Purpose: This study aims to assess the implementation of published research, contraindications, and warnings on the prescription of dual renin-angiotensin-hormone system (RAS) blockade in ambulatory care in Germany.
Methods: Cohort study based on health claims data of 6.7 million subjects from 2008 to 2015. Yearly prevalence and incidence for dual RAS blockade with (a) angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers (ACEI + ARB) and (b) aliskiren and ACEI or ARB (aliskiren + ACEI/ARB) were calculated. We assessed prescriber specialty and associations between discontinuing dual RAS blockade with specialist (internal medicine, cardiology, nephrology) visits and hospital discharge in the previous year.
Results: A total of 2 984 517 patients were included (age 51.4 ± SD 18.4 y, 48.5% male). Prescription rates for ACEI + ARB decreased from 0.6% (n = 17 907) to 0.4% (n = 12 237) and for aliskiren + ACEI/ARB from 0.23% (n = 6634) to 0.03% (n = 818). Incident prescriptions decreased from 0.23% (n = 6705) to 0.19% (n = 5055) (ACE + ARB) and from 0.1% (n = 2796) to 0.005% (n = 142) (aliskiren + ACE/ARB); 59% of ACEI + ARB and 48% of aliskiren + ACE/ARB combinations were prescribed only by one physician. Of those, 73% (ACEI + ARB) and 58% (aliskiren + ACE/ARB) were primary care providers (PCPs). Discontinuing dual RAS blockade was associated with specialist care and hospital discharge in the previous year (specialist care: RR 1.4, 95% CI, 1.3-1.6; hospital visit: RR 1.5, 95% CI, 1.3-1.6).
Conclusions: Our results suggest a delayed uptake of treatment recommendation for ACEI + ARB and a higher impact of Dear Doctor letters addressing PCPs directly compared with published research, contraindications, and warnings. Targeted continuous medical education, practice software alerts, and stronger involvement of pharmacists might improve the implementation of medication safety recommendations in ambulatory care.
Keywords: ACE inhibitors; ARB; Dear Doctor letter; dual RAS blockade; pharmacoepidemiology.
© 2020 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.