Comparing Reminders Sent via SMS Text Messaging and Email for Improving Adherence to an Electronic Health Program: Randomized Controlled Trial

Adam Kulhánek   ^{1, 2} , PhD ;   Katerina Lukavska   ^{1, 2, 3} , PhD ;   Roman Gabrhelík   ^{1, 2} , PhD ;   Daniel Novák   ⁴ , PhD ;   Václav Burda   ^{2, 4} , ING ;   Jindřich Prokop   ⁴ , ING ;   Marianne T S Holter   ^{5, 6} , PhD ;   Håvar Brendryen   ^{5, 6} , PhD

¹ Department of Addictology, General University Hospital in Prague, Prague, Czech Republic

² Department of Addictology, First Faculty of Medicine, Charles University, Prague, Czech Republic

³ Department of Psychology, Faculty of Education, Charles University, Prague, Czech Republic

⁴ Department of Cybernetics, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czech Republic

⁵ The Norwegian Centre for Addiction Research (SERAF), Faculty of Medicine, University of Oslo, Oslo, Norway

⁶ Department of Psychology, Faculty of Social Sciences, University of Oslo, Oslo, Norway