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.

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.

Home-based aerobic interval training improves peak oxygen uptake equal to residential cardiac rehabilitation: a randomized, controlled trial.

UNLABELLED: Aerobic capacity, measured as the peak oxygen uptake, is a strong predictor of survival in cardiac patients. Aerobic interval training (AIT), walking/running four times four minutes at 85-95% of peak heart rate, has proven to be effective in increasing peak oxygen uptake in coronary heart disease patients. As some patients do not attend organized rehabilitation programs, home-based exercise should be an alternative. We investigated whether AIT could be performed effectively at home, and compared the effects on peak oxygen uptake with that observed after a standard care, four-week residential rehabilitation. Thirty patients undergoing coronary artery bypass surgery were randomized to residential rehabilitation or home-based AIT. At six months follow-up, peak oxygen uptake increased 4.6 (±2.7) and 3.9 (±3.6) mL·kg(-1) min(-1) (both p<0.005, non-significant between-group difference) after residential rehabilitation and AIT, respectively. Quality of life increased significantly in both groups, with no statistical significant difference between groups. We found no evidence for a different treatment effect between patients randomized to home-based AIT compared to patients attending organized rehabilitation (95% confidence interval -1.8, 3.5). AIT patients reported good adherence to exercise training. Even though these first data indicate positive effects of home-based AIT in patients undergoing coronary artery bypass surgery, more studies are needed to provide supporting evidence for the application of this rehabilitation strategy. TRIAL REGISTRATION: ClinicalTrials.gov NCT00363922.

Effect of exercise training on inflammation status among people with metabolic syndrome.

BACKGROUND: Metabolic syndrome is associated with chronic low-grade inflammation, a condition thought to play a key role in the pathogenesis of the syndrome. Among a number of proinflammatory cytokines, interleukin-18 (IL-18) seems to be the best marker for inflammation among people with metabolic syndrome. The aim of this study was to examine the effect of aerobic training versus strength training on circulating IL-18 and other proinflammatory markers in people with metabolic syndrome. METHODS: Thirty-one inactive men and women with metabolic syndrome were randomized to either high-intensity aerobic interval training (AIT, n=11), strength training (ST, n=10), or a control group (n=10). Exercise training was carried out three times per week for 12 weeks. Serum insulin, high-sensitivity C-reactive protein (hsCRP), IL-18, IL-6, and tumor necrosis factor-α (TNF-α) were measured before and after the intervention. RESULTS: Serum IL-18 was reduced by 43% after AIT (P<0.001). Although there was no change in TNF-α from baseline after AIT, the levels were lower compared to the ST (P=0.032) and control groups (P=0.039) after the intervention. Total body fat was reduced after AIT (from 33.9 ± 7.3% to 32.2 ± 7.9%, P<0.001) and ST (from 31.2 ± 3.9% to 29.7 ± 3.4%, P=0.025). There were no changes in serum IL-6, insulin, or hsCRP within or between the groups. CONCLUSION: Both ST and AIT reduced fat mass. However, only the latter intervention was associated with a more favorable inflammatory status among people with metabolic syndrome. CLINICAL TRIAL REGISTRATION INFORMATION: http://clinicaltrials.gov/show/NCT00986024/ .

Strength training versus aerobic interval training to modify risk factors of metabolic syndrome.

Metabolic syndrome is characterized by central obesity, elevated blood pressure, high fasting glucose and triglyceride levels, and low HDL levels. Regular physical activity can improve the metabolic profile and reduce the risks of cardiovascular diseases and premature mortality. However, the optimal training regime to treat metabolic syndrome and its associated cardiovascular abnormalities remains undefined. Forty-three participants with metabolic syndrome were randomized to one of the following groups: aerobic interval training (AIT; n = 11), strength training (ST; n = 11), a combination of AIT and ST (COM; n = 10) 3 times/wk for 12 wk, or control (n = 11). Risk factors comprising metabolic syndrome were evaluated before and after the intervention. Waist circumference (in cm) was significantly reduced after AIT [95% confidence interval (CI): -2.5 to -0.04], COM (95% CI: -2.11 to -0.63), and ST (95% CI: -2.68 to -0.84), whereas the control group had an increase in waist circumference (95% CI: 0.37-2.9). The AIT and COM groups had 11% and 10% increases in peak O2 uptake, respectively. There were 45% and 31% increases in maximal strength after ST and COM, respectively. Endothelial function, measured as flow-mediated dilatation (in %), was improved after AIT (95% CI: 0.3-3), COM (95% CI: 0.3-3), and ST (95% CI: 1.5-4.5). There were no changes in body weight, fasting plasma glucose, or HDL levels within or between the groups. In conclusion, all three training regimes have beneficial effects on physiological abnormalities associated with metabolic syndrome.

Pre-pregnancy physical activity and preeclampsia risk: a prospective population-based cohort study.

OBJECTIVE: To test the hypothesis that women physically active prior to pregnancy are at reduced risk of preeclampsia. Design. Population-based prospective cohort study. Setting. Linkage between the HUNT-1 Study (health study) and the Medical Birth Registry of Norway. POPULATION: Women with singleton live births after participation in the HUNT-1 Study were included, if the newborn's gestational age was more than 22 weeks or birthweight above 500 g. Women pregnant during participation in the health study were excluded. METHODS: The physical activity level was measured by a questionnaire. Information on the women's coming birth was provided by the Medical Birth Registry of Norway. Odds ratios of preeclampsia were calculated and adjusted for maternal age, parity, smoking and body mass index. MAIN OUTCOME MEASURE: Preeclampsia. RESULTS: Of 3,656 women included, 167 (4.6%) developed preeclampsia. Overall, we found no link between pre-pregnancy physical activity and preeclampsia. Only among the women physically active for 120 min/week or more, a tendency for reduced risk was found (adjusted odds ratio 0.6:95% CI 0.3-1.2). CONCLUSION: Women physically active prior to pregnancy were not at reduced risk of developing preeclampsia.

Repeated image analyses improves accuracy in assessing arterial flow-mediated dilatation.

OBJECTIVES: A high degree of variability has been reported regarding the ultrasound-based assessment of flow-mediated dilatation. We wanted to investigate the variability and find out how it might be reduced most efficiently. DESIGN: Brachial artery flow-mediated dilatation was measured by high-resolution ultrasound in 22 healthy adults on two consecutive days. Two observers analysed all images twice. The total variance was split into variance components and estimated hierarchically using the method of restricted maximum likelihood. RESULTS: The relative proportional contributions from intraobserver (residual), interobserver, interpatient and interday variance components, with percentage dilatation as outcome variable, were 0.41, 0.18, 0.25, and 0.15, respectively. CONCLUSIONS: The major source of variability when assessing flow-mediated dilatation was found to be intraobserver variability. The simplest way to reduce total variability is for the observer to average results from repeated image analyses. We suggest that three repetitions are sufficient. This will reduce the total variance by 30%.

Blood flow velocity profiles in the aortic annulus: a 3-dimensional freehand color flow Doppler imaging study.

BACKGROUND: The use of a single sample volume in Doppler measurements of the velocity time integral (VTI) in the aortic annulus may introduce errors in calculations of stroke volumes, shunts, regurgitant fractions, and aortic valve area. To study the blood flow velocity distribution and assess this potential error, we used a dynamic 3-dimensional color flow Doppler imaging method. METHODS AND RESULTS: Seventeen healthy volunteers were studied. The ultrasound data were captured from 10 to 20 heartbeats at a high frame rate (mean 57 frames per second) while freely tilting the transducer in the apical position. A magnetic position-sensor system recorded the spatial position and orientation of the probe. The raw digital ultrasound data were analyzed off-line with no loss of temporal resolution. Blood flow velocities were integrated across a spherical surface that tracked the aortic annulus during systole. The ratios of the systolic maximum to the systolic mean VTI ranged from 1.2 to 1.5 (mean 1.4). At the time of systolic peak flow, the ratios of the maximum to the mean velocity ranged from 1.1 to 2.0 (mean 1.5). The location of the maximum velocities and VTI showed individual variation. CONCLUSION: The blood flow velocity profile was nonuniform. By using a single sample volume in Doppler measurements of the VTI in the aortic annulus, errors ranging from 20% to 50% may be introduced in calculations of stroke volumes.