This is a small study out of Japan involving only 42 patients. The main conclusion is no surprise; for men with moderate to severe lower urinary tract symptoms (e.g., needing to urinate frequently at night), ADT reduces those symptoms significantly. What is surprising is that men on ADT with mild lower urinary tract symptoms have a significant increase in the need to go to the bathroom at night.
The authors speculate on how the lack of testosterone could account for this. One possibility is the problem is really an indirect one. Low testosterone can lead to poor sleep quality. Maybe the men are just sleeping badly and figure, since they are awake, they might as well go to the bathroom. The article does not resolve the question of whether the men are waking up because of an urgent need to urinate, or because they are sleeping poorly and figure that it is best to empty their bladder now that they are awake.
Washino S, Hirai M, Saito K, Kobayashi Y, Arai Y, Miyagawa T. 2016. Impact of androgen deprivation therapy on volume reduction and lower urinary tract symptoms in patients with prostate cancer. Low Urin Tract Symptoms [Epub ahead of print] 12 December 2016. www.ncbi.nlm.nih.gov/pubmed/27943566