3.1 Characteristics of the study population
During the observation period from June 2018 to June 2020 135 patients
underwent testing with the 16-gene PGx panel (Figure 1 ).
Patient characteristics are presented in Table 1 , including a
stratification over drug-specific indication vs. screening. Compared to
33 subjects with a screening indication, the 102 patients with a
drug-specific indication for PGx testing were older (median 70 vs. 58
years) and took a higher number of drugs (median 6 vs. 3). The three
most frequent drug-specific indications for PGx-testing were therapy
with clopidogrel (n = 60), tamoxifen (n = 15) and
polypsychopharmacotherapy (n = 9). Medications in the tested population
were predominantly related to cardiovascular diseases, but we also
observed frequent use of analgesics, antidepressants, antidiabetics and
benzodiazepines.
Furthermore, drug-gene interactions may be particularly relevant in the
presence of additional drug-drug interactions that affect the same
metabolic pathway or in case of impaired renal function. It is therefore
of interest that 19.3% of the study population took inhibitors of
CYP2D6 and 8.2% of CYP2C19, and that 14.1% had an eGFR below 60
ml/min.