“…Furthermore, the objectives of the investigation varied. Of the 29 articles included, 18 (62%) articles focused on 1 app [ 16 , 18 , 19 , 22 , 25 , 26 , 30 , 32 , 33 , 36 - 44 ], 2 (7%) articles focused on multiple apps [ 24 , 35 ], and 9 (31%) articles did not focus on a specific app or device [ 17 , 21 , 23 , 24 , 27 - 29 , 34 , 35 ]; 8 (28%) studies included had a qualitative design [ 16 , 18 , 21 , 32 , 34 , 37 , 39 , 42 ], 5 (17%) studies were quantitative [ 22 , 24 , 27 , 31 , 35 ], 12 (41%) had a mixed methods design (qualitative and quantitative) [ 19 , 20 , 25 , 26 , 30 , 33 , 36 , 38 , 40 , 41 , 43 , 44 ], and 4 (14%) studies were reviews [ 17 , 23 , 28 , 29 ] ( Multimedia Appendix 1 ). Most qualitative studies were based on interviews [ 16 , 26 , 30 , 32 - 34 , 39 - 42 , 44 ], focus group studies [ 18 , 21 ,…”