SMS Reminders to Improve Medication Adherence of Aromatase Inhibitors
Condition: Breast Cancer; Medication Adherence
MeSH terms: Breast Neoplasms
Study type: Interventional

Summary: 
      The purpose of this study is to determine whether weekly SMS reminders are effective in
      improving medication adherence of adjuvant aromatase inhibitors in women with breast cancer.
    

Detailed description: 
      This study is a prospective randomised controlled parallel trial of SMS reminder versus
      standard care to investigate whether SMS reminder improves adherence to oral aromatase
      inhibitor (AI) therapy amongst women with breast cancer at 1-year follow-up.

      All subjects will be randomised to receive either SMS reminder or standard care in a 1:1
      ratio. Balanced permuted block randomisation will be implemented with random varying of block
      sizes of 4 or 6.

      The sample size is estimated based on the primary endpoint of medication adherence (as
      measured via SMAQ) at 1-year. Assuming that the proportion of medication adherence in the
      intervention and control groups are 80% and 60% respectively, then based on a 5% significance
      level and a power of 90%, a minimum sample of 240 subjects (i.e. 120 per group) will be
      required. Further assuming an attrition rate of 10%, the anticipated trial size is 280
      overall.

      The assessment of medication adherence at 1-year (as measured via SMAQ) between the SMS
      reminder and control groups will be made using chi-square test. Adjustment for baseline
      covariate and potential confounders will be made using the logistic regression where
      appropriate.

      Other measures of adherence such as the 1-year MPR, PDC and pill count will be compared
      between treatment arms via the t- test, with adjustment for confounders made via the analysis
      of covariance (ANCOVA).

      Natural log transformation will be implemented on the estrone and androstenedione measures to
      normalise the data. The assessment of secondary outcomes involving the log transformed
      estrone and androstenedione levels will be made using the analysis of covariance (ANCOVA) to
      adjust for the respective baseline levels and other potential confounders. Comparison of
      estradiol levels (defined as <18.4 versus ≥18.4) between the two arms will be made using
      chi-square test. The logistic regression analysis will be implemented to adjust for baseline
      covariate and other potential confounders where appropriate.

      The assessment of knowledge, attitude, behavior, as well as barrier and facilitating factors
      between the intervention and control groups will be made using chi-square test, with
      treatment effect quantified based on odds ratio estimate and its 95% CI. Further adjustment
      for baseline scores and other potential confounders will be made using the logistic
      regression where appropriate.

      Additionally, the investigators will compare the 4 different measures of adherence in a
      separate paper, to determine which of these provide a more meaningful or reliable information
      in the local context based on sensitivity analysis.

      All analyses will be performed according to intention-to-treat using STATA, assuming a
      two-sided test at the 5% level of significance.
    

Intervention name(s): SMS reminder
Intervention type(s): Other
Intervention description(s): Weekly SMS reminder to take aromatase inhibitors as prescribed by doctor for 1 year
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Health Services Research
Keywords: Aromatase inhibitors; Reminder Systems