Dapagliflozin in Type 2 Diabetes Patients, a Retrospective Cohort Study From Turkey
Condition: Type 2 Diabetes Mellitus
MeSH terms: Diabetes Mellitus; Diabetes Mellitus, Type 2
Study type: Observational

Summary: 
      Background/Rationale:

      Objectives and Hypotheses: To describe characteristics of patients with type 2 diabetes (T2D)
      prescribed dapagliflozin in routine internal medicine and endocrinology outpatient clinical
      care in Turkey; to describe changes in HbA1c(%), weight(kg), BMI(kg/m^2) and blood pressure
      (BP)(mmHg) in these patients; and the discontinuation rates of dapagliflozin in the first 6
      months of treatment.

      Methods:

      Study design: a retrospective observational cohort study. Data Source(s): Patient medical
      records of 81 different centres. Study Population: patients with a diagnosis of T2D, a first
      prescription for dapagliflozin, between July 2016 and Aug 2017 and who have been registered
      in the participating centre at least 6 months prior to first prescription of dapagliflozin.

      Study variables: patient characteristics: age, gender, smoking status, co-morbidities,
      duration of diabetes, prescribed medicines, HbA1c(%), weight(kg), body mass index
      (BMI)(kg/m^2) and blood pressure (BP)(mmHg).

      Outcome(s): description of patient characteristics, HbA1c(%), weight(kg), BMI(kg/m^2) and
      BP(mmHg) at baseline and during use of dapagliflozin at first visit (2,3 or 4 months) and
      second visit (5 or 6 months).

      Sample Size Estimations:1500 patients Statistical Analysis: the baseline characteristics and
      follow up variables will be described using frequency and percentage distributions for
      categorical variables. Continuous and count variables will be described using mean (±
      standard deviation), median (quartiles) and 95% confidence intervals. Proportion of patients
      falling above/below certain weight(kg)/BMI(kg/m^2), HbA1c(%) and BP(mmHg) thresholds will be
      derived. HbA1c(%), weight(kg), BMI(kg/m^2) and BP(mmHg) will be described at baseline and
      during use of dapagliflozin. Over all questionnaire response rate and rate of response to
      reasons for prescribing dapagliflozin will be described.

      Limitations: Variation in timing and completeness of clinical measures. The patient medical
      records are not collected for research purposes and the diagnostic and procedure coding on
      such data may be recorded incorrectly or not recorded at all, thereby potentially introducing
      measurement error with respect to code-based variables. The centres participating in the
      study, record that a prescription was issued, but not whether it was dispensed from the
      pharmacy.
    

Detailed description: 
      This study is a descriptive retrospective observational cohort study using data from Turkish
      patient medical records from 81 different internal medicine and/or endocrinology clinics
      across the whole country.

      The study cohort will include T2D patients who received at least one prescription for
      dapagliflozin for the first time between July 2016 and Aug 2017 and who have been registered
      in that centre for at least 6 months prior to the first dapagliflozin prescription.

      The selection of sites and investigators will be made with an aim to achieve
      representativeness of the way dapagliflozin treated T2D patients are managed across Turkey.
      The National Coordinator will provide advice regarding the proportion of the different types
      of centres (Internal medicine, endocrinology clinics, different types of hospitals,
      geographical distribution) and investigators (different types of specialists) involved in
      dapagliflozin treated T2D patient management. The National Coordinator will also provide
      insight on the national situation regarding dapagliflozin medication prescription
      (reimbursement, public or private insurance). All this information will be used to select
      sites and investigators for the study, resembling as closely as possible, the real-world
      situation.

      Sites will also be evaluated for existence and use of electronic medical records as part of
      feasibility. Data quality of sites will be assessed before initiation visit. The study centre
      database should provide at least 20 patients to the study. In case the study centre, can
      provide more than 20 patients, then patients will be selected randomly by the Contract
      Research Organization. Contract Research Organization will also record total number of
      eligible patients, their age and sex details before performing randomization. The
      randomization process will be performed at the study site after initiation visit by Contract
      Research Organization. The investigator of the centre will enter only selected patients to
      study Case Report Form. The Contract Research Organization will also perform 100% source
      document verification following completion of Case Report Forms by the investigator. All
      centres will be evaluated by Contract Research Organization at initiation visit in terms of
      data quality (Baseline, first visit and second visit data of eligible patients)

      The date of the first prescription for dapagliflozin in patient medical records is the index
      date. Patients will be followed from the index date until the earliest of transfer out date,
      death date or end date of patient records (last date of data collection). Required data
      mentioned in baseline characteristics (section 5.1) will be recorded at index date, first
      visit (2 or 3 or 4 months after index date) and second visit (5 or 6 months after index date)
      of treatment (section 5.2).

      Dataset quality will be assessed by Contract Research Organization at initiation visit. Site
      investigator is responsible for entering data to Case Report Forms. Paper based Case Report
      Form system will be used for this study. Datasets can differ for each hospital and patient's
      records can be electronic and/or printed. The investigator will collect all necessary data
      for each patient retrospectively from the most reliable data source in the clinic. All
      collected data will be verified by the Contract Research Organization.
    

Intervention name(s): Forxiga
Intervention type(s): Drug
Intervention description(s): Oral antidiabetics
Intervention MeSH terms: Dapagliflozin
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        The study cohort will be selected from patient records of 81 different centres. 1500
        patients are planned to include in this study.
      
Keywords: Diabetes; Dapagliflozin; Endocrinology; Internal diseases; Type II diabetes mellitus; HbA1c; BMI; BP