Sweden Better than United Kingdom at Saving Lives of MI Patients

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Patients with acute myocardial infarction (MI) who live in Sweden have better 30-day survival rates than their counterparts who live in the United Kingdom. The discrepancy is due in part to earlier and more extensive use of primary percutaneous coronary intervention (PCI) and more frequent use of beta blockers at discharge, according to a study published online January 22, 2014, ahead of print in The Lancet.

Researchers led by Harry Hemingway, PhD, MSc, of University College London (London, United Kingdom), examined data on 119,786 patients in Sweden and 391, 077 patients in the United Kingdom admitted between 2004 and 2010. The researchers chose the 2 countries because both have universal health care systems and continuous national clinical registries for ACS with mandatory participation for all hospitals.

Prehospital use of antiplatelet and beta-blocker therapy was higher in Sweden, but use of statins upon admission was lower. Total reperfusion for STEMI was more common in the United Kingdom than in Sweden (77% vs 71%), as was fibrinolysis (54% vs 12%), while primary PCI was more than twice as common in Sweden (59% vs 22%). Additionally, in both countries the use of primary PCI for STEMI increased over time while use of fibrinolysis decreased. By 2009, rates of primary PCI in the United Kingdom were equivalent to those of Sweden.

UK Mortality Consistently Higher

Overall, coronary interventions other than primary PCI and use of intravenous GP IIb/IIIa inhibitors were higher in Sweden. Swedish patients who survived to hospital discharge were more likely than those in the United Kingdom to be prescribed dual antiplatelet therapy or beta blockers, but less likely to be prescribed an ACE inhibitor or angiotensin-receptor blocker (ARB) or given a statin (table 1).

Table 1. Discharge Medications

Cumulative 30-day mortality was higher in the United Kingdom than in Sweden (10.5% vs 7.6%). In-hospital mortality was also higher in the United Kingdom than in Sweden (8.8% vs 5.8%), even when including clinically important subgroups. The mortality difference remained significant after adjustment for differences in patient case mix (standardized mortality ratio 1.37; 95% CI 1.30-1.45).

According to the study authors, the disparities are cause for concern and suggest “that more than 10,000 deaths at 30 days would have been prevented or delayed had UK patients experienced the care of their Swedish counterparts.”

The United Kingdom did not have a national policy for primary PCI until October 2008, which Dr. Hemingway and colleagues say could explain the rapid increase in the use of this treatment from 2008 onwards, noting that “it took until 2011-12 for rates to exceed 90%.” Additionally, since nationwide registries in Sweden have been in effect longer than those in the United Kingdom, the actual difference in mortality could be even larger, they say.

Inequalities Worth Addressing

In an editorial accompanying the study, Chris Gale, PhD, of the University of Leeds (Leeds, United Kingdom), and Keith Fox, MBChB, of the University of Edinburgh (Edinburgh, Scotland), say the study reveals “large international inequalities in the management and outcomes for these patients.”

At the same time, they note that the data highlight similarities between the 2 countries for thrombolysis and primary PCI process measures and point out that overall, reperfusion rates were 6% higher in the United Kingdom than in Sweden. This suggests that “unmeasured factors, such as imbalanced case ascertainment, unmeasured confounders, non-modeled covariates or missing data, and hospital care systems are probably responsible for the international difference in mortality,” they write.

Finally, Drs. Gale and Fox say efforts to improve outcomes in the United Kingdom should concentrate on “data enhancement through the linkage of electronic health-care records and the early and systematic implementation of evidence-based therapies across the National Health Service.”

Study Details

The study population was drawn from 86 hospitals in Sweden and 242 in the United Kingdom. The proportion of patients with STEMI was lower in Sweden than in the United Kingdom (32% vs 40%), though median delay from symptom onset to hospital admission was similar.

 

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Sources:
1. Chung S-C, Gedeborg R, Nicholas O, et al. Acute myocardial infarction: A comparison of short-term survival in national outcome registries in Sweden and the UK. Lancet. 2014;Epub ahead of print.

2. Gale C, Fox K. International comparisons of acute myocardial infarction. Lancet. 2014; Epub ahead of print.

 

 

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