Text Message Intervention for Prevention of Cardiovascular Disease in Primary Care Patients With Hypertension
Condition: Hypertension; Cardiovascular Risk Factor
MeSH terms: Hypertension; Cardiovascular Diseases
Study type: Interventional

Summary: 
      The primary objective of the study is to examine the impact of lifestyle advices,
      administered through regularly sent SMS, on hypertension in a primary health care setting.
      The secondary objective is to evaluate changes in other cardiovascular risk factors and
      general health, e.g. tobacco use, obesity, blood lipids, blood glucose, self-rated health and
      health-related quality of life.
    

Detailed description: 
      Background- The globalization of unhealthy lifestyles and demographic ageing of the world's
      population has contributed to the fact that high blood pressure is classified by World Health
      Organization as the world's leading risk for mortality.

      Persistent hypertension is a key risk factor for coronary heart disease (CHD), stroke and
      other cardiovascular diseases (CVD), such as heart failure. CVD is, despite a decline in
      recent decades, still the leading cause of death in Sweden (4). The prevalence of
      hypertension in adults is around 40% according to a recent multinational study (5). In 30-40%
      of hypertensive individuals, additional metabolic risk factors such as dyslipidemia, insulin
      resistance and elevated glucose occur simultaneously, which further multiply the risk for
      heart disease, diabetes and stroke. An unhealthy lifestyle with physical inactivity and
      excess energy intake is the major driver of these metabolic risk factors. In most cases
      lifestyle intervention can reverse or reduce the unfavorable metabolic profile.

      Primary healthcare in Sweden is managing the first-line healthcare, offering both prevention
      and treatment for a majority of chronic diseases. In Sweden, the vast majority of patients
      with hypertension are treated in primary health care. If the hypertension is well controlled,
      the GP typically meets the patient once a year for medical checkup, blood tests and medical
      prescription.

      Interventions by SMS-texting have been shown to significantly improve compliance to
      medications, follow-up rate or disease monitoring.

      Trial Design - Randomised clinical trial

      Intervention - The experimental treatment will consist of an SMS-intervention addressing
      metabolic risk factors associated with cardiovascular disorders in patients with
      hypertension.

      After baseline measurement participants in the intervention group will receive four
      semi-personalized messages per week in addition to their usual care according to the National
      Board of Health and Welfare guidelines for hypertension treatment. The text messages will be
      developed to support healthy life style changes i.e. regarding general cardiovascular health,
      tobacco use, physical activity and diet.

      Control Treatment - The control group will receive usual care according to the National Board
      of Health and Welfare guidelines for hypertension treatment.

      Recruitment - The participants will be recruited consecutively from three different PHCCs in
      Skåne. Patients with hypertension will receive information about the study at their annual
      check-up or other appointment with their GP. If they choose to participate, they will be
      contacted by phone by a research assistant for additional information, possibility to ask
      questions about the study, and scheduling a baseline control at their PHCC.

      Baseline examination - Included patients that consent to take part in the study will be
      invited to their PHCC for a baseline visit. The following measurements will be assessed by a
      research assistant: blood pressure (in sitting position after 5 minutes rest; mean of two
      measurements in a standardized procedure with validated electronic BP devices), BMI and
      waist-hip circumference. Furthermore, the patients will complete a short questionnaire for
      evaluation of medical history, medication, tobacco and alcohol use, physical activity level,
      self-rated health and health-related quality of life. Blood samples for fasting plasma
      glucose, HbA1c and cholesterol will be drawn in the morning within a few days after the
      baseline visit.

      Randomization- Randomization to study groups will be performed after completion of baseline
      assessments and questionnaires. A computer generated random number schedule with block sizes
      of four will be prepared. To assure allocation concealment, the information about group
      affiliation will be delivered through sealed envelopes.

      The research assistant, the patients' GPs, as well as all researchers except Magnus Sandberg
      (MS) will be blinded to group allocation. If the patients have questions regarding the SMS
      function they will be able to contact MS for help.

      Follow up- Follow up control will be performed after 6 months with the same assessments as at
      the baseline visit.

      Power and sample size - For the pilot study we have assumed that a total number of 60
      patients (20 patients per PHCC) will be sufficient to evaluate the feasibility of the
      intervention and the logistics of the assessments.

      For the future full scale study, each group must contain 143 participants. The sample size is
      based on an assumed statistical power of 80 %, a two-sided test, a significance level of 5 %,
      a difference of 5 mm Hg between the groups, a standard deviation of 14 mm Hg and a drop out
      rate of 15 %.

      Analysis plan - Data will be analysed according to the Intention-to-treat principle.
      Differences in mean change of end points between intervention and control groups will be
      calculated by ANCOVA, with baseline values as covariates.
    

Intervention name(s): SMS
Intervention type(s): Behavioral
Intervention description(s): The experimental treatment will consist of health promoting text messages addressing metabolic risk factors associated with cardiovascular disorders in patients with hypertension. Participants will receive four semi-personalized messages per week in addition to their usual care. The text messages will be developed to support healthy life style changes i.e. regarding general cardiovascular health, tobacco use, physical activity and diet.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Randomized controlled trial
Masking: Triple (Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Hypertension; Text Messaging; Primary Prevention; Cardiovascular Risk Factor; Primary Health Care; Health Promotion