CPRD StudyPrimary Care PASS Study

Abstract 138: Evaluating Prescriber Concordance With Prescribing: Results from a Post-Marketing Study

Deborah Layton, Naseer Qayum, Claire Doe, Shayne Freemantle, Saad AW Shakir


At launch (2005), ivabradine (Procoralan©) was indicated for treatment of chronic stable angina pectoris in patients (pts) with normal sinus rhythm, with a contraindication (CaI)/ intolerance for beta-blockers. A drug utilisation study was conducted to support risk management of the drug. Study objectives incl examining CaI, warnings for use (WFU) and incidence of 2 adverse events: visual phosphenes (phos) and bradycardia (brad) (persistent hr<50bpm).


To develop a tool to support assessment of prescribing discordance with recommendations and explore impact on phos and brad incidence.


An observational single exposure cohort study. Exposure data were collected from dispensed prescriptions (Rx) Nov 2005- May 2009; outcome data (inc. pre-existing pt medical conditions/drugs whichcarried CaI/WFU) from forms sent to physicians (GPs) ≥ 6 months after each pt’s 1st Rx. An algorithm based prescribing framework was developed and assisted with the assessment of available information according to CaI/ WFU in SPC. To explore impact of prescriber discordance, phos and brad risk (%) and 95% CI were calculated by group (≥ 1 CaI; ≥ 1 WFU; both CaI/WFU; concordant or unknown). Descriptive statistics were calculated.


Final cohort (4624), median age 68 yrs (IQR 60, 77); 57% (2663) male. CaI/WFU were assessed for 3357 pts: 74% (2491) were concordant, 21% (701) had WFU, 4% (124) had CaI, and 1% (41) had both CaI/WFU. Brad was reported for 96/4624 pts (2.1% (1.6,2.5)); 73 were assessed: 4/124 pts (3.2% (0.9,8.3) were CaI, 17/701 (2.4% (1.4,3.9)) had WFU, 1/41 had both CaI/WFU, and 51/2491 pts (2.0 (1.5,2.7)) were concordant. Phos was reported for 140/4624 pts (3.0% (2.5,3.6)); 104 were assessed:2/124 pts (1.6% (0.2,5.8)) were CaI, 23/701 had WFU (3.3% (2.1,4.9)), 1/41 had both CaI/WFU, and 78/2491 (3.1% (2.5,3.9)) were concordant.


In this study, the incidence of brad and phos was common in all concordance groups, although estimates lacked precision. This study demonstrates the feasibility of using a framework to assess prescribing discordance as reported in drug utilisation studies to identify at-risk populations, which may help support post-marketing risk:benefit evaluations.