/thickeningagentsforreflux/