Sampling bias in an international internet survey of diversion programs in the criminal justice system

Despite advances in the storage and retrieval of information within health care systems, health researchers conducting surveys for evaluations still face technical barriers that may lead to sampling bias. The authors describe their experience in administering a Web-based, international survey to English-speaking countries. Identifying the sample was a multistage effort involving (a) searching for published e-mail addresses, (b) conducting Web searches for publicly funded agencies, and (c) performing literature searches, personal contacts, and extensive Internet searches for individuals. After pretesting, the survey was converted into an electronic format accessible by multiple Web browsers. Sampling bias arose from (a) system incompatibility, which did not allow potential respondents to open the survey, (b) varying institutional gate-keeping policies that "recognized" the unsolicited survey as spam, (c) culturally unique program terminology, which confused some respondents, and (d) incomplete sampling frames. Solutions are offered to the first three problems, and the authors note that sampling bias remains a crucial problem.     

Relief of symptoms and improvement of health-related quality of life five years after coronary artery bypass graft in women and men

BACKGROUND: Severe coronary artery disease can be successfully treated with coronary artery bypass graft (CABG), with considerable improvement in the symptoms of angina pectoris. Approximately three of four patients are free of ischemic events for 5 years; however, increased survival is demonstrated only in selected subgroups with advanced coronary artery disease, and this effect has not been established in elderly patients. HYPOTHESIS: The study was undertaken to determine the relief of symptoms and improvement in other aspects of health-related quality of life (QoL) during 5 years after CABG in women and men. METHODS: Patients who underwent CABG in western Sweden were approached prior to and 5 years after surgery. Health-related QoL was estimated with Physical Activity Score (PAS), Nottingham Health Profile, and Psychological General Well-Being Index. RESULTS: Women (n = 381) had a 5-year mortality of 17% compared with 13% for men (n = 1,619; NS). After 5 years, 1,719 patients (survivors) were available for the survey; of these, 876 (51%) answered the inquiry both prior to and after 5 years. Both women and men improved markedly and highly significantly, both with respect to symptoms and other aspects of health-related QoL. Women suffered more than men in terms of limitation of physical activity, dyspnea, chest pain, and others aspects of health-related QoL. There was a significant interaction between time and gender, with more improvement in men with regard to chest pain when walking uphill or quickly on level ground, when walking on level ground at the speed of other persons their own age, when under stress, and in windy and cold weather. For those parameters as well as for PAS, improvement was more marked in men than in women. In the other aspects of health-related QoL, there was no interaction between time and gender. CONCLUSION: Five years after CABG, limitation of physical activity, symptoms of dyspnea, and chest pain were reduced, and various aspects of health-related QoL had improved in both women and men. In general, women suffered more than men both prior to and after CABG; however, in some aspects the improvement was more pronounced in men. Because of the limited response rate, the results may not be applicable to a nonselected population who had undergone CABG.     

Ameloblastoma: current etiopathological concepts and management

Ameloblastoma is a benign odontogenic tumor of epithelial origin. It is locally aggressive with unlimited growth capacity and has a high potential for malignant transformation as well as metastasis. Ameloblastoma has no established preventive measures although majority of patients are between ages 30 and 60 years. Molecular and genetic factors that promote oncogenic transformation of odontogenic epithelium to ameloblastoma are strongly linked to dysregulation of multiple genes associated with mitogen‐activated protein kinase, sonic hedgehog, and WNT/β‐catenin signaling pathways. Treatment of ameloblastoma is focused on surgical resection with a wide margin of normal tissue because of its high propensity for locoregional invasion; but this is often associated with significant patient morbidity. The relatively high recurrence rate of ameloblastoma is influenced by the type of molecular etiological factors, the management approach, and how early the patient presents for treatment. It is expected that further elucidation of molecular factors that orchestrate pathogenesis and recurrence of ameloblastoma will lead to new diagnostic markers and targeted drug therapies for ameloblastoma.     

Statistical profiling of hospital performance using acute coronary syndrome mortality

Background

In order to improve the quality of care delivered to patients and to enable patient choice, public reports comparing hospital performances are routinely published. Robust systems of hospital ‘report cards’ on performance monitoring and evaluation are therefore crucial in medical decision-making processes. In particular, such systems should effectively account for and minimise systematic differences with regard to definitions and data quality, care and treatment quality, and ‘case mix’.

Methods

Four methods for assessing hospital performance on mortality outcome measures were considered. The methods included combinations of Bayesian fixed- and random-effects models, and risk-adjusted mortality rate, and rank-based profiling techniques. The methods were empirically compared using 30-day mortality in patients admitted with acute coronary syndrome. Agreement was firstly assessed using median estimates between risk-adjusted mortality rates for a hospital and between ranks associated with a hospital’s risk-adjusted mortality rates. Secondly, assessment of agreement was based on a classification of hospitals into low, normal or high performing using risk-adjusted mortality rates and ranks.

Results

There was poor agreement between the point estimates of risk-adjusted mortality rates, but better agreement between ranks. However, for categorised performance, the observed agreement between the methods’ classification of the hospital performance ranged from 90 to 98%. In only two of the six possible pair-wise comparisons was agreement reasonable, as reflected by a Kappa statistic; it was 0.71 between the methods of identifying outliers with the fixed-effect model and 0.77 with the hierarchical model. In the remaining four pair-wise comparisons, the agreement was, at best, moderate.

Conclusions

Even though the inconsistencies among the studied methods raise questions about which hospitals performed better or worse than others, it seems that the choice of the definition of outlying performance is less critical than that of the statistical approach. Therefore there is a need to find robust systems of ‘regulation’ or ‘performance monitoring’ that are meaningful to health service practitioners and providers.     

Full-length but not truncated CD34 inhibits hematopoietic cell differentiation of M1 cells

CD34 is expressed on human and murine hematopoietic stem and progenitor cells and its clinical usefulness for isolation of stem/progenitor cells has been well established. Although expression of CD34 is regulated in a developmental stage-specific manner, the function of CD34 is not known. Recently we have shown that both a full-length and truncated form of CD34 protein is expressed by hematopoietic cells (Blood 84:691, 1994). To test whether failure to suppress either form of CD34 could affect terminal myeloid differentiation, we constitutively expressed these CD34 proteins in murine M1 myeloid leukemia cells, which can be terminally differentiated to macrophages by treatment with interleukin-6 of leukemia inhibitory factor. Surprisingly our results show that forced expression of the full-length but not the truncated form of CD34 impedes terminal differentiation by these agents. Because the difference between the two forms of CD34 protein resides in the length of their respective cytoplasmic tail domains, our findings strongly suggest that the cytoplasmic domain region of full-length CD34 is responsible for the observed maturation arrest phenotype. These findings suggest a potential negative regulatory role for full-length CD34 in hematopoietic cell differentiation and may explain, at least in part, the block in maturation observed in CD34+ acute myeloid leukemia.     

The E/e filling index and right ventricular pressure in relation to applied international Doppler recommendations of left ventricular filling assessment.

AIM: A ratio>15 between the early diastolic pulsed Doppler velocities of the mitral inflow (E) and the basal left ventricular (LV) tissue (e) has been demonstrated to predict an elevated LV filling pressure (FP). An elevated LVFP implies an elevated right ventricular pressure (RVp). In order to investigate the sensitivity of the E/e filling index, we compared E/e and RVp, in their ability to identify a Doppler-assumed elevation of LVFP. METHODS AND RESULTS: Application of pulsed Doppler international recommendations grouped 134 patients with acute coronary syndromes (ACS) and 50 age- and sex-matched controls, according to LV filling: normal; delayed relaxation; an isolated pathological mitral-pulmonary venous-A-wave-duration difference; pseudo normal; or a restrictive filling pattern. An E/e>15 and an RVp>30 mmHg showed the following (%) sensitivity (32/94), specificity (95/76), positive (68/59), and negative (80/97) predictive values of a Doppler-assumed elevation of LVFP, in terms of either a pseudo normal or a restrictive filling pattern. CONCLUSION: The low sensitivity of E/e to detect a Doppler-assumed elevation of LVFP could limit its clinical usefulness as a single variable, in ACS. The high sensitivity and negative predictive value of RVp support its use as an additional LV filling variable in these patients.     

Effect of a media campaign on delay times and ambulance use in suspected acute myocardial infarction

Twenty-five patients older than 60 years of age underwent cardiac transplantation using an immunosuppression protocol with cyclosporin and azathioprine, but without routine use of oral steroids. There were 24 men and 1 woman (age range 60 to 69 years, mean 63). The etiology of heart disease was coronary artery disease in 21 and idiopathic dilated cardiomyopathy in 4. Six patients had previous coronary artery bypass operations, 1 had undergone repair of an abdominal aneurysm and 1 had pulmonary embolism. Sixteen patients were in New York Heart Association class IV and 9 in class III. Donor mean age was 30 (14 to 46) years. Hospital stay after transplantation was 10 to 90 days (median 11). Four died within 30 days and none from 5 to 59 months (mean 22). The 1-year actuarial survival was 84%. The incidence of rejection was 2.16 episodes per patient. Only 1 patient (4%) had serious infection. Six patients received antihypertensive treatment, 3 had reversible impairment of renal function, 2 had gout and 1 had drop foot. No patient had convulsions, transient ischemic attack or cerebrovascular accident. None had significant psychological problems. The 21 patients currently alive are in New York Heart Association class I. Quality of life, assessed by the Nottingham Health Profile, showed marked improvement. It is concluded that the initial results of cardiac transplantation in the seventh decade of life are encouraging.     

A controlled double-blind study of high-dose dihydroergotoxine mesylate (Hydergine) in mild dementia

In a double-blind study of 41 outpatients aged 55 to 80 years with mild memory impairment, the efficacy of dihydroergotoxine mesylate (DEM, Hydergine) at 6 mg per day, administered orally, was tested during a twelve-week period. Specific etiologies for the amnesic syndrome were ruled out by history, physical examination, and laboratory tests. Subjects with a Hamilton Depression Scale rating above 18, ie, possible pseudodementia, were excluded. Physician rating of memory, employing the Inventory of Psychic and Somatic Complaints in the Elderly (IPSC-E), indicated statistically significant improvement of memory function in DEM treated subjects (N = 22) v those on placebo (N = 19), (F = 3.34; df = 1,39; P less than .04). In contrast, structured testing of recent memory using digit symbol substitution and Zahlenverbindungs test (ZVT) showed improvement in both groups (P less than .001) with no significant intergroup differences (P less than .10). Out results indicate that in cases of mild, though subjectively distressing impairment, DEM at higher dosages may help to enhance short-term memory function.     

Deleterious effect of brachtherary on vasomotor response to exercise

Background In-stent restenosis(ISR) is one of the major drawbacks of coronary stenting. Intraeoronary radiation therapy (RT)is effective in reducing excessive neointimal proliferation but long term results with regard to vascular integrity and vasomotor responsiveness are largely tmknown. Thus, the present study was to determine the exercise-induced vasomotor response of inadiated coronary arteries.