Angiotensin-converting enzyme inhibitor prescription for heart failure in general practice, and the impact of a Rapid Access Heart Failure Clinic in Cardiff

We assessed whether the presence of a Rapid Access Heart Failure Clinic (RAHFC) had an impact on the angiotensin-converting enzyme (ACE) inhibitor prescribing habits of primary care physicians. We selected 10 general practices (GP) that referred and 10 practices that did not refer patients to the RAHFC. The study covered a period of two years immediately preceding the commencement of the RAHFC and about 1.5 years afterwards. A total of 309 patients, divided into two groups, were studied. Cohort 1 consisted of 198 patients (103 from referring and 95 from non-referring GP) with a new diagnosis of chronic heart failure (CHF) made by the GP pre-RAHFC. Cohort 2 consisted of 111 patients (48 from referring and 63 from non-referring GP) diagnosed as having CHF post-RAHFC. In cohort 1, 27.1% of patients in the referring practices were on ACE inhibitor versus 40.0% in the non-referring practices (p=0.056).
ACE inhibitor prescription was reassessed 1.5 years post-RAHFC: it had significantly increased to 51.4% (p<0.001) in the referring practices, but not in the non-referring practices (43.1%, p=0.659). Interestingly, the increase in ACE inhibitor prescription among referring practices was predominantly due to initiation by the primary care physicians themselves (76% of cases) rather than by the RAHFC. The baseline trend of lower ACE inhibitor prescription rate in cohort 1 in the referring practices compared to non-referring practices was not seen in cohort 2 (54.1% vs. 50.7%, p=0.844).
Using ACE inhibitor prescription status as an indicator of diagnostic certainty of CHF by primary care physicians, it has sensitivity, specificity, positive and negative predictive values of 45.5%, 52.9%, 38.5% and 60.0%, respectively, for the presence of CHF as confirmed by the RAHFC.
In conclusion, RAHFC facilitated increased ACE inhibitor prescription by primary care physicians. However, CHF was commonly misdiagnosed in the community and this might lead to inappropriate ACE inhibitor prescription.