The causes and effects of socio-demographic exclusions from clinical trials

OBJECTIVES

To investigate the exclusion from trials of women, older people and minority ethnic groups, focusing on two drug exemplars, statins and non-steroidal anti-inflammatory drugs (NSAIDs).

DATA SOURCES

Medical and ethical databases. Workshops with stakeholders.

REVIEW METHODS

Literature was reviewed on exclusions in healthcare research and three workshops were held with stakeholders. Twenty-seven randomised controlled trials (RCTs) of statins use for secondary prevention of coronary heart disease (CHD) and 25 NSAIDs trials for pain in osteoarthritis (OA) were analysed. Using a Scottish cohort with record-linkage, profiling was carried out for 3188 people needing secondary prevention for CHD (1993-1996), ascertaining the independent effects of statins, and 131,410 people dispensed NSAIDs (1989-1996), examining adverse effects. Routine data sources were accessed to profile the need for secondary prevention of CHD in England and usage was estimated by consulting published surveys. The Somerset and Avon Survey of Health (SASH) 1996-97 and published data were accessed for information on potential need and usage of NSAIDs in OA. For both drugs, the socio-demographic profiles of trial samples, the population in potential need and those on treatment were compared. An evidence synthesis was produced to clarify the effects of statins on women and older people and the relationship of absolute effectiveness outcomes with underlying risk levels of disease events was modelled, examining the likely effects of trial exclusions.

RESULTS

The average age of statins trial participants was 58.5 years; only 16.3% were women. Statins reduced cardiovascular disease (CVD) incidence by about 25% in both men and women. Older people up to 75 years of age also benefited. Meta-analysis and two landmark trials confirmed these results. The average age of NSAIDs trial participants was 61.9 years and women were well represented (68.5%). Gastrointestinal (GI) adverse events were commonly reported, but renal side-effects were not. Outcomes were seldom reported according to socio-demographic group. For both drugs, USA trials were more inclusive than UK/European trials. Ethnicity was not well reported for either drug. Some 23% of the cohort were treated with statins. Users were younger than non-statins users (but no more likely to be male) and had superior outcomes. High current exposure to NSAIDs elevated the risk of GI side-effects by about 50% versus no current exposure and renal impairment risk by nearly 140%. Side-effect risk increased with age; being female diminished risk. Approximately 537,000 incident cases of CVD would qualify for statins use in England each year. Women constitute 45% of this population with need, two-thirds of whom are aged 65 years or over. Need varies by ethnic group. No sex bias in prescribing statins was detected, but use was commoner in younger people. For NSAIDs, 6.3% of adults aged 35+ years reported hip and/or knee pain associated with OA; 3.9% of adults used prescribed analgesics for this and they were more likely to be women and to be >65 years old. For statins, women formed almost half of the 'with need' and 'on treatment' populations, but were markedly under-represented in trials. Those aged 65+ years formed nearly two-thirds of the 'with need' population, but only one-fifth of trial samples, and were less likely to be treated than younger subjects. For NSAIDs, women formed similar proportions. Associations of side-effects with socio-demographic factors was revealed in cohort data but not in trials.

CONCLUSIONS

The issue of exclusion from trials of women, older people and ethnic minorities has been relatively neglected in the UK research community, and there is confusion about diversity issues. Under-representation occurs, but in drug trials at least this may not always affect the external validity of relative effect estimates. However, measures of absolute effectiveness, absolute harm and cost-effectiveness are associated with underlying risk levels in different socio-demographic groups. Under-representation will therefore bias absolute effect estimates. The following areas are suggested for future research: multi-disciplinary assessment of realistic options for trialists to address the issue of exclusions; clarification of the use of ethnic categories in health research and of the implications of the different dimensions of ageing and sex/gender; identification of barriers and facilitators to the involvement of different population groups in research, further investigation of the susceptibility of older men to NSAID adverse events, and the development of a 'register of registries and databases' and exploration of how linked health information systems in the UK could be improved.

Frauenfußball

Women's soccer participation is becoming a trend in sport. With increasing number of licensed female soccer players, there is also an increase in sport specific injuries. This fact has socioeconomic importance. The larger pelvic bone leading to an increased internal rotation of the femur, the narrower intercondylar notch as well as the unfavorable strength ratio of the hamstrings vs. the quadriceps muscle lead to an increased risk for injuries of the anterior cruciate ligament in female soccer.Several studies showed that intervention programs based on neuromuscular or proprioceptive training or intensive strengthening of the hamstrings can reduce the incidence of injuries. Moreover, the importance of sufficient rehabilitation after injuries has to be emphasized, as the reoccurrence of injury is high.

Non-linear analysis of the electroencephalogram for detecting effects of low-level electromagnetic fields

The study compared traditional spectral analysis and a new scale-invariant method, the analysis of the length distribution of low-variability periods (LDLVPs), to distinguish between electro-encephalogram (EEG) signals with and without a weak stressor, a low-level modulated microwave field. During the experiment, 23 healthy volunteers were exposed to a microwave (450 MHz) of 7 Hz frequency on-off modulation. The field power density at the scalp was 0.16 mW cm(-2). The experimental protocol consisted of ten cycles of repetitive microwave exposure. Signals from frontal EEG channels FP1 and FP2 were analysed. Smooth power spectrum and length distribution curves of low-variability periods, as well as probability distribution close to normal, confirmed that stationarity of the EEG signal during recordings was achieved. The quantitative measure of LDLVPs provided a significant detection of the effect of the stressor for the six subjects exposed to the microwave field but for none of the sham recordings. The spectral analysis revealed a significant result for one subject only. A significant effect of the exposure to the EEG signal was detected in 25% of subjects, with microwave exposure increasing EEG variability. The effect was not detectable by power spectral measures.

T-helper cell tolerance to ubiquitous nuclear antigens

Systemic autoimmune diseases are characterized by the development of antinuclear autoantibodies. In order to understand the immunologic events leading to the development of such antibodies, knowledge of mechanisms of immune tolerance to nuclear antigens is required. By utilizing adoptive T-cell transfer strategies with transgenic mouse models expressing nuclear neo-self antigens, T-cell tolerance to the lupus-related nuclear antigens human La and nRNP A has been demonstrated. These findings also indicate the existence in normal animals of autoreactive B cells continuously presenting nuclear antigen, suggesting that nuclear antigens are not sequestered from the immune system. Investigations of CD4+ T-cell tolerance to non-nuclear antigens have revealed a number of mechanisms that protect the host from autoreactivity, including autoreactive T-cell deletion, regulatory T-cell development and anergy induction. Recent studies using T-cell receptor and neo-self nuclear antigen transgenic mice are revealing the importance of such mechanisms in maintaining tolerance to nuclear antigens. Mechanisms of tolerogenic antigen presentation, identification of tolerogenic antigen source(s) and the pathways leading to loss of tolerance to nuclear antigens in systemic autoimmune disease states are currently being sought.

Fluctuation pressure of a stack of membranes

We calculate the universal constants in Helfrich's pressure law for a stack of N membranes between walls by strong-coupling theory. Using the close analogy between this system and a stack of strings, where the universal constants are exactly known, we construct a smooth potential that keeps the membranes apart. The strong-coupling limit of the perturbative treatment of the free energy yields pressure constants for an arbitrary number of membranes, which are in very good agreement with values from Monte Carlo simulations.

Anatomical origin of dendritic cells determines their life span in peripheral lymph nodes

Dendritic cells (DCs) exhibit considerable heterogeneity in their anatomical location, surface phenotype, and functional properties. In this study, we demonstrate that peripheral lymph nodes contain at least four major, functionally separable, and independently derived, DC subsets, which can be clearly demarcated by their CD11c, CD40, and CD8 expression pattern. Surprisingly, all DCs derived directly from the bone marrow, the myeloid- and the lymphoid-related subsets, turned over fast with t(1/2) of a couple of days. In contrast, DCs exported from the skin, both dermal and epidermal, accumulated 3- to 4-fold slower, turnover that is dramatically increased by cutaneous inflammation.

The effect of skin diseases on quality of life in patients from different social and ethnic groups in Cape Town, South Africa

BACKGROUND

Skin diseases can greatly affect the quality of life (QoL). Little is known, however, of their impact on QoL in the developing world. This study was designed to assess the effect of skin diseases in such a setting.

METHODS

A questionnaire survey of patients using the Dermatology Life Quality Index (DLQI), modified to the cultural needs of the population. The adapted instrument was translated into Afrikaans and Xhosa. Six hundred and seven patients attending general dermatology clinics at Groote Schuur Hospital and 53 controls were recruited. Influences on QoL of clinical severity, employment, education, age, sex, and home language were examined.

RESULTS

Participants included 313 (52%) English-speaking, 215 (35%) Afrikaans-speaking, and 79 (13%) Xhosa-speaking dermatology patients. Independent risk factors for having a high disability score were dermatologists' assessment of severity, younger age, unemployment, and language (odds ratio, 0.13; 95% confidence interval (CI) of 0. 03-0.5 for Xhosa speakers compared to Afrikaans speakers). Gender was not associated with a high score, but females were more likely to report effects of skin disease on self-esteem, clothing choice, treatment problems, and anxiety.

CONCLUSIONS

In this multicultural setting, social class and language group, but not gender, influenced the impact of skin disease on overall QoL. Xhosa speakers were apparently less affected than other patients. This could be due to cultural differences in the experience of skin disease and in the perception of disability, or to biases in questionnaire responses. Anxiety and depression were relevant dimensions of QoL in this study and should be considered for inclusion in future research. The adapted and translated DLQI was valid and reliable.

The zinc finger protein Gfi-1 can enhance STAT3 signaling by interacting with the STAT3 inhibitor PIAS3

STAT factors act as signal transducers of cytokine receptors and transcriptionally activate specific target genes. The recently discovered protein PIAS3 binds directly to STAT3 and blocks transcriptional activation. Here, we present experimental evidence implementing the zinc finger protein Gfi-1 as a new regulatory factor in STAT3-mediated signal transduction. The interaction between the two proteins first became evident in a yeast two-hybrid screen but was also seen in coprecipitation experiments from eukaryotic cells. Moreover, we found that both Gfi-1 and PIAS3 colocalize in a characteristic nuclear dot structure. While PIAS3 exerts a profound inhibitory effect on STAT3-mediated transcription of target promoters, Gfi-1 can overcome the PIAS3 block and significantly enhances STAT3-mediated transcriptional activation. In primary T cells, Gfi-1 was able to amplify IL-6-dependent T-cell activation. As Gfi-1 is a known, dominant proto-oncogene, our findings bear particular importance for the recently described ability of STAT3 to transform cells malignantly and offer an explanation of the oncogenic potential of Gfi-1 in T lymphocytes.

Generation of an apoptotic intracellular peptide by gamma-secretase cleavage of Alzheimer's amyloid beta protein precursor

The amyloid beta protein precursor (AbetaPP) is sequentially processed by beta- and gamma-secretases to generate the Abeta peptide. The biochemical path leading to Abeta formation has been extensively studied since extracellular aggregates of amyloidogenic forms of Abeta peptide (Abeta42) are considered the culprit of Alzheimer's disease. Aside from its pathological relevance, the biological role of AbetaPP proteolysis is unknown. Although never previously described, cleavage of AbetaPP by gamma-secretase should release, together with Abeta, a COOH-terminal AbetaPP Intracellular Domain, herein termed AID. We have now identified AID-like peptides in brain tissue of normal control and patients with sporadic Alzheimer's disease and demonstrate that AID acts as a positive regulator of apoptosis. Thus, overproduction of AID may add to the toxic effect of Abeta42 aggregates and further accelerate neurodegeneration.

Transcription efficiency of human polymerase III genes in vitro does not depend on the RNP-forming autoantigen La

Transcription of class III genes is conducted by multi-protein complexes consisting of polymerase III itself and several transcription factors. We established a reconstituted in vitro transcription system from which the autoantigen La was removed by immunodepletion. This system showed no RNP formation, but was still fully active in transcription. Supplementing such La-free transcription reactions with recombinant La restored the formation of La complexes with the newly synthesised RNA, but did not lead to enhanced transcription efficiency. Furthermore, we developed a technique for the generation and isolation of transcription complexes, assembled from purified transcription factors and isolated by glycerol centrifugation. These complexes were fully competent to re-initiate RNA synthesis but they were not associated with La and their transcription rate could not be stimulated by addition of recombinant La. Therefore, we conclude that La does not act as a human polymerase III transcription factor.

Medical or surgical treatment for chronic gastrooesophageal reflux? A systematic review of published evidence of effectiveness

OBJECTIVE

To compare the effectiveness of medical (antacids, histamine antagonists and proton pump inhibitors) and surgical (fundoplication) treatment of chronic GORD.

SUBJECTS

Patients with objective (endoscopic or pH) evidence of chronic reflux reported in 6 randomised trials and 3 cohort studies, 1966-1999.

METHODS

Systematic review of comparative studies identified from electronic searches, citations, manual searches of journals, and correspondence with authors and experts.

MAIN OUTCOME MEASURES

Improvements in prevalence or severity of symptoms, oesophagitis, pH reflux duration, lower oesophageal sphincter pressure, patients' satisfaction, and side-effects.

RESULTS

Improved outcomes were more common after surgical than medical treatment with significant differences in objective outcomes in 5/6 randomised trials and in 2/3 cohort studies. Subjective outcomes (symptoms and patients' satisfaction) were also more common among surgical patients in all but one study that assessed them. Odds ratios for improvement with surgical rather than medical treatment ranged from 1.2 to 200, and numbers needed to treat ranged from 1.2 to 58, where these could be calculated. Studies were too heterogeneous for meta-analysis.

CONCLUSIONS

In trials of chronic severe GORD, surgery is consistently more effective than medical treatment in relieving symptoms and objective oesophagitis, although omeprazole can give similar symptom relief with adjustment of the dose.

Frequency and evaluation of t(14;18) translocation in Sjögren's syndrome

In most cases of follicular lymphoma, t(14;18) chromosomal translocation can be detected in lymphocytes of peripheral blood and bone marrow. Nevertheless, certain other types of diseases can also be characterised by the presence of the translocation. Patients of Sjogren's syndrome have an increased frequency of developing non-Hodgkin's lymphoma, e.g. follicular lymphoma; in turn, they may have translocation-bearing cells. One hundred Sjögren's syndrome patients were screened using a nested polymerase chain reaction technique to identify whether they had the translocation in their peripheral blood lymphocytes. Five percent of that population revealed a temporary or long-lasting presence of the translocation, sometimes even in the lymphocytes from bone marrow. Our results indicate that in addition to the conventional diagnostic methods of lymphoma, there are certain other factors, e.g. the duration of the presence of t(14; 18) translocation and the source of lymphocytes, that should be considered for successful early diagnoses and perhaps for treatment of the lymphoma in the Sjögren's patients.

Recursive graphical construction of feynman diagrams and their multiplicities in straight phi(4) and straight phi2A theory

The free energy of a field theory can be considered as a functional of the free correlation function. As such it obeys a nonlinear functional differential equation that can be turned into a recursion relation. This is solved order by order in the coupling constant to find all connected vacuum diagrams with their proper multiplicities. The procedure is applied to a multicomponent scalar field theory with a straight phi(4) self-interaction and then to a theory of two scalar fields straight phi and A with an interaction straight phi2A. All Feynman diagrams with external lines are obtained from functional derivatives of the connected vacuum diagrams with respect to the free correlation function. Finally, the recursive graphical construction is automatized by computer algebra with the help of a unique matrix notation for the Feynman diagrams.

[Trichobezoar in a 16-year old girl. Case report and review of literature]

We present the case of a 16-year-old girl with a 12-year history of trichotillomania and trichotillophagia in combination with mental retardation and early childhood deprivation, all contributing to the growth of a stomach ulcer and an oversized, stomach-shaped trichobezoar which had to be removed by gastrotomy. Included are a discussion of psychodynamic aspects, therapeutic strategies, and significant literature, concluding with a short, historic view on the varieties and therapy of bezoars.

Sjögren's autoimmunity: how perturbation of recognition in endomembrane traffic may provoke pathological recognition at the cell surface

CD4 T cell antigen recognition requires presentation by major histocompatibility complex Class II molecules (MHC II). B cell surface immunoglobulins recognize antigens independently of MHC II, but activation typically requires CD4 cell cytokines as accessory signals. Plasma membrane-endomembrane traffic in lacrimal gland acinar cells, targets of autoimmune activity in Sjögren's syndrome, may satisfy both requirements. The Golgi protein galactosyltransferase and the lysosomal proteins cathepsin B and cathepsin D appear at the plasma membranes during sustained secretomotor stimulation. The RNA transcription termination factor La, a frequent target of Sjögren's autoantibodies, appears in the acinar cell cytoplasm and plasma membranes during viral infection and during in vitro exposure to cytokines. MHC II cycle through endomembrane compartments which contain La, galactosyltransferase, cathepsin B and cathepsin D and which are sites of proteolysis. This traffic may permit trilateral interactions in which B cells recognize autoantigens at the surface membranes, CD4 T cells recognize peptides presented by MHC II, B cells provide accessory signals to CD4 T cells, and CD4 T cells provide cytokines that activate B cells. Acinar cells stimulate lymphocyte proliferation in autologous mixed cell reactions, confirming that they are capable of provoking autoimmune responses.

Clinical research: is the filling missing from the medical research sandwich?

Clinical research is essential for patients to benefit from the advances of medical science. Particularly needed are thorough and imaginative investigations into applied physiology, clinical observation, and patients' experience. This can help clinicians and their patients to distinguish between pathology and healthy variation, interpret diagnostic information, understand what patients want and gain from health care, and apply study results to individuals' problems. Clinical research has not grown as much as other forms of medical research, and is sometimes regarded as unscientific. Young academic clinicians are often persuaded that the only road to science leads through the laboratory. Clinical research, however, offers equal opportunities for original enquiry, rigour and excellence. The medical research sandwich will continue to provide an unbalanced diet unless research leaders and funders take the clinical setting more seriously.

LaXp180, a mammalian ActA-binding protein, identified with the yeast two-hybrid system, co-localizes with intracellular Listeria monocytogenes

The Listeria monocytogenes surface protein ActA is an important virulence factor required for listerial intracellular movement by inducing actin polymerization. The only host cell protein known that directly interacts with ActA is the phosphoprotein VASP, which binds to the central proline-rich repeat region of ActA. To identify additional ActA-binding proteins, we applied the yeast two-hybrid system to search for mouse proteins that interact with ActA. A mouse cDNA library was screened for ActA-interacting proteins (AIPs) using ActA from strain L. monocytogenes EGD as bait. Three different AIPs were identified, one of which was identical to the human protein LaXp180 (also called CC1). Binding of LaXp180 to ActA was also demonstrated in vitro using recombinant histidine-tagged LaXp180 and recombinant ActA. Using an anti-LaXp180 antibody and fluorescence microscopy, we showed that LaXp180 co-localizes with a subset of intracellular, ActA-expressing L. monocytogenes but was never detected on intracellularly growing but ActA-deficient mutants. Furthermore, LaXp180 binding to intracellular L. monocytogenes was asymmetrical and mutually exclusive with F-actin polymerization on the bacterial surface. LaXp180 is a putative binding partner of stathmin, a protein involved in signal transduction pathways and in the regulation of microtubule dynamics. Using immunofluorescence, we showed that stathmin co-localizes with intracellular ActA-expressing L. monocytogenes.