Large differences between patients with acute myocardial infarction included in two Swedish health registers.

BACKGROUND: Acute myocardial infarction (MI) is a leading cause for morbidity and mortality in Sweden. We aimed to compare patients with an acute MI included in the Register of information and knowledge about Swedish heart intensive care admissions (RIKS-HIA, now included in the register Swedeheart) and in the Swedish statistics of acute myocardial infarctions (S-AMI). METHODS: Population based register study including RIKS-HIA, S-AMI, the National patient register and the Cause of death register. Odds ratios were determined by logistic regression analysis. RESULTS: From 2001 to 2007, 114,311 cases in RIKS-HIA and 198,693 cases in S-AMI were included with a discharge diagnosis of an acute MI. Linkage was possible for 110,958 cases. These cases were younger, more often males, had fewer concomitant diseases and were more often treated with invasive coronary artery procedures than patients included in S-AMI only. There were substantial regional differences in proportions of patients reported to RIKS-HIA. CONCLUSIONS: Approximately half of all patients with an acute MI were included in RIKS-HIA. They represented a relatively more healthy population than patients included in S-AMI only. S-AMI covered almost all patients with an acute MI but had limited information about the patients. Used in combination, these two registers can give better prerequisites for improved quality of care of all patients with acute coronary syndromes.

Refinement of Swedish administrative registers to monitor stroke events on the national level.

BACKGROUND: Routinely collected databases are kept for administrative purposes. We have refined the analyses of the Swedish National Patient Register and the Cause of Death Register and explored their validity to monitor stroke at the population level. METHODS: First-ever strokes (incident cases) and all stroke events were measured by combining the two administrative registers and adding refinements. The administrative registers were validated against the Northern Sweden MONICA, a well-validated population-based epidemiological stroke register. Positive predictive values (PPVs) and sensitivity were calculated. RESULTS: After refinements (restriction to first-ever strokes and additional minor delineations), the PPV of the two administrative registers combined was 94% and sensitivity 92% when compared with all MONICA stroke categories together. For stroke attacks (first and recurrent events together), the PPV in the administrative registers was 85% and sensitivity 91%. The PPV was higher in women than in men, whereas the sensitivity was similar. The PPV was lower but sensitivity higher in people below compared with those above 75 years of age. Both PPV and sensitivity were lower among fatal cases than among cases that survived 28 days. CONCLUSIONS: After refinement, Swedish national administrative registers may, with some caveats, be used as a low-resource-consuming alternative to crudely monitor stroke incidence rates at the national level. If further accuracy is strived for, high-quality conventional epidemiological registers are required.

Hazard function and secular trends in the risk of recurrent acute myocardial infarction: 30 years of follow-up of more than 775,000 incidents.

BACKGROUND: The incidence of a first acute myocardial infarction (AMI) has fallen considerably during the last decades. However, no previous studies have analyzed the underlying hazards function of experiencing a recurrent AMI, and none has analyzed the change of risk for a recurrent AMI over the last 3 decades. METHODS AND RESULTS: The study was based on the Swedish national myocardial infarction register. The register contained more than 1 million AMI events. After exclusion of events occurring in subjects younger than 20 or older than 84 years and events with uncertain first AMI status, 775 901 events occurring between 1972 and 2001 remained for analysis. During the study period, the risk of a new event among survivors of a previous AMI decreased sharply during the first 2 years after the previous event, had its minimum after 5 years, and then increased slowly again. The risk for a recurrent AMI during the first year after a previous event was fairly stable over the years until the late 1970s and then decreased by 36% in women and 40% in men until the late 1990s, irrespective of age and AMI number, mirroring the incidence decrease over the years for primary events. CONCLUSIONS: The risk of a recurrent AMI event was highly dependent on time from the previous event, a novel finding which may affect risk scoring. There were strong secular trends toward diminishing risk for a recurrent AMI in recent years, even when other outcome affecting variables were taken into account.

The incidence of adverse events in Swedish hospitals: a retrospective medical record review study.

OBJECTIVES: To estimate the incidence, nature and consequences of adverse events and preventable adverse events in Swedish hospitals. DESIGN: A three-stage structured retrospective medical record review based on the use of 18 screening criteria. SETTING: Twenty-eight Swedish hospitals. Population A representative sample (n = 1967) of the 1.2 million Swedish hospital admissions between October 2003 and September 2004. MAIN OUTCOME MEASURES: Proportion of admissions with adverse events, the proportion of preventable adverse events and the types and consequences of adverse events. RESULTS: In total, 12.3% (n = 241) of the 1967 admissions had adverse events (95% CI, 10.8-13.7), of which 70% (n = 169) were preventable. Fifty-five percent of the preventable events led to impairment or disability, which was resolved during the admission or within 1 month from discharge, another 33% were resolved within 1 year, 9% of the preventable events led to permanent disability and 3% of the adverse events contributed to patient death. Preventable adverse events led to a mean increased length of stay of 6 days. Ten of the 18 screening criteria were sufficient to detect 90% of the preventable adverse events. When extrapolated to the 1.2 million annual admissions, the results correspond to 105,000 preventable adverse events (95% CI, 90,000-120,000) and 630,000 days of hospitalization (95% CI, 430,000-830,000). CONCLUSIONS: This study confirms that preventable adverse events were common, and that they caused extensive human suffering and consumed a significant amount of the available hospital resources.

Differences between coronary disease and stroke in incidence, case fatality, and risk factors, but few differences in risk factors for fatal and non-fatal events.

AIMS: To compare incidence and mortality of coronary and stroke events, and risk factors for non-fatal and fatal events, respectively. METHODS AND RESULTS: Incidence and mortality were compared in all coronary (n=559 341) and stroke (n=530 689) events in Sweden from 1987 to 2001. Data from 28 years of follow-up of a random sample of 7400 men aged 47-55 and free of disease at baseline were used to compare risk factors. Incidence and 28 days of case fatality were considerably higher for coronary disease than for stroke, especially for men. Incidence of coronary disease decreased, especially for men (P=0.0001 for both sexes), and mortality declined for both men and women during 1987-2001 (P=0.0001 for both sexes). Stroke incidence declined slightly (P=0.0001 for both sexes), and there was a decline of mortality (P=0.0001 for both sexes). Out-of-hospital mortality during the first 28 days was higher than in-hospital mortality for coronary events, whereas for stroke, in-hospital mortality was higher (in men) or the same (in women) as out-of-hospital mortality. High serum cholesterol was a strong risk factor for coronary events, but not for stroke. High blood pressure was a stronger risk factor for stroke. About 50% of men with both stroke and coronary disease died from coronary disease. CONCLUSION: Several differences regarding incidence, mortality, prognosis, and risk factors for stroke and coronary disease point towards different pathologies.

Decreasing one-year mortality and hospitalization rates for heart failure in Sweden; Data from the Swedish Hospital Discharge Registry 1988 to 2000.

AIMS: To investigate if improved treatment of coronary heart disease and hypertension, the major causes of chronic heart failure (CHF), in the last 20 years has had an impact on the incidence of CHF and survival. METHODS: National Swedish registers on hospital discharges and cause-specific deaths were used to calculate age- and sex-specific trends and sex ratios for heart failure admissions and deaths. The study included all men and women 45 to 84 years old hospitalized for the first time for heart failure in 19 Swedish counties between 1988 and 2000, a mean annual population 2.9 million. A total of 156?919 hospital discharges were included. RESULT: In 1988, a total of 267 men and 205 women per 100?000 inhabitants (age adjusted) were discharged for the first time with a principal diagnosis of heart failure. After 1993 a yearly decrease was observed, with 237 men and 171 women per 100?000 inhabitants discharged during 2000. The 30-day mortality decreased significantly. The decrease in 1-year mortality was more pronounced in the younger age groups, with a total reduction in mortality of 69% among men and 80% among women aged 45-54 years. The annual decrease was 9% among men and 10% among women aged 45-54 years (95% CI -7% to -12% and -6% to -14% respectively) and 4% among men and 5% among women (95% CI -4% to -5% for both) aged 75-84 years. CONCLUSION: The decrease in incidence and improved prognosis after a first hospitalization for heart failure coincides with the establishment of ACE-inhibitor therapy, the introduction of beta-blockers for treatment of heart failure, home-care programmes for heart failure, and more effective treatment and prevention of underlying diseases. Notwithstanding, despite considerable improvement, 1-year mortality after a first hospitalization for heart failure is still high.

Inequality in access to coronary revascularization in Sweden.

OBJECTIVES: To investigate social and gender equality in access to coronary revascularization for those treated for coronary heart disease in Sweden between 1991 and 2000. DESIGN: All Swedish residents between 25 and 74 years old with a hospital stay for coronary heart disease were eligible for the study, in total about 153,000 persons. The Swedish Hospital Discharge Register from 1988 through 2000 was used to define the study population. Poisson regression analyses were used to estimate the effect of socio-economic status on the likelihood for coronary artery bypass grafting (CABG) within 2 years. In the analysis of gender differences, the likelihood for percutaneous coronary intervention (PCI) was also included. RESULTS: Males were 1.5 times more likely to undergo revascularization procedures than females even after adjusting for confounding factors and the fact that women are less eligible for interventions. The analyses also showed significant socio-economic inequalities in access to CABG among men, but not among women. CONCLUSIONS: There are gender and socio-economic inequalities in access to cardiac procedures in Sweden.

[Mortality after myocardial infarction has decreased in nearly all Swedish counties during the 1990's. Greatest improvement seen in those counties with the worst initial results]. / Dödlighet efter hjärtinfarkt har minskat i nästan alla landsting under 1990-talet. Störst förbättringar i de landsting som hade sämst resultat från början.

In an international perspective, Sweden has a very low case fatality after acute myocardial infarction (AMI). The aim of this study was to present trends and regional differences in case fatality within 28 days of the first AMI for males and females in Sweden after adjusting for co-morbidity. Adjustments in order to remove random effects on the rank order of county councils were made. The study was based on national data on more than 500,000 cases of AMI. Between 1987 and 1999, case fatality after AMI decreased from 47% to 37% among men and from 44% to 34% among women. The case fatality in the individual counties varied from 29% to 37% for men and from 31% to 40% for women. Further analysis is needed in order to explain these variations.