Towards texture accurate slice interpolation of medical images using PixelMiner

Quantitative image analysis models are used for medical imaging tasks such as registration, classification, object detection, and segmentation. For these models to be capable of making accurate predictions, they need valid and precise information. We propose PixelMiner, a convolution-based deep-learning model for interpolating computed tomography (CT) imaging slices. PixelMiner was designed to produce texture-accurate slice interpolations by trading off pixel accuracy for texture accuracy. PixelMiner was trained on a dataset of 7829 CT scans and validated using an external dataset. We demonstrated the model's effectiveness by using the structural similarity index (SSIM), peak signal to noise ratio (PSNR), and the root mean squared error (RMSE) of extracted texture features. Additionally, we developed and used a new metric, the mean squared mapped feature error (MSMFE). The performance of PixelMiner was compared to four other interpolation methods: (tri-)linear, (tri-)cubic, windowed sinc (WS), and nearest neighbor (NN). PixelMiner produced texture with a significantly lowest average texture error compared to all other methods with a normalized root mean squared error (NRMSE) of 0.11 (p < .01), and the significantly highest reproducibility with a concordance correlation coefficient (CCC) ≥ 0.85 (p < .01). PixelMiner was not only shown to better preserve features but was also validated using an ablation study by removing auto-regression from the model and was shown to improve segmentations on interpolated slices.

054 The individual costs of multiple sclerosis

Background

The UK Multiple Sclerosis Register (UKMSR) captures data from multiple sources including directly from people with MS (pwMS) via online questionnaires. There is little research into the non-medical (personal) costs of MS. In partnership with Sanofi we investigated healthcare resource use and costs (excluding drugs), including who bears these costs, by disease severity and type

Methods

A cost of illness questionnaire was deployed to 3035 pwMS on the UKMSR. Respondent’s answers were linked to retrospective UKMSR data. Resource consumption was categorised as being direct (medical) or indirect (non-medical) and costed by NHS and Social Services estimates for 2018.

Results

£509,003 was calculated as non-medical costs over a year and £435,488 in medical costs generated over 3 months (n=537, 6935 interventions). PwMS reported self-funding 75% of non-medical costs these were mainly home modifications. Costs, increased with disability but those with indirect costs (n=138) had higher medical costs, were more disabled and were more likely to be unemployed than those with medical interventions only (n=399).

Conclusions

The importance of disability in driving costs is again clearly illustrated with balance between indirect and direct costs consistent with the UK health environment as a whole. PwMS and their families fund 75% of non-medical costs that can facilitate early discharge and reduce the need to rehabilita- tion/nursing home services.

richard.nicholas@btinternet.com

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Idiopathic canine juvenile cranial hyperostosis in a Pit Bull Terrier

CASE HISTORY

An 8-month-old male Pit Bull Terrier was presented with bilateral firm swellings of the cranium in the region of the frontal sinuses. The dog was aggressive when approached and had also been anorexic during the 3.5 days prior to presentation.

CLINICAL FINDINGS

Using computed tomography (CT) and radiology, periosteal new bone formation and hyperostosis were detected on the frontal, parietal and mandibular bones bilaterally. Histopathology of the calvarial and mandibular bones was similar, comprised of thick trabeculae of immature woven and mature lamellar bone separated by cementing lines. Sites of prominent osteoblastic and osteoclastic activity were also present.

DIAGNOSIS

Craniomandibular osteopathy with clinical similarities to calvarial hyperostosis.

CLINICAL RELEVANCE

Pit Bull Terriers are not predisposed to either craniomandibular osteopathy or calvarial hyperostosis. This observation, in addition to the clinical and pathological similarities between the two diseases, suggests that craniomandibular osteopathy and calvarial hyperostosis may represent a single disorder, with predilection sites that vary between breeds of dog. We propose a new term, idiopathic canine juvenile cranial hyperostosis, for this disorder, to include both craniomandibular osteopathy and calvarial hyperostosis.

A retrospective study of drug response indicator test (DRIT) as a predictive test for therapeutic treatment outcomes of advanced breast cancer patients (ABC)

Abstract #6075

We conducted a retrospective study of DRIT, an investigational diagnostic test to predict chemotherapy and endocrine therapy treatment outcomes in ABC. DRIT is a quantitative measurement of Drug Response Indicator (DRI) expression levels in formalin fixed, paraffin embedded tumor tissue. DRI chosen for each drug is related to the perceived mechanism of action of the drug. The quantitative measurement of DRI expression in the tumor tissue is based on the fluorescent dye-labeled monoclonal antibody (mAb) staining, followed by acquisition of digital images using computer-assisted microscopy, calibrated to an external standard. DRI expression measurement results in classification of the tumor as sensitive or resistant to a particular drug based on our in vitro studies of drug sensitivity/resistance in cell lines. If a tumor is classified as sensitive to a drug/s by DRIT, this predicts that the patient (Pt) will respond to treatment, while if a tumor is classified as resistant this predicts that the Pt will not respond to the drug/s therapy. Clinically the treatment outcome is classified into a responsive group (non-progressive disease,CR, PR, SD) & a non-responsive group (progressive disease, PD). The drugs & DRI tested are: capcitabine/thymidylate synthase; Taxanes /β-tubulin isoform III, trastuzamab/HER-2, Endocrine therapy/estrogen receptor, gemcitabine/ribonucleotide reductase. 51 ABC received mono or doublet therapy as first 3 lines of therapy-(80 treatments). The percent accuracy (number of accurate predictions/number of treatment interventions) for monotherapy is 87% (61/70), 100% (10/10) for doublet therapy and 89% (71/80) for all treatments. The accuracy of prediction for responsive patients is 86% (60/69) and 100% (11/11) for non responsive patients. DRIT diagnostic performance for 80 treatment outcome predictions for endocrine therapy and mono and doublet chemotherapy is as follows: sensitivity 1.00, specificity 0.55, positive predictive value 0.87, negative predictive value 1.00, and overall accuracy 0.88. For the standard of care outcomes, the favorable response rate for the 80 treatments is 75% (60/80), the potential favorable response rate with DRIT input is 86% (60/69) with 11 ineffective treatments identified by DRIT accurately 100% (11/11). Thus, DRIT input can identify effective (86%) & ineffective (100%) treatments in this cohort of ABC patients. DRIT is under developement as a diagnostic test to predict treatment outcomes prior to the selection of a particular drug for anticancer therapy, so that the most effective drug can be prescribed for an individual cancer patient. This retrospective study in ABC patients shows that DRIT has a potential to be a useful test to predict treatment outcomes.&#x2028; Supported in part by Maryland Industry Partnership Program – MIPS.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6075.

Conflicts of interest in divisions of general practice

Community-based healthcare organisations manage competing, and often conflicting, priorities. These conflicts can arise from the multiple roles these organisations take up, and from the diverse range of stakeholders to whom they must be responsive. Often such conflicts may be titled conflicts of interest; however, what precisely constitutes such conflicts and what should be done about them is not always clear. Clarity about the duties owed by organisations and the roles they assume can help identify and manage some of these conflicts. Taking divisions of general practice in Australia as an example, this paper sets out to distinguish two main types of conflicts of interest, so that they may be more clearly identified and more effectively managed.

The maturation of balance in children

Background: Balance function is known to change with age during infancy and childhood. However, the relative contributions of the three primary inputs to position sense are not fully understood.

Methods: In this paper we report the computerised dynamic posturography findings in a group of 60 healthy children from the age of five to 17.

Results: The results confirm that there is a progressive improvement in balance function with age. The EquiTest system that was used gave indications of the relative contributions of the three principal contributors to overall balance function and showed that somatosensory function was intact throughout the age range tested and that there are significant increases in vestibular function with age and visual contribution with height. The technique used was found to be reliable and repeatable in this paediatric sample.

Conclusions: It is hoped that a better understanding of the normal age related development of balance will be helpful in dealing with children presenting with disequilibrium and vertigo.

Comparison of bacteria populations in clean and recycled sand used for bedding in dairy facilities

Bedding samples were collected twice from commercial dairy free-stall facilities that used recycled sand and clean sand in both the summer and winter. Collection began on the day sand was taken from the pile (d 0) and placed in the free stalls, and continued for 5 to 7 additional days. The number of colonies per gram of bedding of gram-negative bacteria, coliforms, Streptococcus spp., and Klebsiella spp. were estimated for each sand sample as well as amounts of dry and organic matter. Clean sand (CS) and recycled sand (RS) had the same bacterial counts when compared at any sampling time. The mean counts of bacterial populations did vary over the course of the study in both CS and RS. There was a significant increase in bacterial counts from d 0 to d 1 for gram-negative bacteria, coliforms, and Streptococcus spp. in both winter and summer. Counts of gram-negative bacteria, coliforms, Klebsiella spp., and Streptococcus spp. did not differ from d 1 to 7 in the winter. Total counts of gram-negative bacteria did not differ from d 1 to 7 in the summer. On d 1 in the summer, coliform counts were lower than at d 5 to 7, and Klebsiella spp. counts were lower than on d 3 to 7. Streptococcus spp. counts were high on d 1 and were constant through d 7 in both winter and summer trials. The number of coliform and Klebsiella spp. in both CS and RS was below the threshold thought to cause mastitis during the sampling times. The number of Streptococcus spp. was high in both CS and RS during the sampling periods. Other management factors need to be identified to decrease the number of Streptococcus spp. in bedding. Recycled sand had a higher organic matter and lower dry matter compared with CS in winter and summer. The results for this study were obtained from multiple herd comparisons, and herd was a significant effect suggesting that different management systems influence the number and types of bacteria in both CS and RS.

[Hypocretin (orexin) deficiency in narcolepsy-cataplexy]

A mutation in the HCRT locus was proved in 18-yrs old male suffering from narcolepsy-cataplexy. He has demonstrated cataplectic attacks (brief spells of head dropping provoked by laughter) as well as imperative sleep in spells of several minutes up to one hour since the age of six months. He has suffered from severe bulimia since five years; later hypnagogic hallucinations, sleep paralysis and unquiet nocturnal sleep accompanied by periodic limb movements appeared. Symptoms are partially controlled with methylphenidate and either imipramine, clomipramine or fluoxetine. Periodic leg movements poorly responded to L-DOPA and clonazepam treatment. He is HLA-DQB1*0602 negative. Repeated MSLT (over 16 years followed-up period) showed extremely short latency with predominant SOREMPs and also nocturnal PSG recordings revealed fragmented sleep with SOREMPs. This case report demonstrates that hypocretin (orexin) mutations in human can produce the full narcolepsy phenotype and validates data recently reported in dog and mouse models suggesting a role for hypocretin (orexin) in the pathophysiology of narcolepsy and the regulation of REM sleep.

Relative contribution of mental health and exercise-related pain increment to treadmill test intolerance in patients with chronic low back pain

STUDY DESIGN

A cross-sectional study.

OBJECTIVES

To determine the relative contribution of pain increase and mental health to testing performance during a single bout of exercise in patients with chronic low back pain.

BACKGROUND

Controversy exists as to which factors principally limit physical performance in patients with chronic low back pain. Some believe psychological factors limit physical performance, whereas others believe activity-related increases in pain intensity limit performance.

METHODS

Seventy-five patients with chronic low back pain reported pain intensity before and after undergoing a maximal, symptom-limited modified treadmill test. Walking time (in minutes) and aerobic fitness were measured. The Short Form 36 Health Survey was administered to all patients.

RESULTS

Fifty-four percent of the sample stopped testing because of a significant increase in pain intensity (P = 0.0001). Treadmill performance was lower in patients who stopped because of pain than in those who stopped because of fatigue (P = 0.02). The patients who stopped because of pain were also more likely to have low mental health as assessed by the Short Form 36 Health Survey. Low mental health, however, did not have a statistically significant influence on treadmill performance.

CONCLUSION

The data indicate that impairment of physical performance during treadmill testing in patients with chronic low back pain is attributable to testing-induced increase in pain intensity rather than to individual low mental health scores.

A guide to undertaking a literature review

BACKGROUND

The National Information Service of the General Practice Evaluation Program (GPEP) produced publications relating to research undertaken under the auspices of the program with the view to adding value to such research. Two anthologies of literature reviews from GPEP research have been produced, one in 1998 and the other in 2000. A thorough guide to undertaking and writing a literature review was part of the second anthology. This paper is a shortened version of that guide.

OBJECTIVE

This paper is designed as an overview for general practitioners who wish to undertake a research project. In this overview the authors describe the reasons researchers undertake a literature review and the steps involved in conducting and writing up a review, including the development of search strategies.

DISCUSSION

The literature review described in this paper is a narrative review. This type of review involves performing thorough literature searches, describing how these were done, grouping findings according to themes, critically discussing findings and placing the proposed research in context.

Health status and satisfaction with health care: a longitudinal study among patients served by the Veterans Health Administration

As the Veterans Health Administration (VHA) places high priority on becoming a performance-based organization, there is an increasing need to quantify and refine its outcome measurement system. Using panel data from VHA ambulatory care patients (1996-1998), we conducted cross-lagged correlations and ordinary least squares regression to examine the relationship between 2 VHA health care values: health status and satisfaction with care. The study results indicated that patients' health status was significantly associated with their satisfaction with care, indicating that patients with better health status were more likely to be satisfied with health care. Although satisfaction with care was both a consequence and a determinant of health status, the effects of health status on satisfaction seemed to be more important than the effects of satisfaction on health status. More research is needed for a better understanding of the dynamic relationship between health status and satisfaction with care.

Low cerebrospinal fluid hypocretin (Orexin) and altered energy homeostasis in human narcolepsy

Hypocretins (orexins) are hypothalamic neuropeptides involved in sleep and energy homeostasis. Hypocretin mutations produce narcolepsy in animal models. In humans, narcolepsy is rarely due to hypocretin mutations, but this system is deficient in the cerebrospinal fluid (CSF) and brain of a small number of patients. A recent study also indicates increased body mass index (BMI) in narcolepsy. The sensitivity of low CSF hypocretin was examined in 38 successive narcolepsy-cataplexy cases [36 human leukocyte antigen (HLA)-DQB1*0602-positive] and 34 matched controls (15 controls and 19 neurological patients). BMI and CSF leptin levels were also measured. Hypocretin-1 was measurable (169 to 376 pg/ml) in all controls. Levels were unaffected by freezing/thawing or prolonged storage and did not display any concentration gradient. Hypocretin-1 was dramatically decreased (<100 pg/ml) in 32 of 38 patients (all HLA-positive). Four patients had normal levels (2 HLA-negative). Two HLA-positive patients had high levels (609 and 637 pg/ml). CSF leptin and adjusted BMI were significantly higher in patients versus controls. We conclude that the hypocretin ligand is deficient in most cases of human narcolepsy, providing possible diagnostic applications. Increased BMI and leptin indicate altered energy homeostasis. Sleep and energy metabolism are likely to be functionally connected through the hypocretin system.

Health status assessments using the Veterans SF-12 and SF-36: methods for evaluating otucomes in the Veterans Health Administration

This article describes a study in which the administration of two health surveys, the Veterans SF-36 and SF-12, by telephone and mail-out was used to assess the differences in the health surveys' costs and scores by mode of administration and determine which mode was cost-efficient. The study employed a crossover design: after 12 unsuccessful attempts to contact patients by telephone, the patients were administered the survey by mail, and after 2 unsuccessful mail-outs, up to three attempts were made to interview the patients by telephone. The analysis of the data showed that mail administration, with or without crossover to telephone, was more cost-efficient than telephone administration, having both lower average total and variable costs per completed questionnaire. Overall, telephone administration was about 30% more expensive that mail administration, primarily due to the cost of labor. The marginal cost of an additional completed Veterans SF-12 or Veterans SF-36 was also substantially lower for mail administration. Mail administration without crossover to telephone administration was the most cost-efficient strategy for administering both the Veterans SF-12 and SF-36. The results of this study strongly suggest the need to consider the mode of administration if questionnaires like the Veterans SF-12 or SF-36 are to be used to assess health outcomes within and across large health care systems.

Advancing health promotion in Australian general practice

Health promotion activities, while having the potential to prevent disease and decrease the burden of ill health, often play a minor role in the health care offered by general practitioners. There are several identified barriers to the involvement of Australian general practitioners in health promotion. These include structural barriers and barriers within the practice setting, individual practitioner and patient factors, and difficulties in evaluating the outcomes of health promotion activities. This article explores the barriers to the engagement of Australian general practice with health promotion and reviews several recent initiatives that have the potential to increase the health promotion activities of general practitioners. These initiatives act at the level of the individual practitioner, the practice, and in the community. Despite the lack of a coordinated national approach, these strategies form an important development in general practice.

Physical and radiation hybrid mapping of canine chromosome 12, in a region corresponding to human chromosome 6p12-q12

The positional cloning of the hypocretin receptor 2, the gene for autosomal recessive canine narcolepsy, has led to the development of a physical map spanning a large portion of canine chromosome 12 (CFA12), in a region corresponding to human chromosome 6p12-q13. More than 40 expressed sequence tags (ESTs) were used in homology search experiments, together with chromosome walking, to build both physical and radiation hybrid maps of the CFA12 13-21 region. The resulting map of bacterial artificial chromosome ends, ESTs, and microsatellite markers represents the longest continuous high-density map of the dog genome reported to date. These data further establish the dog as a system for studying disease genes of interest to human populations and highlight feasible approaches for positional cloning of disease genes in organisms where genomic resources are limited.

Complex HLA-DR and -DQ interactions confer risk of narcolepsy-cataplexy in three ethnic groups

Human narcolepsy-cataplexy, a sleep disorder associated with a centrally mediated hypocretin (orexin) deficiency, is tightly associated with HLA-DQB1*0602. Few studies have investigated the influence that additional HLA class II alleles have on susceptibility to this disease. In this work, 1,087 control subjects and 420 narcoleptic subjects with cataplexy, from three ethnic groups, were HLA typed, and the effects of HLA-DRB1, -DQA1, and -DQB1 were analyzed. As reported elsewhere, almost all narcoleptic subjects were positive for both HLA-DQA1*0102 and -DQB1*0602. A strong predisposing effect was observed in DQB1*0602 homozygotes, across all ethnic groups. Relative risks for narcolepsy were next calculated for heterozygous DQB1*0602/other HLA class II allelic combinations. Nine HLA class II alleles carried in trans with DQB1*0602 were found to influence disease predisposition. Significantly higher relative risks were observed for heterozygote combinations including DQB1*0301, DQA1*06, DRB1*04, DRB1*08, DRB1*11, and DRB1*12. Three alleles-DQB1*0601, DQB1*0501, and DQA1*01 (non-DQA1*0102)-were found to be protective. The genetic contribution of HLA-DQ to narcolepsy susceptibility was also estimated by use of lambda statistics. Results indicate that complex HLA-DR and -DQ interactions contribute to the genetic predisposition to human narcolepsy but that additional susceptibility loci are also most likely involved. Together with the recent hypocretin discoveries, these findings are consistent with an immunologically mediated destruction of hypocretin-containing cells in human narcolepsy-cataplexy.

Application of the privacy principles to general practice

BACKGROUND

There are escalating requirements for general practitioners to comply with recognised privacy principles. With amendments to the Commonwealth Privacy Act (1988) imminent, there is an urgent need to formulate methods for applying these principles to general practice.

OBJECTIVE

The article provides an explanation of the origins of the privacy principles and a simple self audit which general practitioners can use to assess the extent to which their usual practices conform with them.

DISCUSSION

A careful review of the principles indicates that new measures will be needed before most general practices will be able to approach required standards of conduct. Practical strategies for achieving best practice are discussed and challenges confronting general practices in applying the principles are canvassed. Ethics committees should be used more often to provide independent review of practice policies and proposals to use patient information in new ways. General practitioners can expect increasing scrutiny and debate concerning confidentiality. In order to maintain patient trust in GPs as responsible data custodians, the privacy principles can be seen as a quality improvement tool.

Handling information ethically. Some strategies for discussion

BACKGROUND

A lack of consensus currently exists about which uses of patient data require informed consent or review by a human research ethics committee. However, any use of patient data other than for clinical care, requires the consent of the patient.

OBJECTIVE

The aim of this paper is to discuss strategies for strengthening current practices regarding the use of patient information in general practice research, evaluation and audit.

DISCUSSION

Increasing community discussion and debate with respect to the use of patient data for research and evaluation is a pressing issue. Divisions of general practice are well placed to lead in this debate given the extent of community representation in many divisions' activities. Development of guidelines for use by those undertaking research and evaluation activities in general practice, based upon the Privacy Principles, will ensure a high standard of protection for patients. Community based Human Research Ethics Committees may be an appropriate way of providing education and training as well as a review of general practice research and related activities.

Deconditioning in patients with chronic low back pain: fact or fiction?

STUDY DESIGN

Prospective case series with historical controls (normative data).

OBJECTIVES

To compare aerobic fitness levels in patients with chronic low back pain with those published on a sample of 295 healthy subjects.

SUMMARY OF BACKGROUND DATA

Clinical belief holds that patients with chronic low back pain have low fitness levels as a result of inactivity because of pain. Because few studies have investigated the level of aerobic fitness in these patients, however, it remains unclear how fitness levels in patients with chronic low back pain patients compare with those published a sample of the normative population.

METHODS

A sample of 50 patients with chronic low back pain with a mean pain duration of 40 months referred to an outpatient pain clinic performed a symptom-limited modified treadmill test. Aerobic fitness levels were determined by indirect calorimetry to measure oxygen consumption (VO2). Predicted maximum oxygen consumption (VO2max) levels were calculated for all subjects. Multiple regression analysis with adjustment for age and sex yielded prediction equations for men and women separately. Ninety-five percent confidence intervals were calculated for predicted mean oxygen consumption (VO2) and the slope of the equations. These were compared to established prediction equations on healthy subjects.

RESULTS

Prediction equations for estimated maximum oxygen consumption (VO2max) in patients with chronic low back pain equal those in healthy sedentary men and active women.

CONCLUSIONS

Levels of aerobic fitness in patients with chronic low back pain are comparable with those in healthy subjects.

A mutation in a case of early onset narcolepsy and a generalized absence of hypocretin peptides in human narcoleptic brains

We explored the role of hypocretins in human narcolepsy through histopathology of six narcolepsy brains and mutation screening of Hcrt, Hcrtr1 and Hcrtr2 in 74 patients of various human leukocyte antigen and family history status. One Hcrt mutation, impairing peptide trafficking and processing, was found in a single case with early onset narcolepsy. In situ hybridization of the perifornical area and peptide radioimmunoassays indicated global loss of hypocretins, without gliosis or signs of inflammation in all human cases examined. Although hypocretin loci do not contribute significantly to genetic predisposition, most cases of human narcolepsy are associated with a deficient hypocretin system.

Handling information. Some ethical issues

BACKGROUND

General practitioners are increasingly involved in a range of activities which require the use of data from patients' case notes. These activities include audit, evaluation and research. Any use of patient data has the potential to breach patient confidentiality and privacy. However, at present the requirements in terms of obtaining informed consent vary. Research is usually acknowledged as requiring consent, but this is not always the case for audit and evaluation activities.

OBJECTIVES

The aim of this paper is to define audit, evaluation and research activities in general practice and to clarify the ethical issues involved in using patient data for these purposes. We argue that the ethical issues raised by accessing patient case notes are similar for all of these activities.

DISCUSSION

The ethical obligation to obtain patient consent prior to accessing or using patient information is the same for many general practice audit, evaluation and research activities. However, the avenues for obtaining ethical clearance may be hard to access for GPs. In addition, the special relationship between patients and their GP and the requirements specified by health research ethics committees such as de-identification of case notes create problems for these activities in general practice.

Aerobic fitness testing in patients with chronic low back pain: which test is best?

STUDY DESIGN

This is a randomized comparison of three exercise tests in a sample of 30 patients with chronic low back pain.

OBJECTIVES

To determine, by comparing three exercise tests, which test yields the highest peak and predicted oxygen consumption in a sample of patients with chronic low back pain.

SUMMARY OF BACKGROUND DATA

Little is known about the level of aerobic fitness in patients with chronic low back pain, although many rehabilitation programs emphasize aerobic exercise as an important part of their therapy. Measurement of aerobic fitness levels in these patients remains a problem. In healthy individuals, the highest oxygen consumption values come from exercise tests that use the largest muscle groups. For a number of reasons, this may not be true in patients with chronic low back pain.

METHODS

In this study, 30 participants with chronic low back pain performed three symptom-limited maximal exercise tests: a treadmill, an upper extremity ergometer, and a bicycle ergometer. The tests were administered in randomized order. Heart rate was continuously monitored and oxygen consumption in terms of mL/kg/minute was measured by indirect calorimetry each 30 seconds.

RESULTS

The statistical difference among the tests was highly significant (P < 0.0001). The treadmill test yielded the highest peak and predicted oxygen consumption followed by the bicycle and the upper extremity ergometer test, respectively.

CONCLUSIONS

The treadmill test is the best test for measuring aerobic fitness levels in patients with chronic low back pain. It yielded the highest peak oxygen consumption compared with the other tests, coming closest to measuring maximal oxygen consumption.

Depression and health-related quality of life in ethnic minorities seeking care in general medical settings

BACKGROUND

To examine ethnic groups differences in (a) prevalence of depressive disorders and (b) health related quality of life in fee-for-service and managed care patients (n=21504) seeking care in general medical settings.

METHODS

Data are from the Medical Outcomes Study, a multi-site observational study of outpatient practices. The study screened patients of clinicians (family practice, internal medicine, cardiology, diabetology and endocrinology) for four chronic medical conditions; depression, coronary heart disease, hypertension and diabetes. A brief eight-item depression screener followed by the Diagnostic Interview Schedule-Depression Section (DIS) for screener positives identified depressed patients (n=2195). The Short Form Health Survey (SF-36) assessed health-related quality of life. Patient self-report determined ethnicity.

RESULTS

Before adjusting for demographic factors, African-Americans and Hispanics had highest rates of depressive symptoms. Asian-Americans had the lowest. After adjusting for demographics (particularly gender and income), we found few statistically significant differences in prevalence or severity of depression. However, among the depressed, Whites were the most, and African-Americans the least likely to report suicidal ideation (p<0. 01), and Hispanics and Whites were more likely to have melancholia (p<0.01). African-Americans reported the poorest quality of life.

LIMITATIONS

DSM III criteria (though few changes in DSM IV), and relatively small sample size of Asian-Americans compared to other groups.

CONCLUSIONS

Gender and socioeconomic status are more significant factors than ethnicity in determining risk for depressive disorder. However, ethnic differences in symptom presentation, and health-related quality of life could have clinical and social consequences, and merit further study.

Association Between Body Weight and In-Hospital Clinical Outcome Following Thrombolytic Therapy: A Report from the National Registry of Myocardial Infarction

Background: In epidemiologic studies, excessive body weight, independent of other risk factors, portends a poor prognosis among patients with coronary artery disease experiencing acute myocardial infarction (MI). At least one recent study has suggested that patients of excessive body weight when receiving thrombolytic therapy are often under-dosed, potentially reducing early coronary arterial patency and adversely affecting in-hospital clinical outcome. Concern has also been raised that body weight may influence treatment utilization, delays, and complication rates. Despite these concerns, the association between body weight and patient outcome following coronary thrombolysis has received limited attention. Methods/Results: Demographic, procedural, and outcome data from patients with MI were collected at 1073 United States hospitals participating in The National Registry of Myocardial Infarction from 1990 through 1994. Among 350,755 patients with MI enrolled, 87,688 (25.1%) were treated with tissue plasminogen activator (t-PA). Divided into body weight tertiles, 23.5% of patients were less than 70 kg (low weight), 36.8% were 70-85 kg (moderate weight), and 37.5% were greater than 85 kg (high weight). Patients of low weight were older (p < 0.001), received treatment later (p < 0.001), and were less likely to undergo cardiac catheterization, coronary angioplasty, or bypass surgery (p < 0.001) than moderate- or high-weight patients. Low-weight patients also experienced minor bleeding, major bleeding, recurrent MI, and death more often (p < 0.001). Adjusted for age, low body weight was independently associated with in-hospital mortality. Despite receiving a lower dose of t-PA per kg body weight, high-weight patients had a low incidence of cardiogenic shock, recurrent MI, death, and hemorrhagic complications.When high-weight women and men were compared, several interesting observations emerged. Mortality was increased twofold in women (6.8% vs. 3.0; p < 0.001), even adjusting for their older age. Despite being at increased risk, women were less likely than their male counterparts to undergo cardiac catheterization (p = 0.001) or bypass surgery (p = 0.008). Conclusions: The National Registry of Myocardial Infarction provides a unique resource for assessing health care trends in the United States. Our findings suggest that low body weight is associated with increased in-hospital morbidity and mortality. They also suggest that current dosing strategies for t-PA administration are probably adequate for high-weight patients. The excessive mortality and limited use of in-hospital interventions among high-weight women deserve further study to address gender-related differences in disease processes, as well as potential bias or discrimination.

The sleep disorder canine narcolepsy is caused by a mutation in the hypocretin (orexin) receptor 2 gene

Narcolepsy is a disabling sleep disorder affecting humans and animals. It is characterized by daytime sleepiness, cataplexy, and striking transitions from wakefulness into rapid eye movement (REM) sleep. In this study, we used positional cloning to identify an autosomal recessive mutation responsible for this sleep disorder in a well-established canine model. We have determined that canine narcolepsy is caused by disruption of the hypocretin (orexin) receptor 2 gene (Hcrtr2). This result identifies hypocretins as major sleep-modulating neurotransmitters and opens novel potential therapeutic approaches for narcoleptic patients.

Dobutamine stress echocardiography in women with chest pain. Pilot phase data from the National Heart, Lung and Blood Institute Women's Ischemia Syndrome Evaluation (WISE)

OBJECTIVES

The aim of this project was to assess the utility of dobutamine stress echocardiography (DSE) for evaluation of women with suspected ischemic heart disease.

BACKGROUND

Most investigations addressing efficacy of diagnosis and treatment of coronary artery disease (CAD) have been performed in predominantly male populations. As part of the Women's Ischemia Syndrome Evaluation (WISE) study, DSE was assessed in women participating at the University of Florida clinical site.

METHODS

Women with chest pain or other symptoms suggestive of myocardial ischemia and clinically indicated coronary angiography were eligible for the WISE study. Enrolled subjects underwent DSE using a modified protocol. Coronary stenosis was assessed by core laboratory quantitative coronary angiography (QCA).

RESULTS

The 92 women studied ranged in age from 34 to 82 years (mean 57.5). All women had > or = 1 major risk for CAD, and most (89, 97%) had > or = 2 risk factors. In 78 women (85%), left ventricular wall motion was normal at baseline and during peak infusion. The remaining 14 women had wall motion abnormalities during DSE. By QCA, 25 women (27%) had > or = 50% coronary stenosis, including 10 with single-vessel obstruction. Dobutamine stress echocardiography was abnormal in 10 of these 25 women, yielding overall sensitivity of 40%, and 60% for multivessel stenosis. Exclusion of women with inadequate heart rate response yielded overall sensitivity of 50%, and 81.8% for multivessel stenosis. Dobutamine stress echocardiography was normal in 54 of the 67 women with < 50% coronary narrowing, specificity 80.6%.

CONCLUSIONS

Dobutamine stress echocardiography reliably detects multivessel stenosis in women with suspected CAD. However, DSE is usually negative in women with single-vessel stenosis, and in the larger subset without coronary stenosis. Ongoing protocols of the WISE study are expected to improve diagnostic accuracy in women with single-vessel disease, as well as provide important data in the substantial number of women with chest pain but without epicardial coronary artery stenosis.

Health status in VA patients: results from the Veterans Health Study

Recently, the Veterans Administration (VA) Under Secretary for Health has designated functional status as one of the domains of value for the system, given its increasing importance for clinical care. The Veterans Health Study (VHS) was designed to assist the VA in monitoring outcomes and measuring the case mix of patients who use the VA. The Veterans SF-36 (short form functional status assessment for veterans) was administered to 2425 veterans receiving ambulatory care. Measures of the Veterans SF-36 were strongly correlated with sociodemographics and morbidities of the veterans. Young veterans had poorer mental health status than older veterans. Veterans who used ambulatory care in the VHS reported lower levels of health status, reflecting more disease than a non-VA civilian population. These measures of health are important indicators of the disease burden or case mix of the patients and are pertinent to health systems such as the VA for resource allocation decisions and as outcomes of care.

A milled implant-supported removable partial denture

Implant supported prostheses are highly successful restorations. There are multitudes of differing designs for these restorations. It is advantageous to retain some nervous input from the remaining dentition. The treatment modality presented in this paper not only has the support, stability, and retention necessary for all restorations, some of the remaining teeth are retained and are included in the restoration design.

Employment after coronary angioplasty or coronary bypass surgery in patients employed at the time of revascularization

BACKGROUND

Patients who undergo coronary angioplasty have a shorter convalescence than those who undergo coronary bypass surgery. This may improve subsequent employment.

OBJECTIVE

To compare employment patterns after coronary angioplasty or surgery.

DESIGN

Multicenter, randomized clinical trial.

SETTING

Seven tertiary care hospitals.

PATIENTS

409 employed patients with multivessel coronary artery disease.

INTERVENTION

Coronary bypass surgery or balloon angioplasty.

MEASUREMENTS

Time to return to work and time spent working during 4 years of follow-up.

RESULTS

Patients who underwent angioplasty returned to work 6 weeks sooner than patients who underwent coronary bypass surgery (P < 0.001), but long-term employment did not differ significantly (P > 0.2). Long-term employment was significantly lower among patients who were 60 to 64 years of age (P < 0.001), those who worked less than full-time at study entry (P < 0.001), and those who had less formal education (P = 0.005). Patients with only one source of health insurance were more likely to continue working (P = 0.005).

CONCLUSIONS

Faster recovery after angioplasty speeds return to work but does not improve long-term employment, which is primarily associated with nonmedical factors.

Corrosion behavior of sensitized duplex stainless steel

The present work investigates the corrosion behavior of 2205 duplex stainless steel in 0.9% NaCl solution after various heat-treatments, and compares it to that of 316L austenitic stainless steel. Both stainless steels were heat-treated at 500, 650, and 800 degrees C in air for 1 h, followed by furnace cooling. Each heat-treated sample was examined for their microstructures and Vickers micro-hardness, and subjected to the X-ray diffraction for the phase identification. Using potentiostatic polarization method, each heat-treated sample was corrosion-tested in 37 degrees C 0.9% NaCl solution to estimate its corrosion rate. It was found that simulated sensitization showed an adverse influence on both steels, indicating that corrosion rates increased by increasing the sensitization temperatures.

Health-related quality of life in patients served by the Department of Veterans Affairs: results from the Veterans Health Study

BACKGROUND

The Department of Veterans Affairs Health Care System (VA) is the largest integrated single payer system in the United States. To date, there has been no systematic measurement of health status in the VA. The Veterans Health Study has developed methods to assess patient-based health status in ambulatory populations.

OBJECTIVES

To describe the health status of veterans and examine the relationships between their health-related quality of life, age, comorbidity, and socioeconomic and service-connected disability status.

METHODS

Participants in the Veterans Health Study, a 2-year longitudinal study, were recruited from a representative sample of patients receiving ambulatory care at 4 VA facilities in the New England region. The Veterans Health Study patients received questionnaires of health status, including the Medical Outcomes Study Short Form 36-Item Health Survey; and a health examination, clinical assessments, and medical history taking. Sixteen hundred sixty-seven patients for whom we conducted baseline assessments are described.

RESULTS

The VA outpatients had poor health status scores across all measures of the Medical Outcomes Study Short Form 36-Item Health Survey compared with scores in non-VA populations (at least 50% of 1 SD worse). Striking differences also were found with the sample stratified by age group (20-49 years, 50-64 years, and 65-90 years). For 7 of the 8 scales (role limitations due to physical problems, bodily pain, general health perceptions, vitality, social functioning, role limitations due to emotional problems, and mental health), scores were considerably lower among the younger patients; for the eighth scale (physical function), scores of the young veterans (aged 20-49 years) were almost comparable with the levels in the old veterans (>65 years). The mental health scores of young veterans were substantially worse than all other age groups (P<.001) and scores of screening measures for depression were significantly higher in the youngest age group (51%) compared with the oldest age groups (33% and 16%) (P<.001).

CONCLUSIONS

The VA outpatients have substantially worse health status than non-VA populations. Mental health differences between the young and old veterans who use the VA health care system are sharply contrasting; the young veterans are sicker, suggesting substantially higher resource needs. Mental health differences may explain much of the worse health-related quality of life in young veterans. As health care systems continue to undergo a radical transformation, the Department of Veterans Affairs should focus on the provision of mental health services for its younger veteran.

The importance of radiating leg pain in assessing health outcomes among patients with low back pain. Results from the Veterans Health Study

STUDY DESIGN

Cross-sectional data were analyzed from the Veterans Health Study, an observational study of patients receiving ambulatory care.

OBJECTIVE

To develop a method of stratifying patients with low back pain by combining patient reports of radiating leg pain with the results of straight leg raising tests.

SUMMARY AND BACKGROUND DATA

Four hundred thirty-four participants with low back pain were identified through patient reports of ever having had low back pain, of low back pain that began more than 3 months ago, and of a health-care visit for low back pain in the past year. Four hundred twenty-eight patients with low back pain were included in the current analysis.

METHODS

Participants were mailed a health-related quality of life questionnaire and had an interview that included a low back pain questionnaire and a straight leg raising test. Patients' reports of radiating leg pain and results of the straight leg raising tests were combined into four hierarchical groups. This stratification was evaluated in relation to responses to the health-related quality of life questionnaire, localized low back pain, disability, and use of medical services.

RESULTS

The intensity of localized low back pain and disability increased from Group 1 (low back pain alone) to Group 4 (pain below knee with positive straight leg raising test result), whereas health-related quality of life decreased. Group 4 patients were 5.1 times more likely than were Group 1 patients to use medications for low back pain (95% confidence interval 1.2, 22.9), 6.8 times more likely to have a spinal magnetic resonance study (95% confidence interval, 2.7, 17.2), and 3.9 times more likely to have surgery (95% confidence interval, 1.3, 11.4).

CONCLUSIONS

The method of measuring correlation performs well in identifying patients with different levels of localized low back pain intensity, health-related quality of life, and use of services. It may be useful in studies of health outcomes, in clinical trials, and in predicting demands on health care resources.

Comparing generic and disease-specific measures of physical and role functioning: results from the Veterans Health Study

OBJECTIVES

This study compared the performance of generic measures of Medical Outcome Study Short Form 36-Item Health Survey physical functioning and role limitations with disease-specific measures of physical functioning and role limitations using specific disease attributions for chronic lung disease, chronic low back pain, and osteoarthritis of the knee.

METHODS

Data were analyzed from the Veterans Health Study among patients receiving Veteran's Administration ambulatory care. Patients identified as having one of the three study conditions were included in the study (n = 932).

RESULTS

The study revealed that the generic physical functioning and role limitations scales had higher correlations with other generic SF-36 scales, whereas disease-specific attribution measures had larger R2 values in explaining variability in symptom-based disease severity and larger t statistic values in discriminating the impacts of patients taking medications and having surgery.

CONCLUSIONS

The generic measures of physical functioning and role limitations were more applicable in assessing a broad array of health-related quality-of-life issues, whereas disease-specific measures of physical functioning and role limitations were more useful in evaluating clinical management and limitations associated with specific disease conditions. The results of the study suggest that the use of disease-specific attribution assessments was more cost-efficient than the development of new disease-specific instruments. Disease-specific attribution could be used to complement generic measures in assessing patient outcomes.

Cognitive function 5 years after randomization to coronary angioplasty or coronary artery bypass graft surgery

BACKGROUND

Coronary bypass surgery often leads to short-term cognitive dysfunction, whereas coronary angioplasty does not. Perioperative cognitive dysfunction usually resolves, although a subgroup of surgical patients may continue to exhibit long-term cognitive dysfunction. The purpose of this study was to compare cognitive function 5 years after randomization to a strategy of either initial coronary surgery or initial angioplasty.

METHODS AND RESULTS

Five centers in the Bypass Angioplasty Revascularization Investigation participated in this ancillary study. Patients with multivessel coronary disease randomized to angioplasty or surgery were eligible at the time of their 5-year clinic visit. A battery of five measures previously shown to be sensitive to perioperative changes in cognitive function was administered, including the Logical and Figural Memory Scales from the Wechsler Memory Scale, the Digit Symbol and Digit Span subtests from the Wechsler Adult Intelligence Scale, and Part B of the Reitan Trail Making Test. The 125 study patients were generally similar to the 133 patients who were eligible but did not participate, although study participants were significantly younger (P=.003). The 64 patients randomly assigned to angioplasty had baseline characteristics similar to those of 61 patients randomly assigned to surgery. Cognitive function scores were not significantly different between angioplasty or surgery patients in an intention-to-treat analysis (P=.57). There also was no difference in cognitive function scores when the data were analyzed according to whether the patient had ever undergone bypass surgery (P=.59).

CONCLUSIONS

Long-term cognitive function is similar after coronary bypass surgery and coronary angioplasty in the majority of patients.

A symptom-based measure of the severity of chronic lung disease: results from the Veterans Health Study

STUDY OBJECTIVES

We developed a symptom-based measure of severity for chronic lung disease (CLD) that can be readily administered in ambulatory care settings and be used to supplement general health-related quality of life (HRQoL) assessments and pathophysiologic indicators in research and clinical care.

DESIGN

Cross-sectional data from the Veterans Health Study, an observational study of health outcomes in patients receiving Veterans Affairs (VA) ambulatory care.

SETTING

Four VA outpatient clinics.

STUDY SUBJECTS

Two hundred ninety-two participants with CLD were identified on the basis of patient report of having a physician's diagnosis of chronic bronchitis, emphysema, or asthma and either using inhaled medications or having a productive cough on most days for 3 months.

MEASUREMENTS AND RESULTS

Participants were scheduled for an in-person interview in which they completed a CLD questionnaire and measurements of peak expiratory flow rate (PEFR). They were also mailed an HRQoL questionnaire, the Short Form Health Survey (SF-36). The CLD questionnaire included six symptom items chosen by an expert panel (two items each for dyspnea, wheezing, and productive cough). The combination of these items yielded a CLD severity index that correlated significantly with all eight scales of the SF-36 (range of r, -0.19 to -0.37; p<0.01). In contrast, PEFR had statistically significant correlations only with two SF-36 scales: physical functioning and bodily pain.

CONCLUSIONS

The CLD severity index is a reliable and valid patient-administered instrument that may be used to evaluate the effects of CLD on general HRQoL and predict future health services utilization.

Arterial injuries in orthopaedics: the posteromedial approach for vascular control about the knee

Combined orthopaedic and vascular injuries are becoming more common owing to an increasing incidence of high-energy trauma and gunshot wounds. We present our experience using the posteromedial approach in treating eight orthopaedic patients with popliteal arterial injuries. All patients underwent popliteal exploration by a vascular surgeon through a posteromedial approach (releasing the pes anserinus and the medial gastrocnemius). The arterial injuries were reconstructed in five patients using a reverse saphenous vein graft and directly repaired in three patients. Two patients had delayed healing of their incisions as a result of the original injury. There were no neural injuries. The posteromedial approach is extensile and utilitarian, and it represents the exposure of choice for arterial injuries about the knee.