BACKGROUND & AIMS: OBJECTIVES:To evaluate screening for retinopathy of prematurity (ROP) in Sweden and to investigate possible modifications of the present screening guidelines. METHODS:Infants in Sweden with a gestational age (GA) of 31 weeks + 6 days or less are screened for ROP. Data from the Swedish national register for ROP (SWEDROP) during 2008 and 2009 were extracted and compared with a national perinatal quality register. RESULTS:In SWEDROP, there were 1791 infants born before a GA of 32 weeks from January 1, 2008, through December 31, 2009. Another 70 infants were registered in the perinatal quality register but not in SWEDROP (dropout rate, 3.8% [70 of 1861 infants]). Seven infants died before termination of screening. In the final study cohort (1784 infants), 15.6% had mild ROP and 8.5% had severe ROP. Treatment was performed in 4.4% of the infants, none of whom had a GA at birth of more than 28 weeks. Nine infants with a GA of more than 28 weeks at birth developed stage 3 ROP, which regressed spontaneously. The total number of examinations was 9286 (964 in infants with a GA of 31 weeks), and the mean (range) number of examinations of each infant was 5.2 (1-30). CONCLUSIONS:The SWEDROP, a quality register for ROP, has a national coverage (ie, participation) of 96%. Data from 2008 to 2009 show that it seems possible to reduce the upper limit for screening in Sweden by 1 week, including only infants with a GA of 30 weeks + 6 days or less. However, such a change should be combined with a strong recommendation to neonatologists to refer also severely ill and more "mature" infants.

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BACKGROUND & AIMS: :Over 3500 patients with recent onset inflammatory polyarthritis (IP) have been recruited by the Norfolk Arthritis Register (NOAR) since 1990. Longitudinal data from this cohort have been used to examine the prevalence and predictors of remission, functional disability, radiological outcome, cardiovascular mortality and co-morbidity and the development of non-Hodgkin's lymphoma. Rheumatoid factor titre, high baseline C-reactive protein and high baseline HAQ score are all predictors of a poor outcome. There is a strong association between possession of the shared epitope and the development of erosions. Patients who satisfy the American College of Rheumatology criteria for rheumatoid arthritis (RA) have a worse prognosis than those who do not. However, it appears that these patients are a poorly defined subset of all those with IP rather than having an entirely separate disease entity. New statistical techniques offer exciting possibilities for using longitudinal datasets such as NOAR to explore the long-term effects of treatment in IP and RA.

背景与目标： 诺福克关节炎注册 (NOAR) 1990年招募了3500多名近期发病的炎症性多关节炎 (IP) 患者。来自该队列的纵向数据已用于检查缓解，功能障碍，放射学结果，心血管死亡率和合并症的患病率和预测因素以及非霍奇金淋巴瘤的发展。类风湿因子滴度，高基线C反应蛋白和高基线HAQ评分都是不良预后的预测指标。拥有共同的表位与侵蚀的发展之间存在很强的联系。符合美国风湿病学会类风湿关节炎 (RA) 标准的患者的预后比不符合该标准的患者差。然而，这些患者似乎是所有IP患者中定义不明确的子集，而不是具有完全独立的疾病实体。新的统计技术为使用纵向数据集 (例如NOAR) 探索IP和RA治疗的长期影响提供了令人兴奋的可能性。

BACKGROUND & AIMS: Objectives:The Salford Asthma Register was launched at the beginning of 1995 to record the details of all asthma patients in Salford, Greater Manchester, UK. Design:An IT system was developed for the registration, annual review, audit and feedback of data to general practices on the status of their registered asthma patients. Setting and subjects:On joining the Salford Asthma Register, each practice submits a list of their current asthma patients to a central database maintained at Hope Hospital. Patients with chronic obstructive pulmonary disease (COPD) and children below one year of age are excluded from the register. Main outcome measures:An annual review sheet for every registered patient is generated by the database and returned to the practice. Asthma patients numbering 10,841 have been registered from 41 general practices covering 70% of the population of Salford. Of these, 2244 (20.7%) have had an annual review and 1545 (14.3%) have been recorded as resolved. All participating practices have received annual asthma reports comparing their asthma management with the district average. Most asthma measures (peak expiratory flow, daytime and nighttime symptoms) progressively deteriorated from the BTS Step 1 to Step 5. We were able to identify possible under-treatment in some patients in Step 1 and provide feedback to the practices concerned. Conclusions: In this observational study, we have shown that it is possible to establish a broad-based asthma database in an NHS district, which provides valuable feedback to the primary care team. We feel that this database and asthma monitoring methodology could be utilised elsewhere in the country. This could be an important tool in clinical governance.

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BACKGROUND & AIMS: INTRODUCTION:Many previous studies have been limited by self- or proxy-reported injury or short follow-up. We investigated whether head or brain injuries are associated with Alzheimer's disease (AD), possible modifying factors and dose-response relationship. METHODS:Nested register-based case-control study of all community dwellers who received clinically verified AD diagnosis in Finland in 2005 to 2011 (n = 70,719) and one to four matched controls for each case (n of controls = 282,862). RESULTS:The magnitude of association between hospital-treated head and/or brain injuries was strongly dependent on the lag time between exposure and outcome. With a 5-year lag time, head injury (adjusted odds ratio; 95% confidence interval 1.19; 1.15-1.23) or brain injury (1.23; 1.18-1.29) was associated with higher risk of AD. Dose-response relationship with number and severity of injuries was observed. Associations were stronger in those with earlier onset of AD. CONCLUSIONS:Stronger associations with shorter lag times indicate that head and/or brain injuries may also reflect the ongoing AD disease process.

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BACKGROUND & AIMS: BACKGROUND:There is an increased interest in the analysis of large, national palliative care data sets including patient reported outcomes (PROs). No study has investigated if it was best to include or exclude data from services with low response rates in order to obtain the patient reported outcomes most representative of the national palliative care population. Thus, the aim of this study was to investigate whether services with low response rates should be excluded from analyses to prevent effects of possible selection bias. METHODS:Data from the Danish Palliative Care Database from 24,589 specialized palliative care admittances of cancer patients was included. Patients reported ten aspects of quality of life using the EORTC QLQ-C15-PAL-questionnaire. Multiple linear regression was performed to test if response rate was associated with the ten aspects of quality of life. RESULTS:The score of six quality of life aspects were significantly associated with response rate. However, in only two cases patients from specialized palliative care services with lower response rates (< 20.0%, 20.0-29.9%, 30.0-39.9%, 40.0-49.9% or 50.0-59.9) were feeling better than patients from services with high response rates (≥60%) and in both cases it was less than 2 points on a 0-100 scale. CONCLUSIONS:The study hypothesis, that patients from specialized palliative care services with lower response rates were reporting better quality of life than those from specialized palliative care services with high response rates, was not supported. This suggests that there is no reason to exclude data from specialized palliative care services with low response rates.

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BACKGROUND & AIMS: AIMS:To quantify the association between depression and acute myocardial infarction (AMI) in a large sample using case registers, and examine whether any such link is specific to depression or might more reflect mental illness status in general. METHODS AND RESULTS:Accessing the Danish Psychiatric Central Research Register (PCR), patients with a diagnosis of depression were extracted and followed for up to 24 years for episodes of AMI. We used mentally healthy age- and sex-matched controls, and as comparator diagnostic groups, we studied patients with anxiety and schizophrenia. A positive association between depression and AMI was found with an incidence rate ratio (IRR) of 1.16 (CI: 1.10-1.22). The association was not unique for the depressed individuals, but was also found for anxiety patients, where it was even stronger (IRR=1.56, CI: 1.35-1.79) than for the depressed patients. A negative association (IRR=0.77, CI: 0.65-0.91) was quantified for schizophrenia, arguing against any link with AMI being determined by psychiatric disorder status per se. LIMITATIONS:Being a register study, not all potential confounding variables could be examined. CONCLUSION:Findings quantify significant associations between depression and AMI as well as between anxiety and AMI, and argue that these two psychiatric disorders should be added to the list of risk factors to coronary artery disease.

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BACKGROUND & AIMS: OBJECTIVES:The aims of this article are to (1) determine whether and to what extent general perceived health and quality of supervision predict voluntary early retirement pension (VERP) and (2) assess whether quality of supervision modifies the association between general perceived health and VERP. METHODS:Employees aged 49-64 years who participated in the Danish Work Environment Cohort Study in 2000 were selected. Their questionnaire data about health and work were linked to register data on social transfer payments, among others VERP, from 2001 to 2012 in the Danish Register for Evaluation of Marginalization ( N=1167). Cox proportional hazards analyses were performed to identify the prospective association of general perceived health and quality of supervision on VERP. Relative excess risks due to interaction (RERIs) were calculated to assess whether quality of supervision modified the association between health and VERP. RESULTS:Employees with poor health at baseline had an increased risk of VERP during follow-up (hazard ratio [HR]=1.23; 95% confidence interval [CI] 1.02-1.49). Quality of supervision at baseline was not associated to VERP during follow-up (HR=1.04; 95% CI 0.90-1.21). There was no statistically significant interaction of poor health and poor quality of supervision with regard to risk of VERP (RERI=-0.33; 95% CI -1.79 to 1.14). CONCLUSIONS:This study did not support the notion that quality of supervision buffers the association between poor health and VERP. Future research is needed to determine whether other aspects of supervision, for example supervisors' opportunities to effectuate workplace adjustments, may modify the association of poor health and VERP.

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BACKGROUND & AIMS: Objectives:The aim was to study work ability in patients with RA compared with the general population by investigating the rates and risks of long-term sickness absence, unemployment and disability pension, and the chance of returning to work and the changes in these risks over time (1994-2011). Methods:This was a cohort study with up to 17 years of follow-up (mean 6.95 years/person) including 6677 RA patients of working age (identified in the nationwide DANBIO registry) and 56 955 matched controls from the general population. A multi-state model was used to analyse all shifts between the work-related states (long-term sickness absence, unemployment and disability pension, as well as the chance of returning to work) and calculate hazard rates (HRs). Analyses were stratified by disease duration and controlled for socio-demographic factors, physical job exposure and somatic and psychiatric co-morbidities. Results:RA patients had increased risk of long-term sickness absence (e.g. early RA: HR = 4.00, 95% CI: 3.64, 4.30) and disability pension (e.g. established RA: HR = 2.75, 95% CI: 2.54, 2.98) relative to controls. From 1994-99 to 2006-11, a decrease in the effect of established RA was observed [long-term sickness absence: from HR = 2.25 (95% CI: 1.99, 2.54) to 1.63 (95% CI: 1.51, 1.75); and disability pension: from HR = 3.49 (95% CI: 2.83, 4.32) to 2.40 (95% CI: 2.15, 2.69)]. RA patients had a lower chance of returning to work from long-term sickness absence or unemployment (HR = 0.60, HR=0.80), and this did not change over time. Conclusion:RA patients remain at high risk for long-term sickness absence and disability pension, despite a positive development between 1996-99 and 2006-11. Returning to work after sick leave or unemployment remains a challenge for RA patients.

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BACKGROUND & AIMS: BACKGROUND:The aim of this study was to examine the incidence and risk factors for anal sphincter tears (ASTs) at delivery. METHODS:A national population-based study was conducted with data from the Medical Birth Register including all primiparas with singleton pregnancy, who gave birth vaginally in Sweden from 1994 to 2004 (n=365,886). Women with a third and fourth degree AST were compared with those who gave birth during the same period without incurring such tears. RESULTS:The incidence of third degree AST increased by >60%, from 3.4% in 1994 to 5.2% in 2004 in spontaneous births, and from 8.7 to 14.8% in instrumental deliveries during the study period. The proportion of fourth degree AST increased from 0.3 to 0.55% in spontaneous births and from 0.8 to 1.4% in instrumental-assisted deliveries during the same period. Compared with non-instrumental delivery, vacuum extraction (VE) deliveries were related to an increased risk of AST. An infant birth weight of >4,000 g was also associated with an increased risk for both third and fourth degree AST. In addition, women born in Africa and Asia had significantly higher risk for both third and fourth degree AST compared to women born in Sweden. CONCLUSION:The incidence of third and fourth degree AST increased in both spontaneous births and instrumental deliveries. Instrumental delivery and an infant birth weight >4,000 g are the main risk factors for AST. Women from Africa and Asia have pronounced risks.

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BACKGROUND & AIMS: OBJECTIVE:It is unclear whether hydroxyapatite (HA) coating of uncemented cups used in primary total hip arthroplasty (THA) improves bone ingrowth and reduces the risk of aseptic loosening. We therefore investigated survival of different uncemented cups that were available with or without HA coating. METHOD:We investigated three different cup types used with or without HA coating registered in the Nordic Arthroplasty Register Association (NARA) database that were inserted due to osteoarthritis (n = 28,605). Cumulative survival rates and adjusted hazard ratios (HRs) for the risk of revision were calculated. RESULTS:Unadjusted 13-year survival for cup revision due to aseptic loosening was 97.9% (CI: 96.5-99.4) for uncoated and 97.8% (CI: 96.3-99.4) for HA-coated cups. Adjusted HRs were 0.66 (CI 0.42-1.04) for the presence of HA coating during the first 10 years and 0.87 (CI 0.14-5.38) from year 10-13, compared with uncoated cups. When considering the endpoint cup revision for any reason, unadjusted 13-year survival was similar for uncoated (92.5% [CI: 90.1-94.9]) and HA-coated (94.7% [CI: 93.2-96.3]) cups. The risk of revision of any component due to infection was higher in THA with HA-coated cups than in THA with uncoated cups (adjusted HR 1.4 [CI 1.1-1.9]). CONCLUSIONS:HA-coated cups have a similar risk of aseptic loosening as uncoated cups, thus the use of HA coating seems to not confer any added value in terms of implant stability. The risk of infection seemed higher in THA with use of HA-coated cups, an observation that must be investigated further.

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BACKGROUND & AIMS: :In the present study, we evaluated whether childhood differences in body height between singletons and twins persist into adulthood. Data from the Medical Birth Register of Norway were linked with data from the Norwegian National Conscript Service. This study used data on the 457,999 males who were born alive and without physical anomalies in single or twin births in Norway during 1967-1984 and who were examined at the mandatory military conscription (age 18-20 years; 1985-2003). For sibling comparisons, the authors selected the 1,721 sibships of full brothers that included at least 1 male born in a single birth and at least 1 male born in a twin birth (4,520 persons, including 2,493 twins and 2,027 singletons). An analysis of the total study population using generalized estimating equations showed that the twins were 0.6 cm (95% confidence interval: 0.4, 0.7) shorter than were the singletons after adjustment for a series of background factors. The fixed-effects regression analysis of the sibships that included both twins and singletons showed that the twins were 0.9 cm (95% confidence interval: 0.6, 1.2) shorter than were their singleton brothers. The study suggests that male twins born in Norway during 1967-1984 were slightly shorter in early adulthood than were singletons.

背景与目标： : 在本研究中，我们评估了单身和双胞胎之间的童年身高差异是否会持续到成年。来自挪威医疗出生登记册的数据与来自挪威国家应征者服务局的数据相关联。这项研究使用了有关1967-1984年间挪威单胎或双胎出生且没有身体异常的457,999名男性的数据，并在强制性征兵中接受了检查 (年龄18-20岁; 1985-2003岁)。为了进行兄弟姐妹比较，作者选择了完整兄弟的1,721兄弟姐妹，其中包括至少1个单胎出生的男性和至少1个双胞胎出生的男性 (4,520人，包括2,493个双胞胎和2,027个单胎)。使用广义估计方程对总研究人群进行的分析表明，在调整了一系列背景因素后，双胞胎的0.6厘米 (95% 置信区间: 0.4，0.7) 比单身夫妇短。对包括双胞胎和单胎的同胞进行的固定效应回归分析表明，双胞胎的0.9厘米 (95% 置信区间: 0.6，1.2) 比他们的单胎兄弟短。研究表明，1967-1984年在挪威出生的男性双胞胎在成年初期比单身双胞胎短。

BACKGROUND & AIMS: INTRODUCTION:The cementation of a total hip prosthesis may cause bone necrosis, either by direct toxicity or by generation of heat during the polymerization process. This necrotic bone may create conditions that encourage the growth of bacteria. We compared the revision rates due to infection in primary uncemented total hip arthroplasties (THAs) with those of cemented THAs with antibiotic-loaded cement and to those of cemented THAs without antibiotic cement. METHODS:Data from the Norwegian Arthroplasty Register for the period 1987-2003 were used. To have comparable groups, we analyzed only primary THAs performed because of primary osteoarthrosis, and where both the acetabular and the femoral component of the prosthesis were either uncemented or cemented (n = 56,275). RESULTS:In total, 252 revisions due to infection were reported. Compared to the uncemented THAs (n = 5,259), the risk of revision due to infection for THAs without antibiotic cement (n = 15,802) was increased 1.8 times (CI 1.0-3.1; p = 0.04). No differences could be detected when compared to THAs with antibiotic-loaded cement (n = 35,214) (RR 1.2, CI 0.7-2.0; p = 0.5). The average operating time for uncemented THAs was 15 min less than for cemented THAs. INTERPRETATION:The risk of revision due to infection was the same for uncemented and for cemented arthroplasties with antibiotic-loaded cement, but higher for cemented arthroplasties without antibiotic cement. Our findings can be explained by reduced resistance to infection caused by the cement, which appears to be neutralized by adding antibiotic to the cement.

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BACKGROUND & AIMS: :The antibiotic trimethoprim acts as a folate antagonist. Since trophoblasts are very sensitive to drugs that interfere with the folic acid cycle and thereby inhibit DNA synthesis, use of trimethoprim during the first trimester could be associated with miscarriage. A nationwide cohort study including all women in Denmark with a registered pregnancy between 1997 and 2005 was conducted. We used nationwide registers to identify all women giving birth, having a record of miscarriage or induced abortion. Data on exposure to trimethoprim were obtained from the National Prescription Register. Cox proportional hazard regression analysis with exposure to trimethoprim as a time-dependent variable was used to estimate the risk of miscarriage. The adjusted hazard ratio of having a miscarriage after exposure to trimethoprim in the first trimester compared to non-exposure was 2∙04 (95% confidence interval 1∙43-2∙91). Our results indicate that trimethoprim exposure in the first trimester is associated with a doubling of the hazard of miscarriage.

背景与目标： : 抗生素甲氧苄啶起叶酸拮抗剂的作用。由于滋养细胞对干扰叶酸循环从而抑制DNA合成的药物非常敏感，因此在孕早期使用甲氧苄啶可能与流产有关。进行了一项全国性的队列研究，包括丹麦所有有注册怀孕1997年和2005的妇女。我们使用全国范围的登记册来识别所有有流产或人工流产记录的分娩妇女。甲氧苄啶暴露的数据来自国家处方登记册。使用暴露于甲氧苄啶作为时间相关变量的Cox比例风险回归分析来估计流产的风险。与未接触相比，在孕早期暴露于甲氧苄啶后流产的调整的风险比为2*04 (95% 置信区间1*43-2*91)。我们的结果表明，孕早期甲氧苄氨嘧啶暴露与流产危险加倍有关。

BACKGROUND & AIMS: STUDY QUESTION:Are the fetal outcomes of singleton pregnancies that result from cleavage stage embryo transfer (ET) different from the outcomes from Day 5/6 blastocyst stage ET? SUMMARY ANSWER:There was a significantly higher risk of preterm birth (<37 weeks) in singletons after extended embryo culture (Day 5/6) compared with cleavage stage (Day 3) transfer. WHAT IS KNOWN ALREADY:Two recent studies, from Sweden and the USA, reported an increased risk of preterm birth in singleton pregnancies after Day 5/6 ET compared with Day 3 ET. The US study also showed increased early preterm births and the Swedish study showed increased fetal malformations in this group. STUDY DESIGN, SIZE AND DURATION:A retrospective cohort study was performed. Data were collected from the Canadian ART Register database for all singleton births after fresh IVF/ICSI ET cycles (2001-2009). PARTICIPANTS/MATERIALS, SETTING, METHODS:A total of 12 712 singleton births were included. Of these, 9506 resulted from a Day 3 ET and 3206 resulted from a blastocyst (Day 5/6) ET. MAIN RESULTS AND THE ROLE OF CHANCE:Preterm birth rate <37 weeks (unadjusted by potential confounding factors) was higher with Day 5/6 versus Day 3 transfers (17.2 versus 14.1%, P < 0.001). Using logistic regression analysis to adjust for confounding factors, preterm birth rate <37 weeks was the only outcome significantly increased after Day 5/6 compared with Day 3 transfer (odds ratio 1.32, 95% confidence interval 1.17-1.49). The following confounding factors were adjusted for: year of treatment (2001-2009), maternal age (continuous), parity (0 versus ≥1 birth), diagnosis category, number of oocytes retrieved [≤20 versus >20 (high responder group)], insemination method (IVF versus ICSI), number of embryos transferred (1, 2 or ≥3) and the presence of a vanishing twin (≥1 fetal heart on the initial ultrasonographic examination). LIMITATIONS, REASONS FOR CAUTION:Post-natal follow-up studies will be required to determine if this difference we observed translates into adverse long-term effects on these offspring. The rate of early preterm births (<32 weeks) was higher in Day 5/6 versus Day 3, but the low number of cases in this category did not have the power to show a difference (3.0 versus 2.7%, P = 0.34). WIDER IMPLICATIONS OF THE FINDINGS:We found a significantly higher risk of preterm birth (<37 weeks) in singletons after extended embryo culture (Day 5/6) compared with cleavage stage (Day 3) transfer, even when adjusting for confounding factors. Our findings are in agreement with the previous two studies; however, we did not show a difference in the very preterm deliveries (unlike the US study) or in fetal malformations (as in the Swedish study). We hypothesize that there may be a deleterious effect of prolonged in vitro embryo culture on subsequent placentation. Longer term follow-up studies will be required to determine if prolonged in vitro culture to the blastocyst stage has an adverse effect on the long-term health of offspring when compared with shorter cleavage stage culture. STUDY FUNDING/COMPETING INTEREST(S):None.

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BACKGROUND & AIMS: PURPOSE:To describe the content and potentials of the new Swedish national register on prescribed and dispensed medicines. METHODS:The Swedish Prescribed Drug Register contains information about age, sex and unique identifier of the patient as well as the prescriber's profession and practice. Information regarding drug utilization and expenditures for prescribed drugs in the entire Swedish population was extracted from the first six months July-December 2005 and compared with total drug sales in the country including OTC and hospital use. RESULTS:The total quantity of drugs sold in Sweden was 2666 million DDDs, corresponding to 1608 DDD/1000 inhabitants daily. The total expenditures were 1.6 billion Euro. The prescribed drugs, included in the register, accounted for 84% of the total utilization and 77% of the total expenditures. About half of all men and two-thirds of all women in the country purchased drugs. The proportion increased by age. The most common drugs for chronic treatment were diuretics among women (8.8% of the population) and antithrombotic agents among men (7.6%). Psychotropic drugs, corticosteroids and analgesics were more common among women, while men used antithrombotic agents, antidiabetic drugs, lipid lowering agents and ACE inhibitors to a greater extent. CONCLUSIONS:The new register provides valuable data on exposure to drugs and is useful to study patterns of drug utilization. The possibilities for record linkage to other health registers gives from an international perspective good opportunities to explore drug and disease associations and the risks, benefits, effectiveness and health economical effects of drug use.

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