Garbage codes in the Norwegian Cause of Death Registry 1996-2019.

BACKGROUND: Reliable statistics on the underlying cause of death are essential for monitoring the health in a population. When there is insufficient information to identify the true underlying cause of death, the death will be classified using less informative codes, garbage codes. If many deaths are assigned a garbage code, the information value of the cause-of-death statistics is reduced. The aim of this study was to analyse the use of garbage codes in the Norwegian Cause of Death Registry (NCoDR). METHODS: Data from NCoDR on all deaths among Norwegian residents in the years 1996-2019 were used to describe the occurrence of garbage codes. We used logistic regression analyses to identify determinants for the use of garbage codes. Possible explanatory factors were year of death, sex, age of death, place of death and whether an autopsy was performed. RESULTS: A total of 29.0% (290,469/1,000,128) of the deaths were coded with a garbage code; 14.1% (140,804/1,000,128) with a major and 15.0% (149,665/1,000,128) with a minor garbage code. The five most common major garbage codes overall were ICD-10 codes I50 (heart failure), R96 (sudden death), R54 (senility), X59 (exposure to unspecified factor), and A41 (other sepsis). The most prevalent minor garbage codes were I64 (unspecified stroke), J18 (unspecified pneumonia), C80 (malignant neoplasm with unknown primary site), E14 (unspecified diabetes mellitus), and I69 (sequelae of cerebrovascular disease). The most important determinants for the use of garbage codes were the age of the deceased (OR 17.4 for age ≥ 90 vs age < 1) and death outside hospital (OR 2.08 for unknown place of death vs hospital). CONCLUSION: Over a 24-year period, garbage codes were used in 29.0% of all deaths. The most important determinants of a death to be assigned a garbage code were advanced age and place of death outside hospital. Knowledge of the national epidemiological situation, as well as the rules and guidelines for mortality coding, is essential for understanding the prevalence and distribution of garbage codes, in order to rely on vital statistics.

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.

Injury death certificates without specification of the circumstances leading to the fatal injury - the Norwegian Cause of Death Registry 2005-2014.

BACKGROUND: For injury deaths, the underlying cause of death is defined as the circumstances leading to the injury. When this information is missing, the ICD-10 code X59 (Exposure to unspecified factor) is used. Lack of knowledge of factors causing injuries reduces the value of the cause of death statistics. The aim of this study was to identify predictors of X59-coded deaths in Norway, and to assess methods to identify the true underlying cause of injury deaths. METHODS: We used data from the Norwegian Cause of Death Registry from 2005 to 2014. We used logistic regression to identify determinants of X59-coded deaths. For redistribution of the X59 deaths, we used a multinomial logistic regression model based on the cases where injury circumstances were known. The data were divided into training and test sets. The model was developed on the training set and assessed on the test set before it was applied to the X59 deaths. The models used death certificate information on the nature of injury and demographic characteristics as predictor variables. Furthermore, we mailed a query to the certifying physicians of X59 deaths reported in the year 2015, where we asked for additional information on the circumstances leading to the fatal injury. RESULTS: There were 24,963 injury deaths reported to the Cause of Death Registry of Norway 2005-2014. Of these, 6440 (25.8%) lacked information on the circumstances leading to the death. The strongest predictor for a X59 death was the nature of injury (hip fracture), followed by lack of information on the scene of injury. Applying our redistribution algorithm, we estimated that 97% of the X59-coded deaths were accidental falls. The strongest covariate was the nature of injury, followed by place of death and age at death. In 2015, there were 591 X59-coded deaths. Queries were sent to the certifying doctors in 559 cases. Among the informative replies to the query, 88% of the deaths were reclassified to accidental falls. CONCLUSIONS: A large proportion of injury deaths in Norway lack information on the circumstances leading to the fatal injury. Typically, these deaths represent accidental falls causing hip fracture in elderly individuals.

Births in Norwegian midwife-led birth units 2008-10; a population-based study. / Fødestuefødsler i Norge 2008­10 ­ en populasjonsbasert studie.

BAKGRUNN: Fødestuene utgjør en del av en differensiert og desentralisert fødselsomsorg i Norge. Hensikten med studien var å undersøke forekomst og karakteristika ved planlagte og ikke-planlagte fødestuefødsler og årsaker til overflytting samt resultater for mor og barn. MATERIALE OG METODE: I perioden 2008-10 ble et tilleggsskjema til rutinemeldingen til Medisinsk fødselsregister fortløpende utfylt av jordmor for 2 514 av i alt 2 556 (98,4 %) fødestuefødsler og for 220 fødsler som var planlagt i fødestue, men der fødselen foregikk andre steder. Data fra tilleggsskjema ble så koblet med rutinedata i Medisinsk fødselsregister og resultater fra fødestuefødsler sammenlignet med resultater fra en lavrisikofødepopulasjon i sykehus. RESULTATER: Av de 2 514 fødestuefødslene var 2 320 (92,3 %) planlagt å foregå der, mens 194 (7,7 %) ikke var det. Ved planlagt fødestuefødsel ble totalt 6,9 % overflyttet til sykehus under fødsel, hvorav 19,5 % blant førstegangsfødende. Det var 0,4 % operative vaginale fødsler ved vanlige fødestuer, 3,5 % ved forsterkede fødestuer og 12,7 % ved fødsler overflyttet fra fødestue til sykehus. Blant barn født i fødestue hadde 0,6 % apgarskår < 7 ved 5 minutter, mot 1,0 % blant barn født i lavrisikosammenligningsgruppen i sykehus (p = 0,04). FORTOLKNING: Fødestuer bør rapportere resultater for alle som var selektert for å føde der, uansett om fødselen endte med å foregå i fødestuen eller andre steder.

Trends in incident acute myocardial infarction in Norway: An updated analysis to 2014 using national data from the CVDNOR project.

Background We updated the information on trends of incident acute myocardial infarction in Norway, focusing on whether the observed trends during 2001-2009 continued throughout 2014. Methods All incident (first) acute myocardial infarctions in Norwegian residents age 25 years and older were identified in the Cardiovascular Disease in Norway 1994-2014 project. We analysed overall and age group-specific (25-64 years, 65-84 years and 85 + years) trends by gender using Poisson regression analyses and report the average annual changes in rates with their 95% confidence intervals. Results During 2001-2014, 221,684 incident acute myocardial infarctions (59.4% men) were identified. Hospitalised cases accounted for 79.9% of all incident acute myocardial infarctions. Overall, incident acute myocardial infarction rates declined on average 2.6% per year (incidence rate ratio 0.974, 95% confidence interval 0.972-0.977) in men and 2.8% per year (incidence rate ratio 0.972, 95% confidence interval 0.971-0.974) in women, contributed by declining rates of hospitalisations (1.8% and 1.9% per year in men and women, respectively) and deaths (6.0% and 5.8% per year in men and women, respectively). Declining rates were observed in all three age groups. The overall acute myocardial infarction incidence rates continued to decline from 2009 onwards, with a steeper decline compared to 2001-2009. During 2009-2014, gender-adjusted acute myocardial infarction incidence among adults age 25-44 years declined 5.3% per year, contributed mostly by declines in hospitalisation rates (5.1% per year). Conclusion Acute myocardial infarction incidence rates continued to decline after 2009 in Norway in both men and women. The decline started to involve individuals aged 25-44 years, marking a turning point in the previously reported stagnation of rates during 2001-2009.

B Vitamins and Hip Fracture: Secondary Analyses and Extended Follow-Up of Two Large Randomized Controlled Trials.

Elevated plasma homocysteine levels are associated with increased risk of fractures in observational studies. However, it is unsettled whether homocysteine-lowering treatment affects fracture risk. The aim of this study was to investigate the effect of an intervention with B vitamins on the risk of hip fracture in a secondary analysis of combined data from two large randomized controlled trials originally designed to study cardiovascular diseases. Both trials had identical design, intervention, and primary objective. Based on a two-by-two factorial design, the intervention consisted of a daily capsule with either (1) folic acid (0.8 mg) plus vitamin B12 (0.4 mg) and vitamin B6 (40 mg); (2) folic acid (0.8 mg) plus vitamin B12 (0.4 mg); (3) vitamin B6 alone (40 mg); or (4) placebo. The participants were followed with respect to hip fracture during the trial or during an extended follow-up (from the trial start for each patient until the end of 2012). No statistically significant association was found between folic acid plus vitamin B12 treatment and the risk of hip fracture, neither during the trial (median 3.3 years; hazard ratio [HR] 0.87; 95% confidence interval [CI], 0.48 to 1.59) nor during the extended follow-up (median 11.1 years; HR 1.08; 95% CI, 0.84 to 1.40). Nor were there significant differences in the risk of hip fracture between groups receiving versus not receiving vitamin B6 during the trial (HR 1.42; 95% CI, 0.78 to 2.61). However, during the extended follow-up, those receiving vitamin B6 showed a significant 42% higher risk of hip fracture (HR 1.42; 95% CI, 1.09 to 1.83) compared to those not receiving vitamin B6 . In conclusion, treatment with folic acid plus vitamin B12 was not associated with the risk of hip fracture. Treatment with a high dose of vitamin B6 was associated with a slightly increased risk of hip fracture during the extended follow-up (in-trial plus post-trial follow-up). © 2017 American Society for Bone and Mineral Research.

Trends in the risk of early and late-onset heart failure as an adverse outcome of acute myocardial infarction: A Cardiovascular Disease in Norway project.

Aims Heart failure is a serious complication of acute myocardial infarction, leading to a poor prognosis. We explored trends in the risk of heart failure among patients hospitalised with an incident acute myocardial infarction in Norway during 2001-2009. Methods and results A total of 69,372 patients were followed for an episode of heart failure occurring either during (early-onset heart failure) or within one year of discharge from the incident acute myocardial infarction hospitalisation (late-onset heart failure). Logistic regression and competing risk regression models were used to explore trends in early and late-onset heart failure respectively. Overall, 17.1% of patients had early-onset heart failure. The odds of heart failure increased by 2.3% per year (odds ratio = 1.023; 95% confidence interval: 1.015-1.031), influenced by an increase of 5.9% per year among younger (25-69 years) patients while no statistically significant changes occurred among older (70-84 years) patients. Among 47,673 patients discharged alive, without early-onset heart failure, 5.4% experienced late-onset heart failure. The risk of heart failure declined by 6.3% per year (subhazard ratio = 0.937; 95% confidence interval: 0.921-0.954). The decline was statistically significant in both age groups (6.8% per year and 5.9% per year respectively). Overall, the risk of heart failure occurring at any time during the follow up did not change significantly. However, it increased by 3.3% per year in younger patients and declined by 1.5% per year in older patients. Conclusions Heart failure occurring during acute myocardial infarction hospitalisation accounts for the majority of heart failure cases and is characterised by unfavourable trends, while heart failure rates following acute myocardial infarction discharge declined over the study period.

Prognostic Impact of In-Hospital and Postdischarge Heart Failure in Patients With Acute Myocardial Infarction: A Nationwide Analysis Using Data From the Cardiovascular Disease in Norway (CVDNOR) Project.

BACKGROUND: Heart failure (HF) is a serious complication of acute myocardial infarction (AMI). We explored the excess mortality associated with HF as an early or late complication of AMI and describe changes over time in such excess mortality. METHODS AND RESULTS: All patients hospitalized with an incident AMI and without history of prior HF hospitalization were followed up to 1 year after AMI discharge for episodes of HF. New HF episodes were classified as in-hospital HF if diagnosed during the AMI hospitalization or postdischarge HF if diagnosed within 1 year after discharge from the incident AMI. Logistic and Cox regression models were used to explore the excess mortality associated with HF categories. Changes over time in the excess mortality were assessed by testing the interaction between HF status and study year. In-hospital HF increased in-hospital mortality 1.79 times (odds ratio [OR], 1.79; 95% CI: 1.68-1.91). The excess mortality associated with HF increased by 4.3 times from 2001 to 2009 (P interaction<0.001) as a consequence of a greater decline of in-hospital mortality among AMI patients without (9% per year) compared to those with in-hospital HF (3% per year). Postdischarge HF increased all-cause and CVD mortality 5.98 times (hazard ratio, 5.98; 95% CI: 5.39-6.64) and 7.93 times (subhazard ratio, 7.93; 95% CI: 6.84 -9.19), respectively. The relative excess 1-year mortality associated with HF did not change significantly over time. CONCLUSIONS: Development of HF-either as an early or late complication of AMI-has a negative impact on patients' survival. Changes in the excess mortality associated with HF are driven by modest improvements in survival among AMI patients with HF as compared to those without HF.

Time Trends and Educational Inequalities in Out-of-Hospital Coronary Deaths in Norway 1995-2009: A Cardiovascular Disease in Norway (CVDNOR) Project.

BACKGROUND: Recent time trends and educational gradients characterizing out-of-hospital coronary deaths (OHCD) are poorly described. METHODS AND RESULTS: We identified all deaths from coronary heart disease occurring outside the hospital in Norway during 1995 to 2009. Time trends were explored using Poisson regression analysis with year as the independent, continuous variable. Information on the highest achieved education was obtained from The National Education Database and classified as primary (up to 10 years of compulsory education), secondary (high school or vocational school), or tertiary (college/university). Educational gradients in OHCD were explored using Poisson regression, stratified by sex and age (<70 and ≥70 years), and results were expressed as incidence rate ratios (IRRs) and 95%CIs. Of 100 783 coronary heart disease deaths, 58.8% were OHCDs. From 1995 to 2009, age-adjusted OHCD rates declined across all education categories (primary, secondary, and tertiary) in younger men (IRR=0.35; 95%CI 0.32-0.38; IRR=0.38; 95%CI 0.35-0.42; IRR=0.33; 95%CI 0.28-0.40), younger women (IRR=0.47; 95% CI 0.40-0.56; IRR=0.55; 95%CI 0.45-0.67; IRR=0.28; 95% CI 0.16-0.47), older men (IRR=0.20; 95%CI 0.19-0.22; IRR=0.20; 95%CI 0.18-0.22; IRR=0.20; 95%CI 0.17-0.23), and older women (IRR=0.26; 95%CI 0.24-0.28; IRR=0.25; 95%CI 0.23-0.28; IRR=0.28; 95%CI 0.22-0.34). Tertiary education was associated with lower risk of OHCD compared to primary education (IRR=0.37; 95%CI 0.35-0.40 in younger men, IRR=0.26; 95%CI 0.22-0.30 in younger women, IRR=0.52; 95%CI 0.49-0.55 in older men, and IRR=0.61; 95%CI 0.57-0.66 in older women). These gradients did not change over time (P interaction=0.25). CONCLUSIONS: Although OHCD rates declined substantially during 1995 to 2009, they displayed educational gradients that remained constant over time.

Validation of data in the Medical Birth Registry of Norway on delivery after a previous cesarean section.

INTRODUCTION: Trial of labor (TOL) is an option in most deliveries after a previous cesarean section (CS). The Medical Birth Registry of Norway (MBRN) has received compulsory notification of all deliveries in the country since 1967, including data that could identify TOL in epidemiologic research. The objective of this study was to validate MBRN data for identification of TOL deliveries after a previous cesarean section (CS). MATERIAL AND METHODS: The MBRN provided a random national sample of 500 birth order two deliveries during 1989-2012 in women with a registered birth order one CS delivery. The reporting maternity units were asked to complete a questionnaire on data items in both deliveries, using hospital record data as the gold standard. RESULTS: Completed questionnaires were returned for 477 women (95.5%) with data on both deliveries. An algorithm to identify TOL using MBRN data from the birth order two delivery had a positive predictive value of 93.2%, a negative predictive value of 93.5%, a sensitivity of 96.1%, and a specificity of 88.8%. Validity of MBRN data on mode and onset of delivery, CS subtype, and planned mode of delivery is also reported. CONCLUSIONS: MBRN data on planned and actual mode of delivery, CS subtype, and the algorithm to identify TOL in deliveries after a previous CS had satisfactory quality for a registry-based study of TOL.

Educational inequalities in mortality of patients with atrial fibrillation in Norway.

OBJECTIVES: We explored the educational gradient in mortality in atrial fibrillation (AF) patients. DESIGN: We prospectively followed patients hospitalized with AF as primary discharge diagnosis in the Cardiovascular Disease in Norway 2008-2012 project. The average length of follow-up was 2.4 years. Mortality by educational level was assessed by Cox proportional hazard models. Population attributable fractions (PAF) were calculated. Analyses stratified by age (≤75 and >75 years of age), and adjusted for age, gender, medical intervention, and Charlson Comorbidity Index. RESULTS: Of 42,138 AF patients, 16% died by end of 2012. Among younger patients, those with low education (≤10 years) had a HR of 2.3 (95% confidence interval 2.0, 2.6) for all-cause mortality relative to those with any college or university education. Similar results were observed for cardiovascular mortality. Disparities in mortality were greater among younger than older patients. A PAF of 35.9% (95% confidence interval 27.9, 43.1) was observed for an educational level of high school/vocational school or less versus higher education in younger patients. CONCLUSIONS: Increasing educational level associated with better prognosis suggesting underlying education-related behavioral and medical determinants of mortality. A considerable proportion of mortality within 5 years following hospital discharge could be prevented.

Higher education is associated with reduced risk of heart failure among patients with acute myocardial infarction: A nationwide analysis using data from the CVDNOR project.

AIMS: Coronary heart disease (CHD) outcomes are characterised by socioeconomic gradients. Although heart failure (HF) is a severe complication of CHD, sparse evidence exists on the association between socioeconomic status and HF among coronary patients. This study aimed to explore potential educational differences in the risk of HF among acute myocardial infarction (AMI) patients in Norway during 2001-2009. METHODS AND RESULTS: A total of 70,506 patients hospitalised for an incident (first) AMI and without history of HF were included in the analyses. Information on education was obtained from the Norwegian Education Database and categorised into primary, secondary or tertiary. In 12,487 (17.7%) patients, HF was present at admission or developed during the AMI hospitalisation (early-onset HF). Compared to patients with primary education, patients with secondary or tertiary education had 9% [incidence rate ratio (IRR) = 0.91; 95% confidence interval (CI): 0.87-0.94] and 20% (IRR = 0.80; 95% CI: 0.75-0.86) lower risks of early-onset HF, respectively. Of the 54,095 AMI patients discharged alive without concurrent HF, 6375 (11.8%) were subsequently hospitalised with or died from late-onset HF during a median follow-up period of 3.4 years. Compared to patients with primary education, those with secondary or tertiary education had 14% [hazard ratio (HR = 0.86; 95% CI: 0.82-0.91] and 27% (HR = 0.73; 95% CI: 0.66-0.80) lower risks of HF, respectively. Educational differences in the risk of HF were not influenced by gender. CONCLUSIONS: We observed an inverse association between educational level and risk of HF. More efforts in preventing this severe complication of AMI among less educated patients may help to reduce the socioeconomic gap in survival following coronary events.

The universal 2012 definition of myocardial infarction compared to the 2007 definition.

OBJECTIVES: The third Universal 2012 definition of myocardial infarction (MI) has not been compared to the Universal 2007 definition with regard to the number of cases identified, classification and mortality. DESIGN: We examined potential MI events according to the two universal definitions in 1494 patients admitted to the University hospital during the 12 months. Patients were included either because of an MI discharge diagnosis (815 patients) or due to elevated troponin I levels without an MI discharge diagnosis (679 patients). RESULTS: Applying the Universal 2012 definition resulted in 760 of the 1494 patients suffering from MI, as compared to 769 according to the Universal 2007 definition. The lower number of MI events applying the 2012 definition was mainly explained by the stricter definition of Type 4a MI. The 760 MI events were classified as Type 1 (685), 2 (27), 3 (28), 4a (13), 4b (3) and 5 (4). CONCLUSIONS: The application of the third Universal 2012 definition of MI instead of the Universal 2007 definition resulted in a 1% reduction of the total number of MIs. For a practical clinical purpose, the reduction was confined to patients with Type 4a MI. The change of definition had no impact on all-cause mortality.

Coronary angiography and myocardial revascularization following the first acute myocardial infarction in Norway during 2001-2009: Analyzing time trends and educational inequalities using data from the CVDNOR project.

BACKGROUND: We analyzed trends in the utilization of coronary angiography and revascularization - including percutaneous coronary intervention (PCI) or coronary artery bypass surgery (CABG) - related to the first AMI and explored potential educational inequalities in such procedures. METHODS AND RESULTS: All first AMI patients aged 35-89, hospitalized during 2001-2009 were retrieved from 'The Cardiovascular Disease in Norway' project. Information on education was obtained from The Norwegian Education Database. Gender and age group-specific trends in coronary procedures were analyzed using Joinpoint regression. Educational inequalities were explored using multivariable Poisson regression and reported as incidence rate ratios (IRR). A total of 104 836 patients (37.3% women) were included. Revascularization rates increased on average 9.0% and 15.4% per year among younger (35-64years) and older (65-89years) men. Corresponding increases among women were 5.6% and 16.6%. Compared to patients with primary education only, those with secondary and tertiary education had 8% (IRR=1.08, 95% CI; 1.06-1.10) and 12% (IRR=1.12, 95% CI; 1.09-1.14) higher revascularization rates. Educational inequalities were entirely driven by educational differences in receiving coronary angiography (IRR=1.10, 95% CI; 1.08-1.11 for secondary versus primary and IRR=1.14, 95% CI; 1.12-1.16 for tertiary versus primary education level.) Among diagnosed patients, no educational differences were observed in coronary revascularization rates. CONCLUSION: Revascularization rates increased whereas educational differences in revascularization decreased among AMI patients in Norway during 2001-2009. Lower coronary revascularization rates among patients with low education were explained by educational differences in receiving coronary angiography.

Heart Failure Complicating Acute Myocardial Infarction; Burden and Timing of Occurrence: A Nation-wide Analysis Including 86 771 Patients From the Cardiovascular Disease in Norway (CVDNOR) Project.

BACKGROUND: Coronary heart disease (CHD) represents often the underlying conditions for the development of heart failure (HF). We aimed at exploring the burden and timing of HF complicating an acute myocardial infarction (AMI), using the total population of AMI patients hospitalized during 2001-2009 in Norway. METHODS AND RESULTS: A total of 86 771 patients with a first AMI during 2001-2009 and without previous HF were identified in the "Cardiovascular Disease in Norway" project and followed until HF development, death, or December 31, 2009. In 16 219 patients (18.7%), HF was present on admission or developed during hospitalization for the incident AMI. HF occurrence varied according to age (8.9%, 15.2%, and 25.6% among men and 10.2%, 16.8%, and 27.1% among women ages 25-54, 55-74, and 75-85 years). Among 63 853 patients discharged alive without HF, 8058 (12.6%) were hospitalized with or died because of HF during a median follow-up time of 3.2 years. HF incidence rates (IRs) per 1000 person-years during follow-up were 31 (95% CI, 30-32) for men and 46 (95% CI, 44-47) for women (P<0.01). IRs of HF were highest during the first 6 months of follow-up, after which they leveled off and remained stable until the end of follow-up. CONCLUSIONS: In this nation-wide cohort study, we observed that HF remains a frequent complication of the first AMI; both during the acute phase and shortly after the discharge from the hospital.

Comparison of the validity of stroke diagnoses in a medical quality register and an administrative health register.

AIMS: Health registers are essential sources of data used in a wide range of stroke research, including epidemiological, clinical and healthcare studies. Regardless of the type of register, the data must be of high quality to be useful. In this study, we investigated and compared the correctness and completeness of the Norwegian Patient Register (an administrative health register) and the Norwegian Stroke Register (a medical quality register for acute stroke). METHODS: We reviewed the medical records for 5192 admissions to hospital in 2012 and defined cases of stroke in the two registers as true positive, false positive, true negative or false negative. We calculated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value with 95% confidence intervals assuming a normal approximation of the binomial distribution. RESULTS: The Norwegian Stroke Register was highly correct and relatively complete (sensitivity 88.1%, specificity 100% and PPV 98.6%). The Norwegian Patient Register was more complete, but less correct, when we included both the main and secondary diagnoses of stroke (sensitivity 96.8%, specificity 99.6% and PPV 79.7%); restricting the analyses to the main diagnoses of stroke resulted in less complete and more correct registrations (sensitivity 86.1%, specificity 99.9% and PPV 93.5%). CONCLUSIONS: The Norwegian Stroke Register and the Norwegian Patient Register are adequately complete and correct to serve as valuable sources of data for epidemiological, clinical and healthcare studies, as well as for administrative purposes.

Comparison of data from the Cause of Death Registry and the Norwegian Patient Register.

BACKGROUND: The quality of the data in the Cause of Death Registry is crucial to produce reliable statistics on causes of death. The Cancer Registry of Norway uses data from the Norwegian Patient Register to request information from hospitals regarding patients registered with cancer in the patient registry, but not in the cancer registry. We wanted to investigate whether data from the Norwegian Patient Register can also be used to advantage in the Cause of Death Registry. MATERIAL AND METHOD: Data from the Cause of Death Registry on deaths that occurred during the period 2009 ­ 2011 (N = 124,098) were collated with data on contact with somatic hospitals and psychiatric institutions during the last year of life, retrieved from the Norwegian Patient Register. Causes of death were grouped in the same way as in standard statistics on causes of death. RESULTS: Out of 124,098 deaths, altogether 34.9% occurred in somatic hospitals. A total of 80.9% of all deceased had been admitted to a somatic hospital and/or had attended an outpatient consultation during their last year of life. The proportion with hospital contact was highest for those whose cause of death was cancer. In cases of unknown/unspecified cause of death, more than half also had contact with hospitals, but the majority of these were registered with only outpatient consultations. Altogether 5.4% of all deceased had been admitted to and/or had an outpatient consultation in a psychiatric institution during their last year of life. For those whose cause of death was suicide, this proportion amounted to 41.8%. INTERPRETATION: In case of incomplete information on the cause of death, data from the Norwegian Patient Register can supply valuable information on where the patient has been treated, thus enabling the Cause of Death Registry to contact the hospitals in question. However, any potential benefit is restricted by the fact that deceased persons with unknown/unspecified causes of death had less frequently been admitted to hospital during their last year of life.

Use of Loop Diuretics is Associated with Increased Mortality in Patients with Suspected Coronary Artery Disease, but without Systolic Heart Failure or Renal Impairment: An Observational Study Using Propensity Score Matching.

BACKGROUND: Loop diuretics are widely used in patients with heart and renal failure, as well as to treat hypertension and peripheral edema. However, there are no randomized, controlled trials (RCT) evaluating their long term safety, and several observational reports have indicated adverse effects. We sought to evaluate the impact of loop diuretics on long term survival in patients with suspected coronary artery disease, but without clinical heart failure, reduced left ventricular ejection fraction or impaired renal function. METHOD AND FINDINGS: From 3101 patients undergoing coronary angiography for suspected stable angina pectoris, subjects taking loop diuretics (n=109) were matched with controls (n=198) in an attempted 1:2 ratio, using propensity scores based on 59 baseline variables. During median follow-up of 10.1 years, 37.6% in the loop diuretics group and 23.7% in the control group died (log-rank p-value 0.005). Treatment with loop diuretics was associated with a hazard ratio (95% confidence interval) of 1.82 (1.20, 2.76), and the number needed to harm was 7.2 (4.1, 30.3). Inclusion of all 3101 patients using propensity score weighting and adjustment for numerous covariates provided similar estimates. The main limitation is the potential of confounding from unmeasured patient characteristics. CONCLUSIONS: The use of loop diuretics in patients with suspected coronary artery disease, but without systolic heart failure or renal impairment, is associated with increased risk of all-cause mortality. Considering the lack of randomized controlled trials to evaluate long term safety of loop diuretics, our data suggest caution when prescribing these drugs to patients without a clear indication.