(170) Evaluating Provider and Pharmacy Discordance in Potential Calcium Channel Blocker – Loop Diuretic Prescribing Cascades

Publication Number: 844

Background: Prescribing Cascades (PC) occurs when an adverse event of a medication is treated with a new medication. Identifying indicators that may suggest influence prescribing cascades are important in the prevention of prescribing cascades.

Objectives: To understand the extent to which multiple providers and/or pharmacies contribute to the dihydropyridine calcium channel blocker (DH-CCB)-loop diuretic (LD) prescribing cascade.

Methods: Study Population and

Design: A secondary analysis of a retrospective cohort study using Medicare data (2011-2018) of adults aged ≥66 years who initiated a LD following initiation of a DH-CCB or renin-angiotensin-aldosterone inhibitor (RAASi; angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker) within 360 days.
Exposures: Prescriber and pharmacy discordance in among patients newly initiated on DH-CCB – LD dyad vs. RAASi – LD dyad.
Main Outcomes: Discordance odd ratios with 95% CIs were estimated for both dyads’ patients. Sensitivity analyses were performed for dyads initiated within 180 days and 90 days. Additionally, we restricted the analyses to patients with ≥2 unique providers in the prior 360 days of cohort entry (i.e., DH-CCB or RAASi initiation) using national provider identifier (NPI).

Results: Overall, 1987 patients comprised the DH-CCB – LD dyad, and 3148 patients comprised the RAASi – LD dyad, in which 1250 (63%) patients and 1813 (58%) patients had dyad medications prescribed by discordant providers, respectively. Provider discordance was 25% (OR 1.25 [95% CI, 1.11 – 1.40]), 27% (OR 1.27[95% CI, 1.10 – 1.46]), and 43% (OR 1.43 [95% CI, 1.20 – 1.70]) higher in the DH-CCB – LD dyad vs. RAASi -– LD dyad at 360, 180, and 90 days, respectively. When restricted to patients with ≥2 unique providers prior to cohort entry, the provider discordance increased to 28% (OR 1.28 [95%CI, 1.13-1.45]), 32% (OR 1.30 [95%CI,1.12-1.51]), and 49% (OR 1.49 [95% CI, 1.24-1.80]) higher at 360, 180, and 90 days, respectively. There was no difference in pharmacy discordance between DH-CCB – LD and RAASi – LD dyads (OR 1.06 [95% CI, 0.93 – 1.22]).

Conclusions: Our findings suggest that providers initiating LDs in some cases may be unaware of the DH-CCB prescription; however, having no difference in pharmacy discordance may suggest that pharmacists could play a role in mitigating the DH-CCB – LD prescribing cascade.