6 The cost-effectiveness of the Dutch In Balance fall prevention intervention | 105 Recruitment, randomization, stratification, blinding and treatment allocation Recruitment was done via flyers, advertisements in local papers and the network of the In Balance therapists. Participants were randomized at a 1:1 ratio to the intervention or control group, with stratification based on frailty status. The allocation sequence was generated online using Sealed Envelope by MvG. Sealed randomization envelopes in blocks of 10 (5 envelopes per group) were prepared. Participants were enrolled and assigned to a group by one of the researchers by opening an envelope. All investigators and assessors involved in this study were blinded to group assignment during the data collection. Due to the nature of this study, participants and therapists could not be blinded to group allocation. Intervention and control group In Balance is a group-based fall prevention intervention with a duration of 14 weeks. It is provided by certified physical- and exercise therapists. Exercises based on Tai Chi are combined with education to improve balance and strength as well as to increase awareness of postural imbalance and fall risk (16). The intervention consists of three phases: an information phase (one week), an educational phase (three weeks), and an exercise phase with two training sessions per week (10 weeks). For a detailed description of the intervention, we refer to van Gameren et al. (198). The control group received written general recommendations on physical activity through a flyer according to the physical activity guidelines of the World Health Organization (90). Outcome measures Costs Costs were assessed using the iMTA Medical Consumption Questionnaire (iMCQ) and the iMTA Productivity Cost Questionnaire (iPCQ) at 4, 8, and 12 months after the baseline assessment. The iMCQ was used to measure healthcare costs (including primary and secondary care, home care, and medication), and patient and family costs (informal care). Costs in other sectors were measured using the iPCQ and included costs due to lost productivity (i.e., absenteeism from paid and unpaid work, and presenteeism from paid work). Healthcare utilization was valued using standard costs from the Dutch guideline for economic evaluations (258). Medication costs were determined based on the average daily price for generic medications from the Dutch Healthcare Institute (259). Participants were instructed to report only their prescribed extramural medication. For valuing absenteeism from unpaid work, for example (voluntary) work or informal care, we used a shadow price (i.e., the wage rate for a legally employed cleaner) from the Dutch guideline for economic evaluations (258). To calculate absenteeism from paid work, we applied the friction cost method (260). This method assumes that absent workers are replaced after the friction period and that productivity is restored after that (261). The duration of the friction period used in this study is 115 days
RkJQdWJsaXNoZXIy MjY0ODMw