Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “confidence limits”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25Linked to original sources
PubMed1997

The Wisconsin Age-related Macular Degeneration grading system: performance in an independent centre.

INTRODUCTION: Age-related Macular Degeneration (AMD) is the commonest cause of blindness in developed nations. Despite this, the epidemiology of AMD is poorly understood. A need for the documentation of AMD prevalence and incidence at a population level has stimulated the development of a comprehensive, observer-based, photographic grading method for AMD in Wisconsin. AIM: To independently assess the performance of the Wisconsin method by self-taught graders outside its centre of inception. METHOD: The inter-observer variability and confidence limits for detection of change were assessed for two self-taught graders (ophthalmologists). Self teaching was achieved exclusively from documentation and photographs provided by the system developers in Wisconsin. 295 retinal photographs of elderly people were independently assessed for 13 features by each of the two graders. RESULTS: Weighted and unweighted kappa statistics, % exact and one step apart agreement, and confidence limits for detection of change were calculated for the graded features on a "by eye' basis, and where appropriate, on a "by retinal subfield' basis. Levels of agreement for weighted kappa were moderate to substantial for most features. 95% and 90% confidence limits for significant change beyond measurement error were determined in terms of scale increments. CONCLUSION: We conclude that the Wisconsin AMD grading system can be independently learnt from documentation and photographs alone, and that an acceptable level of performance is attainable by self-taught graders.

Aged↗
PubMed1999

An evaluation of risk estimation procedures for mixtures of carcinogens.

The estimation of health risks from exposure to a mixture of chemical carcinogens is generally based on the combination of information from several available single compound studies. The current practice of directly summing the upper bound risk estimates of individual carcinogenic components as an upper bound on the total risk of a mixture is known to be generally too conservative. Gaylor and Chen (1996, Risk Analysis) proposed a simple procedure to compute an upper bound on the total risk using only the upper confidence limits and central risk estimates of individual carcinogens. The Gaylor-Chen procedure was derived based on an underlying assumption of the normality for the distributions of individual risk estimates. In this paper we evaluated the Gaylor-Chen approach in terms of the coverage probability. The performance of the Gaylor-Chen approach in terms the coverages of the upper confidence limits on the true risks of individual carcinogens. In general, if the coverage probabilities for the individual carcinogens are all approximately equal to the nominal level, then the Gaylor-Chen approach should perform well. However, the Gaylor-Chen approach can be conservative or anti-conservative if some or all individual upper confidence limit estimates are conservative or anti-conservative.

Carcinogens, Environmental↗
PubMed2006

A search for thresholds and other nonlinearities in the relationship between hexavalent chromium and lung cancer.

The exposure-response relationship for airborne hexavalent chromium exposure and lung cancer mortality is well described by a linear relative rate model. However, categorical analyses have been interpreted to suggest the presence of a threshold. This study investigates nonlinear features of the exposure response in a cohort of 2,357 chemical workers with 122 lung cancer deaths. In Poisson regression, a simple model representing a two-step carcinogenesis process was evaluated. In a one-stage context, fractional polynomials were investigated. Cumulative exposure dose metrics were examined corresponding to cumulative exposure thresholds, exposure intensity (concentration) thresholds, dose-rate effects, and declining burden of accumulated effect on future risk. A simple two-stage model of carcinogenesis provided no improvement in fit. The best-fitting one-stage models used simple cumulative exposure with no threshold for exposure intensity and had sufficient power to rule out thresholds as large as 30 microg/m3 CrO3 (16 microg/m3 as Cr+6) (one-sided 95% confidence limit, likelihood ratio test). Slightly better-fitting models were observed with cumulative exposure thresholds of 0.03 and 0.5 mg-yr/m3 (as CrO3) with and without an exposure-race interaction term, respectively. With the best model, cumulative exposure thresholds as large as 0.4 mg-yr/m3 CrO3 were excluded (two-sided upper 95% confidence limit, likelihood ratio test). A small departure from dose-rate linearity was observed, corresponding to (intensity)0.8 but was not statistically significant. Models in which risk-inducing damage burdens declined over time, based on half-lives ranging from 0.1 to 40 years, fit less well than assuming a constant burden. A half-life of 8 years or less was excluded (one-sided 95% confidence limit). Examination of nonlinear features of the hexavalent chromium-lung cancer exposure response in a population used in a recent risk assessment supports using the traditional (lagged) cumulative exposure paradigm: no intensity (concentration) threshold, linearity in intensity, and constant increment in risk following exposure.

Air Pollutants, Occupational↗
PubMed2006

Can electrocardiogram electrodes replace bispectral index electrodes for monitoring depth of anesthesia?

BACKGROUND: Bispectral index has been introduced to provide optimal level of anesthesia. However, Bispectral index monitoring may not be cost effective in a relatively short procedures due to the high costs of the electrode. The authors conducted the present study to compare the feasibility of commercially available electrocardiogram (ECG) electrodes instead of the Bispectral index (BIS) monitoring. MATERIAL AND METHOD: The authors evaluated the difference in signal quality index (SQI) and BIS values collected from two BIS monitors, using ECG electrodes and BIS electrodes on the same patients before anesthesia, during light anesthesia, deep anesthesia and the emergence period Both sets of electrodes were placed at bifrontal areas throughout the procedure. Statistical analysis was evaluated by mean difference 95% confidence limits of agreement and visualized by Bland-Altman plot. A parametric analysis was analyzed using paired t-test. RESULTS: There were 390 parallel signal quality index and BIS values recorded in the present study. During anesthesia the mean BIS values were 58.63 +/- 18.77 in the ECG electrode group and 56.99 +/- 19.84 in the BIS electrode group, which were not statistically different. The mean SQI values were 79.2 +/- 24.8 and 82.8 +/- 21.6 using ECG electrodes and BIS electrodes, respectively. The mean difference between BIS values was 1.65 with 95% confidence limits of agreement between 0.91 and 2.38. CONCLUSION: Commercial ECG electrodes could be used for monitoring depth of anesthesia with clinically acceptable mean bias and 95% confidence limits of agreement of BIS value obtained from BIS electrode.

Anesthesia, General↗
PubMed1992

Single-dose and steady-state pharmacokinetics of diltiazem administered in two different tablet formulations.

Single-dose and steady state pharmacokinetics of diltiazem administered in two different oral formulations were assessed with particular reference to rate and extent of absorption. Following single dose administration a significant difference in tmax was observed (2.9 +/- 1.9 and 6.8 +/- 2.6 hr respectively) whereas differences in AUC, t1/2 and Cmax were not significant. The AUC (mean +/- S.D.) values following single dose administration of Cardil and Cardizem were 678.4 +/- 321.5 and 948.6 +/- 580.6 ng.ml-1.hr respectively. The mean and the 95% confidence limits for the observed ratio AUCCardil/AUCCardizem are 0.89 and 0.44-1.34 respectively. At steady-state a significant difference between Cmax/Cmin and tmax was seen Cmax/Cmin being 4.9 and 3.2 respectively and Tmax being 2.7 +/- 2.0 and 6.0 +/- 2.8 hr respectively, whereas Cmax and AUC did not differ significantly. The AUC (mean +/- S.D.) values in steady state of Cardil and Cardizem were 880.1 +/- 399.8 and 1056.8 +/- 509.8 ng.ml-1.hr respectively. The mean and the 95% confidence limits for the observed ratio AUCCardil/AUCCardizem are 0.96 and 0.66-1.26 respectively. Although the observed ratios AUCCardil/AUCCardizem in both the single-dose and the steady-state study do not differ significantly from 1.0, the confidence limits exceed the acceptable values given by Poulsen & Juul (personal communication 1990) (a 20% decrease or increase of the ratio to 0.8 or 1.2).

Absorption↗
PubMedDate not supplied

Method for estimating confidence levels for measurements by blood glucose monitoring systems.

A joint conference on self-monitoring of blood glucose (SMBG) has proposed that all glucose monitoring systems generate values that are within 10% of the actual blood glucose level 100% of the time. To estimate the confidence limits of blood glucose measurements made in a typical university ambulatory care setting and to ascertain whether they met the proposed standard, we performed duplicate determinations of blood glucose using a reflectance meter and applied to the measurements a method for calculating the closeness of measured values to a "true" mean. Based on paired measurements in 100 consecutive diabetic subjects, we were able to show that one measurement would be within 11.9% of a true mean value 95% of the time and within 8.4% of the mean 90% of the time. The 95 and 90% confidence limits for the average of two repeated measurements were calculated to be 8.4 and 5.9%, respectively. Our methodology can be applied to any set of SMBG values to calculate their confidence limits and to determine whether the measurements meet recommended standards.

Blood Glucose Self-Monitoring↗
PubMed1984

Effect of amiodarone on left ventricular ejection and filling in hypertrophic cardiomyopathy as assessed by radionuclide angiography.

Left ventricular (LV) function at rest was assessed by radionuclide angiography in 30 patients with hypertrophic cardiomyopathy (HC) before and during treatment with amiodarone (600 to 800 mg for 1 week, 200 to 400 mg/day thereafter) for an initial maintenance period of 1 month in 30 patients and 6 months in 12 patients. The reproduciblity of the measurements was assessed by performing control studies within 24 hours in 13 patients and at 1 to 6 months in 6 patients, and 95% confidence limits for spontaneous change were determined. There was a significant decrease in heart rate at 1 month (from 67 +/- 9 vs 61 +/- 9 beats/min, p less than 0.004) with no further decrease at 6 months. Systemic blood pressure did not change. After amiodarone therapy, for each of the measurements of LV function except peak ejection rate, there was no mean change and the number of patients in whom the values increased and decreased by more than the 95% confidence limits were approximately equal. Peak ejection rate showed a significant decrease at 1 month, but this effect was not maintained at 6 months; 4 of 6 patients who showed a significant decrease at 1 month were reevaluated at 6 months, and in all 4 the values had returned to control levels. These findings suggest that the 95% confidence limits for spontaneous change were not wide enough and that chronic oral amiodarone therapy does not alter radionuclide indexes of LV function at rest in patients with hypertrophic cardiomyopathy.

Adolescent↗
PubMed1985

A new approach to establishing individualized maintenance doses of phenytoin.

A new method for arriving at individualized doses of phenytoin (PHT) is described. This method, designated the eta method, operates on two measurements of unbound plasma PHT. One plasma sample is collected 48 h after a single, oral PHT dose (approximately 4.5 mg/kg). From the single dose, single sample measurements of plasma unbound PHT individual estimates of intrinsic unbound PHT clearance (CLuint) can be made. With the use of CLuint and weight-adjusted mean population values of Vmax predicted plasma concentrations of unbound PHT for 11 subjects exhibited a mean prediction error (mpe) of 0.07 mg/L with 95% confidence limits of -0.11 to 0.26 mg/L and an error coefficient of variation [root mean squared error (rmse)/mean unbound concentration at steady state (Cuss)] of 0.4. The second plasma unbound PHT is collected at steady state. From CLuint and one Cuss measurement, Vmax and Km can be directly calculated. Doses calculated by the eta method to produce plasma unbound PHT concentrations of approximately 1.0 mg/L were identical to those calculated by the Bayesian method to yield plasma total PHT concentrations of approximately 10 mg/L. When those doses were administered to six subjects, the plasma unbound PHT concentrations predicted by the eta method exhibited a mpe of -0.13 mg/L, with 95% confidence limits ranging from -0.33 to 0.06 mg/L and an error coefficient of variation of 0.2. The plasma PHT concentrations predicted by the Bayesian method exhibited an mpe of -1.30 mg/L, with 95% confidence limits of -4.02 to 1.42 mg/L and an error coefficient of variation of 0.3. Values of Vmax and doses of PHT calculated to produce a Cuss of 1.0 mg/L calculated by the eta method were nearly identical to Vmax values and doses of PHT calculated by Bayesian double feedback (based on two different Css values) to produce a Css of 10.0 mg/L.

Adult↗
PubMed1994

Predicting in-hospital mortality after hip fracture in elderly patients.

Ninety-seven patients aged 88 +/- 4 years (range, 80-97 years) (study group), and 74 aged 75 +/- 3 years (range, 70-79 years) (control group), were prospectively studied to investigate whether basic medical variables can predict in-hospital mortality in very old patients undergoing hip surgery because of femoral fracture. Mortality was 16.5% and 6.7% in the study and control groups, respectively (p = 0.054). In the study group, mortality was significantly correlated with age (p < 0.01), venous disorders (p < 0.05), malnutrition (p < 0.0001), duration of surgery (p < 0.006), and postoperative noninfectious complications (p < 0.005). In the control group, age was the only significant correlate of mortality (p < 0.005). After exclusion of surgery-related variables, the logistic regression analysis confirmed the predictive role of venous disorders (odds ratio = 2.04, confidence limits = 1.09-3.79) and malnutrition (odds ratio = 6.01, confidence limits = 1.85-19.47) but not of age in the study group. However, the goodness-of-fit test showed that the statistical model did not fit the data adequately. We conclude that in-hospital mortality after hip surgery in the very old cannot be predicted on the basis of underlying medical conditions alone.

Age Factors↗
PubMed1997

Non-parametric deconvolution provides an objective assessment of GH responsiveness to GH-releasing stimuli in normal subjects.

OBJECTIVE: Deconvolution analysis has been proposed as an effective method for analysing the physiology of GH secretion. In the literature, it has been applied to spontaneous secretion data characterized by long and uniform sampling paradigms. In the present study we investigated the applicability of non-parametric deconvolution to the analysis of response-to-stimuli (RTS) data characterized by infrequent and non-uniform sampling. PATIENTS: Thirty-six healthy adult male volunteers (age range 24-37 years) were randomly subdivided into two groups (group I, n = 30; group II, n = 6). DESIGN: Subjects of group I were tested with a single 1 microgram/kg body weight GH-releasing hormone (GHRH) bolus, administered at 0 minutes. Subjects of group II were tested, in random order, with a 4- or 5-day interval, with (1) two consecutive 1 microgram/kg body weight GHRH boluses at 0 and 120 minutes and (2) two consecutive 1 microgram/kg body weight hexarelin boluses, administered at 0 and 120 minutes. MEASUREMENTS: GH levels were determined at 0, 15, 30, 45, 60, 90 and 120 minutes (group I) and -30, 0, 15, 30, 45, 60, 120, 135, 150, 165, 180 and 240 minutes (group II). A numerically efficient regularization-based non-parametric deconvolution algorithm incorporating non-negativity constraints was used to estimate the time profile of the instantaneous secretion rate (ISR). Confidence limits allowing for both measurement error and kinetic model uncertainty were computed using a Monte-Carlo procedure. In order to validate the deconvolution method, a simulated benchmark problem was set up. RESULTS: The analysis of the benchmark problem showed that the proposed method is capable of providing an accurate reconstruction of the ISR (as measured by the root mean square (RMS) error). Moreover, it appeared that reliable confidence limits cannot be obtained unless the kinetic model uncertainty is taken into account. The analysis of the data showed a clear rise in the ISR subsequent to the first bolus (either GHRH or hexarelin), with most of the response occurring within 60 minutes of the stimulus. In group I, it was also seen that discarding the samples collected at times 90 and 120 minutes only marginally affected the estimate of the cumulated ISR over 0-60 minutes (the variation was always less than 3%). The analysis of GH responsiveness to repeated stimuli (group II) showed that the amount of hormone secreted after the second bolus was clearly reduced in comparison with the elicited by the first stimulus, most of the response occurring within 60 minutes of the injection. The amount of GH secreted after the second stimulus ranged from 13 to 36% (GHRH 17-36%; hexarelin 13-36%) of the overall amount of hormone secreted after time 0 minutes. CONCLUSIONS: Even with relatively few samples, non-parametric deconvolution of response-to-stimulus data is capable of providing a reliable, smooth and non-negative estimate of the GH instantaneous secretion rate that offers a realistic representation of the GH secretory dynamics. The non-parametric approach compares favourably with respect to discrete deconvolution methods, that yield discontinuous instantaneous secretion rates profiles, and parametric methods that would require more stringent assumptions on the shape of the instantaneous secretion rate. When assessing confidence limits it is essential to take into account both measurement error and kinetic model uncertainty. Using deconvolution in normal subjects, the estimated instantaneous secretion rate between 0 and 60 minutes is scarcely affected by samples taken after time 60 minutes. Since most of the secretory response takes place during this time interval, there is motivation for investigating the use of shorter sampling protocols in conjunction with deconvolution analysis. Although pulse detection and the assessment of the shape of spontaneous pulses have not been investigated, it could be interesting to apply non-parametric deconvolution to spontaneous sec

Adult↗
PubMed1993

Antimicrobial prophylaxis in urologic surgery: does it give some benefit?

Three types of antibiotic prophylactic regimens were evaluated versus a control without prophylaxis (group A: 3,912 cases) in urologic surgery. The antibiotic regimens were: group B = cefazolin 1 g/12 h/3 days (3,660 cases); group C = cefonicid 1 g/24 h/3 days (2,076 cases), and group D = cefonicid 1 g single dose (3,169 cases). The parameters used were the comparison of the corresponding rates of postsurgical sepsis and operative wound infections. Numeric investigations for the validity of a retrospective study (unpaired data) were performed: homogenicity test, relative risk point estimate and confidence limits (95%), and etiological fraction point estimate and confidence limits (95%). Chi-square for other purposes were performed. Endoscopic handling was considered homogeneous (same infective risk), while open surgery was heterogeneous (p < 0.001). In order to avoid probable bias, a correction factor was used. Although in different degrees, prophylaxis significantly reduced the morbidity of surgical wound infections (p < 0.001; etiological fraction > 90%). The differences (p < 0.01) between groups B and C/D were attributed to pharmacokinetic causes (short T 1/2 of cefazolin). To obtain the maximum protective effect, the use of antibiotics with a T 1/2 of > 4 h is suggested. There was no resistant mutans in previously sensitive strains. However, a significant selection of intrinsically resistant strains was observed. Monodose offers at lest the same advantages as multiple-dose therapy. In addition, the monodose selected in a lesser proportion both the resistant strains (p < 0.001) and the number of microbial associations (p < 0.01).

Cefazolin↗
PubMed1995

Reproducibility of digital exercise echocardiography.

We determined the intra, inter-observer and temporal variability of upright bicycle exercise echocardiography in 50 consecutive patients with suspected coronary heart disease. Using significant artery stenoses as reference, the sensitivity of digital exercise echocardiography was 89% and the specificity 92%. Regarding the presence or absence of exercise-induced ischaemia, intra-observer agreement was 86% (73-94% with 95% confidence limits, kappa value (K) 0.70 (0.50-0.91)). Inter-observer agreement between two independent observers was 92 (81-98)% (K = 0.81 (0.63-0.99)). Temporal variability was examined by repeating exercise echocardiography after one week in 30 stable patients; it demonstrated 90 (78-97)% agreement (K = 0.71 (0.40-1.00)). The inter-observer agreement appeared to be lower in patients or myocardial segments with wall motion abnormalities at rest (86% and 82%, respectively) than in patients or segments with normal myocardial function at rest (96% and 94%, respectively); ns, P < 0.05, respectively). Analysis of specific regions showed a significantly higher level of agreement (P < 0.05) regarding exercise-induced ischaemia in segments supposed to be supplied by the circumflex branch of the left coronary artery (96%) than in the perfusion bed of the left anterior descending branch (87%) and right coronary artery (88%). Comparing estimated values of echocardiographic ejection fraction, analysis of intra-observer variability showed a correlation coefficient of 0.91 and 95% confidence limits of a single estimate of ejection fraction of +/- 10.3%. Corresponding analyses of inter-observer and temporal variability showed correlation coefficients of 0.93 and 0.84, respectively, and 95% confidence limits of single estimates of ejection fraction of +/- 9.6% and +/- 13.0%, respectively. Thus, the diagnostic result and the reproducibility of digital exercise echocardiography are satisfactory and comparable with those obtained by myocardial scintigraphy. However, approximately 10% of the examination results may be reversed when the test is repeated or reevaluated by the same or by another observer. The result seems to be less reproducible in patients with abnormal wall motion at rest than in patients with normal myocardial function before exercise.

Adult↗
PubMed1988

Phenotyping polymorphic drug metabolism in the French Caucasian population.

Because of the large interethnic differences in the incidence of poor metabolizer phenotypes, French Caucasians have been studied for two independent polymorphisms, debrisoquine/dextromethorphan and mephenytoin metabolism. One hundred and thirty-two unrelated French Caucasians were phenotyped using oral doses of dextromethorphan 20 mg and mephenytoin 100 mg. Individual dextrorphan excretion over 8 h and the dextromethorphan/dextrorphan metabolic ratio were calculated. Extensive metabolizers were taken as subjects with a high dextrorphan output (15.56 mumol/8 h) and a low metabolic ratio (0.0023), and poor metabolizers were those with a low dextrorphan output (0.39 mumol/8 h) and a high metabolic ratio (7.00). Individual 4-hydroxymephenytoin excretion and mephenytoin hydroxylation indices were also determined. Extensive metabolizers eliminated large amounts of 4 hydroxymephenytoin (133.2 mumol/8 h) and had a hydroxylation index of 1.99, and poor metabolizers, because of impaired mephenytoin metabolism, had a high hydroxylation index (277). The incidence of the poor metabolizer phenotype was 3% for dextromethorphan (95% confidence limits 0.5%-8.5%) and 6% for mephenytoin (95% confidence limits 2%-12.5%).

Adult↗
PubMed1993

Toremifene and tamoxifen in advanced breast cancer--a double-blind cross-over trial.

Toremifene (TOR) is a triphenylethylene derivative related to tamoxifen (TAM). TOR has antitumor activity, not dependent on estrogen receptors, and responses with TOR have been observed in patients with progressive disease during TAM-treatment. To elucidate possible cross-resistance between these two antiestrogens, we compared their anti-tumor activity in a randomized, double-blind, cross-over study. 66 postmenopausal women with advanced estrogen receptor positive or unknown breast cancer and a median age of 63 years (range 38-82) were included. Patients were randomized to TAM 40 mg/day or TOR 240 mg/day. Treatment continued until progressive disease, when cross-over to the alternative treatment was done. The response rate with first line TOR was 29% (95% confidence limits 10-41%) and with TAM 42% (95% confidence limits 25-61%). Response rates and response durations, survival and toxicity were not significantly different between the two treatments. 44 patients progressing on first line TAM or TOR were evaluable for second line TOR or TAM treatment. As no responses were observed, the possibility of over-looking a response rate of 20% or more is less than 1%. In conclusion, this study strongly indicates that TOR and TAM are clinically cross-resistant in patients with advanced breast cancer.

Adult↗
PubMed1994

Influence of catheterisation on the results of sonographic urethrocystography in patients with genuine stress incontinence.

Using introital sonography as an alternative to lateral chain urethrocystography during urodynamic studies, a prospective investigation was carried out in 47 patients with lower urinary tract complaints, to determine the correlation of sonographic assessment with and without bladder catheterisation. The apparent location of the bladder neck in relation to the pubic symphysis and measurements of the posterior urethrovesical angle at rest and during straining during cystometry with and without intravesical urodynamic pressure transducers were determined. In 22 (46.8%) patients the bladder neck at rest was below the lower edge of the symphysis. This finding was not influenced by the presence of a catheter. Correlation coefficients (r) for posterior urethrovesical angles at rest and during straining measured with and without catheters were 0.95 (95% confidence limits 0.92-0.98; P < 0.01) and 0.98 (95% confidence limits 0.96-0.99; P < 0.01), respectively. The coefficients of determination (r2) at rest and during straining were 0.92 and 0.95, respectively. Sonography with and without cystometry equipment in place gave similar results.

Adult↗
PubMed1987

Outcome in suspected acute myocardial infarction with normal or minimally abnormal admission electrocardiographic findings.

Seven hundred seventy-five consecutive patients with symptoms suggestive of acute myocardial infarction (AMI) who were admitted to the cardiac care unit from the emergency room were studied; 107 had normal electrocardiographic findings and 73 had only minimal nonspecific changes. AMI subsequently evolved in 11 patients (10%) with normal electrocardiographic findings and in 6 (8%) with minimal changes, compared with 245 (41%) with frankly abnormal emergency room findings. Only 1 (1%; 95% confidence limits 0.02 to 5%) and 4 (6%; 95% confidence limits 2 to 15%) of those with normal and nonspecific initial electrocardiographic findings, respectively, had a complication for which they potentially benefited from intensive care unit intervention, although many patients received prophylactic therapy. Thus, the initial emergency room electrocardiogram can effectively separate patients into high- and low-risk groups for AMI and serious complications. Admission to a monitored intermediate care ward may be an acceptable practice in patients with chest pain and a normal or minimally changed initial electrocardiogram.

Age Factors↗
PubMed1995

Allograft aortic valve replacement: long-term follow-up.

Aortic valve replacement using an allograft aortic valve has been performed on 804 patients. From December 1969 to May 1975, 124 patients received a nonviable allograft valve sterilized by incubation with low-dose antibiotics and stored for weeks by refrigeration at 4 degrees C (series 1). From June 1975 to January 1994, 680 patients received viable allograft valves, now cryopreserved early within 2 hours of collection from transplant recipient donors, 6 hours for multiorgan donor valves and 23 hours (mean) for autopsy valves from donor death. The 30-day mortality was 8.9% +/- 5% (95% confidence limits) for series I and 2.8% +/- 1% (95% confidence limits) for series II. Actuarial patient survival including hospital mortality at 15 years was 56% +/- 5% for series I and 62% +/- 5% for series II. The probability of a thromboembolic event was low, freedom at 15 years being 95% +/- 1% for patients receiving allografts with or without associated coronary bypass procedures and 81% +/- 5% for patients having allografts with other associated procedures (eg, mitral valve operations). Actuarial freedom from endocarditis was similar for the two series, 91% +/- 3% (series I) and 94% +/- 2% (series II) at 15 years. The freedom from valve incompetence, from reoperation for all causes, and from structural deterioration demonstrated clearly the inferiority of the 4 degrees C stored allograft valves. For structural deterioration as identified clinically, at reoperation and at death, freedom from this event at 15 years was 45% +/- 6% for series I and 80% +/- 5% for series II (p value for the difference is 0).(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1988

Ectopic pregnancy and prior induced abortion.

As part of the Women's Health Study, a case-control study conducted in nine cities in the United States, women hospitalized with an ectopic pregnancy and women hospitalized with non-gynecologic, medical or surgical diagnoses were interviewed concerning past reproductive history. There were 462 women meeting eligibility criteria in the ectopic pregnancy case group and 2326 women meeting the criteria for the control group. After adjustment for a number of possible confounders, the relative risk of ectopic pregnancy for women with a history of one induced abortion was 1.0 (95% confidence limits: 0.5 to 1.8) and was 0.9 (95% confidence limits: 0.8 to 1.1) for women with a history of two or more prior induced abortions. These results suggest that prior induced abortion does not significantly increase the risk of subsequent ectopic pregnancy.

Abortion, Induced↗