Evolution of Prescribing Patterns of Antidiabetic and Anti-Obesity Drugs in the Tuscany Region: An Integrated of Utilization and Safety Analysis, and the Role of AIFA Note 100 (PATTERN-100 Prescribing PATTERNs of Antidiabetic and Anti-obesity Drugs: Utilization, Safety and the Role of AIFA Note 100)

Study type

• Study topic:
  Human medicinal product

  Other
• Study topic, other:
  Antidiabetics and anti-obesity drugs use
• Study type:
  Non-interventional study
• Scope of the study:
  Drug utilisation
• Data collection methods:
  Secondary use of data

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Anatomical Therapeutic Chemical (ATC) code:
  (A10) DRUGS USED IN DIABETES

  DRUGS USED IN DIABETES
• Medical condition to be studied:
  Diabetes mellitus

  Obesity

Population studied

• Short description of the study population:
  Drug Utilization Analysis; The study population will be identified from all individuals registered in the regional healthcare registry during the study period (1 January 2016 to 31 December 2025). Among these individuals, all subjects with at least one dispensing of an antidiabetic drug of interest during the study period will be identified. The date corresponding to the first dispensing of any antidiabetic drug of interest during the study period will be defined as the index date. Subjects with less than two years of observation before the index date will be excluded from the study population.; ; Pharmacovigilance Analysis; All reports recorded in the italian national pharmacovigilance network (Rete Nazionale di Farmacovigilanza RNF for the Tuscany Region will be included if they concern adverse events occurring during the study period and list, as suspected or interacting drugs, molecules belonging to the ATC classes of interest (antidiabetics).
• Age groups:
  • Adult and elderly population (≥18 years)

    • Adults (18 to < 65 years)

      • Adults (18 to < 46 years)
      • Adults (46 to < 65 years)
    • Elderly (≥ 65 years)

      • Adults (65 to < 75 years)
      • Adults (75 to < 85 years)
      • Adults (85 years and over)

Study design details

• Study design:
  1) A retrospective observational cohort study on healthcare administrative data; 2) A pharmacovigilance study of reports of suspected adverse drug reactions to antidiabetic medications ; Study period: Jan 2016 - Dec 2025; Country: Italy, Tuscany Region
• Main study objective:
  This study aims to describe the evolution of utilization patterns of medications used for the treatment of diabetes and obesity in the Tuscany Region, and specifically within its three Regional Health Areas, during the period 2016–2025. In addition, safety data will be analysed to support the interpretation of utilization findings.; ; Objectives; -To assess trends in the number of incident and prevalent users of antidiabetic drugs of interest within each Regional Health Area during the study period (2016–2025), before and after the introduction of AIFA Note 100 in January 2022 and its subsequent update in July 2025.; -To describe the characteristics of new users of specific antidiabetic drug classes of interest in terms of demographic characteristics, comorbidities, and prior antidiabetic treatments from 2016 to 2025, with particular emphasis on the periods before and after the introduction of AIFA Note 100 and its subsequent update.; -To evaluate trends in reports of suspected adverse reactions to antidiabetic drugs originating from the regional territory during the study period and compare them with trends in drug utilization.; ; The description of utilization patterns observed before and after the implementation and modification of AIFA Note 100 is intended solely to characterize potential changes in the use of antidiabetic medications within the evolving regulatory context. The findings of this study are expected to generate hypotheses that may be explored in future dedicated investigations. Therefore, the present study is not intended to assess causal relationships, nor to identify determinants or predictors of prescribing patterns.
• Setting:
  Drug Utilization Analysis; The study population will be identified from all individuals registered in the regional healthcare registry during the study period (1 January 2016 to 31 December 2025). Among these individuals, all subjects with at least one dispensing of an antidiabetic drug of interest during the study period will be identified. The date corresponding to the first dispensing of any antidiabetic drug of interest during the study period will be defined as the index date. Subjects with less than two years of observation before the index date will be excluded from the study population.; Pharmacovigilance Analysis; All reports recorded in the italian national pharmacovigilance network (Rete Nazionale di Farmacovigilanza RNF for the Tuscany Region will be included if they concern adverse events occurring during the study period and list, as suspected or interacting drugs, molecules belonging to the ATC classes of interest (antidiabetics).
• Comparators:
  Not applicable
• Outcomes:
  -Trends in the number of incident and prevalent users of antidiabetic drugs of interest within each Regional Health Area during the study period (2016–2025), before and after the introduction of AIFA Note 100 in January 2022 and its subsequent update in July 2025.; -Characteristics of new users of specific antidiabetic drug classes of interest in terms of demographic characteristics, comorbidities, and prior antidiabetic treatments from 2016 to 2025, with particular emphasis on the periods before and after the introduction of AIFA Note 100 and its subsequent update.; -Trends in reports of suspected adverse reactions to antidiabetic drugs originating from the regional territory during the study period and compare them with trends in drug utilization.
• Data analysis plan:
  Drug Utilization Analysis; All analyses will be descriptive. Continuous variables will be summarized as median and interquartile range (IQR); categorical variables as absolute frequencies and percentages.; For each calendar year (2016-2025), users will be classified as prevalent users (at least one dispensing in the year) or incident/new users (no dispensing of the same drug in the preceding two years). Annual trends in incident and prevalent users of each antidiabetic drug class (DPP-4 inhibitors, SGLT2 inhibitors, GLP-1 receptor agonists, tirzepatide, and combinations) will be described for each Regional Health Area throughout 2016-2025. New users will be characterized by age, sex, prior metformin use, prior use of other antidiabetics, and comorbidities, stratified by Regional Health Area and period (pre-, during, and post-update of Note 100).; An additional analysis will explore the impact of body mass index (BMI) on antidiabetic drug utilization among users who delivered a child in the year preceding the index dispensing, identified via linkage with the Birth Registry (CAP) database, recording maternal weight, height, and gestational/pre-existing diabetes. Pre-pregnancy BMI (kg/height² in m²) will be categorized as underweight (<18.5), normal weight (18.5-24.9), or overweight/obesity (>24.9).; Pharmacovigilance; Analyses will be descriptive, characterizing clinical and demographic features of patients reporting adverse drug reactions (ADRs) to antidiabetic drugs, and reported events (MedDRA classification, seriousness, outcome), from the National Pharmacovigilance Network (RNF). Categorical variables as frequencies/percentages; continuous variables by mean and median, per distribution.; Annual reporting rates = number of reports / number of antidiabetic drug users × 1,000. Administrative databases will estimate annual users, i.e. all individuals with at least one dispensing of a drug of interest per study year.
• Summary results:
  As of the current registration date, data extraction and statistical analyses have not yet been finalized.