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Shifts in doctor-patient communication between 1986 and 2002: a study of videotaped general practice consultations with hypertension patients.

BACKGROUND: Departing from the hypotheses that over the past decades patients have become more active participants and physicians have become more task-oriented, this study tries to identify shifts in GP and patient communication patterns between 1986 and 2002. METHODS: A repeated cross-sectional observation study was carried out in 1986 and 2002, using the same methodology. From two existing datasets of videotaped routine General Practice consultations, a selection was made of consultations with hypertension patients (102 in 1986; 108 in 2002). GP and patient communication was coded with RIAS (Roter Interaction Analysis System). The data were analysed, using multilevel techniques. RESULTS: No gender or age differences were found between the patient groups in either study period. Contrary to expectations, patients were less active in recent consultations, talking less, asking fewer questions and showing less concerns or worries. GPs provided more medical information, but expressed also less often their concern about the patients' medical conditions. In addition, they were less involved in process-oriented behaviour and partnership building. Overall, these results suggest that consultations in 2002 were more task-oriented and businesslike than sixteen years earlier. CONCLUSION: The existence of a more equal relationship in General Practice, with patients as active and critical consumers, is not reflected in this sample of hypertension patients. The most important shift that could be observed over the years was a shift towards a more businesslike, task-oriented GP communication pattern, reflecting the recent emphasis on evidence-based medicine and protocolized care. The entrance of the computer in the consultation room could play a role. Some concerns may be raised about the effectiveness of modern medicine in helping patients to voice their worries.

Adult↗

Analysis of 3-D myocardial motion in tagged MR images using nonrigid image registration.

Tagged magnetic resonance imaging (MRI) is unique in its ability to noninvasively image the motion and deformation of the heart in vivo, but one of the fundamental reasons limiting its use in the clinical environment is the absence of automated tools to derive clinically useful information from tagged MR images. In this paper, we present a novel and fully automated technique based on nonrigid image registration using multilevel free-form deformations (MFFDs) for the analysis of myocardial motion using tagged MRI. The novel aspect of our technique is its integrated nature for tag localization and deformation field reconstruction using image registration and voxel based similarity measures. To extract the motion field within the myocardium during systole we register a sequence of images taken during systole to a set of reference images taken at end-diastole, maximizing the normalized mutual information between the images. We use both short-axis and long-axis images of the heart to estimate the full four-dimensional motion field within the myocardium. We also present validation results from data acquired from twelve volunteers.

Algorithms↗

Gait improvement surgery in diplegic children: how long do the improvements last?

Gait improvement surgery in ambulatory children with cerebral palsy performed as single-event multilevel surgery is today a well-established modality of treatment, but follow-up studies are lacking. Preoperative and follow-up gait analysis data of 32 diplegic children who underwent single-event multilevel surgery for gait improvement between 1995 and 1998 were evaluated retrospectively. Relevant sagittal plane kinematic parameters of the hip, knee, and ankle joint and time-distance parameters were considered for outcome measures in this study. Postoperative gait analysis was performed three times in all the cases: after discontinuation of the dynamic AFOs (mean 1.0 +/- 0.3 years), after discontinuation of the night splints (mean 2.3 +/- 0.7 years), and at least 1.5 years after discontinuation of physiotherapy and splints (mean 4.4 +/- 1.1 years). The aim of the study was to ascertain whether the improvements in gait function were maintained over these examinations. The authors found that gait function continued to change over 1, 2, and 3 years of follow-up. A general decrease in gait function was measurable in this collective between the first postoperative and the second postoperative evaluations. The results indicate that evaluation of gait improvement surgery in cerebral palsy performed at a minimum of 3 years after surgery would give the most predictive outcome of treatment.

Adolescent↗

Women's health in a rural community in Kerala, India: do caste and socioeconomic position matter?

OBJECTIVES: To examine the social patterning of women's self-reported health status in India and the validity of the two hypotheses: (1) low caste and lower socioeconomic position is associated with worse reported health status, and (2) associations between socioeconomic position and reported health status vary across castes. DESIGN: Cross-sectional household survey, age-adjusted percentages and odds ratios, and multilevel multinomial logistic regression models were used for analysis. SETTING: A panchayat (territorial decentralised unit) in Kerala, India, in 2003. PARTICIPANTS: 4196 non-elderly women. OUTCOME MEASURES: Self-perceived health status and reported limitations in activities in daily living. RESULTS: Women from lower castes (scheduled castes/scheduled tribes (SC/ST) and other backward castes (OBC) reported a higher prevalence of poor health than women from forward castes. Socioeconomic inequalities were observed in health regardless of the indicators, education, women's employment status or household landholdings. The multilevel multinomial models indicate that the associations between socioeconomic indicators and health vary across caste. Among SC/ST and OBC women, the influence of socioeconomic variables led to a "magnifying" effect, whereas among forward caste women, a "buffering" effect was found. Among lower caste women, the associations between socioeconomic factors and self-assessed health are graded; the associations are strongest when comparing the lowest and highest ratings of health. CONCLUSIONS: Even in a relatively egalitarian state in India, there are caste and socioeconomic inequalities in women's health. Implementing interventions that concomitantly deal with caste and socioeconomic disparities will likely produce more equitable results than targeting either type of inequality in isolation.

Adult↗

Using SAS to conduct nonparametric residual bootstrap multilevel modeling with a small number of groups.

In multilevel modeling, researchers often encounter data with a relatively small number of units at the higher levels. As a result, of this and/or non-normality of the residuals, model parameter estimates, particularly the variance components and standard errors of parameter estimates at the group level, may be biased, thus the corresponding statistical inferences may not be trustworthy. This problem can be addressed by using bootstrap methods to estimate the standard errors of the parameter estimates for significance testing. This study illustrates how to use statistical analysis system (SAS) to conduct nonparametric residual bootstrap multilevel modeling. Specific SAS programs for such modeling are provided.

Models, Statistical↗

Application of multilevel models to morphometric data. Part 2. Correlations.

Multilevel organization of morphometric data (cells are "nested" within patients) requires special methods for studying correlations between karyometric features. The most distinct feature of these methods is that separate correlation (covariance) matrices are produced for every level in the hierarchy. In karyometric research, the cell-level (i.e., within-tumor) correlations seem to be of major interest. Beside their biological importance, these correlation coefficients (CC) are compulsory when dimensionality reduction is required. Using MLwiN, a dedicated program for multilevel modeling, we show how to use multivariate multilevel models (MMM) to obtain and interpret CC in each of the levels. A comparison with two usual, "single-level" statistics shows that MMM represent the only way to obtain correct cell-level correlation coefficients. The summary statistics method (take average values across each patient) produces patient-level CC only, and the "pooling" method (merge all cells together and ignore patients as units of analysis) yields incorrect CC at all. We conclude that multilevel modeling is an indispensable tool for studying correlations between morphometric variables.

Algorithms↗

Social neuroscience: understanding the pieces fosters understanding the whole and vice versa.

Social science and neuroscience perspectives represent two ends of a continuum of levels of organization studied in psychology. Human behavior as a whole unfolds at social levels of organization, whereas much of the research in psychology has focused on cognitive and biological pieces of this whole. Recent evidence underscores the complementary nature of social, cognitive, and biological levels of analysis and how research integrating these levels can foster more comprehensive theories of the mechanisms underlying complex behavior and the mind. This research underscores the unity of psychology and the importance of retaining multilevel integrative research that spans molar and molecular levels of analysis.

Cognitive Science↗

Coupling 16S-ITS rDNA clone libraries and automated ribosomal intergenic spacer analysis to show marine microbial diversity: development and application to a time series.

We outline an approach to simultaneously assess multilevel microbial diversity patterns utilizing 16S-ITS rDNA clone libraries coupled with automated ribosomal intergenic spacer analysis (ARISA). Sequence data from 512 clones allowed estimation of ARISA fragment lengths associated with bacteria in a coastal marine environment. We matched 92% of ARISA peaks (each comprising >1% total amplified product) with corresponding lengths from clone libraries. These peaks with putative identification accounted for an average of 83% of total amplified community DNA. At 16S rDNA similarities <98%, most taxa displayed differences in ARISA fragment lengths >10 bp, readily detectable and suggesting ARISA resolution is near the 'species' level. Prochlorococcus abundance profiles from ARISA were strongly correlated (r2=0.86) to Prochlorococcus cell counts, indicating ARISA data are roughly proportional to actual cell abundance within a defined taxon. Analysis of ARISA profiles for 42 months elucidated patterns of microbial presence and abundance providing insights into community shifts and ecological niches for specific organisms, including a coupling of ecological patterns for taxa within the Prochlorococcus, the Gamma Proteobacteria and Actinobacteria. Clade-specific ARISA protocols were developed for the SAR11 and marine cyanobacteria to resolve ambiguous identifications and to perform focused studies. 16S-ITS data allowed high-resolution identification of organisms by ITS sequence analysis, and examination of microdiversity.

Automation↗

Application of multilevel models to morphometric data. Part 1. Linear models and hypothesis testing.

Morphometric data usually have a hierarchical structure (i.e., cells are nested within patients), which should be taken into consideration in the analysis. In the recent years, special methods of handling hierarchical data, called multilevel models (MM), as well as corresponding software have received considerable development. However, there has been no application of these methods to morphometric data yet. In this paper we report our first experience of analyzing karyometric data by means of MLwiN - a dedicated program for multilevel modeling. Our data were obtained from 34 follicular adenomas and 44 follicular carcinomas of the thyroid. We show examples of fitting and interpreting MM of different complexity, and draw a number of interesting conclusions about the differences in nuclear morphology between follicular thyroid adenomas and carcinomas. We also demonstrate substantial advantages of multilevel models over conventional, single-level statistics, which have been adopted previously to analyze karyometric data. In addition, some theoretical issues related to MM as well as major statistical software for MM are briefly reviewed.

Adenoma↗

Multilevel logistic regression modelling with correlated random effects: application to the Smoking Cessation for Youth study.

A multilevel logistic regression model is presented for the analysis of clustered and repeated binary response data. At the subject level, serial dependence is expected between repeated measures recorded on the same individual. At the cluster level, correlations of observations within the same subgroup are present due to the inherent hierarchical setting. Two random components are therefore incorporated explicitly within the linear predictor to account for the simultaneous heterogeneity and autoregressive structure. Application to analyse a set of longitudinal data from an adolescent smoking cessation intervention that motivated this study is illustrated.

Adolescent↗

Getting the big picture in community science: methods that capture context.

Community science has a rich tradition of using theories and research designs that are consistent with its core value of contextualism. However, a survey of empirical articles published in the American Journal of Community Psychology shows that community scientists utilize a narrow range of statistical tools that are not well suited to assess contextual data. Multilevel modeling, geographic information systems (GIS), social network analysis, and cluster analysis are recommended as useful tools to address contextual questions in community science. An argument for increased methodological consilience is presented, where community scientists are encouraged to adopt statistical methodology that is capable of modeling a greater proportion of the data than is typical with traditional methods.

Cluster Analysis↗

Introduction to the Special Section on Applied Longitudinal Methods in Aging Research.

This article introduces articles that appear in the special section on applied longitudinal methods in aging research. These articles apply quantitative statistical techniques such as multilevel modeling and structural equation models to the analysis of longitudinal data. They exemplify how applications of these techniques can advance scientific research on the effects of aging on psychological constructs. ((c) 2003 APA, all rights reserved)

Journal Article↗

Reconstructing the AIDS epidemic among injection drug users in Brazil.

The HIV/AIDS epidemic among injection drug users (IDUs) in Brazil has been unique in terms of temporal and geographical contrasts. This analysis explores these contrasts through the use of multilevel modeling. Standardized AIDS incidence rates among IDUs for Brazilian municipalities (1986-2000) were used as the dependent variable, with a set of social indicators as independent variables (covariates). In some States of the North/Northeast, the epidemic among IDUs has been incipient. The São Paulo epidemic extended to reach a network of municipalities, most of which located far from the capital. More recently, on a smaller scale, a similar extension has been observed in the southernmost States of the country. Both "number of physicians per inhabitant" and "standard distance to the State capital" were found to be associated with AIDS incidence. AIDS cases among IDUs appeared to cluster in wealthier, more developed municipalities. The relative weight of such extensive dissemination in key, heavily populated States prevails in the Brazilian IDU epidemic, defining a central-western-southeastern strip of wealthier middle-sized municipalities and more recently a southern strip of municipalities deeply affected by the epidemic in this population.

Acquired Immunodeficiency Syndrome↗

Multimodal assessment after surgery for cervical spondylotic myelopathy.

OBJECT: Investigators reporting decompressive surgery to treat patients with cervical spondylotic myelopathy (CSM) have described inconsistent benefits. In the present study the authors used three types of outcomes instruments to assess the results of CSM surgery. METHODS: The authors collected prospective baseline and 6-month follow-up data in a cohort of 62 patients with CSM. Data collection included those pertaining to demographics; symptoms; physical findings; myelopathy severity; health status measured with the Short Form-36; and health values according to the standard gamble, time trade-off, visual analog scale, and willingness to pay. Rank-order methods were used to compare surgical and nonsurgical patients, and multivariate regression techniques adjusting for baseline characteristics were performed to examine the effects of surgery. During the study period, 28 patients underwent surgery, 34 did not, and there were no baseline differences between the two groups in demographics, symptoms, myelopathy scores, health status, or health values (p > or = 0.120 in all domains); there was a greater prevalence of hand intrinsic muscle atrophy (p = 0.035) and Hoffmann sign (p = 0.006) in the surgery-treated group. Neither raw comparisons nor regression analyses showed a consistent surgery-related benefit. There were sporadic associations between worse outcomes and older patients, higher income, Babinski sign, longer duration of CSM symptoms, hand clumsiness, lower-extremity numbness, and multilevel surgery (p < or = 0.049 for all). CONCLUSIONS: Analysis of results obtained in the 62 patients with CSM failed to show a surgery-related benefit despite the use of three classes of outcomes instruments. Patient demographics, symptoms, physical signs, and the surgical approach may explain some of the variation in outcomes in patients with CSM.

Adult↗

[The automatization of the control over the processes determining the risk of HIV-infection spreading among servicemen].

The possibilities of the control over the processes determining the HIV-infection spreading risk are considered. In the view of that the automated system which enables to evaluate risk factors predetermining the appearance of new infection cases was proposed. These factors are systematised in a multilevel database. On the basis of the statistical analysis of the risk factors situations of the spread of the HIV infection are revealed and analysed and measures for their liquidation are worked out promptly. The system is universal and can be used for the prevention of the beginning of other extreme situations caused by the spread of different infections. The examples of the comparative analysis of the risk of sexual behaviour in various groups of servicemen are given.

Adolescent↗

[Single event multilevel surgery to improve gait in diplegic cerebral palsy - a prospective controlled trial].

AIM: To evaluate prospectively the outcome of gait-improvement surgery in children with spastic diplegia. METHOD: Three-dimensional gait analysis was performed in twenty children with spastic diplegia. Ten children underwent single event multilevel surgery for gait improvement. Indications for individual procedures followed a fixed set of selection criteria. The other ten children continued with their physiotherapy programme and served as a control group. A second gait analysis was performed in all children after 1.5 years. Time-distance parameters and kinematics of the pelvis, hip, knee and ankle joints in the sagittal plane served as main outcome measures RESULTS: The patients walked faster with an increased stride length after surgery in comparison to the conservatively treated controls. The average pelvic tilt increased slightly and the range of motion of the knee joint increased considerably after multilevel surgery. The motion at the ankle remained unchanged over the study period in both the groups. An improved knee extension during the stance phase of gait served to improve stance limb stability and facilitated an unhindered swing phase of the opposite limb. CONCLUSION: This prospective trial showed favourable changes in gait function after multilevel surgery in spastic diplegic children.

Child↗

Stability of the whole lumbar spine after multilevel fenestration and discectomy.

STUDY DESIGN: An investigation of the in vitro biomechanical effects of multilevel fenestrations and discectomies on the behavior of whole lumbar spine motion, using a material testing system (Instron 1341, Instron Limited, High Wycombe, England) and Elite three-dimensional motion analysis system (BTS, Milano, Italy). OBJECTIVES: To investigate the effects of multilevel fenestrations and discectomies on the stability of the whole lumbar spine, including segmental stiffness and sagittal (horizontal and vertical) translation. SUMMARY OF BACKGROUND DATA: In the management of lumbar spinal stenosis, wide decompressive laminectomy with partial or total facetectomy has been the standard procedure for multilevel nerve decompression. Main complications with these procedures have been instability and chronic pain syndrome. Multilevel fenestration with undermining enlargement of the spinal canal has been selected for multilevel nerve decompression in recent years. However, the biomechanical effects of multilevel fenestration and discectomy have been controversial and difficult to validate. This study investigated the in vitro biomechanical effects of multilevel fenestrations and discectomies on motion behavior of the whole lumbar spine. METHODS: Seven fresh human specimens from L1 to sacrum were used in this study. The fenestrations and discectomies consisted of L3-L4 bilateral fenestration, L4-L5 bilateral fenestration, L5-S1 bilateral fenestration, L4-L5 discectomy, and L5-S1 discectomy. Flexion, lateral bending, and axial rotation (torsion) loading were applied. Ranges of motion were determined two-dimensionally by the Elite system with an infrared camera. The postoperation results were compared with the intact conditions. RESULTS: After multiple fenestrations, the sagittal ranges of motion at L4-L5 increased by 18% anteroposteriorly and 16% vertically under the flexion loads. At L5-S1, the motions increased by 19% and 45%, respectively. After fenestrations and discectomies, the ranges of motion in the sagittal plane increased by 28% horizontally and 71% vertically at L4-L5, and 14% and 166% at L5-S1. Motion increases were statistically significant (P < 0.05) in vertical translations. However, after the multilevel surgeries, no significant motions were found in each of the lumbar segments during lateral bending and axial rotation. CONCLUSIONS: The results demonstrate that multilevel fenestrations and discectomies affect lumbar spinal stability in flexion, but have no effect on the stability of the lumbar spine in lateral bending or axial rotation.

Adult↗

Multilevel modelling and public health policy.

BACKGROUND: Multilevel modelling is a statistical technique that extends ordinary regression analysis to the situation where the data are hierarchical. Such data form an increasingly common evidence base for public health policy, and as such it is important that policy makers should be aware of this methodology. METHOD: This paper therefore lays out the a basic description of multilevel modelling, discusses the problems of alternative approaches, and details the relevance for public health policy before describing which levels are relevant and illustrating the different kinds of hypotheses that can be tested using multilevel modelling. A series of examples is used throughout the paper. These relate to regional variations in the incidence of heart disease, the allocation of health resources, the relationship between neighbourhood disorder and mental health, the demand-control model in occupational health, and a school intervention to prevent cardiovascular disease.

Community Health Services↗