961 resultados para statistical significance


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OBJECTIVES To assess discrepancies in the analyzed outcomes between protocols and published reviews within Cochrane oral health systematic reviews (COHG) on the Cochrane Database of Systematic Reviews (CDSR). STUDY DESIGN AND SETTING All COHG systematic reviews on the CDSR and the corresponding protocols were retrieved in November 2014 and information on the reported outcomes was recorded. Data was collected at the systematic review level by two reviewers independently. RESULTS One hundred and fifty two reviews were included. In relation to primary outcomes, 11.2% were downgraded to secondary outcomes, 9.9% were omitted altogether in the final publication and new primary outcomes were identified in 18.4% of publications. For secondary outcomes, 2% were upgraded to primary, 12.5% were omitted and 30.9% were newly introduced in the publication. Overall, 45.4% of reviews had at least one discrepancy when compared to the protocol; these were reported in 14.5% reviews. The number of review updates appears to be associated with discrepancies between final review and protocol (OR: 3.18, 95% CI: 1.77, 5.74, p<0.001). The risk of reporting significant results was lower for both downgraded outcomes [RR: 0.52, 95% CI: 0.17, 1.58, p = 0.24] and upgraded or newly introduced outcomes [RR: 0.77, 95% CI: 0.36, 1.64, p = 0.50] compared to outcomes with no discrepancies. The risk of reporting significant results was higher for upgraded or newly introduced outcomes compared to downgraded outcomes (RR = 1.19, 95% CI: 0.65, 2.16, p = 0.57). None of the comparisons reached statistical significance. CONCLUSION While no evidence of selective outcome reporting was found in this study, based on the present analysis of SRs published within COHG systematic reviews, discrepancies between outcomes in pre-published protocols and final reviews continue to be common. Solutions such as the use of standardized outcomes to reduce the prevalence of this issue may need to be explored.

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The rates of childhood and adolescent obesity in the United States have been increasing steadily. American youth continue to eat more (increase energy intake) and reduce physical activity (decrease energy expenditure) resulting in increased body weight and body fatness. One way to help reduce body weight in children is to increase physical activity. The purpose of this study was to determine if an age appropriate before-school physical activity intervention would be successful in increasing energy expenditure, intensity of activity, and behavioral approaches in overweight girls. The subjects were recruited from Parker Memorial School in Tolland, Connecticut, and two testing periods occurred over an eight week period. Video recordings of each physical activity session were analyzed to determine energy expenditure, exercise intensity, and behaviors during exercise. Data was evaluated for normal distribution, and paired t-tests were used to determine statistical significance. This study showed that the age appropriate before school physical activity intervention was able to increase energy expenditure and exercise intensity and have a positive effect on behavioral approaches in overweight girls.

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The Financial Accounting Standards Board (FASB) mandated the expensing of stock options with FAS 123 (R). As of March 2006, 749 companies had accelerated the vesting of their employee stock options and avoided a reduction in their reported profits that otherwise would have occurred under the new standard. There are many different motives for the acceleration strategy, and the focus of this study is to determine whether shareholders viewed these motives as either positive or negative. A favorable return subsequent to an acceleration announcement would signify that shareholder's viewed management's motives as positive. An unfavorable return subsequent to an acceleration announcement would signify that shareholder's viewed management's motives as negative. The evidence from this study suggests that shareholders reacted favorably, on average, to acceleration announcements. However, these results lack statistical significance and are based on a small sample, thus, they should be interpreted with caution.

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Although Pap screening has decreased morbidity and mortality from cervical cancer, reported statistics indicate that among ethnic groups, Hispanic women are one of the least likely to follow screening guidelines. Human papillomavirus (HPV), a major risk factor for cervical cancer, as well as pre-cancerous lesions, may be detected by early Pap screening. With a reported 43% prevalence of HPV infection in college women, regular Pap screening is important. The purpose of this descriptive, cross-sectional survey was to examine self-reported cervical cancer screening rates in a target population of primarily Mexican-American college women, and to discover if recognized correlates for screening behavior explained differences in screening rates between this and two other predominant groups on the University of Houston Downtown campus, non-Hispanic white and African-American. The sample size consisted of 613 women recruited from summer 2003 classes. A survey, adapted from an earlier El Paso study, and based on constructs of the Health Belief Model (HBM), was administered to women ages 18 and older. It was found that although screening rates were similar across ethnic groups, overall, the Hispanic group obtained screening less frequently, though this did not reach statistical significance. However, a significant difference in lower screening rates was found in Mexican American women ages <25. Additionally, of the predicted correlates, the construct of perceived barriers from the HBM was most significant for the Mexican American group for non-screening. For all groups, knowledge about cervical cancer was negatively correlated with ever obtaining Pap screening and screening within the past year. This implies that if health counseling is given at the time of women's screening visits, both adherence to appropriate screening intervals and risk factor avoidance may be more likely. Studies such as these are needed to address both screening behaviors and likelihood of follow-up for abnormal results in populations of multicultural, urban college women. ^

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The purpose of this research was to determine if principles from organizational theory could be used as a framework to compare and contrast safety interventions developed by for-profit industry for the time period 1986–1996. A literature search of electronic databases and manual search of journals and local university libraries' book stacks was conducted for safety interventions developed by for-profit businesses. To maintain a constant regulatory environment, the business sectors of nuclear power, aviation and non-profits were excluded. Safety intervention evaluations were screened for scientific merit. Leavitt's model from organization theory was updated to include safety climate and renamed the Updated Leavitt's Model. In all, 8000 safety citations were retrieved, 525 met the inclusion criteria, 255 met the organizational safety intervention criteria, and 50 met the scientific merit criteria. Most came from non-public health journals. These 50 were categorized by the Updated Leavitt's Model according to where within the organizational structure the intervention took place. Evidence tables were constructed for descriptive comparison. The interventions clustered in the areas of social structure, safety climate, the interaction between social structure and participants, and the interaction between technology and participants. No interventions were found in the interactions between social structure and technology, goals and technology, or participants and goals. Despite the scientific merit criteria, many still had significant study design weaknesses. Five interventions tested for statistical significance but none of the interventions commented on the power of their study. Empiric studies based on safety climate theorems had the most rigorous designs. There was an attempt in these studies to address randomization amongst subjects to avoid bias. This work highlights the utility of using the Updated Leavitt's Model, a model from organizational theory, as a framework when comparing safety interventions. This work also highlights the need for better study design of future trials of safety interventions. ^

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This paper investigates the effects on open-seat races in the United States House of Representatives. This project focuses on the influence that the House leadership exerts on races. Generally, the leadership influences race through spending by party organizations and leadership visits. During each election cycle, national party organizations spend millions of dollars to get their candidates into office. I have developed a multiple regression model that measures different types of spending from the Democratic Congressional Campaign Committee, the National Republican Congressional Committee, and the Republican National Committee and the effects of these spending types on the election results. Also, the study examines the number of visits by each party’s leadership to each race. I introduced control variables that account for the year, the competitiveness of each race, and the individual candidate fundraising. In terms of statistical significance, the results were mixed showing one type of party spending to be highly influential in the outcome of the race. Competitiveness and individual candidate fundraising also achieved statistical significance. The study also includes a qualitative investigation of leadership visits and individual case studies in order to understand better the way in which the data interact in real campaigns.

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The objectives of this study were to investigate the relationship between fasting serum insulin levels and Acanthosis Nigricans (AN) (a dermatological condition characterized by hyperpigmentation and thickening of the skin in specific body areas such as the neck and knuckles) and obesity among 6 to 9 year old children. Children were selected at random from a pediatric clinic located on the U.S.-Mexico border. Because none of the children participants had a weight for height at or above the 97th percentile of the CDC growth charts, obesity was defined as weight for height at or above the 95th percentile and at risk of overweight between the 85 th and 95th percentiles of the CDC growth charts. Anthropometrics, blood samples for fasting serum insulin and blood glucose, and a picture of the neck were obtained at baseline (n = 85) and 6 months later (n = 49). None of the children partipating had high fasting serum insulin levels and only 2 children had AN degree 2 (moderately severe). At baseline children with a weight for height at or above the 95th, percentile had 15 units less of insulin than children who weighed less. However, 6 months later this was not confirmed, thus the baseline result is considered to be an anomaly. Eventhough statistical significance was not reached, results showed that children without AN had 5 percentiles lower weight for height than children with AN. The most important recommendation from this study is the need to monitor longitudinal growth in children to characterize the individual child's growth pattern. AN seems to be related to longitudinal growth changes. ^

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Type II diabetes mellitus is a growing problem worldwide and although its association with increased cardiovascular morbidity and mortality is well known, its role in the development of cancer is now being further elucidated. Recently, there has been increasing evidence that not only are diabetics more susceptible towards development of particular types of cancer, but also have worse oncologic outcomes. This retrospective chart review investigates whether diabetics with colon cancer have a poorer prognosis than their nondiabetic counterparts. Patients with high risk Stage II and Stage III colon cancer who were diagnosed and/or treated at The University of Texas M.D. Anderson Cancer Center from 1/1/2000 till 12/1/2004 were included in our study. We carried out a survival analysis using Kaplan-Meier method and multivariable analysis to assess differences in outcomes of the two population groups. We found that the decreased overall survival in diabetics did not reach statistical significance but this could be due to a lower event rate in our study. Larger studies are required to investigate this further. ^

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Cardiovascular disease has been the leading cause of death in the United States for over fifty years. While multiple risk factors for cardiovascular disease have been identified, hypertension is one of the most commonly recognized and treatable. Recent studies indicate that the prevalence of hypertension among children and adolescents is between 3-5%, much higher than originally estimated and likely rising due to the epidemic of obesity in the U.S. In 2004, the National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents published new guidelines for the diagnosis and treatment of hypertension in this population. Included in these recommendations was the creation of a new diagnosis, pre-hypertension, aimed at identifying children at-risk for hypertension to provide early lifestyle interventions in an effort to prevent its ultimate development. In order to determine the risk associated with pre-hypertension for the development of incident HTN, a secondary analysis of a repeated cross-sectional study measuring blood pressure in Houston area adolescents from 2000 to 2007 was performed. Of 1006 students participating in the blood pressure screening on more than one occasion not diagnosed with hypertension at initial encounter, eleven were later found to have hypertension providing an overall incident rate of 0.5% per year. Incidence rates were higher among overweight adolescents–1.9% per year [IRR 8.6 (1.97, 51.63)]; students “at-risk for hypertension” (pre-hypertensive or initial blood pressure in the hypertensive range but falling on subsequent measures)–1.4% per year [IRR 4.77 (1.21, 19.78)]; and those with blood pressure ≥90th percentile on three occasions–6.6% per year [IRR 21.87 (3.40, 112.40)]. Students with pre-hypertension as currently defined by the Task Force did have an increased rate of hypertension (1.1% per year) but it did not reach statistical significance [IRR 2.44 (0.42, 10.18)]. Further research is needed to determine the morbidity and mortality associated with pre-hypertension in this age group as well as the effectiveness of various interventions for preventing the development of hypertensive disease among these at-risk individuals. ^

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Background. Each year thousands of people participate in mass health screenings for diabetes and hypertension, but little is known about whether or not those who receive higher than normal screening results obtain the recommended follow-up medical care, or what barriers they perceive to doing so. ^ Methods. Study participants were recruited from attendees at three health fairs in low-income neighborhoods in Houston, Texas Potential participants had higher than normal blood pressure (> 90/140 mgHg) or blood glucose readings (100 mm/dL fasting or 140 mm/dL random). Study participants were called at one, two, and three months and asked if they had obtained follow-up medical care; those who had not yet obtained follow-up care were asked to identify barriers. Using a modified Aday-Andersen model of health service access, the independent variables were individual and community characteristics and self-perceived need. The dependent variable was obtaining follow-up care, with barriers to care a secondary outcome. ^ Results. Eighty-two study participants completed the initial questionnaire and 59 participants completed the study protocol. Forty-eight participants (59% under an intent to treat analysis, 81% of those completing the study protocol) obtained follow-up care. Those who completed the initial questionnaire and who reported a regular source of care were significantly more likely to obtain follow-up care. For those who completed the study protocol the relationship between having a regular source of care and obtaining follow-up care approached but did not reach significance. For those who completed the initial questionnaire, self-described health status, when examined as a binary variable (good, very good, excellent, or poor, fair, not sure) was associated with obtaining follow-up care for those who rated their health as poor, fair, or not sure. While the group who completed the study protocol did not reach statistical significance, the same relationship between self-described health status of poor, fair, or not sure and obtaining follow-up care was present. The participants who completed the study protocol and described their blood pressure as OK or a little high were statistically more likely to get follow-up care than those who described it as high or very high. All those on oral medications for hypertension (12/12) and diabetes (4/4) who were told to obtain follow-up care did so; however, the small sample size allows this correlation to be of statistical significance only for those treating hypertension. ^ The variables significantly associated with obtaining follow-up care were having a regular source of care, self-described health status of poor, fair, or not sure, self-described blood pressure of OK or a little high, and taking medication for blood pressure. ^ At the follow-up telephone calls, 34 participants identified barriers to care; cost was a significant barrier reported by 16 participants, and 10 reported that they didn’t have time because they were working long hours after Hurricane Ike. ^ The study included the offer of access assistance: information about nearby safety-net providers, a visit to or information from the Health Information Center at their Neighborhood Center location, or information from Project Safety Net (a searchable web site for safety net providers). Access assistance was offered at the health fairs and then again at follow-up telephone calls to those who had not yet obtained follow-up care. Of the 48 participants who reported obtaining follow-up care, 26 said they had made use of the access assistance to do so. The use of access assistance was associated with being Hispanic, not having health insurance or a regular source of care, and speaking Spanish. It was also associated with being worried about blood glucose. ^ Conclusion. Access assistance, as a community enabling characteristic, may be useful in aiding low-income people in obtaining medical care. ^

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Background. Cardiovascular disease (CVD) exhibits the most striking public health significance due to its high prevalence and mortality as well as huge economic burdens all over the world, especially in industrialized countries. Major risk factors of CVDs have been the targets of population-wide prevention in the United States. Economic evaluations provide structured information in regard to the efficiency of resource utilization which can inform decisions of resource allocation. The main purpose of this review is to investigate the pattern of study design of economic evaluations for interventions of CVDs. ^ Methods. Primary journal articles published during 2003-2008 were systematically retrieved via relevant keywords from Medline, NHS Economic Evaluation Database (NHS EED) and EBSCO Academic Search Complete. Only full economic evaluations for narrowly defined CVD interventions were included for this review. The methodological data of interest were extracted from the eligible articles and reorganized in Microsoft Access database. Chi-square tests in SPSS were used to analyze the associations between pairs of categorical data. ^ Results. One hundred and twenty eligible articles were reviewed after two steps of literature selection with explicit inclusion and exclusion criteria. Descriptive statistics were reported regarding the evaluated interventions, outcome measures, unit costing and cost reports. The chi-square test of the association between prevention level of intervention and category of time horizon showed no statistical significance. The chi-square test showed that sponsor type was significantly associated with whether new or standard intervention being concluded as more cost effective. ^ Conclusions. Tertiary prevention and medication interventions are the major interests for economic evaluators. The majority of the evaluations were claimed from either a provider’s or a payer’s perspective. Almost all evaluations adopted gross costing strategy for unit cost data rather than micro costing. EQ-5D is the most commonly used instrument for subjective outcome measurement. More than half of the evaluations used decision analytic modeling techniques. The lack of consistency in study design standards in published evaluations appears in several aspects. Prevention level of intervention is not likely to be a factor for evaluators to decide whether to design an evaluation in a lifetime horizon or not. Published evaluations sponsored by industry are more likely to conclude that new intervention is more cost effective than standard intervention.^

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The purpose of this study was to exam the relationship between internet use and depression among a population of individuals who have sustained spinal cord injury. This was cross-sectional survey design conducted among spinal cord injury (SCI) patients in the Model Spinal Cord Injury System. We included a total of 1,011 SCI-patients who were interviewed face-to-face or by telephone interview over approximately a three year time period (2004–2006). All data were collected through a telephone survey which included the Patient Health Questionnaire-9 (PHQ-9) to assess depression. We examined various scales of this survey, included a reduced 3-item scale (items 1, 2 and 6) to avoid the presence of somatic symptoms among SCI patients from influencing classification of depression. The frequency of internet usage was grouped as daily/weekly/monthly/non user. Covariates examined as possible confounders included demographic characteristics, occupational status, educational level, injury type, daily function of living, pain level, self-perceived health status and satisfaction with life. We observed a negative association between the frequency of internet use and the level of depression. Daily use of internet was associated with lower PHQ-9 score and depression; however this association did not reach statistical significance after for the mentioned covariates. In conclusion, the factors related to lower depression in SCI patients who use the internet are complicated. Daily internet usage was associated with lower levels of depression. The accuracy of 3-item scale needs further validation and investigation. Further study of internet usage pattern in SCI patient is recommended. ^

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Trauma is a leading cause of death worldwide, and is thus a major public health concern. Improving current resuscitation strategies may help to reduce morbidity and mortality from trauma, and clinical research plays an important role in addressing these issues. This thesis is a secondary analysis of data that was collected for a randomized clinical trial being conducted at Ben Taub General Hospital. The trial is designed to compare a hypotensive resuscitation strategy to standard fluid resuscitation for the early treatment of trauma patients in hemorrhagic shock. This thesis examines the clinical outcomes from the first 90 subjects enrolled in the study, with the primary aim of assessing the safety of hypotensive resuscitation within the trauma population. ^ Patients in hemorrhagic shock who required emergent surgery were randomized to one of two arms of the study. Those in the experimental (LMAP) arm were managed with a hypotensive resuscitation strategy in which the target mean arterial pressure was 50mmHg. Those in the control (HMAP) arm were managed with standard fluid resuscitation to a target mean arterial pressure of 65mmHg. Patients were followed for 30 days. Mortality, post-operative complications, and other clinical data were prospectively gathered by the Ben Taub surgical staff and then secondarily analyzed for the purpose of this thesis.^ Subjects in the LMAP group had significantly lower early post-operative mortality compared to those in the HMAP group. 30-day mortality was also lower in the LMAP group, although this did not reach statistical significance. There were no statistically significant differences between the two groups with regards to development of ischemic, hematologic or infectious complications, length of hospitalization, length of ICU stay or duration of mechanical ventilation. ^ Based upon the data presented in this thesis, it appears that hypotensive resuscitation is a safe strategy for use in the trauma population. Specifically, hypotensive resuscitation reduced the risk of early post-operative death from coagulopathic bleeding and did not result in an increased risk of ischemic or other post-operative complications. The preliminary results described in this thesis provide convincing evidence support the continued investigation and use of hypotensive resuscitation in a trauma setting.^

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Coronary artery disease (CAD) is the most common cause of morbidity and mortality in the United States. While Coronary Angiography (CA) is the gold standard test to investigate coronary artery disease, Prospective gated-64 Slice Computed Tomography (Prosp-64CT) is a new non-invasive technology that uses the 64Slice computed tomography (64CT) with electrocardiographic gating to investigate coronary artery disease. The aim of the current study was to investigate the role of Body Mass Index (BMI) as a factor affecting occurrence of CA after a Prosp-64CT, as well as the quality of the Prosp-64CT. Demographic and clinical characteristics of the study population were described. A secondary analysis of data on patients who underwent a Prosp-64CT for evaluation of coronary artery disease was performed. Seventy seven patients who underwent Prosp-64CT for evaluation for coronary artery disease were included. Fifteen patients were excluded because they had missing data regarding BMI, quality of the Prosp-64CT or CA. Thus, a total of 62 patients were included in the final analysis. The mean age was 56.2 years. The mean BMI was 31.3 kg/m 2. Eight (13%) patients underwent a CA within one month of Prosp-64CT. Eight (13%) patients had a poor quality Prosp-64CT. There was significant association of higher BMI as a factor for occurrence of CA post Prosp-64CT (P<0.05). There was a trend, but no statistical significance was observed for the association of being obese and occurrence of CA (P=0.06). BMI, as well as obesity, were not found to be significantly associated with poor quality of Prosp-64CT (P=0.19 and P=0.76, respectively). In conclusion, BMI was significantly associated with occurrence of CA within one month of Prosp-64CT. Thus, in patients with a higher BMI, diagnostic investigation with both tests could be avoided; rather, only a CA could be performed. However, the relationship of BMI to quality of Prosp-64CT needs to be further investigated since the sample size of the current study was small.^

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Baseline elevation of troponin I (TnI) has been associated with worse outcomes in heart failure (HF). However, the prevalence of persistent TnI elevation and its association with clinical outcomes has not been well described. HF is a major public health issue due to its wide prevalence and prognosticators of this condition will have a significant impact on public health. Methods: A retrospective study was performed in 510 patients with an initial HF admission between 2002 to 2004, and all subsequent hospital admissions up to May 2009 were recorded in a de-identified database. Persistent TnI elevation was defined as a level ≥0.05 ng/ml on ≥3 HF admissions. Baseline characteristics, hospital readmissions and all cause mortality were compared between patients with persistent TnI elevation (Persistent), patients with no persistence of TnI (Nonpersistent) and patients who had less than three hospital admissions (admission <3) groups. Also the same data was analyzed using the mean method in which the mean value of all recorded troponin values of each patient was used to define persistence i.e. patients who had a mean troponin level ≥0.05 ng/ml were classified as persistent. Results: Mean age of our cohort was 68.4 years out of which 99.6% subjects were male, 62.4% had ischemic HF. 78.2% had NYHA class III to IV HF, mean LVEF was 25.9%. Persistent elevation of TnI was seen in 26% of the cohort and in 66% of patients with more than 3 hospital admissions. Mean TnI level was 0.67 ± 0.15 ng/ml in the 'Persistent' group. Mean TnI using the mean method was 1.11 ± 7.25 ng/ml. LVEF was significantly lower in persistent group. Hypertension, diabetes, chronic renal insufficiency and mean age did not differ between the two groups. 'Persistent' patients had higher mortality (HR = 1.26, 95% CI = 0.89–1.78, p = 0.199 when unadjusted and HR = 1.29, 95% CI = 0.89–1.86, p = 0.176 when adjusted for race, LVEF and ischemic etiology) HR for mortality in persistent patients was 1.99 (95% CI = 1.06–3.73, p = 0.03) using the mean method. The following results were found in those with ischemic cardiomyopathy (HR = 1.44034, 95% CI = 0.92–2.26, p = 0.113) and (HR = 1.89, 95% CI = 1.01–3.55, p = 0.046) by using the mean method. 2 out of three patients with HF who were readmitted three or more times had persistent elevation of troponin I levels. Patients with chronic persistence of troponin I elevation showed a trend towards lesser survival as compared to patients who did not have chronic persistence, however this did not reach statistical significance. This trend was seen more among ischemic patients than non ischemic patients, but did not reach statistical significance. With the mean method, patients with chronic persistence of troponin I elevation had significantly lesser survival than those without it. Also ischemic patients had significantly lesser survival than non ischemic patients. ^