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The Importance of Considering Both Primary and Secondary Diagnostic Codes When Using Administrative Health Data to Study Acute Coronary Syndrome Epidemiology (ANZACS-QI 47)
Abstract
Aims:
Routinely collected health administrative data has become an important data source for investigators assessing disease epidemiology. Our aim was to investigate the implications of identifying acute coronary syndrome (ACS) events in New Zealand (NZ) national hospitalisation data using either the first (primary) or subsequent (secondary) codes.
Methods:
Using national health datasets we identified all NZ hospitalisations (2014 to 2016) for patients ≥20 years with a primary or secondary International Classification of Diseases 10th Revision, Australian Modification (ICD10-AM) ACS code. Outcomes included 1-year all-cause and cause specific mortality, hospitalised non-fatal myocardial infarction, heart failure, stroke, or major bleeding, and a composite comprising these outcomes.
Results:
Of 35,646 ACS hospitalisations, 78.5% were primary and 21.5% secondary diagnoses. Compared to primary coding, patients with a secondary diagnosis were older (mean 77 vs 69 years), more likely to be females (48 vs 36%), had more comorbidity, and were less likely to receive coronary angiography or revascularisation. Higher adverse event rates were observed for the secondary diagnosis group including a three-fold higher 1-year mortality (40 vs 13%) and two-fold higher composite adverse outcome (54 vs 26%).The use of primary codes alone, rather than combined primary and secondary codes, resulted in overestimation of coronary angiography and revascularisation rates, and underestimation of the 1-year case fatality (13.1 vs 19.0%) and composite adverse event rate (26 vs 32%).
Conclusion:
Patient characteristics and outcomes of ACS events recorded as primary versus secondary codes are very different. These findings have important implications for designing studies utilising ICD10-AM codes.
Aims:
Guidelines recommend management with an invasive coronary angiogram in acute coronary syndromes (ACS), but most studies excluded patients with advanced chronic kidney disease (CKD). Our aims were to describe, in a comprehensive ACS cohort, the incidence of CKD, coronary angiography utilisation and outcomes, according to CKD stage.
Methods:
National datasets were used to identify hospitalised ACS patients (2013 to 2018) in the Northern region of New Zealand. CKD stage was obtained from a linked laboratory dataset. Outcomes included all-cause and cause-specific mortality, and non-fatal myocardial infarction, heart failure and stroke.
Results:
Thirty-eight percent (38%) of the 23,432 ACS patients had CKD stage 3 or higher: 2,403 (10%) had stages 4/5 CKD. Overall 61% received coronary angiography. Compared with normal renal function the adjusted rate of coronary angiography was lower in CKD stage 3b (RR 0.75, 95% confidence intervals [CIs] 0.69, 0.82) and stages 4/5 without dialysis (RR 0.41, 95% CIs 0.36, 0.46), but similar for those on dialysis (RR 0.89, 95% CIs 0.77, 1.02). All-cause mortality (mean follow-up 3.2 years) increased with CKD stage from 8% (normal kidney function) to 69% (stages 4/5 CKD without dialysis). Compared with coronary angiography, the adjusted all-cause and CVD mortality risks were higher in those without coronary angiography, except for those on dialysis, where these risks converged.
Conclusions:
Invasive management fell below an eGFR of 45 mL/min (≤ stage 3b), and nearly half of all deaths occurred in these patients. Clinical trials are needed to assess the role of invasive management in ACS and advanced CKD.
Background:
Coronary heart disease (CHD), the leading cause of death globally, might be developed or exacerbated by air pollution, resulting high burden to patients. To date, limited studies have estimated the relations between short-term exposure to air pollution and CHD disease burden in China, with inconsistent results. Hence, we aimed to estimate the short-term impact and burden of ambient PM pollutants on hospitalizations of CHD and specific CHD.
Methods:
PM10 and PM2.5 were measured at 82 monitoring stations in 9 cities in Sichuan Province, China during 2017-2018. Based on the time-stratified case-crossover design, the effects of short-term exposure to particle matter (PM) pollution on coronary heart disease (CHD) hospital admissions were estimated. Meanwhile, the linked burden of CHD owing to ambient PM pollution were estimated.
Results:
A total of 104,779 CHD records were derived from 153 hospitals from these 9 cities. There were significant effects of PM pollution on hospital admissions (HAs) for CHD and specific CHD in Sichuan Province. A 10 μg/m3 increase of PM10 and PM2.5 was linked with a 0.46% (95% CI: 0.08, 0.84%), and 0.57% (95% CI: 0.05, 1.09%) increments in HAs for CHD at lag7, respectively. The health effects of air pollutants were comparable modified by age, season and gender, showing old (≥ 65 years) and in cold season being more vulnerable to the effects of ambient air pollution, while gender-specific effects is positive but not conclusive. Involving the WHO's air quality guidelines as the reference, 1784 and 2847 total cases of HAs for CHD could be attributable to PM10 and PM2.5, separately. The total medical cost that could be attributable to exceeding PM10 and PM2.5 were 42.04 and 67.25 million CNY from 2017 to 2018, respectively.
Conclusions:
This study suggested that the short-term exposure to air pollutants were associated with increased HAs for CHD in Sichuan Province, which could be implications for local environment improvement and policy reference.
Background
Major adverse cardiovascular events (MACE) are increasingly used as composite outcomes in randomized controlled trials (RCTs) and observational studies. However, it is unclear how observational studies most commonly define MACE in the literature when using administrative data.
Methods
We identified peer-reviewed articles published in MEDLINE and EMBASE between January 1, 2010 to October 9, 2020. Studies utilizing administrative data to assess the MACE composite outcome using International Classification of Diseases 9th or 10th Revision diagnosis codes were included. Reviews, abstracts, and studies not providing outcome code definitions were excluded. Data extracted included data source, timeframe, MACE components, code definitions, code positions, and outcome validation.
Results
A total of 920 articles were screened, 412 were retained for full-text review, and 58 were included. Only 8.6% (n = 5/58) matched the traditional three-point MACE RCT definition of acute myocardial infarction (AMI), stroke, or cardiovascular death. None matched four-point (+unstable angina) or five-point MACE (+unstable angina and heart failure). The most common MACE components were: AMI and stroke, 15.5% (n = 9/58); AMI, stroke, and all-cause death, 13.8% (n = 8/58); and AMI, stroke and cardiovascular death 8.6% (n = 5/58). Further, 67% (n = 39/58) did not validate outcomes or cite validation studies. Additionally, 70.7% (n = 41/58) did not report code positions of endpoints, 20.7% (n = 12/58) used the primary position, and 8.6% (n = 5/58) used any position.
Conclusions
Components of MACE endpoints and diagnostic codes used varied widely across observational studies. Variability in the MACE definitions used and information reported across observational studies prohibit the comparison, replication, and aggregation of findings. Studies should transparently report the administrative codes used and code positions, as well as utilize validated outcome definitions when possible.
Background
In recent years, there has been a growing interest in outcomes of patients with acute myocardial infarction (AMI) using large administrative datasets. The present study was designed to compare the characteristics, management strategies and acute outcomes between patients with primary and secondary AMI diagnoses in a national cohort of patients.
Methods
All hospitalizations of adults (≥18 years) with a discharge diagnosis of AMI in the US National Inpatient Sample between January 2004 and September 2015 were included, stratified by primary or secondary AMI. The International Classification of Diseases, ninth revision and Clinical Classification Software codes were used to identify patient comorbidities, procedures and clinical outcomes.
Results
A total of 10,864,598 weighted AMI hospitalizations were analysed, of which 7,186,261 (66.1%) were primary AMIs and 3,678,337 (33.9%) were secondary AMI. Patients with primary AMI diagnoses were younger (median 68 vs. 74 years, p<0.001) and less likely to be female (39.6% vs. 48.5%, p<0.001). Secondary AMI was associated with lower odds of receipt of coronary angiography (aOR 0.19; 95%CI 0.18-0.19) and percutaneous coronary intervention (0.24; 0.23-0.24). Secondary AMI was associated with increased odds of MACCE (1.73; 1.73-1.74), mortality (1.71; 1.70-1.72), major bleeding (1.64; 1.62-1.65), cardiac complications (1.69; 1.65-1.73), and stroke (1.68; 1.67-1.70) (p<0.001 for all).
Conclusions
Secondary AMI diagnoses account for one-third of AMI admissions. Patients with secondary AMI are older, less likely to receive invasive care and have worse outcomes than patients with a primary diagnosis code of AMI. Future studies should consider both primary and secondary AMI diagnoses codes in order to accurately inform clinical decision-making and health planning.
Objectives
To describe the prevalence of multimorbidity (presence of two or more long-term health conditions) in the New Zealand (NZ) population, and compare risk of health outcomes by multimorbidity status.
Design
Cross-sectional analysis for prevalence of multimorbidity, with 1-year prospective follow-up for health outcomes.
Setting
NZ general population using national-level routine health data on hospital discharges and pharmaceutical dispensing.
Participants
All NZ adults (aged 18+, n=3 489 747) with an active National Health Index number at the index date (1 January 2014).
Outcome measures
Prevalence of multimorbidity was calculated using two data sources: prior routine hospital discharge data (61 ICD-10 coded diagnoses from the M3 multimorbidity index); and recent pharmaceutical dispensing records (30 conditions from the P3 multimorbidity index).
Methods
Prevalence of multimorbidity was calculated separately for the two data sources, stratified by age group, sex, ethnicity and socioeconomic deprivation, and age and sex standardised to the total population. One-year risk of poor health outcomes (mortality, ambulatory sensitive hospitalisation (ASH) and overnight hospital admission) was compared by multimorbidity status using logistic regression adjusted for confounders.
Results
Prevalence of multimorbidity was 7.9% using past hospital discharge data, and 27.9% using past pharmaceutical dispensing data. Prevalence increased with age, with a clear socioeconomic gradient and differences in prevalence by ethnicity. Age and sex standardised risk of 1-year mortality was 2.7% for those with multimorbidity (defined on hospital discharge data), and 0.5% for those without multimorbidity (age and sex-adjusted OR 4.8, 95% CI 4.7 to 5.0). Risk of ASH was also increased for those with multimorbidity (eg, pharmaceutical discharge definition: age and sex-standardised risk 6.2%, compared with 1.8% for those without multimorbidity; age and sex-adjusted OR 3.6, 95% CI 3.5 to 3.6).
Conclusions
Multimorbidity is common in the NZ adult population, with disparities in who is affected. Providing for the needs of individuals with multimorbidity requires collaborative and coordinated work across the health sector.
Long-term disease progression following myocardial infarction (MI) is not well understood. We examined the risk of subsequent cardiovascular events in patients discharged after MI in Sweden.
This was a retrospective, cohort study linking morbidity, mortality, and medication data from Swedish national registries. Of 108 315 patients admitted to hospital with a primary MI between 1 July 2006 and 30 June 2011 (index MI), 97 254 (89.8%) were alive 1 week after discharge and included in this study. The primary composite endpoint of risk for non-fatal MI, non-fatal stroke, or cardiovascular death was estimated for the first 365 days post-index MI and Day 366 to study completion. Risk and risk factors were assessed by Kaplan-Meier analysis and Cox proportional hazards modelling, respectively. Composite endpoint risk was 18.3% during the first 365 days post-index MI. Age [60-69 vs. <60 years: HR (95% CI): 1.37 (1.30-1.45); 70-79 vs. <60 years: 2.13 (2.03-2.24); >80 vs. <60 years: 3.96 (3.78-4.15)], prior MI [1.44 (1.40-1.49)], stroke [1.49 (1.44-1.54)], diabetes [1.37 (1.34-1.40)], heart failure [1.57 (1.53-1.62)] and no index MI revascularisation [1.88 (1.83-1.93)] were each independently associated with a higher risk of ischaemic events or death. For patients without a combined endpoint event during the first 365 days, composite endpoint risk was 20.0% in the following 36 months.
Risk of cardiovascular events appeared high beyond the first year post-MI, indicating a need for prolonged surveillance, particularly in patients with additional risk factors.
Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.
To describe patterns of statin use and predictors of poor maintenance over a 3-year period following an acute coronary syndrome (ACS).
National hospitalisation, mortality and pharmaceutical dispensing data were linked for all subjects aged 35-84 years discharged from a public hospital with an ACS in New Zealand in 2007. A Medication Possession Ratio (MPR; percentage of follow-up days patients were dispensed statins) was calculated for each patient. Adequate maintenance was defined by a MPR ≥80%.
In 2007, 11 348 patients aged 35-84 years were discharged from hospital with ACS. Within 90 days of discharge, 83% had received a statin. Over the follow-up period, 66% were adequately maintained on a statin (MPR ≥80%): 69% in the first year, 67% in the second year and 66% in the third year. Patients taking statins prior to admission and those who underwent a coronary procedure were 20-50% more likely to have a MPR ≥80% over 3 years than others. In contrast, people aged 35-45 years and those of Maori or Pacific ethnicity were 13-25% less likely to have a MPR ≥80% than those aged 55-64 years and Europeans.
One-third of patients were not adequately maintained on statins over the 3-year period following ACS, but 82% of those on a statin prior to admission had an MPR ≥80% over 3 years of follow-up. These findings define achievable treatment levels and identify groups who may benefit from efforts to improve statin use.
This study examines the recent trends in ischaemic heart disease (IHD) incidence and case fatality in Hong Kong and explores the possible risk factors.
Retrospective observational study.
All public hospitals in Hong Kong.
Incidence rate was defined as the number of IHD inpatient episodes divided by the size of the corresponding population. Short-term and long-term case fatality rate was defined as deaths from all causes occurring within 30 and 31-365 days, respectively, divided by the number of IHD inpatient episodes among the corresponding population.
Poisson and logistic regression models were used to examine the IHD incidence and short-term/long-term case fatality trends, respectively, for different age and sex groups.
IHD incidence was stable in most age groups. However, the incidence in men aged 15-24, 35-44 and ≥85 years showed increasing trends, whereas the incidence in men aged 55-64 years and women aged 35-74 years showed decreasing trends. Overall, the short-term/long-term case fatality rates were unchanged over time for both sexes. Short-term case fatality showed increasing trends in women aged 65-74 and ≥85 years, while long-term case fatality in men aged 55-64 and 75-84 years and women aged ≥75 years showed increasing trends.
Hong Kong trends resembled those in the USA, England and Wales, showing stable or slow decline in the IHD rates, while increasing trends were observed for some age groups, particularly young adults. Public health promotion efforts should focus on reducing cardiovascular risk factors, such as hypertension prevalence.
Background:
Second myocardial infarction (SMI) is a significant health problem. There are no nationwide studies on SMI among foreign-born populations that include detailed information about country of birth.
Design:
Nationwide cohort study of 331,748 men and 186,755 women aged 30-84, living in Sweden, and diagnosed with first myocardial infarction (FMI) between January 1987 and December 2007.
Methods:
Trends in, and risk of, SMI after day 28 of FMI association with gender, educational level, and country of birth were analysed. A hazard ratio (HR) with a 95% confidence interval (CI) yielded a risk estimate of SMI among FMI patients based on the Cox proportional hazard model.
Results:
Men had a higher risk of SMI than women (HR 1.14, 95% CI 1.12-1.55) with a downward trend over time, regardless of country of birth (p-trend <0.0001). Low educational level increased the HR of SMI irrespective of gender or country of birth. Foreign-born men and women had a slightly increased HR than Sweden-born. Men born in India, Palestine, Uganda, Algeria, and Tunisia and women born in India, Palestine, and Lebanon had approximately a 2-fold risk. Men born in the Netherlands had the lowest risk (HR 0.65, 95% CI 0.44-0.94). Foreign-born who had lived in Sweden for less than 35 years had a higher risk than those that had lived there for 35 years or longer.
Conclusions:
Although the risk of SMI continued to decrease over time, low socioeconomic position independent of country of birth and gender remained an important risk indicator deserving further attention.
Long-term disorders are the main challenge facing health-care systems worldwide, but health systems are largely configured for individual diseases rather than multimorbidity. We examined the distribution of multimorbidity, and of comorbidity of physical and mental health disorders, in relation to age and socioeconomic deprivation.
In a cross-sectional study we extracted data on 40 morbidities from a database of 1,751,841 people registered with 314 medical practices in Scotland as of March, 2007. We analysed the data according to the number of morbidities, disorder type (physical or mental), sex, age, and socioeconomic status. We defined multimorbidity as the presence of two or more disorders.
42·2% (95% CI 42·1-42·3) of all patients had one or more morbidities, and 23·2% (23·08-23·21) were multimorbid. Although the prevalence of multimorbidity increased substantially with age and was present in most people aged 65 years and older, the absolute number of people with multimorbidity was higher in those younger than 65 years (210,500 vs 194,996). Onset of multimorbidity occurred 10-15 years earlier in people living in the most deprived areas compared with the most affluent, with socioeconomic deprivation particularly associated with multimorbidity that included mental health disorders (prevalence of both physical and mental health disorder 11·0%, 95% CI 10·9-11·2% in most deprived area vs 5·9%, 5·8%-6·0% in least deprived). The presence of a mental health disorder increased as the number of physical morbidities increased (adjusted odds ratio 6·74, 95% CI 6·59-6·90 for five or more disorders vs 1·95, 1·93-1·98 for one disorder), and was much greater in more deprived than in less deprived people (2·28, 2·21-2·32 vs 1·08, 1·05-1·11).
Our findings challenge the single-disease framework by which most health care, medical research, and medical education is configured. A complementary strategy is needed, supporting generalist clinicians to provide personalised, comprehensive continuity of care, especially in socioeconomically deprived areas.
Scottish Government Chief Scientist Office.
With advances in the effectiveness of treatment and disease management, the contribution of chronic comorbid diseases (comorbidities) found within the Charlson comorbidity index to mortality is likely to have changed since development of the index in 1984. The authors reevaluated the Charlson index and reassigned weights to each condition by identifying and following patients to observe mortality within 1 year after hospital discharge. They applied the updated index and weights to hospital discharge data from 6 countries and tested for their ability to predict in-hospital mortality. Compared with the original Charlson weights, weights generated from the Calgary, Alberta, Canada, data (2004) were 0 for 5 comorbidities, decreased for 3 comorbidities, increased for 4 comorbidities, and did not change for 5 comorbidities. The C statistics for discriminating in-hospital mortality between the new score generated from the 12 comorbidities and the Charlson score were 0.825 (new) and 0.808 (old), respectively, in Australian data (2008), 0.828 and 0.825 in Canadian data (2008), 0.878 and 0.882 in French data (2004), 0.727 and 0.723 in Japanese data (2008), 0.831 and 0.836 in New Zealand data (2008), and 0.869 and 0.876 in Swiss data (2008). The updated index of 12 comorbidities showed good-to-excellent discrimination in predicting in-hospital mortality in data from 6 countries and may be more appropriate for use with more recent administrative data.
Incidence rates of cardiovascular diseases are often estimated by linkage to hospital discharge and mortality registries. The validity depends on the quality of the registries and the linkage. Therefore, we validated incidence rates of coronary heart disease (CHD), acute myocardial infarction, unstable angina pectoris, and heart failure, estimated by this method, against the disease registry of the cardiovascular registry Maastricht cohort study. The cohort consists of 21,148 persons, born between 1927 and 1977, who were randomly sampled from Maastricht and surrounding communities in 1987-1997. Incident cases were identified by linkage to the Netherlands causes of death registry and either the hospital discharge registry (HDR) or the cardiology information system (CIS) of the University Hospital Maastricht. Sensitivities and positive predictive values were calculated using the CIS-based registry as gold standard. Relatively high sensitivities and positive predictive values were found for CHD (72 and 91%, respectively) and acute myocardial infarction (84 and 97%, respectively). These values were considerably lower for unstable angina pectoris (53 and 78%, respectively) and heart failure (43 and 80%, respectively). A substantial number of cases (14-47%) were found only in the CIS-based registry, because they were missed or miscoded in the HDR-based registry. As a consequence, the incidence rates in the HDR-based registry were considerably lower than in the CIS-based registry, especially for unstable angina pectoris and heart failure. Incidence rates based on hospital discharge and mortality data may underestimate the true incidence rates, especially for unstable angina pectoris and heart failure.
Treatments for non-ST-segment-elevation myocardial infarction (NSTEMI) reduce ischemic events but increase bleeding. Baseline prediction of bleeding risk can complement ischemic risk prediction for optimization of NSTEMI care; however, existing models are not well suited for this purpose.
We developed (n=71 277) and validated (n=17 857) a model that identifies 8 independent baseline predictors of in-hospital major bleeding among community-treated NSTEMI patients enrolled in the Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA guidelines (CRUSADE) Quality Improvement Initiative. Model performance was tested by c statistics in the derivation and validation cohorts and according to postadmission treatment (ie, invasive and antithrombotic therapy). The CRUSADE bleeding score (range 1 to 100 points) was created by assignment of weighted integers that corresponded to the coefficient of each variable. The rate of major bleeding increased by bleeding risk score quintiles: 3.1% for those at very low risk (score < or = 20); 5.5% for those at low risk (score 21-30); 8.6% for those at moderate risk (score 31-40); 11.9% for those at high risk (score 41-50); and 19.5% for those at very high risk (score >50; P(trend) <0.001). The c statistics for the major bleeding model (derivation=0.72 and validation=0.71) and risk score (derivation=0.71 and validation=0.70) were similar. The c statistics for the model among treatment subgroups were as follows: > or = 2 antithrombotics=0.72; <2 antithrombotics=0.73; invasive approach=0.73; conservative approach=0.68.
The CRUSADE bleeding score quantifies risk for in-hospital major bleeding across all postadmission treatments, which enhances baseline risk assessment for NSTEMI care.
The prevalence, health care expenditures, and hospitalization experiences are important considerations among elderly populations with multiple chronic conditions.
A cross-sectional analysis was conducted on a nationally random sample of 1 217 103 Medicare fee-for-service beneficiaries aged 65 and older living in the United States and enrolled in both Medicare Part A and Medicare Part B during 1999. Multiple logistic regression was used to analyze the influence of age, sex, and number of types of chronic conditions on the risk of incurring inpatient hospitalizations for ambulatory care sensitive conditions and hospitalizations with preventable complications among aged Medicare beneficiaries.
In 1999, 82% of aged Medicare beneficiaries had 1 or more chronic conditions, and 65% had multiple chronic conditions. Inpatient admissions for ambulatory care sensitive conditions and hospitalizations with preventable complications increased with the number of chronic conditions. For example, Medicare beneficiaries with 4 or more chronic conditions were 99 times more likely than a beneficiary without any chronic conditions to have an admission for an ambulatory care sensitive condition (95% confidence interval, 86-113). Per capita Medicare expenditures increased with the number of types of chronic conditions from $211 among beneficiaries without a chronic condition to $13 973 among beneficiaries with 4 or more types of chronic conditions.
The risk of an avoidable inpatient admission or a preventable complication in an inpatient setting increases dramatically with the number of chronic conditions. Better primary care, especially coordination of care, could reduce avoidable hospitalization rates, especially for individuals with multiple chronic conditions.
To study initiation, dosages, and compliance with beta-blockers, angiotensin-converting enzyme (ACE)-inhibitors, and statins in patients after acute myocardial infarction (AMI) and to identify likely targets for improvement.
Patients admitted with first AMI between 1995 and 2002 were identified by linking nationwide administrative registers. A total of 55 315 patients survived 30 days after discharge and were included; 58.3% received beta-blockers, 29.1% ACE-inhibitors, and 33.5% statins. After 1, 3, and 5 years, 78, 64, and 58% of survivors who had started therapy were still receiving beta-blockers, 86, 78, and 74% were receiving ACE-inhibitors, and 85, 80, and 82% were receiving statins, respectively. Increased age and female sex were associated with improved compliance. The dosages prescribed were generally 50% or less of the dosages used in clinical trials, and dosages did not increase during the observation period. Patients who did not start treatment shortly after discharge had a low probability of starting treatment later.
The main problem with underuse of recommended treatment after AMI is that treatment is not initiated at an appropriate dosage shortly after AMI. A focused effort in the immediate post-infarction period would appear to provide long-term benefit.
To compare levels of and trends in incidence and hospital mortality of first acute myocardial infarction (AMI) based on routinely collected hospital morbidity data and on linked registers. Cases taken from routine hospital data are a mix of patients with recurrent and first events, and double counting occurs when cases are admitted for an event several times during 1 year. By linkage of registers, recurrent events and double counts can be excluded.
In 1995 and 2000, 28,733 and 25,864 admissions for AMI were registered in the Dutch national hospital discharge register. Linkage with the population register yielded 21,565 patients with a first AMI in 1995 and 20,414 in 2000.
In 1995 and 2000, the incidence based on the hospital register was higher than based on the linked registers in men (22% and 23% higher) and women (18% and 20% higher). In both years, hospital mortality based on the hospital register and on linked registers was similar. The decline in incidence between 1995 and 2000 was comparable whether based on standard hospital register data or linked data (18% and 20% in men, 15% and 17% in women). Similarly, the decline in hospital mortality was comparable using either approach (11% and 9% in both men and women).
Although the incidence based on routine hospital data overestimates the actual incidence of first AMI based on linked registers, hospital mortality and trends in incidence and hospital mortality are not changed by excluding recurrent events and double counts. Since trends in incidence and hospital mortality of AMI are often based on national routinely collected data, it is reassuring that our results indicate that findings from such studies are indeed valid and not biased because of recurrent events and double counts.
Objective:
To develop and validate an updated morbidity index for short-term mortality risk, using chronic conditions identified from routine hospital admission ICD-10 data.
Study design and setting:
Retrospective cohort study of all adult New Zealand (NZ) residents at 1st Jan 2012.
Participants:
Adult NZ residents aged 18 and over, defined by enrolment with a Primary Healthcare Organisation or accessing public healthcare in preceding year. Data were split into two datasets for index development (70%, n=2,331,645) and validation (30%, n=1,000,166).
Results:
The M3 index was constructed using log hazard ratios for one-year mortality modelled from presence of 61 chronic conditions. Validation results were improved for the M3 index for predicting one-year mortality compared to Charlson and Elixhauser on the c-statistic (M3: 0.931, Charlson 0.921, Elixhauser 0.922; difference M3 vs Charlson = 0.010, 95% CI 0.008, 0.012; M3 vs Elixhauser = 0.009, 95% CI 0.007, 0.012) and integrated discriminative improvement (IDI: M3 vs Charlson=0.024, 95% CI 0.021, 0.026; M3 vs Elixhauser=0.024, 95% CI 0.022, 0.027).
Conclusion:
The M3 index had improved predictive performance for one-year mortality risk over Charlson and Elixhauser indices, allowing better adjustment for mortality risk from chronic conditions. This provides an important tool for population-level analyses of health outcomes.
The All New Zealand Acute Coronary Syndrome Quality Improvement programme (ANZACS-QI) uses a web-based system to create a clinical registry of patients with acute coronary syndrome (ACS) and other cardiac problems admitted to hospitals across New Zealand. This detailed clinical registry is complemented by parallel analyses of, and individual linkage to, New Zealand’s multiple routine health information datasets. The programme is primarily designed to support secondary care clinicians to implement evidence based guidelines and to meet national performance targets for New Zealand cardiac patients. ANZACS-QI simultaneously generates a large-scale research database and provides an electronic data infrastructure for clinical registry studies. ANZACS-QI has been successfully implemented in all the 41 public hospitals across New Zealand where acute cardiac patients are admitted. By June 2015 25,273 patients with suspected ACS and 30,696 referred for coronary angiography were registered in ANZACS-QI. In this report we describe the development and national implementation of ANZACS-QI, its governance, the data collection processes and the current ANZACS-QI cohorts and available outputs.
Atrial fibrillation is the most commonly encountered sustained arrhythmia. The spectrum of symptomatology and presentation are broad. The goals of treatment should include (1) identification of any underlying cause(s) and/or precipitating factor(s), (2) control of ventricular rate, (3) restoration and maintenance of sinus rhythm and (4) prevention of thromboembolism. The characteristics of the arrhythmia differ among patients; hence, some goals will apply in some cases and a different combination in other cases. A thoughtful, individualized approach is essential.
Despite encouraging declines in the incidence of heart failure (HF) complicating acute coronary syndrome (ACS), it remains a common problem with high mortality. Being able to identify patients at high risk of HF after ACS would have great clinical and economic impact. With this study, we assessed the usefulness of the GRACE score to predict HF after an ACS.
We studied 4137 consecutive patients discharged with diagnosis of ACS. We analyzed HF incidence, timing, and association with the follow-up mortality. Cox proportional hazards modeling was performed to assess the accuracy of the GRACE risk score to predict HF admissions in follow-up (median 3.1 years).
A total of 433 patients (10.5%) developed HF. GRACE score was an independent predictor of HF after ACS [hazard ratio (HR) 1.02, 95% confidence interval (CI): 1.01-1.03, p<0.001]. A risk gradient for the development of HF with GRACE risk score was shown: high- and moderate-GRACE risk groups have been linked to a sixfold and twofold increased risk of HF. This risk gradient was maintained in patients with and without prior history of HF, in ST elevation myocardial infarction and non-ST elevation myocardial infarction groups, and in patients with depressed and preserved left ventricular ejection fraction. The development of HF was associated with high mortality (54.5% vs 13.4%; HR=4.48; 95% CI: 3.84-5.24; p<0.001). After adjusting for GRACE risk score, HF development resulted as an independent predictor of mortality.
GRACE risk score has been shown to provide clinically relevant stratification of follow-up HF admission risk at the time of hospital discharge in patients with ACS.
Copyright © 2015. Published by Elsevier Ltd.
A recent increase in the absolute number of hospitalisations for acute myocardial infarction (AMI) in New Zealand may signal a new epidemic of coronary heart disease (CHD).
To quantify the impact of factors other than incidence of disease on these national hospitalisation trends.
A total of 324,663 electronic records of New Zealand public CHD hospitalisations from 1993 to 2005 were examined. Repeat admissions were identified by record linkage using a unique national health identifier for each patient.
Hospitalisations for AMI increased by about 8% a year throughout the 13-year study period. Interhospital transfers increased by 117% over the study period, while readmissions increased by 42%. By 2005 over 60% of all admissions for CHD were readmissions. After accounting for readmissions, hospital transfers and population changes, the age-standardised first AMI hospitalisation rate peaked in 1995 and has since declined by 15%. Reciprocal trends in AMI and angina hospitalisations were seen, indicating changing diagnostic criteria. Overall hospitalisation rates for first CHD events remained relatively steady at about 216.4 events per 100,000 between 1993 and 2000 and subsequently declined by 25% to 162.2 events per 100,000 in 2005.
Recent trends in hospitalisation rates for AMI are significantly influenced by factors other than underlying changes in CHD incidence. Increasing absolute numbers of admissions coded as AMI in New Zealand between 1993 and 2005 can be accounted for by increases in readmissions, increases in interhospital transfers, changes in diagnostic criteria for AMI and in demography.
Survivors of nonfatal coronary heart disease (CHD) can reduce their risk of further events by various preventive interventions. The impact of such measures as delivered over 11 years, on population rates of subsequent major CHD events, has not been extensively studied. This study determined population trends in the prevalence of clinically manifest CHD and the proportion of major CHD events that occur in this population.
A population longitudinal person-based event-linked file of CHD extracted from State Hospital Morbidity Data and Death Registry for 1980 to 2005 was used to identify, for each year from 1995 to 2005, survivors who had a hospitalization for CHD over the previous 15 years (population with established CHD), and to examine the occurrence of CHD death and hospitalization with a principal diagnosis of myocardial infarction in both populations with and without established CHD. The average annual age-standardized prevalence of CHD in the Perth metropolitan region (population 1.6 million) was 28 373 (8.8%) in men and 14 966 (4.0%) in women. Age-specific prevalence increased exponentially with age, from <1% in 35 to 39 age group to 42% in 80 to 84 age group in men and half that in women. The percentage of total CHD events (n=28 941) that occurred in the population with established CHD was approximately 43% in both men and women, 55% and 51%, respectively, for CHD death and 35% and 36% for nonfatal myocardial infarction.
More than 40% of major CHD events annually occur in persons with manifest disease, highlighting the imperative to implement systems of care that support effective secondary prevention.
To investigate the predictive value of acute coronary syndrome (ACS) diagnoses, including unstable angina pectoris, myocardial infarction, and cardiac arrest, in the Danish National Patient Registry.
We identified all first-time ACS diagnoses in the Danish National Patient Registry among participants in the Danish cohort study "Diet, Cancer and Health" through the end of 2003. We retrieved and reviewed medical records based on current European Society of Cardiology criteria for ACS.
We reviewed hospital medical records of 1,577 out of 1,654 patients (95.3%) who had been hospitalized with a first-time ACS diagnosis. The overall positive predictive value for ACS was 65.5% (95% confidence interval [CI]=63.1-67.9%). Stratification by sub-diagnosis and hospital department produced significantly higher positive predictive values for myocardial infarction diagnoses (81.9%; 95% CI=79.5-84.2%) and among patients who received an ACS diagnosis in a ward (80.1%; 95% CI=77.7-82.3%).
The ACS diagnoses contained in hospital discharge registries should be used with caution. If validation is not possible, restricting analyses to patients with myocardial infarction and/or patients discharged from wards might be a useful alternative.
Guidelines for the management of atrial fibrillation
- Camm