Search

Jens Sundbøll,1 Sandra Kruchov Thygesen,1 Katalin Veres,1 Donghua Liao,2 Jingbo Zhao,2 Hans Gregersen,3 Henrik Toft Sørensen11Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark; 2GIOME Academia, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; 3GIOME, Department of Surgery, Chinese University of Hong Kong, Shatin, Hong KongBackground: It remains unclear whether constipation is associated with cancer. We evaluated the risk of malignancies in patients with constipation requiring hospitalization.Methods: Using Danish medical registries, we calculated cumulative incidences and standardized incidence ratios (SIRs) for cancer. SIRs were computed as the observed number of gastrointestinal (GI) cancers and selected non-GI cancers in patients with constipation compared with the expected number based on national incidence rates by sex, age, and calendar year (1978–2013).Results: We identified 1,75,901 patients with constipation (59% females, median age 54 years). The cumulative incidences of GI cancers and non-GI cancers after 15 years of follow-up were 2.5% and 2.6%, respectively. During the first year of follow-up, the SIR for any GI cancer was 5.0 (95% confidence interval (CI): 4.8–5.3), driven by colon and pancreas cancers and higher for younger age groups. Beyond 1 year of follow-up, the risk declined to near unity for colorectal cancer. The risk of other GI cancers (including cancers of the esophagus, stomach, small intestine, liver, and pancreas) remained moderately increased (overall SIR =1.3, 95% CI: 1.2–1.4). Except for ovarian cancer (SIR =7.3, 95% CI: 6.3–8.4), the risk of non-GI cancers was only slightly increased during the first year of follow-up and declined to unity thereafter.Conclusions: Patients with constipation had increased short-term risk of a diagnosis of GI cancer. Beyond 1 year of follow-up, a moderately elevated risk persisted only for GI cancers other than colorectal cancer. The risk of non-GI cancers was elevated only during the first year of follow-up, particularly for ovarian cancer.Keywords: constipation, cancer, cohort study

Yuelian Sun,1 Hans Gregersen,2 Wei Yuan3 1Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark; 2GIOME, Department of Surgery, Chinese University of Hong Kong, Hong Kong, 3Key Laboratory of Reproduction Regulation of NPFPC, SIPPR, IRD, Fudan University, Shanghai, People’s Republic of China Abstract: China has gone through a comprehensive health care insurance reform since 2003 and achieved universal health insurance coverage in 2011. The new health care insurance system provides China with a huge opportunity for the development of health care and medical research when its rich medical resources are fully unfolded. In this study, we review the Chinese health care system and its implication for medical research, especially within clinical epidemiology. First, we briefly review the population register system, the distribution of the urban and rural population in China, and the development of the Chinese health care system after 1949. In the following sections, we describe the current Chinese health care delivery system and the current health insurance system. We then focus on the construction of the Chinese health information system as well as several existing registers and research projects on health data. Finally, we discuss the opportunities and challenges of the health care system in regard to clinical epidemiology research. China now has three main insurance schemes. The Urban Employee Basic Medical Insurance (UEBMI) covers urban employees and retired employees. The Urban Residence Basic Medical Insurance (URBMI) covers urban residents, including children, students, elderly people without previous employment, and unemployed people. The New Rural Cooperative Medical Scheme (NRCMS) covers rural residents. The Chinese Government has made efforts to build up health information data, including electronic medical records. The establishment of universal health care insurance with linkage to medical records will provide potentially huge research opportunities in the future. However, constructing a complete register system at a nationwide level is challenging. In the future, China will demand increased capacity of researchers and data managers, in particular within clinical epidemiology, to explore the rich resources. Keywords: China, health care, insurance, registry, clinical epidemiology

Henrik Gregersen,1 Caroline Brenner Larsen,1 Anne Haglund,1 Rikke Mortensen,2 Niels Frost Andersen,3 Mette Nørgaard21Department of Hematology, Aalborg University Hospital, Aalborg, Denmark; 2Department of Clinical Epidemiology, 3Department of Hematology, Aarhus University Hospital, Aarhus, DenmarkObjective: To estimate the positive predictive value (PPV) and completeness of the monoclonal gammopathy of undetermined significance (MGUS) diagnosis coding in a hospital registry within a population-based health-care setting.Patients and methods: Through the Danish National Patient Registry (DNPR), we identified 627 patients registered with MGUS in two Danish regions during the period January 2001–February 2011. We reviewed the medical records of all patients registered with MGUS at the Department of Hematology, Aalborg University Hospital, and a sample of patients registered at the other three hematological departments in the two regions. We estimated the PPV of the MGUS diagnosis based on this sample of 327 medical records. We also estimated the completeness of the DNPR by linking data from the DNPR and data from a previously validated MGUS cohort of 791 patients identified through the laboratory system covering North Jutland Region.Results: The diagnosis of MGUS was confirmed in 231 patients and assessed as probable in an additional 38 patients, corresponding to a PPV of 82.3% (95% confidence interval [CI] 78.1%–86.4%). By contrast, 58 (17.7%) of the patients did not definitively meet the diagnostic criteria for MGUS. When we excluded patients registered with malignant monoclonal gammopathy recorded prior to or within the first year after registration of MGUS in the DNPR, the PPV increased to 88.3% (95% CI 84.5%–92.1%). The DNPR only registered a diagnosis of MGUS in 133 of the 791 MGUS patients identified through the laboratory system, corresponding to a completeness of 16.8% (95% CI 14.1%–19.6%).Conclusion: The PPV of the diagnosis coding for MGUS in the DNPR is high and can be further improved by simple data restriction. However, the low completeness raises concern that MGUS patients registered in the hospital system may be highly selected.Keywords: monoclonal gammopathy of undetermined significance, hospital discharge data, validation, administrative data, ICD-10

The aims of this study were to evaluate gastric antral mechanical behavior and distension-induced sensorimotor responses in the human gastric antrum using transabdominal ultrasound scanning. Ten healthy volunteers underwent volume-controlled ramp inflation of a bag located in the antrum with volumes up to 125 ml. The active and passive circumferential tensions and stresses were calculated from measurements of pressure, diameter, and wall thickness before and during the administration of the anticholinergic drug butylscopolamine. The bag distensions elicited contractions in the antrum and sensory responses below the pain threshold. Butylscopolamine abolished the contractions and significantly reduced the sensory response. The length-tension diagram known from in vitro studies of smooth muscle strips could be reproduced as tension-volume diagrams in the human gastric antrum. The number of induced contractions and the contraction pressure amplitude (afterload) showed a parabolic behavior as function of the distension volume (preload), with maximum approximately at 70 ml. At the sensation threshold, the luminal circumference showed the lowest variation coefficient (13-25%), whereas the variation coefficient was more than 100% for the pressure, tensions, and stresses. We conclude that the muscle length-tension diagram and typical preload-afterload curves ad modem the Frank-Starling cardiac law can be obtained in the human gastric antrum. The sensory responses were most closely associated with the luminal circumference, indicating that the sensation during antral distension depends on deformation rather than on tension. biomechanics; preload; afterload; stress; strain; ultrasound

Lu, X., J. Yang, J.B. Zhao, H. Gregersen, and G.S. Kassab. Shear modulus of porcine coronary artery: contributions of media and adventitia. Am J Physiol Heart Circ Physiol 285: H1966-H1975, 2003; 10.1152/ajpheart.00357.2003.--The epicardial coronary arteries experience significant torsion in the axial direction due to changes in the shape of the heart during the cardiac cycle. The objective of this study was to determine the torsional mechanical properties of the coronary arteries under various circumferential and longitudinal loadings. The coronary artery was treated as a two-layer composite vessel consisting of intima-medial and adventitial layers, and the shear modulus of each layer was determined. Eight porcine hearts were obtained at a local abattoir, and their right coronary and left anterior descending arteries were isolated and tested in vitro with a triaxial torsion machine (inflation, longitudinal stretch, and circumferential twist). After the intact vessel was tested, the adventitia was dissected away, leaving an intact media that was then tested under identical triaxial loading conditions. We proposed a biomechanical analysis to compute the shear modulus of the adventitia from the measured shear moduli of the intact vessel and the media. To validate our predictions, we used four additional hearts in which the shear modulus of the adventitia was measured after dissection of media. Our results show that the shear modulus does not depend on the shear stress or strain but varies linearly with circumferential and longitudinal stresses and in a nonlinear way with the corresponding strains. Furthermore, we found that the shear modulus of the adventitia is larger than that of the intact vessel, which is larger than the vessel media. These results may have important implications for baroreceptor sensitivity, circulation of the vasa vasorum, and coronary dissection. torsion; two-layer model; polar moment of inertia; triaxial torsion machine

The aims of this study were to investigate gastric antral geometry and stress-strain properties by using transabdominal ultrasound scanning during volume-controlled distensions in the human gastric antrum. Seven healthy volunteers underwent stepwise inflation of a bag located in the antrum with volumes up to 60 ml. The stretch ratio and Cauchy stress and strain were calculated from measurements of pressure, diameter, and wall thickness. A second distension series was conducted in three volunteers during administration of the anticholinergic drug butylscopolamine. Analysis of stretch ratios demonstrated positive strain in the circumferential direction, negative strain in the radial direction, and no strain in the longitudinal direction. The stress-strain relation was exponential and did not differ without or with the administration of butylscopolamine. The wall stress was decomposed into its active and passive components. The well-known length-tension diagram from in vitro studies of smooth muscle strips was reproduced. The maximum active tension appeared at a volume of 50 ml, corresponding to a stretch ratio of 1.5. We conclude that the method provides measures of antral biomechanical wall properties and can be used to reproduce the muscle length-tension diagram in humans. stomach; stress; strain; ultrasound.

Current techniques used to investigate the mechanisms responsible for the sensory responses to distension of the human esophagus provide limited information because the degree of circumferential stretch required to determine tension can only be inferred. We used impedance planimetry to measure the cross-sectional area during esophageal distension to ascertain the degree of stretch and tension that initiated motor and sensory responses. Hyoscine-N-butyl bromide (HBB), a cholinergic muscarinic receptor blocker, was also used to alter esophageal tension during distension. Motor activity was initiated at a lower degree of stretch and tension than that which initiated sensory awareness; both increased directly with increasing distension. HBB reduced both esophageal motility and tension during distension without altering the relationship between sensation intensity and cross-sectional area. Esophageal stretch, rather than tension, thus appears to be the major factor influencing sensory responses to esophageal distension. impedance planimetry; cross-sectional area; tension; esophageal motor activity; esophageal sensation