“…Thirty-three studies (37.5%) stated numbers and reasons for withdrawals in sufficient detail, 57,[115][116][117][118]123,127,128,131,133,134,[137][138][139][140]143,146,147,153,156,159,164,166,167,175,178,181,183,187,189,[197][198][199] while another 33 studies (37.5%) stated the number of withdrawals but did not describe reasons for withdrawals. 107,119,121,122,129,130,132,135,141,142,144,145,150,152,154,155,162,163,165,168,172,176,…”