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At least 919 records · Page 51Linked to original sources
PubMed1989

Outcome of pregnancies complicated by severe hypertension and delivered before 34 weeks; stepwise logistic regression analysis of prognostic factors.

The outcome is described for 106 patients with severe hypertension in pregnancy requiring delivery between 26 and 34 weeks. Management was with methyldopa, hydralazine when required and delivery by caesarean section when indicated. Most patients were delivered for cardiotocographic fetal distress or unstable maternal blood pressure. Eighty-five babies (80%) survived and were well at follow-up at 1 year; the perinatal mortality was 123/1000 total births. One patient had postpartum eclampsia, one had pulmonary oedema and one had transient renal failure, but all mothers left hospital well. Stepwise logistic regression analysis showed that the primary positive factor for survival of a healthy baby was gestational age, which was strongly correlated with birthweight. The need for caesarean section as an emergency, hypotension after parenteral hydralazine, intrauterine growth retardation, and severe proteinuria were adverse factors. Intraventricular haemorrhage had a major adverse effect on neonatal survival; it was predisposed to by prolonged maternal hypertension and by low gestational age.

Adult↗
PubMed1975

Use of the logistic function for the calculation of dose-ratios and potency ratios.

1 Dose-ratios and potency ratios, obtained with the guinea-pig isolated ileum by calculating matching concentrations from a least-squares fit using a logistic relationship between response and dose, differ from those obtained with the more usual assumption that response is a linear function of log dose over a limited range. 2 The differences are not due to the mathematical treatment of the results but arise from changes in sensitivity associated with the production of very high or very low responses. 3 With this preparation there is no advantage in avoiding the linear transformation and fitting the results to the complete dose-response curve though this might not apply to results obtained from other tissues with less variable sensitivity.

Animals↗
PubMed1981

The Hamilton depression scale. Evaluation of objectivity using logistic models.

The consistency of the Hamilton Depression Scale (HDS) as a measure of the severity of depressive states has been examined when the scale was used weekly during a trial when imipramine. By use of logistic models (Rasch) the consistency of the HDS has been considered across patient-variables as age, sex, plasma levels of imipramine, and diagnosis. The results showed that the original 17-item HDS was without adequate consistency, i.e. the total score of the sample of items was no one-dimensional measure of depressive states. However, a melancholia subscale of the HDS contained items the total of which can be used to compare patients quantitatively, although in some part of the analysis one of these items showed ceiling effect. It was concluded that the melancholia subscale (containing the items depressed mood, guilt, work and interests, retardation, psychic anxiety, and general somatic symptoms) can form the basis for further improvements in the field of quantitative rating scales for depressive states.

Adult↗
PubMed1985

Increasing the sensitivity of caries clinical trials by applying logistic modelling to specific teeth.

An alternative statistical approach is proposed for analysing data from longitudinal clinical trials. Caries increments on those teeth which are known to be particularly susceptible to caries for the population under study are represented by a linear logistic probability model. Expression of the caries increments in the form of a probability model should lead to a better understanding of the relative importance of the various factors which contribute to the caries increment in the population under study. When this model was applied to caries increments on the permanent second molars of children aged 11-13 yr at the baseline of two 3-yr trials, the sensitivity of statistical analysis was up to five times greater than that obtained with traditional statistical methods.

Child↗
PubMed2006

Logistic, additive or historical: is EuroSCORE an appropriate model for comparing individual surgeons' performance?

Both versions of the EuroSCORE, the complex logistic and the simpler additive, have been used for comparing institutional performance, but they are no longer robust enough to be used for comparing individual surgeons. It is now time to tighten the standard and add additional data to obtain a more holistic picture of the quality of cardiac surgical care in the UK.

Clinical Competence↗
PubMed1997

Estimating effectiveness of cardiac arrest interventions: a logistic regression survival model.

BACKGROUND: The study objective was to develop a simple, generalizable predictive model for survival after out-of-hospital cardiac arrest due to ventricular fibrillation. METHODS AND RESULTS: Logistic regression analysis of two retrospective series (n=205 and n=1667, respectively) of out-of-hospital cardiac arrests was performed on data sets from a Southwestern city (population, 415,000; area, 406 km2) and a Northwestern county (population, 1,038,000; area, 1399 km2). Both are served by similar two-tiered emergency response systems. All arrests were witnessed and occurred before the arrival of emergency responders, and the initial cardiac rhythm observed was ventricular fibrillation. The main outcome measure was survival to hospital discharge. Patient age, initiation of CPR by bystanders, interval from collapse to CPR, interval from collapse to defibrillation, bystander CPR/collapse-to-CPR interval interaction, and collapse-to-CPR/collapse-to-defibrillation interval interaction were significantly associated with survival. There was not a significant difference between observed survival rates at the two sites after control for significant predictors. A simplified predictive model retaining only collapse to CPR and collapse to defibrillation intervals performed comparably to the more complicated explanatory model. CONCLUSIONS: The effectiveness of prehospital interventions for out-of-hospital cardiac arrest may be estimated from their influence on collapse to CPR and collapse to defibrillation intervals. A model derived from combined data from two geographically distinct populations did not identify site as a predictor of survival if clinically relevant predictor variables were controlled for. This model can be generalized to other US populations and used to project the local effectiveness of interventions to improve cardiac arrest survival.

Adolescent↗
PubMed2000

Predictors of late asthmatic response. Logistic regression and classification tree analyses.

To identify predictors of the late asthmatic response (LAR), we reviewed data from 60 asthmatic subjects who had undergone allergen challenge over the past 5 yr (33 females, age 31.4 +/- 6.7 yr [mean +/- SD], FEV(1) 90% +/- 14% predicted). Variables considered likely predictors of LAR included baseline FEV(1), PC(20) methacholine (PC(20)), sputum eosinophil percent, and the decrease in FEV(1) within 20 min of allergen challenge. A LAR (FEV(1) >/= 15% fall between 3 and 7 h after challenge) was documented in 57% of subjects. A variety of logistic regression methods revealed a significant inverse association between LAR and PC(20) (odds ratio [OR] = 0.14 [95% CI = 0.03-0.66]) and a positive association between LAR and the decrease in FEV(1) at 20 min (OR = 1.18 [1.04 -1.33]). Classification tree analysis revealed that a threshold of 0.25 mg/ml for PC(20) was most predictive of LAR; LAR developed in 87% of those with PC(20) </= 0.25 mg/ml (n = 23) and in 38% of those with PC(20) > 0.25 mg/ml (n = 37). Notably, in subjects with PC(20) > 0.25 mg/ml, the incidence of LAR increased from 38% to 57% if the allergen-induced decline in FEV(1) at 20 min was >/= 27%. Surprisingly, baseline FEV(1) and percent eosinophils in induced sputum were not significantly associated with LAR. We conclude that a threshold value of 0.25 mg/ml for PC(20) methacholine is a good predictor of LAR. Measuring the PC(20) methacholine may be useful as a screening method to improve the efficiency of identifying asthmatic subjects with a LAR.

Asthma↗
PubMed2001

Clinical logistics in treadmill exercise stress testing.

The predictability as to a positive or negative outcome of treadmill exercise stress testing in 341 consecutively studied patients referred for diagnostic purposes is presented. A clinical decision as to the result was derived by asking 2 simple questions and reviewing the pretest ECG. Additional clinical logistics included the type of physician ordering the study, smoking history, symptoms, and basic patient history. The predictable accuracy was 77.7% for the total patient group and 81.5% when the questionable cases (reflecting a neutral or ambivalent cardiologist's opinion) were eliminated.

Adult↗
PubMed1994

Predictors of employment status of treated patients with DSM-III-R diagnosis. Can logistic regression model find a solution?

To investigate the predictors of employment status of patients with DSM-III-R diagnosis, 55 patients were selected by a simple random technique from the main psychiatric clinic in Al Ain, United Arab Emirates. Structured and formal assessments were carried out to extract the potential predictors of outcome of schizophrenia. Logistic regression model revealed that being married, absence of schizoid personality, free or with minimum symptoms of the illness, later age of onset, and higher educational attainment were the most significant predictors of employment outcome. The implications of the results of this study are discussed in the text.

Adolescent↗
PubMed2003

Logistic issues and potential prescribing costs associated with use of neuraminidase inhibitors for the treatment of influenza in primary care.

In the UK, the National Institute for Clinical Excellence has recommended the use of neuraminidase inhibitors for elderly and at-risk patients who present with influenza-like illness within 36 hours of symptom onset. However, few data exist to enable primary care trusts to evaluate the logistics and costs of prescribing. We sought to determine, during a confirmed influenza outbreak, the proportion of eligible patients who currently present in time to benefit from treatment with a neuraminidase inhibitor, and to develop the findings into a model for evaluating potential prescribing costs. Within a single primary care group, demographic and co-morbidity data were collected on all patients consulting their general practitioner or attending an out-of-hours centre with influenza-like illness during the outbreak period. A typical primary care trust serving 100 000 patients might expect to prescribe a neuraminidase inhibitor to 140 eligible at-risk patients in a season of low influenza activity, rising to 300 in a large epidemic. At-risk patients were more likely than non-at-risk patients to consult within 36 hours of the onset of symptoms. However, only 20% of such patients, rising to 47% in out-of-hours centres, consulted in time to benefit from treatment. The low proportion of elderly and at-risk patients who consult their general practitioner in time to benefit from treatment with a neuraminidase inhibitor emphasizes the overriding importance of annual vaccination in these groups. If the full benefits of neuraminidase inhibitors are to be realized, access to treatment for eligible patients must be improved.

Acetamides↗
PubMed2006

Identifying patients at high risk of emergency hospital admissions: a logistic regression analysis.

OBJECTIVE: To use routine data to identify patients at high risk of future emergency hospital admissions. DESIGN: Descriptive analysis of inpatient hospital episode statistics. Predictive model developed using multiple logistic regression. SETTING: National Health Service hospital trusts in England. PARTICIPANTS: All patients with an emergency admission to an NHS hospital between 1 April 2000 and 31 March 2001. MAIN OUTCOME MEASURES: 'High-impact users' were defined as patients who had at least one emergency inpatient admission and who then went on to have at least two further emergency hospital admissions in the 12 months following the start date of that index admission. RESULTS: 2,895,234 patients were admitted as emergencies in 2000/2001, of whom 147,725 (5.1%) did not survive their first spell. Of the 2,747,509 surviving patients, 269,686 (9.8%) subsequently had at least two or more emergency admissions within 365 days of the index date of admission. A further 236,779 (8.6%) died during this period. Risk factors for becoming a high-impact user included the number of emergencies in the 36 months before index spell, comorbidity, age, an admission for an ambulatory care sensitive condition, ethnicity, area-level socioeconomic data, local admission rates, the number of episodes in the index spell, sex and the source of admission. The predictive model based on all emergency admissions produced a receiver operating characteristic curve score of 0.72. CONCLUSIONS: Routine hospital episode statistics can be used to identify patients who are at high risk of suffering future multiple emergency hospital admissions. The potential cost savings in preventing a proportion of these subsequent admissions need to be compared with the costs of case management of these patients.

Adolescent↗
PubMedDate not supplied

Home parenteral nutrition: a hospital-based program with commercial logistic support.

Since home parenteral nutrition was introduced in the 1970's, a number of medical centers have formed successful home parenteral nutrition programs which have reduced expenses to the patient and third party payers by 50 to 73% over in hospital costs. However, the cost of maintaining these programs for training and follow-up has largely been absorbed by the hospital as a nonreimbursable teaching expense. To offset the costs of our growing program in these times of budget "caps," we have established an agreement between our hospital and commercial home care company which provides for patient instruction and follow-up by the hospital parenteral and enteral nutrition team and logistic support by the home care company. We used the average cost of our first five patients to establish a fee schedule which the commercial company agreed to pay the hospital parenteral and enteral nutrition team for its services. This agreement reduces the number of nurses and pharmacists that the commercial company would otherwise have to hire for teaching and follow-up of home care patients, and supports the concept of regional care in medical centers where parenteral and enteral nutrition teams maintain quality control, continuity of care, and efficient teaching programs for patients requiring home parenteral nutrition.

Delivery of Health Care↗
PubMedDate not supplied

ROC curves and the areas under them for dichotomized tests: empirical findings for logistically and normally distributed diagnostic test results.

Many measures, including sensitivity and specificity, predictive values, and likelihood ratios, are available for the assessment of diagnostic tests. A drawback of the use of these measures is that continuous test results are often dichotomized, with consequent loss of information. Receiver operating characteristic (ROC) curves do not depend on discrimination thresholds, and therefore the area under the ROC curve (AUC) is one of the preferred measures. Although quantitative test results are often presented dichotomized, it would be convenient still to be able to estimate the ROC curve and the AUC. The authors present equations for such estimates when only one pair of a true- and a false-positive rate is given, for inherently logistically and normally distributed data. Illustrative empirical data are provided for both distributions. In contradiction to earlier reports, the authors also show that differential disease verification may skew the ROC curve. The ROC curve is thus not invariant to selection bias.

Bayes Theorem↗
PubMed2004

Phoning logistics in a longitudinal follow-up of batterers and their partners.

More needs to be known about the phoning logistics of interviewing subjects for longitudinal follow-up studies in the domestic violence field. Using phoning logs from a 4-year follow-up of batterer intervention, the authors calculated the number, results, and costs of phone calls from a subsample of 100 men and 138 women. The number of calls is high (5.5 per man and 7.1 per woman), locators play a substantial role (for 25% of the men and women), and mailed questionnaires are a useful supplement (increasing response rate 5% for men and 11% for women). On average, about half of the subjects were interviewed at each interval. The main obstacle is not refusals but no response and not being able to locate a subject. Strategies to address "no response" are considered.

Adult↗
PubMed1994

Omnibus Budget Reconciliation Act of 1990 and voluntarism: logistic regression analysis of pharmacist responsibility.

OBJECTIVE: To examine the relationship between pharmacists' willingness to assume further professional responsibilities, as measured by attitudes to the Omnibus Budget Reconciliation Act of 1990 (OBRA '90) requirements, and their attitudes toward voluntarism as their responsibility to society and their level of interest in their jobs. DESIGN: A survey was distributed to a convenience sample of 443 pharmacists who were asked to indicate their responses on a number of items. SETTING: Surveys were distributed to participants in an annual pharmacy continuing education program. PARTICIPANTS: The response rate was 65 percent with completed surveys from 290 Florida pharmacists who were typically male (73 percent) and practicing in the community setting (39 percent) for over 25 years (33 percent). MAIN OUTCOMES: Questions were aimed at gathering the following information: (1) demographics; (2) attitudes concerning the benefits of the three OBRA '90 requirements: patient counseling, prospective drug-use review (DUR), and information recording; (3) attitudes toward voluntarism; and (4) job interest. RESULTS: Pharmacists tended to agree that all three of the OBRA '90 mandates will be beneficial. Fifty-six percent favored the prospective DUR requirements, while 68 percent favored the patient counseling requirements and 66 percent favored the information-recording requirements. Logistic regression analysis showed that unit increases in scaled responses, indicating more favorable attitudes toward believing that voluntarism was one's responsibility, increased the odds of favoring counseling by 38.7 percent and information recording by 32.4 percent. A similar directional relationship was found for the DUR requirement. Job interest did not add to the predictive ability of the variables already in the models. CONCLUSIONS: This study suggests a possible association between pharmacists' attitudes toward social responsibility and their acceptance of expanded professional responsibility.

Attitude of Health Personnel↗
PubMed2003

Endovascular repair of ruptured abdominal aortic aneurysms: logistics and short-term results.

PURPOSE: To report our experience in establishing a treatment protocol for endovascular aneurysm repair (EVAR) of ruptured abdominal aortic aneurysms (rAAA), including an investigation of the reasons for patient exclusion and a report of our short-term results. METHODS: Between 1997 and July 2002, 21 patients with rAAA underwent endovascular repair according to our protocol and were followed prospectively. A retrospective analysis was also conducted of 23 rAAA patients treated with open repair from January 2001 through June 2002. Procedural and clinical data from this sample were compared to 14 contemporaneous emergent EVAR cases and analyzed to determine why the open repair patients were not treated with an endovascular approach. RESULTS: Among the 21 patients treated with emergent EVAR since the beginning of this protocol, 6 (29%) procedures were performed under local anesthesia and 6 were performed percutaneously. Thirty-day mortality was 19%. In the comparison of 14 emergent EVAR cases to 23 open rAAA repairs, the mean duration of symptoms prior to intervention was 12 hours for the EVAR patients and <1 hour for OR patients. No significant difference was found in operating time, but the EVAR group had significantly less blood loss (p=0.0001) and transfusion needs (p=0.02); duration of intensive care unit stay was significantly shorter in the EVAR group (p=0.02). Thirty-day mortality was 29% (4/14) for EVAR and 35% for OR (8/23) (p>0.05). Reasons for not performing EVAR were unavailability of adequate equipment (n=11) or trained staff (n=7), hemodynamically unstable patient (n=2), mycotic aneurysm (n=2), and unfavorable anatomy in a 60-year old patient with a <5-mm-long, sharply angled infrarenal neck. CONCLUSIONS: Endovascular repair of ruptured aortic aneurysms is feasible, and short-term results are promising. Good logistics, adequate training of physicians and staff in an elective setting, and versatile endografts are prerequisites for this type of treatment program.

Aged↗
PubMed2004

Logistics of community smallpox control through contact tracing and ring vaccination: a stochastic network model.

BACKGROUND: Previous smallpox ring vaccination models based on contact tracing over a network suggest that ring vaccination would be effective, but have not explicitly included response logistics and limited numbers of vaccinators. METHODS: We developed a continuous-time stochastic simulation of smallpox transmission, including network structure, post-exposure vaccination, vaccination of contacts of contacts, limited response capacity, heterogeneity in symptoms and infectiousness, vaccination prior to the discontinuation of routine vaccination, more rapid diagnosis due to public awareness, surveillance of asymptomatic contacts, and isolation of cases. RESULTS: We found that even in cases of very rapidly spreading smallpox, ring vaccination (when coupled with surveillance) is sufficient in most cases to eliminate smallpox quickly, assuming that 95% of household contacts are traced, 80% of workplace or social contacts are traced, and no casual contacts are traced, and that in most cases the ability to trace 1-5 individuals per day per index case is sufficient. If smallpox is assumed to be transmitted very quickly to contacts, it may at times escape containment by ring vaccination, but could be controlled in these circumstances by mass vaccination. CONCLUSIONS: Small introductions of smallpox are likely to be easily contained by ring vaccination, provided contact tracing is feasible. Uncertainties in the nature of bioterrorist smallpox (infectiousness, vaccine efficacy) support continued planning for ring vaccination as well as mass vaccination. If initiated, ring vaccination should be conducted without delays in vaccination, should include contacts of contacts (whenever there is sufficient capacity) and should be accompanied by increased public awareness and surveillance.

Computer Simulation↗
PubMed1992

Coronary risk factors used to predict coronary artery disease by logistic regression analysis.

Risk factor analysis in coronary artery disease was conducted in 303 patients who underwent coronary arteriography to identify associations between personal characteristics and the prevalence of coronary heart disease. Age, sex, obesity, smoking, alcohol intake, hypertension, diabetes mellitus, serum uric acid, total cholesterol, LDL- and HDL-cholesterol, triglyceride, and atherogenic indices were statistically analyzed. All 13 variables were first compared between patients with positive and negative ergonovine tests. Only total cholesterol was significantly different, while significant differences in age, sex, history of diabetes, total cholesterol, LDL- and HDL-cholesterol, triglyceride and atherosclerotic indices were observed between patients with and without organic coronary artery stenosis. A multivariate analysis was performed, and the resulting equation was tested using the remaining patients. Logistic analysis of all 13 variables identified 5 (age, sex, diabetes mellitus, LDL- and HDL-cholesterol) which accounted for the differences between patients with and without significant coronary artery disease and that were validated in the test group. The sensitivity for prediction of coronary artery disease was 75.8%, specificity 68.5%, and predictive accuracy 71.5% in the test group. Thus, risk factor analysis appears to be very valuable in screening subjects with high-risk organic coronary stenosis and in optimizing the preventive and therapeutic modalities, but not in predicting vasospastic subjects.

Cholesterol↗