Clinical trial NCT03141593: Oral Vitamin D Substitution Weekly or Monthly and Adherence
Official title: Oral Vitamin D Substitution Weekly or Monthly - Which Procedure Leads to Highest Adherence? A Prospective Intervention Study in Outpatient Care
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE4
Conditions: Vitamin D Deficiency
Keywords: adherence to medication
electronic monitoring
Lead sponsor: University Hospital, Basel, Switzerland
Sponsor class: OTHER
First posted: 2017-05-05
Enrollment: 97
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Patient will be recruited by their general practitioners (GP) and allocated to the GP's form (liquid or solid). Patients will be randomly assigned to start weekly or monthly intake for 3 months, and switch to the other frequence for 3 more months.
Primary purpose: TREATMENT

Brief summary: Vitamin D deficiency (defined as 25(OH)-vitamin D serum level \<50 nmol/l) is cured with supplementation by mouth. National guidelines recommend the administration of 800 IU cholecalciferol daily for an effective treatment, especially during the winter (poor sun exposition). Commercially available pharmaceutical forms are liquid in Switzerland (drops) and solid forms in Germany (tablets and capsules). Because therapeutic range of vitamin D3 is wide and toxicity is seldom reached, even after the consumption of 200'000 IU, and because the administration of 8 drops daily is inconvenient, weekly and monthly administrations of the cumulative amount (i.e., 5'600 IU weekly or 24'000 IU monthly) have been investigated. Both administration schedules are therapeutic equivalent. The study aims to investigate which form (liquid or solid) and which schedule (weekly or monthly) procure the highest adherence behavior with outpatients under polypharmacy i.e., with 4 or more medications daily. The investigators will use commercially available Swiss and German products.

Detailed description: Intervention study in patients with serum vitamin D \<50 nmol/l and polypharmacy, defined as ≥4 medicaments/day. Treatment duration: 6 months. Treatment groups are defined as Lm (liquid monthly 24'000 IU); Lw (liquid weekly 5'600 IU); Sm (solid monthly 20'000 IU) and Sw (solid weekly 5'600 IU). Cross-over design with identical form (liquid or solid) and switching frequence, i.e. from weekly to monthly treatment and vice versa, for 3 months each.

Eligibility criteria: Inclusion Criteria:

* vitamin D deficiency by serum level \<50 nmol/l
* polypharmacy defined as 4 daily medicines or more
* speaking German or Swiss German

Exclusion Criteria:

* hypercalcaemia
* substitution treatment with cholecalciferol in the past 3 months
* medication intake provided by a third person and not by the patient himself

Primary outcomes:
measure: Adherence to medication
timeFrame: 3 months of treatment
Secondary outcomes:
measure: Serum level of vitamin D
timeFrame: 3 and 6 months
measure: Patients preferences
timeFrame: 3 months of treatment
Other outcomes:
Locations:
city: Basel
country: Switzerland
facility: Pharmaceutical Care Research Group
Study officials:
affiliation: University of Basel
name: Kurt E Hersberger, Prof
role: STUDY_DIRECTOR
References: