Exploring variation in timely reperfusion treatment in ST-segment elevation myocardial infarction in Norway: a national register-based cohort study.

OBJECTIVES: This study aimed to investigate determinants of reperfusion within recommended time limits (timely reperfusion) for ST-segment elevation myocardial infarction patients, exploring the impact of geography, patient characteristics and socio-economy. DESIGN: National register-based cohort study. SETTING: Multilevel logistic regression models were applied to examine the associations between timely reperfusion and residency in hospital referral areas and municipalities, patient characteristics, and socio-economy. PARTICIPANTS: 7607 Norwegian ST-segment elevation myocardial infarction patients registered in the Norwegian Registry of Myocardial Infarction during 2015-2018. MAIN OUTCOME MEASURES: The odds of timely reperfusion by primary percutaneous coronary intervention (PCI) or fibrinolysis. RESULTS: Among 7607 ST-segment elevation myocardial infarction patients in Norway, 56% received timely reperfusion. The Norwegian goal is 85%. While 81% of the patients living in the Oslo hospital referral area received timely reperfusion, only 13% of the patients living in Finnmark did so.Patients aged 75-84 years had lower odds of timely reperfusion than patients below 55 years of age (OR 0.73, 95% CI 0.61 to 0.87). Patients with moderate or high comorbidity had lower odds than patients without (OR 0.81, 95% CI 0.68 to 0.95 and OR 0.61, 95% CI 0.44 to 0.84). More than 2 hours from symptom onset to first medical contact gave lower odds than less than 30 min (OR 0.63, 95% CI 0.54 to 0.72). 1-2 hours of travel time to a PCI centre (OR 0.39, 95% CI 0.31 to 0.49) and more than 2 hours (OR 0.22, 95% CI 0.16 to 0.30) gave substantially lower odds than less than 1 hour of travel time. CONCLUSIONS: The varying proportion of patients receiving timely reperfusion across hospital referral areas implies inequity in fundamental healthcare services, not compatible with established Norwegian health policy. The importance of travel time to PCI centre points at the expanded use of prehospital pharmacoinvasive strategy to obtain the goals of timely reperfusion in Norway.

Influenza vaccination and risk for cardiovascular events: a nationwide self-controlled case series study.

BACKGROUND: US and European guidelines diverge on whether to vaccinate adults who are not at high risk for cardiovascular events against influenza. Here, we investigated the associations between influenza vaccination and risk for acute myocardial infarction, stroke and pulmonary embolism during the 2009 pandemic in Norway, when vaccination was recommended to all adults. METHODS: Using national registers, we studied all vaccinated Norwegian individuals who suffered AMI, stroke, or pulmonary embolism from May 1, 2009 through September 30, 2010. We defined higher-risk individuals as those using anti-diabetic, anti-obesity, anti-thrombotic, pulmonary or cardiovascular medications (i.e. individuals to whom vaccination was routinely recommended); all other individuals were regarded as having lower-risk. We estimated incidence rate ratios with 95% CI using conditional Poisson regression in the pre-defined risk periods up to 180 days following vaccination compared to an unexposed time-period, with adjustment for season or daily temperature. RESULTS: Overall, we observed lower risk for cardiovascular events following influenza vaccination. When stratified by baseline risk, we observed lower risk across all three outcomes in association with vaccination among higher-risk individuals. In this subgroup, relative risks were 0.72 (0.59-0.88) for AMI, 0.77 (0.59-0.99) for stroke, and 0.73 (0.45-1.19) for pulmonary embolism in the period 1-14 days following vaccination when compared to the background period. These associations remained essentially the same up to 180 days after vaccination. In contrast, the corresponding relative risks among subjects not using medications were 4.19 (2.69-6.52), 1.73 (0.91-3.31) and 2.35 (0.78-7.06). CONCLUSION: In this nationwide study, influenza vaccination was associated with overall cardiovascular benefit. This benefit was concentrated among those at higher cardiovascular risk as defined by medication use. In contrast, our results demonstrate no comparable inverse association with thrombosis-related cardiovascular events following vaccination among those free of cardiovascular medications at baseline. These results may inform the risk-benefit balance for universal influenza vaccination.

Completeness and correctness of acute myocardial infarction diagnoses in a medical quality register and an administrative health register.

Aims: Health registers are used for administrative purposes, disease surveillance, quality assessment, and research. The value of the registers is entirely dependent on the quality of their data. The aim of this study was to investigate and compare the completeness and correctness of the acute myocardial infarction (AMI) diagnosis in the Norwegian Myocardial Infarction Register and in the Norwegian Patient Register. Methods: All Norwegian patients admitted directly to St Olavs hospital, Trondheim University Hospital, Trondheim University Hospital from 1 July to 31 December 2012 and who had plasma levels of cardiac troponin T measured during their hospitalization (n=4835 unique individuals, n=5882 hospitalizations) were identified in the hospital biochemical database. A gold standard for AMI was established by evaluation of maximum troponin T levels and by review of the information in the medical records. Cases of AMI in the registers were classified as true positive, false positive, true negative, and false negative according to the gold standard. We calculated sensitivity, positive predictive value (PPV), specificity, and negative predictive value (NPV). Results: The Norwegian Myocardial Infarction Register had a sensitivity of 86.0% (95% confidence interval (CI) 82.8-89.3%), PPV of 97.9% (96.4-99.3%), and specificity of 99.9% and NPV of 98.9% (98.6-99.2%) (99.8-100%). The corresponding figures for the Norwegian Patient Register were 85.8% (95% CI 82.5-89.1%), 95.1% (92.9-97.2%), and 99.7% (99.5-99.8%) and 98.9% (98.6-99.2%), respectively. Both registers had a sensitivity higher than 95% when compared to hospital discharge diagnoses. The results were similar for men and women and for cases below and above 80 years of age. Conclusions: The Norwegian Myocardial Infarction Register and the Norwegian Patient Register are adequately complete and correct for administrative purposes, disease surveillance, quality assessment, and research.

Interrater reliability of a national acute myocardial infarction register.

BACKGROUND: Disease-specific registers may be used for measuring and improving healthcare and patient outcomes, and for disease surveillance and research, provided they contain valid and reliable data. The aim of this study was to assess the interrater reliability of all variables in a national myocardial infarction register. METHODS: We randomly selected 280 patients who had been enrolled from 14 hospitals to the Norwegian Myocardial Infarction Register during the year 2013. Experienced audit nurses, who were blinded to the data about the 280 patients already in the register, completed the Norwegian Myocardial Infarction paper forms for 240 patients by review of medical records. We then extracted all registered data on the same patients from the Norwegian Myocardial Infarction Register. To compare the interrater reliability between the register and the audit nurses, we calculated intraclass correlations coefficient for continuous variables, Cohen's kappa and Gwet's first agreement coefficient (AC1) for nominal variables, and quadratic weighted Cohen's kappa and Gwet's second AC for ordinal variables. RESULTS: We found excellent (AC1 >0.80) or good (AC1 0.61-0.80) agreement for most variables, including date and time variables, medical history, investigations and treatments during hospitalization, medication at discharge, and ST-segment elevation or non-ST-segment elevation acute myocardial infarction. However, only moderate agreement (AC1 0.41-0.60) was found for family history of coronary heart disease, diagnostic electrocardiography, and complications during hospitalization, whereas fair agreement (AC1 0.21-0.40) was found for acute myocardial infarction location. A high percentage of missing data was found for symptom onset, family history, body mass index, infarction location, and new Q-wave. CONCLUSION: Most variables in Norwegian Myocardial Infarction Register had excellent or good reliability. However, some important variables had lower reliability than expected or had missing data. Precise definitions of data elements and proper training of data abstractors are necessary to ensure that clinical registries contain valid and reliable data.

Gender differences in the assessment and treatment of myocardial infarction. / Kjønnsforskjeller i utredning og behandling av hjerteinfarkt.

BACKGROUND: Previous studies have shown that there are gender-related differences in the assessment and treatment of myocardial infarction, despite international guidelines that prescribe identical treatment for women and men. We investigated whether these differences occurred in Norway. MATERIAL AND METHOD: All patients admitted to Norwegian hospitals with myocardial infarction from 1 January 2013 to 31 December 2014 and registered in the Norwegian Myocardial Infarction Registry were included. Data from the registry were used to analyse differences in the assessment, treatment, complications and survival of women and men in different age groups. RESULTS: A total of 26 447 myocardial infarctions were registered in the Norwegian Myocardial Infarction Registry in the period 2013 ­ 2014. Fewer women than men were assessed by means of coronary angiography. Percutaneous coronary intervention (PCI) was used to virtually the same extent for both genders if coronary stenosis was found. Women were recommended secondary prophylactic medication to a lesser extent than men. There were no major differences between men and women in the incidence of complications in the course following myocardial infarction or in survival. INTERPRETATION: Fewer women than men suffering acute myocardial infarction were assessed by means of coronary angiography, and women were recommended secondary prophylactic medication less often than men. The reason for the gender differences is not known, but comorbidity and a potentially greater risk of adverse reactions in women may be contributory factors. The different views of doctors providing treatment may also play a part.

Myocardial infarction in Norway in 2013.

BACKGROUND: The Norwegian Myocardial Infarction Registry was established in 2012 as a national quality registry. This first report from the registry presents the number of myocardial infarctions, the treatment provided and the 30-day mortality rate for myocardial infarctions admitted to Norwegian hospitals. MATERIAL AND METHOD: All patients with myocardial infarction admitted to Norwegian hospitals in 2013 and recorded in the Norwegian Myocardial Infarction Registry are included. The number of myocardial infarctions, patient characteristics and their treatment are indicated for myocardial infarctions with and without ST-segment elevation on ECG (STEMI and nSTEMI). The 30-day mortality is calculated for each health region. RESULTS: In 2013, a total of 13,043 myocardial infarctions in 12,336 patients were recorded in the Norwegian Myocardial Infarction Registry. Altogether 3,658 (28%) of the infarctions were classified as STEMI and 9,188 (70%) as nSTEMI. The average age at the time of the infarction was 68.1 years for men and 75.9 years for women. Percutaneous coronary intervention was performed for a total of 2,798 (77%) ST-segment elevation myocardial infarctions, whereas the corresponding number for nSTEMI was 3,179 (35%). The 30-day mortality in the entire infarction population was 10% (< 60 years: 2%, 60-69 years: 4%, 70-79 years: 9%, ≥ 80 years: 20%). We found no differences in mortality between health regions or between men and women. INTERPRETATION: This first report from the Norwegian Myocardial Infarction Registry shows that the treatment service is functioning well for most patients. Secondary prophylaxis using drug therapy and increased use of invasive examination of patients with nSTEMI appear to be areas for improvement.