Room for improvement in intensification of statin therapy after acute myocardial infarction

Arnold SV, Kosiborod M, Tang F, et al.  
Circulation. 2014 Feb 4.

Background

Statin therapy is central to secondary prevention after acute myocardial infarction (AMI), thus prescription of statins at discharge is highly recommended in AMI guidelines [1,2]. Clinical trials have demonstrated that more potent statins are more effective at reducing morbidity and mortality after AMI than less potent statins [3-7]. The 2013 cholesterol guidelines therefore recommend high-intensity statins for all patients with established atherosclerotic CV disease [8].
To date, no studies have addressed the rates of statin intensification and maximisation. This study therefore examined rates of statin initiation, intensification (in patients who arrived on submaximal statin prescription) and maximisation, in over 4000 post-AMI patients from 24 US hospitals, using data from the Translational Research Investigating Underlying disparities in acute Myocardial infarction Patients' Health status (TRIUMPH) study [9].

Main results

• Of 2776 patients who were statin-naïve on presentation with AMI, 87% were started on a statin during hospitalisation, with virtually no site-level variability in statin initiation.
• Of 1230 patients on sub-maximal statin treatment ad admission, 323 (36.3%) received intensified statin treatment during hospitalisation (195 patients had their dose increased and 128 were switched to a more potent statin). There was modest site level variability for statin intensification.
• Rates of intensification and maximisation were highly correlated among hospitals (r=0.81, P<0.001), thus these two changes often seem to occur in parallel. Due to small numbers no significant changes were seen between hospitals with a different prescription policy, but the more aggressively treating hospitals tended to be larger, more urban and were more likely to be academic.
• Few patient factors associated with a greater likelihood of statin initiation, intensification or maximisation were revealed: patients with lower LDL-c levels were less likely to be started on a statin or have their dose intensified or to receive the maximum dose upon discharge.
  Patients who presented with ST-elevations were nearly 50% more likely to have their statin intensified (RR: 1.47, 95% CI: 1.12-1.92) and maximized (RR: 1.49, 95% CI: 1.25-1.77) than those without ST-elevation AMIs, while no difference was seen in the rate of statin initiation between patients with non-ST-elevation and ST-elevation AMIs.

Conclusion

This large prospective cohort study shows that in all studied hospitals in almost all (87%) statin-naïve AMI patients statin treatment is initiated. In patients who were already on submaximal doses of statin at the time of AMI, intensification of statins occurred in only 26% of patients, and maximisation in only 23%. There was more variation between hospitals in the practice of intensifying and maximising statins.
While it is appropriate to target intensive secondary prevention strategies to patients most likely to benefit, there is no clear evidence that there is a differential effect of statin therapy for type of MI or baseline LDL-c levels.
Given the evidence of greater clinical benefit with more potent statin therapy after AMI, and according to the 2013 cholesterol guideline, there is room for improvement considering the low rates and variation in the practice of intensifying and maximising statin therapy. Modifying existing performance measures may facilitate more consistent, evidence-based and improved care.

Editorial comment [10]

The depth of the data collected in TRIUMPH provides an unprecedented opportunity to gain insights into critical aspects of the presentation, care and outcome of patients with acute MI. It could be argued that dose escalation may occur at outpatient follow-up visits, but a previous report from the same group documented that 12 months after MI, only 26% of eligible patients in TRIUMPH were receiving target doses of statins, thus further dose escalation did not occur often in an outpatient setting.
Patients were on average 59 years old, which is relatively young with regard to patients in epidemiology incidence cohorts of acute MI, and the proportion of patients presenting with STEMI was larger than in community cohorts. Thus the proportion of patients in whom dose escalation and optimization occurred is likely higher in TRIUMPH than in routine clinical practice.
This study therefore importantly raises awareness about the importance of drug escalation, which is critical to treatment effectiveness but that can be overlooked in practice. Registries are being promoted for the purpose of quality measurement, but the validity of registry data for the general population should be considered.

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