Use of relative survival to evaluate non-ST-elevation myocardial infarction quality of care and clinical outcomes

Association of treatments for acute myocardial infarction and survival for seven common comorbidity states: a nationwide cohort study

BACKGROUND

Comorbidity is common and has a substantial negative impact on the prognosis of patients with acute myocardial infarction (AMI). Whilst receipt of guideline-indicated treatment for AMI is associated with improved prognosis, the extent to which comorbidities influence treatment provision its efficacy is unknown. Therefore, we investigated the association between treatment provision for AMI and survival for seven common comorbidities.

METHODS

We used data of 693,388 AMI patients recorded in the Myocardial Ischaemia National Audit Project (MINAP), 2003-2013. We investigated the association between comorbidities and receipt of optimal care for AMI (receipt of all eligible guideline-indicated treatments), and the effect of receipt of optimal care for comorbid AMI patients on long-term survival using flexible parametric survival models.

RESULTS

A total of 412,809 [59.5%] patients with AMI had at least one comorbidity, including hypertension (302,388 [48.7%]), diabetes (122,228 [19.4%]), chronic obstructive pulmonary disease (COPD, 89,221 [14.9%]), cerebrovascular disease (51,883 [8.6%]), chronic heart failure (33,813 [5.6%]), chronic renal failure (31,029 [5.0%]) and peripheral vascular disease (27,627 [4.6%]). Receipt of optimal care was associated with greatest survival benefit for patients without comorbidities (HR 0.53, 95% CI 0.51-0.56) followed by patients with hypertension (HR 0.60, 95% CI 0.58-0.62), diabetes (HR 0.83, 95% CI 0.80-0.87), peripheral vascular disease (HR 0.85, 95% CI 0.79-0.91), renal failure (HR 0.89, 95% CI 0.84-0.94) and COPD (HR 0.90, 95% CI 0.87-0.94). For patients with heart failure and cerebrovascular disease, optimal care for AMI was not associated with improved survival.

CONCLUSIONS

Overall, guideline-indicated care was associated with improved long-term survival. However, this was not the case in AMI patients with concomitant heart failure or cerebrovascular disease. There is therefore a need for novel treatments to improve outcomes for AMI patients with pre-existing heart failure or cerebrovascular disease.

Statistics on mortality following acute myocardial infarction in 842 897 Europeans

AIMS

To compare ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) mortality between Sweden and the UK, adjusting for background population rates of expected death, case mix, and treatments.

METHODS AND RESULTS

National data were collected from hospitals in Sweden [n = 73 hospitals, 180 368 patients, Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies (SWEDEHEART)] and the UK [n = 247, 662 529 patients, Myocardial Ischaemia National Audit Project (MINAP)] between 2003 and 2013. There were lower rates of revascularization [STEMI (43.8% vs. 74.9%); NSTEMI (27.5% vs. 43.6%)] and pharmacotherapies at time of hospital discharge including [aspirin (82.9% vs. 90.2%) and (79.9% vs. 88.0%), β-blockers (73.4% vs. 86.4%) and (65.3% vs. 85.1%)] in the UK compared with Sweden, respectively. Standardized net probability of death (NPD) between admission and 1 month was higher in the UK for STEMI [8.0 (95% confidence interval 7.4-8.5) vs. 6.7 (6.5-6.9)] and NSTEMI [6.8 (6.4-7.2) vs. 4.9 (4.7-5.0)]. Between 6 months and 1 year and more than 1 year, NPD remained higher in the UK for NSTEMI [2.9 (2.5-3.3) vs. 2.3 (2.2-2.5)] and [21.4 (20.0-22.8) vs. 18.3 (17.6-19.0)], but was similar for STEMI [0.7 (0.4-1.0) vs. 0.9 (0.7-1.0)] and [8.4 (6.7-10.1) vs. 8.3 (7.5-9.1)].

CONCLUSION

Short-term mortality following STEMI and NSTEMI was higher in the UK compared with Sweden. Mid- and longer-term mortality remained higher in the UK for NSTEMI but was similar for STEMI. Differences in mortality may be due to differential use of guideline-indicated treatments.

Guideline-indicated treatments and diagnostics, GRACE risk score, and survival for non-ST elevation myocardial infarction

Aims

To investigate whether improved survival from non-ST-elevation myocardial infarction (NSTEMI), according to GRACE risk score, was associated with guideline-indicated treatments and diagnostics, and persisted after hospital discharge.

Methods and results

National cohort study (n = 389 507 patients, n = 232 hospitals, MINAP registry), 2003–2013. The primary outcome was adjusted all-cause survival estimated using flexible parametric survival modelling with time-varying covariates. Optimal care was defined as the receipt of all eligible treatments and was inversely related to risk status (defined by the GRACE risk score): 25.6% in low, 18.6% in intermediate, and 11.5% in high-risk NSTEMI. At 30 days, the use of optimal care was associated with improved survival among high [adjusted hazard ratio (aHR) −0.66 95% confidence interval (CI) 0.53–0.86, difference in absolute mortality rate (AMR) per 100 patients (AMR/100–0.19 95% CI −0.29 to −0.08)], and intermediate (aHR = 0.74, 95% CI 0.62–0.92; AMR/100 = −0.15, 95% CI −0.23 to −0.08) risk NSTEMI. At the end of follow-up (8.4 years, median 2.3 years), the significant association between the use of all eligible guideline-indicated treatments and improved survival remained only for high-risk NSTEMI (aHR = 0.66, 95% CI 0.50–0.96; AMR/100 = −0.03, 95% CI −0.06 to −0.01). For low-risk NSTEMI, there was no association between the use of optimal care and improved survival at 30 days (aHR = 0.92, 95% CI 0.69–1.38) and at 8.4 years (aHR = 0.71, 95% CI 0.39–3.74).

Conclusion

Optimal use of guideline-indicated care for NSTEMI was associated with greater survival gains with increasing GRACE risk, but its use decreased with increasing GRACE risk.

Association between time of hospitalization with acute myocardial infarction and in-hospital mortality

AIMS

To study the association between time of hospitalization and in-hospital mortality for acute myocardial infarction (AMI).

METHODS AND RESULTS

Patients admitted with ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) across 243 hospitals in England and Wales between 1 January 2004 and 31 March 2013 were included. The outcome measure was in-hospital mortality. Adjusted odds ratios (ORs) for in-hospital mortality were estimated across six 4-hourly time periods over the 24-h clock using multilevel logistic regression, inverse-probability weighting propensity score, and instrumental variable analysis. Among 615 035 patients [median age 70.0 years, interquartile range 59.0-80.0 years; 406 519 (66.0%) men], there were 52 777 (8.8%) in-hospital deaths. At night, patients with NSTEMI were more frequently comorbid, and for STEMI had longer symptom-onset-to-reperfusion times. For STEMI, unadjusted in-hospital mortality was highest between 20:00 and 23:59 [4-h period range 8.4-9.9%; OR compared with 00:00-03:59 reference 1.13, 95% confidence interval (CI) 1.07-1.20], and for NSTEMI highest between 12:00 and 15:59 (8.0-8.8%; OR compared with 00:00-03:59 reference 1.07, 95% CI 1.03-1.12). However, these differences were only apparent in the earlier years of the study, and were attenuated by adjustment for demographics, comorbidities, and clinical presentation. Differences were not statistically significant after adjustment for acute clinical treatment provided.

CONCLUSION

There is little evidence to support an association between time of hospitalization and in-hospital mortality for AMI; variation in in-hospital mortality may be explained by case mix and the use of treatments.

Temporal trends in relative survival following percutaneous coronary intervention

OBJECTIVE

Percutaneous coronary intervention (PCI) has seen substantial shifts in patient selection in recent years that have increased baseline patient mortality risk. It is unclear to what extent observed changes in mortality are attributable to background mortality risk or the indication and selection for PCI itself. PCI-attributable mortality can be estimated using relative survival, which adjusts observed mortality by that seen in a matched control population. We report relative survival ratios and compare these across different time periods.

METHODS

National Health Service PCI activity in England and Wales from 2007 to 2014 is considered using data from the British Cardiovascular Intervention Society PCI Registry. Background mortality is as reported in Office for National Statistics life tables. Relative survival ratios up to 1 year are estimated, matching on patient age, sex and procedure date. Estimates are stratified by indication for PCI, sex and procedure date.

RESULTS

549 305 procedures were studied after exclusions for missing age, sex, indication and mortality status. Comparing from 2007 to 2008 to 2013-2014, differences in crude survival at 1 year were consistently lower in later years across all strata. For relative survival, these differences remained but were smaller, suggesting poorer survival in later years is partly due to demographic characteristics. Relative survival was higher in older patients.

CONCLUSIONS

Changes in patient demographics account for some but not all of the crude survival changes seen during the study period. Relative survival is an under-used methodology in interventional settings like PCI and should be considered wherever survival is compared between populations with different demographic characteristics, such as between countries or time periods.

Relative survival and excess mortality following primary percutaneous coronary intervention for ST-elevation myocardial infarction

BACKGROUND:

High survival rates are commonly reported following primary percutaneous coronary intervention for ST-elevation myocardial infarction, with most contemporary studies reporting overall survival.

AIMS:

The aim of this study was to describe survival following primary percutaneous coronary intervention for ST-elevation myocardial infarction corrected for non-cardiovascular deaths by reporting relative survival and investigate clinically significant factors associated with poor long-term outcomes.

METHODS AND RESULTS:

Using the prospective UK Percutaneous Coronary Intervention registry, primary percutaneous coronary intervention cases ( n=88,188; 2005-2013) were matched to mortality data for the UK populace. Crude five-year relative survival was 87.1% for the patients undergoing primary percutaneous coronary intervention and 94.7% for patients <55 years. Increasing age was associated with excess mortality up to four years following primary percutaneous coronary intervention (56-65 years: excess mortality rate ratio 1.61, 95% confidence interval 1.46-1.79; 66-75 years: 2.49, 2.26-2.75; >75 years: 4.69, 4.27-5.16). After four years, there was no excess mortality for ages 56-65 years (excess mortality rate ratio 1.27, 0.95-1.70), but persisting excess mortality for older groups (66-75 years: excess mortality rate ratio 1.72, 1.30-2.27; >75 years: 1.66, 1.15-2.41). Excess mortality was associated with cardiogenic shock (excess mortality rate ratio 6.10, 5.72-6.50), renal failure (2.52, 2.27-2.81), left main stem stenosis (1.67, 1.54-1.81), diabetes (1.58, 1.47-1.69), previous myocardial infarction (1.52, 1.40-1.65) and female sex (1.33, 1.26-1.41); whereas stent deployment (0.46, 0.42-0.50) especially drug eluting stents (0.27, 0.45-0.55), radial access (0.70, 0.63-0.71) and previous percutaneous coronary intervention (0.67, 0.60-0.75) were protective.

CONCLUSIONS:

Following primary percutaneous coronary intervention for ST-elevation myocardial infarction, long-term cardiovascular survival is excellent. Failure to account for non-cardiovascular death may result in an underestimation of the efficacy of primary percutaneous coronary intervention.

Multimorbidity and survival for patients with acute myocardial infarction in England and Wales: Latent class analysis of a nationwide population-based cohort

BACKGROUND

There is limited knowledge of the scale and impact of multimorbidity for patients who have had an acute myocardial infarction (AMI). Therefore, this study aimed to determine the extent to which multimorbidity is associated with long-term survival following AMI.

METHODS AND FINDINGS

This national observational study included 693,388 patients (median age 70.7 years, 452,896 [65.5%] male) from the Myocardial Ischaemia National Audit Project (England and Wales) who were admitted with AMI between 1 January 2003 and 30 June 2013. There were 412,809 (59.5%) patients with multimorbidity at the time of admission with AMI, i.e., having at least 1 of the following long-term health conditions: diabetes, chronic obstructive pulmonary disease or asthma, heart failure, renal failure, cerebrovascular disease, peripheral vascular disease, or hypertension. Those with heart failure, renal failure, or cerebrovascular disease had the worst outcomes (39.5 [95% CI 39.0-40.0], 38.2 [27.7-26.8], and 26.6 [25.2-26.4] deaths per 100 person-years, respectively). Latent class analysis revealed 3 multimorbidity phenotype clusters: (1) a high multimorbidity class, with concomitant heart failure, peripheral vascular disease, and hypertension, (2) a medium multimorbidity class, with peripheral vascular disease and hypertension, and (3) a low multimorbidity class. Patients in class 1 were less likely to receive pharmacological therapies compared with class 2 and 3 patients (including aspirin, 83.8% versus 87.3% and 87.2%, respectively; β-blockers, 74.0% versus 80.9% and 81.4%; and statins, 80.6% versus 85.9% and 85.2%). Flexible parametric survival modelling indicated that patients in class 1 and class 2 had a 2.4-fold (95% CI 2.3-2.5) and 1.5-fold (95% CI 1.4-1.5) increased risk of death and a loss in life expectancy of 2.89 and 1.52 years, respectively, compared with those in class 3 over the 8.4-year follow-up period. The study was limited to all-cause mortality due to the lack of available cause-specific mortality data. However, we isolated the disease-specific association with mortality by providing the loss in life expectancy following AMI according to multimorbidity phenotype cluster compared with the general age-, sex-, and year-matched population.

CONCLUSIONS

Multimorbidity among patients with AMI was common, and conferred an accumulative increased risk of death. Three multimorbidity phenotype clusters that were significantly associated with loss in life expectancy were identified and should be a concomitant treatment target to improve cardiovascular outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03037255.

Editor's Choice - Impact of initial hospital diagnosis on mortality for acute myocardial infarction: A national cohort study

AIMS

Early and accurate diagnosis of acute myocardial infarction is central to successful treatment and improved outcomes. We aimed to investigate the impact of the initial hospital diagnosis on mortality for patients with acute myocardial infarction.

METHODS AND RESULTS

Cohort study using data from the Myocardial Ischaemia National Audit Project of patients discharged with a final diagnosis of ST-elevation myocardial infarction (STEMI, n=221,635) and non-STEMI (NSTEMI, n=342,777) between 1 April 2004 and 31 March 2013 in all acute hospitals ( n = 243) in England and Wales. Overall, 168,534 (29.9%) patients had an initial diagnosis which was not the same as their final diagnosis. After multivariable adjustment, for STEMI a change from an initial diagnosis of NSTEMI (time ratio 0.97, 95% confidence interval 0.92-1.01) and chest pain of uncertain cause (0.98, 0.89-1.07) was not associated with a significant reduction in time to death, whereas for other initial diagnoses the time to death was significantly reduced by 21% (0.78, 0.74-0.83). For NSTEMI, after multivariable adjustment, a change from an initial diagnosis of STEMI was associated with a reduction in time to death of 10% (time ratio 0.90, 95% confidence interval 0.83-0.97), but not for chest pain of uncertain cause (0.99, 0.96-1.02). Patients with NSTEMI who had other initial diagnoses had a significant 14% reduction in their time to death (time ratio 0.86, 95% confidence interval 0.84-0.88). STEMI and NSTEMI with other initial diagnoses had low rates of pre-hospital electrocardiograph (24.3% and 21.5%), aspirin on hospitalisation (61.6% and 48.5%), care by a cardiologist (60.0% and 51.5%), invasive coronary procedures (38.8 % and 29.2%), cardiac rehabilitation (68.9% and 62.6%) and guideline indicated medications at time of discharge from hospital. Had the 3.3% of patients with STEMI and 17.9% of NSTEMI who were admitted with other initial diagnoses received an initial diagnosis of STEMI and NSTEMI, then 33 and 218 deaths per year might have been prevented, respectively.

CONCLUSION

Nearly one in three patients with acute myocardial infarction had other diagnoses at first medical contact, who less frequently received guideline indicated care and had significantly higher mortality rates. There is substantial potential, greater for NSTEMI than STEMI, to improve outcomes through earlier and more accurate diagnosis of acute myocardial infarction.

Sex Differences in Treatments, Relative Survival, and Excess Mortality Following Acute Myocardial Infarction: National Cohort Study Using the SWEDEHEART Registry

BACKGROUND

This study assessed sex differences in treatments, all-cause mortality, relative survival, and excess mortality following acute myocardial infarction.

METHODS AND RESULTS

A population-based cohort of all hospitals providing acute myocardial infarction care in Sweden (SWEDEHEART [Swedish Web System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies]) from 2003 to 2013 was included in the analysis. Excess mortality rate ratios (EMRRs), adjusted for clinical characteristics and guideline-indicated treatments after matching by age, sex, and year to background mortality data, were estimated. Although there were no sex differences in all-cause mortality adjusted for age, year of hospitalization, and comorbidities for ST-segment-elevation myocardial infarction (STEMI) and non-STEMI at 1 year (mortality rate ratio: 1.01 [95% confidence interval (CI), 0.96-1.05] and 0.97 [95% CI, 0.95-0.99], respectively) and 5 years (mortality rate ratio: 1.03 [95% CI, 0.99-1.07] and 0.97 [95% CI, 0.95-0.99], respectively), excess mortality was higher among women compared with men for STEMI and non-STEMI at 1 year (EMRR: 1.89 [95% CI, 1.66-2.16] and 1.20 [95% CI, 1.16-1.24], respectively) and 5 years (EMRR: 1.60 [95% CI, 1.48-1.72] and 1.26 [95% CI, 1.21-1.32], respectively). After further adjustment for the use of guideline-indicated treatments, excess mortality among women with non-STEMI was not significant at 1 year (EMRR: 1.01 [95% CI, 0.97-1.04]) and slightly higher at 5 years (EMRR: 1.07 [95% CI, 1.02-1.12]). For STEMI, adjustment for treatments attenuated the excess mortality for women at 1 year (EMRR: 1.43 [95% CI, 1.26-1.62]) and 5 years (EMRR: 1.31 [95% CI, 1.19-1.43]).

CONCLUSIONS

Women with acute myocardial infarction did not have statistically different all-cause mortality, but had higher excess mortality compared with men that was attenuated after adjustment for the use of guideline-indicated treatments. This suggests that improved adherence to guideline recommendations for the treatment of acute myocardial infarction may reduce premature cardiovascular death among women.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02952417.

Relative Survival After Transcatheter Aortic Valve Implantation: How Do Patients Undergoing Transcatheter Aortic Valve Implantation Fare Relative to the General Population?

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is indicated for patients with aortic stenosis who are intermediate-high surgical risk. Although all-cause mortality rates after TAVI are established, survival attributable to the procedure is unclear because of competing causes of mortality. The aim was to report relative survival (RS) after TAVI, which accounts for background mortality risks in a matched general population.

METHODS AND RESULTS

National cohort data (n=6420) from the 2007 to 2014 UK TAVI registry were matched by age, sex, and year to mortality rates for England and Wales (population, 57.9 million). The Ederer II method related observed patient survival to that expected from the matched general population. We modelled RS using a flexible parametric approach that modelled the log cumulative hazard using restricted cubic splines. RS of the TAVI cohort was 95.4%, 90.2%, and 83.8% at 30 days, 1 year, and 3 years, respectively. By 1-year follow-up, mortality hazards in the >85 years age group were not significantly different from those of the matched general population; by 3 years, survival rates were comparable. The flexible parametric RS model indicated that increasing age was associated with significantly lower excess hazards after the procedure; for example, by 2 years, a 5-year increase in age was associated with 20% lower excess mortality over the general population.

CONCLUSIONS

RS after TAVI was high, and survival rates in those aged >85 years approximated those of a matched general population within 3 years. High rates of RS indicate that patients selected for TAVI tolerate the risks of the procedure well.

Excess mortality and guideline-indicated care following non-ST-elevation myocardial infarction

BACKGROUND

Adherence to guideline-indicated care for the treatment of non-ST-elevation myocardial infarction (NSTEMI) is associated with improved outcomes. We investigated the extent and consequences of non-adherence to guideline-indicated care across a national health system.

METHODS

A cohort study ( ClinicalTrials.gov identifier: NCT02436187) was conducted using data from the Myocardial Ischaemia National Audit Project ( n = 389,057 NSTEMI, n = 247 hospitals, England and Wales, 2003-2013). Accelerated failure time models were used to quantify the impact of non-adherence on survival according to dates of guideline publication.

RESULTS

Over a period of 1,079,044 person-years (median 2.2 years of follow-up), 113,586 (29.2%) NSTEMI patients died. Of those eligible to receive care, 337,881 (86.9%) did not receive one or more guideline-indicated intervention; the most frequently missed were dietary advice ( n = 254,869, 68.1%), smoking cessation advice ( n = 245,357, 87.9%), P2Y12 inhibitors ( n = 192,906, 66.3%) and coronary angiography ( n = 161,853, 43.4%). Missed interventions with the strongest impact on reduced survival were coronary angiography (time ratio: 0.18, 95% confidence interval (CI): 0.17-0.18), cardiac rehabilitation (time ratio: 0.49, 95% CI: 0.48-0.50), smoking cessation advice (time ratio: 0.53, 95% CI: 0.51-0.57) and statins (time ratio: 0.56, 95% CI: 0.55-0.58). If all eligible patients in the study had received optimal care at the time of guideline publication, then 32,765 (28.9%) deaths (95% CI: 30,531-33,509) may have been prevented.

CONCLUSION

The majority of patients hospitalised with NSTEMI missed at least one guideline-indicated intervention for which they were eligible. This was significantly associated with excess mortality. Greater attention to the provision of guideline-indicated care for the management of NSTEMI will reduce premature cardiovascular deaths.

Long-term healthcare use and costs in patients with stable coronary artery disease: a population-based cohort using linked health records (CALIBER)

AIMS

To examine long-term healthcare utilization and costs of patients with stable coronary artery disease (SCAD).

METHODS AND RESULTS

Linked cohort study of 94 966 patients with SCAD in England, 1 January 2001 to 31 March 2010, identified from primary care, secondary care, disease, and death registries. Resource use and costs, and cost predictors by time and 5-year cardiovascular disease (CVD) risk profile were estimated using generalized linear models. Coronary heart disease hospitalizations were 20.5% in the first year and 66% in the year following a non-fatal (myocardial infarction, ischaemic or haemorrhagic stroke) event. Mean healthcare costs were £3133 per patient in the first year and £10 377 in the year following a non-fatal event. First-year predictors of cost included sex (mean cost £549 lower in females), SCAD diagnosis (non-ST-elevation myocardial infarction cost £656 more than stable angina), and co-morbidities (heart failure cost £657 more per patient). Compared with lower risk patients (5-year CVD risk 3.5%), those of higher risk (5-year CVD risk 44.2%) had higher 5-year costs (£23 393 vs. £9335) and lower lifetime costs (£43 020 vs. £116 888).

CONCLUSION

Patients with SCAD incur substantial healthcare utilization and costs, which varies and may be predicted by 5-year CVD risk profile. Higher risk patients have higher initial but lower lifetime costs than lower risk patients as a result of shorter life expectancy. Improved cardiovascular survivorship among an ageing CVD population is likely to require stratified care in anticipation of the burgeoning demand.