Swedish National Hospital Discharge Register Research Articles

Mortality, risk factors and causes of death in Swedish patients with open tibial fractures - a nationwide study of 3, 777 patients

BackgroundOpen tibial fractures are serious, complicated injuries. Previous studies suggested an increased risk of death, however, this has not been studied in large population-based settings. We aimed to analyze mortality including causes of death in all patients with open tibial fractures in Sweden. Moreover, we wanted to compare mortality rates with the Swedish population and determine whether treatment-related or demographic variables were independently associated with death.MethodWe searched the Swedish National Hospital Discharge Register for all patients with open tibial fracture between 1998 and 2010. We collected the following variables: age, gender, length of stay, mechanism of injury and treatment rendered. We then cross-referenced the Swedish Cause of Death Register to determine the cause of death, if applicable. We compared mortality in the study population with population-based mortality data from Statistics Sweden and determined whether variables were independently associated with death using regression analysis.ResultsOf the 3777 open tibial fractures, 425 (11.3%) patients died. The most common causes of death for elderly patients were cardiovascular and respiratory disease. Patients aged 15–39 years succumbed to external causes (accidents, suicides or poisoning). Increasing age (OR 25.7 (95% CI 11.8–64.8) p < 0.001), length of hospital stay (HR 1.01, (95% CI 1.01–1.02,) p < 0.001), limb amputation (OR 4.8 (95% CI 1.86–11.1) p < 0.001) and cause of the accident were independently associated with an increased mortality.ConclusionPatients with open tibial fractures have an increased risk of death compared with the general population in all age- and gender-groups. External causes of death are over-represented and indicate a subgroup with a risky behaviour among younger males. Elderly patients have an increased risk of dying comparable to hip fracture patients. They are at risk for cardiovascular and respiratory failure and should be treated with urgency, emphasizing the need for specialized geriatric trauma units.

Type 1 Diabetes in Parents and Risk of Attention Deficit/Hyperactivity Disorder in Offspring: A Population-Based Study in Sweden.

To explore whether a family history of type 1 diabetes (T1D) is associated with an increased incidence of attention deficit/hyperactivity disorder (ADHD) in offspring. Individuals with T1D were identified from the nationwide Swedish National Hospital Discharge Register and Swedish Outpatient Register in Sweden and were linked to the Swedish Multi-Generation Register to identify their offspring. Cox regression was used to calculate the hazard ratio (HR) of ADHD in offspring of patients with T1D compared with the general population. A total of 15,615 individuals were born after their parents were diagnosed with T1D. After a set of confounding factors was controlled for, offspring of T1D patients had a significantly increased risk of ADHD with an HR of 1.29 (95% CI 1.15-1.42). Maternal T1D was associated with an enhanced risk of ADHD (HR 1.35 [95% CI 1.18-1.55]) compared with paternal T1D (HR 1.20 [95% CI 1.03-1.41]), but the difference was not statistically significant. In this retrospective cohort study, we found that a parental history of T1D was associated with a 29% increased risk of being diagnosed with ADHD. However, the underlying mechanisms need to be explored in future studies.

Cardiovascular fitness in late adolescent males and later risk of serious non-affective mental disorders: a prospective, population-based study.

Cardiovascular fitness in late adolescence is associated with future risk of depression. Relationships with other mental disorders need elucidation. This study investigated whether fitness in late adolescence is associated with future risk of serious non-affective mental disorders. Further, we examined how having an affected brother might impact the relationship. Prospective, population-based cohort study of 1 109 786 Swedish male conscripts with no history of mental illness, who underwent conscription examinations at age 18 between 1968 and 2005. Cardiovascular fitness was objectively measured at conscription using a bicycle ergometer test. During the follow-up (3-42 years), incident cases of serious non-affective mental disorders (schizophrenia and schizophrenia-like disorders, other psychotic disorders and neurotic, stress-related and somatoform disorders) were identified through the Swedish National Hospital Discharge Register. Cox proportional hazards models were used to assess the influence of cardiovascular fitness at conscription and risk of serious non-affective mental disorders later in life. Low fitness was associated with increased risk for schizophrenia and schizophrenia-like disorders [hazard ratio (HR) 1.44, 95% confidence interval (CI) 1.29-1.61], other psychotic disorders (HR 1.41, 95% CI 1.27-1.56), and neurotic or stress-related and somatoform disorders (HR 1.45, 95% CI 1.37-1.54). Relationships persisted in models that included illness in brothers. Lower fitness in late adolescent males is associated with increased risk of serious non-affective mental disorders in adulthood.

Polypharmacy and adverse outcomes after hip fracture surgery.

BackgroundWe aimed to explore the effects of polypharmacy and specific drug classes on readmissions and mortality after hip surgery.MethodsWe analyzed data on 272 consecutive hip fracture patients (72.1% females; age 82 ± 9 years) who underwent acute hip replacement. We collected detailed data on the pharmacological treatment upon admission and discharge. Patients were followed up over a period of 6 months after discharge using the Swedish National Hospital Discharge Register and the Swedish National Cause of Death Register.ResultsAfter 6 months, 86 patients (31.6%) were readmitted, while 36 patients (13.2%) died. The total number of medications upon discharge was predictive of rehospitalization (odds ratio (OR) 1.08, 95%CI 1.01–1.17, p = 0.030) but not predictive of mortality. The use of antiosteoporotic agents (OR 1.86, 95%CI 1.06–3.26, p = 0.03), SSRIs (OR 1.90, 95%CI 1.06–3.42, p = 0.03), and eye drops (OR 4.12, 95%CI 1.89–8.97, p = 0.0004) were predictive of rehospitalization. Treatment with vitamin K antagonists (OR 4.29, 95%CI 1.19–15.39, p = 0.026), thiazides (OR 4.10, 95%CI 1.30–12.91, p = 0.016), and tramadol (OR 2.84, 95%CI 1.17–6.90, p = 0.021) predicted readmissions due to a new fall/trauma.ConclusionsThe total number of medications, use of antiosteoporotic agents, SSRIs, and eye drops predicted rehospitalization after hip fracture surgery, while use of vitamin K antagonists, thiazides, and tramadol was associated with readmissions due to a traumatic fall.Trial registrationHip fractures and polypharmacy in the elderly. Stimulus Project for the Elderly 2009-2011 (Reg no 2009-11-26). Swedish National Board of Health and Welfare.

Long-term pattern of opioid prescriptions after femoral shaft fractures.

The use of opioids in non-cancer-related pain following skeletal trauma is controversial due to the presumed risk of dose escalation and dependence. We therefore examined the pattern of opioid prescriptions, that is, those actually dispensed, in patients with femoral shaft fractures. We analysed data from the Swedish National Hospital Discharge Register and the Swedish Prescribed Drug Register between 2005 and 2008. We identified 1471 patients with isolated femoral shaft fractures. The median age was 75 (16-102) years and 56% were female. In this cohort, 891 patients (61%) received dispensed opioid prescriptions during a median follow-up of 20 months (interquartile range 11-32). In the age- and sex-matched comparison cohort (7339 individuals) without fracture, 25% had opioid prescriptions dispensed during the same period. The proportions of patients receiving opioid analgesics at 6 and 12 months after the fracture were 45% (95% CI 42-49) and 36% (32-39), respectively. The median daily morphine equivalent dose (MED) was between 15 and 17 mg 1-12 months post-fracture. After 3 months, less than 5% used prescription doses higher than 20 mg MED per day. Older age (≥ 70 compared with < 70 years) was a significant predictor of earlier discontinuation of opioid use (Hazard ratio [HR] 1.9). A notable proportion of patients continued to receive dispensed prescriptions for opioids for over 6 months (45%) and more than a third of them (36%) continued treatment for at least 12 months. However, the risk of dose escalation seems to be small in opioid-naïve patients.

The risk of atrial fibrillation in the general male population: a lifetime follow-up of 50-year-old men.

This study aimed to estimate the prevalence, incidence rate, and lifetime risk of developing atrial fibrillation (AF) in a population-based study of Swedish men. The study is a part of 'The Study of Men Born in 1913', which is a longitudinal prospective cohort study of 855 men born in 1913 and living in the city of Gothenburg in Sweden. They were followed from the age of 50 years until 98 years with repeated examinations and data from the Swedish National Hospital Discharge Register. A total of 185 (21.6%) men developed AF. The prevalence of AF increased from 0.4% at 50 years old, to 1.9% by 60 years old, to 4.6% by 70 years old, to 12.5% by 80 years old, and to 15.7% by 90 years old. The lifetime risk of developing AF was 22.5%. Atrial fibrillation is rare at the age of 50 in Swedish men, but it increases exponentially with age, markedly accelerating after 70 years old. In nonagenarians, one of five men has or has had AF.

The Genetic Overlap of Type 2 Diabetes and Depression – Finding From the Swedish Twin Registry

Introduction A bidirectional association between type 2 diabetes and depression has been consistently reported. It is associated with worse biomedical outcomes and increased mortality. One possible question is whether the co-occurrence of type 2 diabetes and depression is due to genetic and/or environmental vulnerabilities in common to the two traits. Aims To examine the genetic relationship between type 2 diabetes and depression at a population level. Objectives To quantify the genetic overlap between type 2 diabetes and depression using the Swedish Twin Registry. Method The study included 43,565 twin pairs (12,363 monozygotic pairs and 31,202 dizygotic pairs). The primary outcomes were lifetime diagnosis of type 2 diabetes and depression from the Swedish National Hospital Discharge Registry. Standard bivariate twin models were fitted to the raw data to estimate the genetic and environmental (co)variance of the two traits. Results Heritability estimates for lifetime diagnoses of type 2 diabetes and depression were similar to previous estimates, at 77% and 42% respectively. The phenotypic correlation between type 2 diabetes and depression was 0.14 (95%CI: 0.11-0.17), of which 58% was due to shared genetic influences. When covariates (age and gender) were included, the genetic contribution to the phenotypic correlation reduced to 51%. Conclusion This is the first study to demonstrate a small but significant genetic overlap between type 2 diabetes and depression at a population level, using hospital-registry records.

No signs of dose escalations of potent opioids prescribed after tibial shaft fractures: a study of Swedish National Registries

BackgroundThe pattern of opioid use after skeletal trauma is a neglected topic in pain medicine. The purpose of this study was to analyse the long-term prescriptions of potent opioids among patients with tibial shaft fractures.MethodsData were extracted from the Swedish National Hospital Discharge Register, the National Pharmacy Register, and the Total Population Register, and analysed accordingly. The study period was 2005–2008.ResultsWe identified 2,571 patients with isolated tibial shaft fractures. Of these, 639 (25%) collected a prescription for opioids after the fracture. The median follow-up time was 17 (interquartile range [IQR] 7–27) months. Most patients with opioid prescriptions after fracture were male (61%) and the median age was 45 (16–97) years. The leading mechanism of injury was fall on the same level (41%). At 6 and 12 months after fracture, 21% (95% CI 17–24) and 14% (11–17) were still being treated with opioids. Multiple Cox regression-analysis (adjusted for age, sex, type of treatment, and mechanism of injury) revealed that older patients (age >50 years) were more likely to end opioid prescriptions (Hazard ratio 1.5 [95% CI 1.3-1.9]). During follow-up, the frequency of patients on moderate and high doses declined. Comparison of the daily morphine equivalent dose among individuals who both had prescriptions during the first 3 months and the 6th month indicated that the majority of these patients (11/14) did not have dose escalations.ConclusionsWe did not see any signs in registry-data of major dose escalations over time in patients on potent opioids after tibial shaft fractures.

Circulation: Cardiovascular Interventions Editors’ Picks

<i>Circulation: Cardiovascular Interventions</i> Editors’ Picks

Effects of adjuvant tamoxifen therapy on cardiac disease: results from a randomized trial with long-term follow-up

Tamoxifen is associated with a reduced risk of coronary heart disease (CHD). However, there are few reports on long-term effects. Using data from a large Swedish randomized trial of 5 and 2years of adjuvant tamoxifen in women with early breast cancer, we here present results on morbidity and mortality from cardiac diseases during treatment and long-term after treatment. A total of 4,150 patients were breast cancer recurrence-free after 2years. Data from the Swedish National Hospital Discharge Registry combined with information from the Swedish Cause of Death Registry were used to define events of disease. Hazard ratios were estimated using Cox regression. Patients assigned to 5years in comparison with 2years of postoperative tamoxifen experienced a reduced incidence of CHD [hazard ratio (HR), 0.83; 95% CI 0.70-1.00], especially apparent during the active treatment period (HR 0.65; 95% CI 0.43-1.00). The mortality from CHD was significantly reduced (HR 0.72; 95% CI 0.53-0.97). During the active treatment, the morbidity of other heart diseases was also significantly reduced (HR 0.40; 95% CI 0.25-0.64) but not after treatment stopped (HR 1.06; 95% CI 0.87-1.30). Similar results were seen for both heart failure and atrial fibrillation/flutter. As compared to 2years of therapy, 5years of postoperative tamoxifen therapy prevents CHD as well as other heart diseases. The risk reduction is most apparent during the active treatment period, and later tends to diminish.

Increased occurrence of spinal fractures related to ankylosing spondylitis: a prospective 22-year cohort study in 17,764 patients from a national registry in Sweden.

BackgroundAnkylosing spondylitis (AS) is a rheumatoid disease leading to progressive ossification of the spinal column. Patients suffering from AS are highly susceptible to unstable vertebral fractures and often require surgical stabilisation due to long lever arms. Medical treatment of these patients improved during the last decades, but until now it is unknown whether the annual number of spinal fractures changed during the last years. Since the annual count of fracture is an effective measure for efficacy of injury prevention and patient safety in AS patients, the current recommendations of activity have to be revised accordingly.MethodsData for all patients with AS treated as inpatients between 01/01/1987 and 31/12/2008 were extracted from the Swedish National Hospital Discharge Registry (SNHDR). The data in the registry are collected prospectively, recording all inpatient admissions throughout Sweden. The SNHDR uses the codes for diagnoses at discharge according to the Swedish versions of the International Classification of Diseases (ICD-9 and ICD-10).ResultsDuring the years from 1987 to 2008 17,764 patients with AS were treated as inpatients; of these 724 patients were treated due to spinal fractures. The annual number of cervical, thoracic and lumbar fractures in the registry increased until 2008 (r = 0.94).ConclusionsDespite the improved treatment of AS the annual number of vertebral fractures requiring inpatient care increased during the last two decades. Possible explanations are population growth, greater awareness of fractures, improved diagnostics, improved emergency care reducing fatalities, and a higher activity level of patients receiving modern medical therapy. Obviously the improvement of medical treatment did not reduce the susceptibility of these patients to unstable fractures. Thus the restrictive injury prevention recommendations for patients with AS cannot be defused, but must be critically revised to improve patient safety.

Circulation : Clinical Summaries

<i>Circulation</i> : Clinical Summaries

Long-term follow-up of opioid use in patients with acetabular fractures

IntroductionChronic pain and the pattern of opioid use after skeletal fractures has been a neglected topic in pain medicine. Pelvic and in particular acetabular fractures represent some of the most troublesome injuries for patients with a high incidence of chronic pain after fracture. We examined the long-term opioid analgesic use among patients with acetabular fractures and analysed if potential risk factors would predict a prolonged opioid therapy. Patients and methodsData were extracted from medical databases such as the Swedish National Hospital Discharge Register and the National Pharmacy Register. The study period was 2005–2008. Kaplan–Meier analysis constructed the cumulative opioid consumption with 95% confidence intervals (CI). Cox multiple-regression model was used to study risk factors for a prolonged opioid prescription after admission for fracture. An age- and sex-matched control group was included for comparisons. ResultsWe identified 1017 patients with isolated acetabular fractures. The proportion of dispensing opioids for these patients was 39%, which was 7 times higher than in the age- and sex-matched non-fracture controls (n=5077). The median follow-up time was 14 (interquartile range [IQR] 5–24) months. Most patients with opioid use after fracture were male (60%) and the median age was 76 (IQR 61–85) years. The leading mechanism of injury was fall on the same level (52%). At 6 and 12 months after fracture, 41% (95% CI 36–47) and 33% (28–39) were still treated with opioids. The multiple Cox regression-analysis (adjusted for age, sex, type of treatment, and mechanism of injury) revealed that younger patients (age <70 compared with ≥70 years) were more likely to end using opioids (Hazard ratio 2.0 [95% CI 1.5–2.7]). The median daily morphine equivalent dose was 22 (IQR 14–42)mg within the first month after fracture. DiscussionDuring follow-up, the frequency of patients on moderate and high doses was falling off. There was no evidence of analgesic tolerance in the majority of the patients who were treated for at least 6 months. To set our findings into perspective, studies of patterns of chronic opioid use among patients with other types of fractures would be valuable.

Increased Risk of Cataract Among 28,000 Patients With Celiac Disease

Vitamin deficiencies are prevalent in celiac disease (CD) and are associated with cataract formation, but it is unknown whether persons with CD are at increased risk of cataract. The authors' objective in this population-based cohort study was to determine the risk of cataract among persons with biopsy-verified CD. Data on CD were collected from reports on small intestinal biopsies performed between July 1969 and February 2008 in the 28 regional pathology departments in Sweden. The authors identified 28,756 persons with CD (villous atrophy, Marsh pathology stage 3). For each person with CD, Statistics Sweden selected up to 5 controls matched for age and sex from the Total Population Register. Data on cataract were obtained from the Swedish National Hospital Discharge Register and the National Day-Surgery Register. Cox regression analysis was used to estimate the risk of cataract. During a median follow-up period of 9 years, the authors identified 1,159 cataracts among persons with CD (909 were expected) (hazard ratio = 1.28, 95% confidence interval: 1.19, 1.36). The absolute risk of cataract was 397/100,000 person-years in CD, with an excess risk of 86/100,000 person-years. In conclusion, this study found an increased risk of developing cataract in patients with CD.

Time dependent effects of adjuvant tamoxifen therapy on cerebrovascular disease: results from a randomised trial

Background:Tamoxifen has been associated with an increased risk of stroke. There is, however, little information on the effect in the post-treatment period. Using data from the Swedish Breast Cancer Group adjuvant trial of 5 vs 2 years of tamoxifen treatment, we now report both short-term and long-term effects on morbidity as well as mortality because of cerebrovascular disease.Methods:Data from the Swedish National Hospital Discharge Registry combined with information from the Swedish Cause of Death Registry was used to define events of disease. Hazard ratios (HRs) were estimated using Cox regression.Results:Comparing patients randomised to 5 years of tamoxifen with patients randomised to 2 years of tamoxifen, the incidence of cerebrovascular diseases was increased (HR 1.70, 95% CI 1.05–2.75) during the active treatment phase and reduced after the active treatment period (HR 0.78, 95% CI 0.63–0.96), and the difference in HR between the two time-periods was significant (P=0.0033). The mortality from cerebrovascular diseases was increased during the treatment period (HR 3.18, 95% CI 1.03–9.87) and decreased during the post-treatment period (HR 0.60, 95% CI 0.40–0.90) with a significant difference in HR between the two periods of follow-up (P=0.0066). Similar results were seen for subgroups of cerebrovascular diseases, such as stroke and ischaemic stroke.Conclusion:In an adjuvant setting, tamoxifen was associated with an increased risk of cerebrovascular disease during treatment, but a decreased risk in the post-treatment period.

Extent and consequences of misclassified injury diagnoses in a national hospital discharge registry

BackgroundClassification of injuries and estimation of injury severity on the basis of ICD-10 injury coding are powerful epidemiological tools. Little is known about the characteristics and consequences of primary coding...

Twenty-year trends in incidence and 1-year mortality in Swedish patients hospitalised with non-AMI chest pain. Data from 1987–2006 from the Swedish hospital and death registries

ObjectiveTo study trends for 20 years in incidence and 1-year mortality in hospitalised patients who received a diagnosis of either angina or unexplained chest pain (UCP) in Sweden.Design and settingRegister...

National data of 6409 Swedish inpatients with femoral shaft fractures: Stable incidence between 1998 and 2004

Introduction Femoral shaft fractures are commonly thought to be primarily associated with high-energy trauma in young persons. Only limited attention has been given to low-energy violence as a cause of these fractures among the elderly. National epidemiological data on characteristics of patients with femoral shaft fractures are lacking, so the purpose of this study was to analyse the incidence, admissions, causes of fracture and operations for these fractures on a nationwide basis in Sweden during 1998–2004. Patients and methods Data on all femoral shaft fractures were extracted from the Swedish National Hospital Discharge Registry. Sex- and age-specific fracture incidence, hospital admissions, mechanisms of injury and surgical procedures were analysed using descriptive analysis, linear-regression analysis and other methods as appropriate. Results Over a period of 7 years, 6409 patients with femoral shaft fractures were identified, corresponding to an annual incidence of 10 per 100,000 person-years. Men had a younger median age (27 years, IQR 12–68) than women (79 years, IQR 62–86) ( p < 0.001). Females (54%) generated more admissions than males (46%). The incident rate ratio between men and women was 0.9 ( p < 0.001). Most hospital admissions were generated among females by the 80–89 years age-group and among males <10 years of age. 2% of the fractures were open fractures. The total number of hospital admissions was stable during 1998–2004. The two major mechanisms of injury were falls on the same level (50%) and transport accidents (17%). A significant number of fractures occurred among elderly patients after low-energy trauma. Osteosynthesis with femoral nail (54%) was the preferred operation, followed by osteosynthesis with plate and screws (16%), skeletal traction (14%) and external fixation (6%). Discussion This nationwide study on femoral shaft fractures provides an update on incidence, admissions, external causes and surgical procedures. This information assists health-care providers in planning hospital beds, surgical interventions and risk preventions. Moreover, these data can be used for power calculations for further clinical studies.

Decrease of RA-related orthopaedic surgery of the upper limbs between 1998 and 2004: data from 54 579 Swedish RA inpatients

To describe the overall use and temporal trends in orthopaedic upper limb surgery associated with RA on a nation wide basis in Sweden between 1998 and 2004. Data for all inpatient visits during 1998-2004 for patients older than 18 yrs with RA-related diagnoses were extracted from the Swedish National Hospital Discharge Registry (SNHDR). The SNHDR prospectively collects data on all hospital admissions in Sweden according to the International Classification of Diseases (ICD). Data were analysed with respect to orthopaedic surgery of the hand, elbow and shoulder. During the study period, 54,579 individual RA patients were admitted to a Swedish hospital and 9% of these underwent RA-related surgery of the upper limbs. The RA patient cohort underwent a total of 8251 RA-related upper limb surgical procedures. The hand (77%) was most frequently operated on, followed by the shoulder (13%) and the elbow (10%). There was a statistically significant decrease of 31% for all admissions associated with RA-related upper limb surgery during 1998-2004 (P = 0.001). Some 10% of all RA-related upper limb surgery was due to total joint arthroplasties (TJAs), mostly for the elbow (59%). During 1998-2004, all TJAs, elbow-TJAs and shoulder-TJAs had a stable occurrence. In contrast, the overall numbers of hand-TJAs significantly increased (P = 0.009). Rates of RA-related upper limb surgery decreased and TJAs had a stable occurrence in Sweden during 1998-2004. The findings of this study may reflect trends in disease management and health outcomes of RA patients in Sweden.

Height and body mass index in young adulthood and risk of schizophrenia: a longitudinal study of 1 347 520 Swedish men

Measures of body size reflect genetic and environmental influences on growth and energy balance. Associations between such measures and risk of schizophrenia have been inconsistent. This is a population-based cohort study of 1 347 520 men born in Sweden from 1952 to 1982, with height and body mass index (BMI) data available from conscription records. The Swedish National Hospital Discharge Register was used to identify subjects diagnosed with schizophrenia from 1970 to 2000. Subjects with lower BMI and shorter height had an increased risk of developing schizophrenia. Underweight subjects had an approximately 30% increase in risk compared with normal BMI subjects (adjusted HR = 1.30, 95% CI: 1.20-1.42). Tall subjects had an approximately 15% reduction in risk compared with short subjects (adjusted HR = 0.85, 95% CI: 0.80-0.92). Both height and BMI in early adulthood are strongly and inversely associated with risk of schizophrenia. We discuss these findings in relation to possible genetic and nutritional causal mechanisms.