Effect of Gamification on Improved Adherence to Inhaled Medications in Chronic Obstructive Pulmonary Disease: Randomized Controlled Trial - Xiting Huang; Zhili Jiang; Yifan Dai; Yang Liu; Ziying Dai; Jing Wang; Liping Chen; Zhiqian Wang; Wenxiao Wu; Lihua Huang (Journal of Medical Internet Research)