Analysis of count data using poisson regression

Nurses and other health researchers are often concerned with infrequently occurring, repeatable, health-related events such as number of hospitalizations, pregnancies, or visits to a health care provider. Reports on the occurrence of such discrete events take the form of non-negative integer or count data. Because the counts of infrequently occurring events tend to be non-normally distributed and highly positively skewed, the use of ordinary least squares (OLS) regression with non-transformed data has several shortcomings. Techniques such as Poisson regression and negative binomial regression may provide more appropriate alternatives for analyzing these data. The purpose of this article is to compare and contrast the use of these three methods for the analysis of infrequently occurring count data. The strengths, limitations, and special considerations of each approach are discussed. Data from the National Longitudinal Survey of Adolescent Health (AddHealth) are used for illustrative purposes.     

Using the Delphi technique in economic evaluation: time to revisit the oracle?

BACKGROUND AND OBJECTIVE: Although the Delphi technique has been commonly used as a data source in medical and health services research, its application in economic evaluation of medicines has been more limited. The aim of this study was to describe the methodology of the Delphi technique, to present a case for using the technique in economic evaluation, and to provide recommendations to improve such use. METHODS: The literature was accessed through MEDLINE focusing on studies discussing the methodology of the Delphi technique and economic evaluations of medicines using the Delphi technique. RESULTS AND DISCUSSION: The Delphi technique can be used to provide estimates of health care resources required and to modify such estimates when making inter-country comparisons. The Delphi technique can also contribute to mapping the treatment process under investigation, to identifying the appropriate comparator to be used, and to ensuring that the economic evaluation estimates cost-effectiveness rather than cost-efficacy. CONCLUSION: Ideally, economic evaluations of medicines should be based on real-patient data. In the absence of such data, evaluations need to incorporate the best evidence available by employing approaches such as the Delphi technique. Evaluations based on this approach should state the limitations, and explore the impact of the associated uncertainty in the results.     

Measures That Identify Prescription Medication Misuse,Abuse, and Related Events in Clinical Trials: ACTTION Critique and Recommended Considerations

Accurate assessment of inappropriate medication use events (ie, misuse, abuse, and related events) occurring in clinical trials is an important component in evaluating a medication's abuse potential. A meeting was convened to review all instruments measuring such events in clinical trials according to previously published standardized terminology and definitions. Only 2 approaches have been reported that are specifically designed to identify and classify misuse, abuse, and related events occurring in clinical trials, rather than to measure an individual's risk of using a medication inappropriately: the Self-Reported Misuse, Abuse, and Diversion (SR-MAD) instrument and the Misuse, Abuse, and Diversion Drug Event Reporting System (MADDERS). The conceptual basis, strengths, and limitations of these methods are discussed. To our knowledge, MADDERS is the only system available to comprehensively evaluate inappropriate medication use events prospectively to determine the underlying intent. MADDERS can also be applied retrospectively to completed trial data. SR-MAD can be used prospectively; additional development may be required to standardize its implementation and fully appraise the intent of inappropriate use events. Additional research is needed to further demonstrate the validity and utility of MADDERS as well as SR-MAD.

Health Services Clinical Trials: Design,Conduct, and Cost Methodology

Randomized clinical trials and their developing methodology have had substantial impact on the advancement of medical practice. With the emergence of managed care and increased emphasis on the reduction of medical care expenditures, cost evaluation is now becoming a part of clinical trial research. The papers by Henderson et al. and Manheim that follow address the evolution of health services research, its application to multicenter clinical trials in a major U.S. health-care system, and methods of assessing costs in health services clinical trials.     

Beyond the RCT – understanding the relationship between interventions,individuals and outcome – the example of neurological rehabilitation

Background.?Rehabilitation is highly complex, involving multiple processes, outcomes and stakeholders. The way we deliver our services and work with our clients and their families should be informed by research approaches that produce the wide range of knowledge needed. This article aims to explore the degree to which the dominant approach to ‘evidence’ (the randomised clinical trial or RCT) meets those needs and discuss alternate/additional ways of gaining evidence.

Methods.?A critical review of the literature allowing exploration of problems encountered in rehabilitation RCTs and alterative approaches.

Findings.?We discuss some problematic issues related to using RCTs in rehabilitation research (for example the large number of people excluded from trials, and the small numbers of people with some neurological conditions making RCTs non-viable). Alternative approaches are discussed including clinical practice improvement studies (sometimes called practice-based evidence or PBE), which provide data on patients treated in routine practice; qualitative research, which can provide an understanding of the users of health care services to ensure they are meeting their needs; and metasynthesis, which can be used to summarise several qualitative studies to enhance our understanding of the principles underlying service delivery. Finally, we explore how clinicians and commissioners often use evidence generated by forms of research other than the RCT.

Conclusion.?The best answers about how to enhance rehabilitation outcomes are likely to come from a combination and integration of the most appropriate methods. In conclusion, we urge for more joined up thinking, for learning from different fields so that we can develop more effective and appropriate health care and rehabilitation.     

Systems,economics, and neoliberal politics: Theories to understand missed nursing care

The phenomenon of missed nursing care is endemic across all sectors. Nurse leaders have drawn attention to the implications of missed care for patient outcomes, with calls to develop clear political, methodological, and theoretical approaches. As part of this call, we describe three structural theories that inform frameworks of missed care: systems theory, economic theory, and neoliberal politics. The final section provides commentary on the strengths and limitations of these three theories, in the light of structuration theory and calls to balance this research agenda by reinstating nurse agency and examining the interactions between nurses as agents and the health systems as structures. The paper argues that a better understanding of variations in structure–agency interaction across the healthcare system might lead to more effective interventions at strategic leverage points.     

Economic analysis and clinical trials

Given the increasing interest in the economics of health care, the incorporation of economic analysis in clinical trials is more often being considered, both by medical researchers and by research funding bodies. This article proposes criteria for judging the appropriateness of including economic analysis in a given trial, suggests how that analysis could be phased in order to minimize the work involved, and discusses the wider implications for medical research of more frequent attention to economic concepts.     

Screening for type 2 diabetes

Definitive studies of the effectiveness of screening for type 2 diabetes are currently not available. RCTs would be the best means to assess effectiveness, but several barriers prevent these studies from being conducted. Prospective observational studies may characterize some of the benefits of screening by creating screened and unscreened groups for comparison. The availability of better data systems and health services research techniques will facilitate such comparisons. Unfortunately, the interpretation of the results of such studies is extremely problematic. Several screening tests have been evaluated. Risk assessment questionnaires have generally performed poorly as stand-alone tests. Screening with biochemical tests performs better. Venous and capillary glucose measurements may perform more favorably than urinary glucose or HbA(1c) measurements, and measuring postprandial glucose levels may have advantages over measuring fasting levels. However, performance of all screening tests is dependent on the cutoff point selected. Unfortunately, there are no well-defined and validated cutoff points to define positive tests. A two-stage screening test strategy may assist with a more efficient use of resources, although such approaches have not been rigorously tested. The optimal interval for screening is unknown. Even though periodic, targeted, and opportunistic screening within the existing health care system seems to offer the greatest yield and likelihood of appropriate follow-up and treatment, much of the reported experience with screening appears to be episodic poorly targeted community screening outside of the existing health care system. Statistical models have helped to answer some of the key questions concerning areas in which there is lack of empirical data. Current models need to be refined with new clinical and epidemiological information, such as the UKPDS results (200). In addition, future models need to include better information on the natural history of the preclinical phase of diabetes. Data from ongoing clinical trials of screening and treatment of impaired glucose tolerance, such as the Diabetes Prevention Program, may eventually offer more direct evidence for early detection and treatment of asymptomatic hyperglycemia (201). It will be important to use comprehensive cardiovascular disease modules that assess the conjoint influence of glucose and cardiovascular risk factor reduction, information on QOL, and refined economic evaluations using common outcome measures (cost per life-year or QALY gained) (11,178,202-204). Such studies should consider all of the costs associated with a comprehensive screening program, including, at a minimum, the direct costs of screening, diagnostic testing, and care for patients with diabetes detected through screening. Finally, combinations of screening tests and different screening intervals should be evaluated within economic studies to allow selection of the optimal approach within the financial and resource limitations of the health care system.     

Economic evaluations for intensive care unit randomised clinical trials in Australia and New Zealand: Practical recommendations for researchers

ObjectivesEconomic evaluations of intensive care unit (ICU) interventions have specific considerations, including how to cost ICU stays and accurately measure quality of life in survivors. The aim of this article was to develop best practice recommendations for economic evaluations alongside future ICU randomised controlled trials (RCTs).Review methodsWe collated our experience based on expert consensus across several recent economic evaluations to provide best-practice, practical recommendations for researchers conducting economic evaluations alongside RCTs in the ICU. Recommendations were structured according to the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) Consolidated Health Economic Evaluation Reporting Standards (CHEERS) Task Force Report.ResultsWe discuss recommendations across the components of economic evaluations, including: types of economic evaluation, the population and sample size, study perspective, comparators, time horizon, choice of health outcomes, measurement of effectiveness, measurement and valuation of quality of life, estimating resources and costs, analytical methods, and the increment cost-effectiveness ratio. We also provide future directions for research with regard to developing more robust economic evaluations for the ICU.ConclusionEconomic evaluations should be built alongside ICU RCTs and should be designed a priori using appropriate follow-up and data collection to capture patient-relevant outcomes. Further work is needed to improve the quality of data available for linkage in Australia as well as developing costing methods for the ICU and appropriate quality of life measurements.     

Mathematical methods to assist with hospital operation and planning

Within health Operational Research, the use of 'computer package' methods such as simulation and system dynamics is becoming so prevalent that it feels somewhat old hat to use analytical methods to develop explicit mathematical formulae or even to explore the mathematical structure of problems. This paper will discuss the use of such 'back of the envelope' analysis illustrating its usefulness. It will be shown that not only does this approach yield considerable insight, but also that it can give rise to powerful and practical solution methods. Examples of this will be discussed in relation to issues such as bed needs estimation, admissions and facilities planning. The author is Director of the Clinical Operational Research Unit (CORU) which was established in 1983, receiving core funding from the UK Department of Health. The concept of a full time university-based research unit dedicated to applying expertise in Operational Research (OR) to problems in health care provides a relatively rare research resource. Yet, the scope for such research, applied to an increasing range of health care activity, is enormous. Issues such as treatment evaluation, performance measures, clinical governance, evidence based medicine and health service delivery are all amenable to OR. Further, OR often provides an immensely cost effective alternative to traditional methods of clinical research based on randomised controlled trials or large scale epidemiological studies. The nature of OR, and one of its main strengths, is that it encompasses a wide range of analytical and scientific methods. Mathematical modeling, statistics, computer-based methods, trial design and analysis all contribute to health OR and, under both of its Directors since 1983, a conscious effort has been made within CORU to foster a diversity of research methodologies. Particular emphasis is put on developing new mathematical methods and computer software. This is somewhat at odds with what seems to be a growing trend in health OR towards researchers specialising in just one or two areas of methodology; thus Tom does queueing theory, Dick does simulation and Harry does System Dynamics. Of course there are exceptions, but for whatever reason, the trend towards specialisation seems real. In this paper, benefits of a more diverse approach to health OR is advocated, particularly the use of 'back of envelope' mathematical methods as an alternative to the use of proprietary software packages. Three case studies are described to illustrate this approach.     

Contextual analysis of coping: implications for immigrants' mental health care

Providing high quality and effective health care services that are culturally acceptable and appropriate to clients has become an important issue for many health care providers. This paper explores problems associated with the traditional model that views coping according to hierarchical style and traits. While some scholars who have adopted this theoretical framework have made many contributions to the development of stress and coping theories, limitations are present. Using Vietnamese immigrants' experiences as examples, I argue that coping theories should emphasize the contextual nature of stress and coping, and that coping should be viewed as a dynamic process that varies under different social, cultural, political, economic, and historical conditions. Drawing from the work of others on coping, culture, imperialism, and colonialism, I explore the way that certain cultural conceptualizations determine how individuals cope. An understanding of the contextual nature of coping and of a Vietnamese immigrant's experience of coping with stressors and illness has implications for mental health care practice and research.     

Randomized, controlled trials as minimal risk: an ethical analysis

OBJECTIVE: We aim to clarify the circumstances in which randomized, controlled trials should be designated as minimal risk, allowing institutional review boards to approve their conduct with a waiver of informed consent if obtaining informed consent is not feasible. METHODS: An ethical analysis of the minimal risk standard as applied to randomized, controlled trials was conducted. CONCLUSIONS: In determining whether an randomized, controlled trial should be designated as minimal risk, the potential sources of risk that must be considered are as follows: physical risk from study treatments, the loss of individualized care, risk from nontherapeutic components of the research protocol, and the psychological impact of participation, particularly if the research takes place without informed consent in an emergency setting. The risks of research participation should be considered in comparison with the risk of nonparticipation; e.g., the risks specific to research participation should be considered separately from the risks inherent in treatment of the potential research participant's underling condition. Participation in an randomized, controlled trial may pose no more than minimal risk when: 1) genuine clinical equipoise exists; 2) all of the treatment options included in the research study fall within the current standard of care; 3) there is no currently available treatment with a more favorable risk-benefit profile than the treatments included in the study; 4) the nontherapeutic components of the research are safely under the minimal risk threshold; and 5) the research protocol provides sufficient latitude for treating physicians to individualize care when appropriate. The potential for research participation to have a negative psychological impact on participants or their families should be considered in risk assessment. The requirement for informed consent should only be waived to the extent necessary, and opportunities for the research participant or surrogate to decide whether to participate in the research should be maximized.     

Quality assurance and technology assessment: pieces of a larger puzzle

Increasing integration of health care and health services research has resulted in an overlap between disciplines involved in the evaluation of clinical practice. We have examined the relationships of quality assurance (QA), medical technology assessment (TA), clinical epidemiology (CE) and evidence-based medicine (EBM) from an historical perspective. Clinicians, patients and administrators need local information on effectiveness of routine care. Information from trials alone, efficacy data, will not suffice nor can it be culled from administrative databases designed for other purposes. The current activities of QA should be therefore be expanded to include the study of the effectiveness of interventions in terms of appropriateness of use, patient outcomes and study of the determinants of outcomes, as seen from the perspective of doctors, patients, administrators and policy makers, using data collected during the course of routine patient care. With the assistance of information technology, with methodological support and multidisciplinary cooperation, clinicians can do this as part of a more broadly defined clinical research. Quality assurance and TA both evolved with the objective of studying clinical care but have quite different historical roots, complementary perspectives and objectives, use different methods and involve a different set of practitioners. Quality assurance is a type of 'formative' evaluation conducted in the clinical setting using indicators as flags of process or outcome events of interest, simple surveys and audit studies. Its primary aim is to achieve incremental improvement rather than to simply pass judgement. An important underlying assumption is that health care behaves as a complex dynamic system. Technology assessment, a form of summative evaluation with an orientation towards policy, synthesises information from formal scientific studies of efficacy in the form of clinical trials and studies of cost-effectiveness. For the evaluation of the impact of any technology more complex than a drug, the complementary contributions of both of these disciplines is needed, and QA and TA should work cooperatively in tandem with the support of CE and EBM.     

CONTEXTUAL ANALYSIS OF COPING: IMPLICATIONS FOR IMMIGRANTS' MENTAL HEALTH CARE

Providing high quality and effective health care services that are culturally acceptable and appropriate to clients has become an important issue for many health care providers. This paper explores problems associated with the traditional model that views coping according to hierarchical style and traits. While some scholars who have adopted this theoretical framework have made many contributions to the development of stress and coping theories, limitations are present. Using Vietnamese immigrants' experiences as examples, I argue that coping theories should emphasize the contextual nature of stress and coping, and that coping should be viewed as a dynamic process that varies under different social, cultural, political, economic, and historical conditions. Drawing from the work of others on coping, culture, imperialism, and colonialism, I explore the way that certain cultural conceptualizations determine how individuals cope. An understanding of the contextual nature of coping and of a Vietnamese immigrant's experience of coping with stressors and illness has implications for mental health care practice and research.     

Defining neurosurgical and neurological nursing practice: establishing our clinical parameters, part I

We have examined the education and practice roles of various professional and allied health personnel necessary for providing optimal care to a specialized group of patients, in this case, the neurosurgical/neurological patient group. One needs to investigate these factors in order to plan for effective economic utilization of such personnel in the health care system. The primary goal of all health care providers is quality patient care services, yet secondary concerns cannot be overlooked if we are to accomplish this ultimate goal. Prohibitive health care costs for those we serve and escalating educational costs to become competent to render such services mandate that we choose the most advantageous use of available resource personnel. Placing professionals in appropriate positions which allow them to apply their education and clinical strengths in the care of patients will not only promote excellence in patient care but also excellence in each professional practice role.     

Effectiveness of nurse-led brief alcohol intervention: a cluster randomized controlled trial

AIM: This paper reports an evaluation of the effectiveness and cost-effectiveness of nurse-led screening and brief intervention in reducing excessive alcohol consumption among patients in primary health care. BACKGROUND: Excessive alcohol consumption is a major source of social, economic and health problems. However, such consumption is responsive to brief alcohol intervention. To date, brief intervention research in primary health care has focused on general practitioner-led interventions, and there is only circumstantial evidence of effectiveness in nurse-led interventions. However, nurses are increasingly taking a lead in health promotion work in primary care. METHODS: A pragmatic cluster-randomized controlled trial was carried out between August 2000 and June 2003 to evaluate the effects of a brief intervention compared with standard advice (control condition). A total of 40 general practice clusters (intervention = 21 and control = 19) recruited 127 patients (intervention = 67 and control = 60) to the trial. Excessive consumption was identified opportunistically via the Alcohol Use Disorders Identification Test. After baseline assessment, patients received either a 5-10 minutes brief intervention using the 'Drink-Less' protocol or standard advice (control condition). Follow-up occurred at 6 and 12 months postintervention. RESULTS: Analysis of variance weighted for cluster size revealed no statistically significant differences between intervention and control patients at follow up. A majority of patients in both conditions reduced their alcohol consumption between assessment and subsequent measurement. Economic analysis suggested that the brief intervention led to no statistically significant changes in subsequent health service resource use relative to standard treatment. CONCLUSION: The brief intervention evaluated in this trial had no effect over standard advice delivered by nurses in primary health care. However, there was a reduction in excessive drinking across both arms of the trial over time. Due to nurse drop-out, this trial was significantly underpowered. Future research should explore barriers to nurses' involvement in research trials, particularly with an alcohol focus. A larger trial is required to evaluate the effectiveness of nurse-led screening and brief alcohol intervention in primary care.     

Recruitment issues when primary care population clusters are used in randomised controlled clinical trials: Climbing mountains or pushing boulders uphill?

Cluster randomised controlled trials for health promotion, education, public health or organisational change interventions are becoming increasingly common to inform evidence-based policy. However, there is little published methodological evidence on recruitment strategies for primary care population clusters. In this paper, we discuss how choosing which population cluster to randomise can impact on the practicalities of recruitment in primary care. We describe strategies developed through our experiences of recruiting primary care organisations to participate in a national randomised controlled trial of a policy to provide community breastfeeding groups for pregnant and breastfeeding mothers, the BIG (Breastfeeding in Groups) trial. We propose an iterative qualitative approach to recruitment; collecting data generated through the recruitment process, identifying themes and using the constant comparative method of analysis. This can assist in developing successful recruitment strategies and contrasts with the standardised approach commonly used when recruiting individuals to participate in randomised controlled trials. Recruiting primary care population clusters to participate in trials is currently an uphill battle in Britain. It is a complex process, which can benefit from applying qualitative methods to inform trial design and recruitment strategy. Recruitment could be facilitated if health service managers were committed to supporting peer reviewed, funded and ethics committee approved research at national level.     

Economic evaluation of nurse practitioner and clinical nurse specialist roles: A methodological review

BackgroundAdvanced practice nurses (e.g., nurse practitioners and clinical nurse specialists) have been introduced internationally to increase access to high quality care and to tackle increasing health care expenditures. While randomised controlled trials and systematic reviews have demonstrated the effectiveness of nurse practitioner and clinical nurse specialist roles, their cost-effectiveness has been challenged. The poor quality of economic evaluations of these roles to date raises the question of whether current economic evaluation guidelines are adequate when examining their cost-effectiveness.ObjectiveTo examine whether current guidelines for economic evaluation are appropriate for economic evaluations of nurse practitioner and clinical nurse specialist roles.MethodsOur methodological review was informed by a qualitative synthesis of four sources of information: 1) narrative review of literature reviews and discussion papers on economic evaluation of advanced practice nursing roles; 2) quality assessment of economic evaluations of nurse practitioner and clinical nurse specialist roles alongside randomised controlled trials; 3) review of guidelines for economic evaluation; and, 4) input from an expert panel.ResultsThe narrative literature review revealed several challenges in economic evaluations of advanced practice nursing roles (e.g., complexity of the roles, variability in models and practice settings where the roles are implemented, and impact on outcomes that are difficult to measure). The quality assessment of economic evaluations of nurse practitioner and clinical nurse specialist roles alongside randomised controlled trials identified methodological limitations of these studies. When we applied the Guidelines for the Economic Evaluation of Health Technologies: Canada to the identified challenges and limitations, discussed those with experts and qualitatively synthesized all findings, we concluded that standard guidelines for economic evaluation are appropriate for economic evaluations of nurse practitioner and clinical nurse specialist roles and should be routinely followed. However, seven out of 15 current guideline sections (describing a decision problem, choosing type of economic evaluation, selecting comparators, determining the study perspective, estimating effectiveness, measuring and valuing health, and assessing resource use and costs) may require additional role-specific considerations to capture costs and effects of these roles.ConclusionCurrent guidelines for economic evaluation should form the foundation for economic evaluations of nurse practitioner and clinical nurse specialist roles. The proposed role-specific considerations, which clarify application of standard guidelines sections to economic evaluation of nurse practitioner and clinical nurse specialist roles, may strengthen the quality and comprehensiveness of future economic evaluations of these roles.     

Design of trials with dying patients: a feasibility study of cluster randomisation versus randomised consent

There is little rigorous evidence to underpin clinical guidelines for palliative care. However, research in palliative care is difficult, especially with dying patients. Consent is a major issue, since staff do not wish to invite dying patients to participate in trials. We, therefore, conducted a feasibility study in two units within the North West Wales NHS Trust. We explored two novel approaches to research in palliative care -cluster randomisation and randomised consent. All patients admitted to the two units during the study were asked for permission to use their data for research. We allocated the two units, at random, to use cluster randomisation or randomised consent for three months, and then to crossover to the other design. Of 24 patients dying during cluster-randomised phases, 13 gave consent on admission to use their data and were, thus, eligible to enter the trial; however, defined eligibility criteria reduced these to six active participants. Of 29 patients dying during randomised consent phases, seven gave consent on admission to use their data; although two were eligible for randomisation, neither entered the trial. We judge that cluster randomisation is the more effective design for research with dying patients. Computer simulation, based on data from 1500 dying patients on the Welsh Integrated Care Pathway, shows that crossover cluster trials need much smaller samples than simple cluster trials. Furthermore, this study has shown that crossover cluster trials are entirely feasible. We recommend a 'definitive' trial to test the crossover design more widely.