Medical and Health Sciences, Clinical Medicine, General Medicine, Medicin och hälsovetenskap, Klinisk medicin, Allmänmedicin, Basic Medicine, Epidemiology, Medicinska och farmaceutiska grundvetenskaper, Epidemiologi, Health Sciences, Health Care Service and Management, Health Policy and Services and Health Economy, Hälsovetenskap, Hälso- och sjukvårdsorganisation, hälsopolitik och hälsoekonomi

Objective We aimed to investigate whether health-promoting text messages sent to patients with hypertension in primary care could affect lifestyle habits, and if the Theory of Planned Behavior could be used to identify moderators of intervention effects. Methods From September 2020 to December 2022, patients with hypertension were randomly selected from the patient register at 10 Swedish primary health care centers and randomized 1:1 to receive health-promoting text messages or treatment as usual (N = 401). The intervention group received four text messages per week for six months. Self-reported measures of lifestyle habits were collected through a questionnaire at baseline and after six months. Predictors of behavioral change according to the Theory of Planned Behavior were collected through a baseline questionnaire. The data were analyzed according to the intention-to-treat principle. We compared lifestyle habits between the intervention and control groups at follow-up with adjustment for baseline measures through logistic regression analysis and analysis of covariance. Results The text message group had a statistically significant decrease in the proportion of participants with alcohol use above four standard drinks per week (OR 0.35, 95 % CI 0.15–0.81), and in the proportion of participants being physically inactive (OR 0.60, 95 % CI 0.37–0.98). The effect could not be explained or predicted by a pragmatic adaptation of the Theory of Planned Behavior. Conclusions Health-promoting text messages could be offered to Swedish primary care patients with hypertension as part of the effort to improve their lifestyle habits.