Description of practices regarding supplementation after HYPOvitaminosis-D investigation in middle-age community dwelling general population (HYPO-D Study)

Study type

• Study topic:
  Disease /health condition

  Human medicinal product
• 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:
  (A11CC) Vitamin D and analogues

  Vitamin D and analogues
• Medical condition to be studied:
  Vitamin D deficiency

Population studied

• Short description of the study population:
  Patients aged 13–60 years who had a 25(OH)D assay between 1 December 2008 and 31 January 2009.
• Age groups:
  • Adolescents (12 to < 18 years)
  • Adults (18 to < 46 years)
  • Adults (46 to < 65 years)
• Estimated number of subjects:
  3000

Study design details

• Main study objective:
  Our purpose was to compare health care use after vitamin D supplementation versus before in patients likely to have 25(OH)D deficiency.
• Outcomes:
  Healthcare use comparison between pre and post-supplementation concerned: the number of physician visits and recorded medical interventions, of different drug prescriptions, of drug classes per distinct dates of prescription -defined by ATC codes, of medical of medical imaging exams, of incident sick leaves and cumulated days of leaves prescribed, and of incident hospitalizations.
• Data analysis plan:
  The study population was described using mean and standard deviation for continuous variables and frequencies and proportions for discrete variables. The supplemented and the not supplemented groups were compared using t-test when variables were continuous and Chi-square test when variables were discrete. Healthcare use within each group was compared before and after the index date using paired t-tests on the same sample for continuous variables, and Mc Nemar Chi-squared test for discrete variables. A threshold of 0.05 was used for statistical significancy.To adjust the comparison before-after supplementation for potential biases due to different types of healthcare users we used KML clustering. Analyses were performed using SAS Enterprise Guide V 4.3 (SAS Institute Inc. Cary, NC, USA). Longitudinal clustering was performed using R version 2.13.0 with KML package.