Characterization of t(12;21) breakpoint junctions in acute lymphoblastic leukemia.
Explore the source record for details and available documents.
Base Sequence↗
Biomedical subjects
C L Christiansen
Publications and source records attributed to C L Christiansen.
Predicting the cumulative risk of false-positive mammograms.
BACKGROUND: The cumulative risk of a false-positive mammogram can be substantial. We studied which variables affect the chance of a false-positive mammogram and estimated cumulative risks over nine sequential mammograms. METHODS: We used medical records of 2227 randomly selected women who were 40-69 years of age on July 1, 1983, and had at least one screening mammogram. We used a Bayesian discrete hazard regression model developed for this study to test the effect of patient and radiologic variables on a first false-positive screening and to calculate cumulative risks of a false-positive mammogram. RESULTS: Of 9747 screening mammograms, 6. 5% were false-positive; 23.8% of women experienced at least one false-positive result. After nine mammograms, the risk of a false-positive mammogram was 43.1% (95% confidence interval [CI] = 36.6%-53.6%). Risk ratios decreased with increasing age and increased with number of breast biopsies, family history of breast cancer, estrogen use, time between screenings, no comparison with previous mammograms, and the radiologist's tendency to call mammograms abnormal. For a woman with highest-risk variables, the estimated risk for a false-positive mammogram at the first and by the ninth mammogram was 98.1% (95% CI = 69.3%-100%) and 100% (95% CI = 99.9%-100%), respectively. A woman with lowest-risk variables had estimated risks of 0.7% (95% CI = 0.2%-1.9%) and 4.6% (95% CI = 1. 1%-12.5%), respectively. CONCLUSIONS: The cumulative risk of a false-positive mammogram over time varies substantially, depending on a woman's own risk profile and on several factors related to radiologic screening. By the ninth mammogram, the risk can be as low as 5% for women with low-risk variables and as high as 100% for women with multiple high-risk factors.
Adult↗
Medical profiling: improving standards and risk adjustments using hierarchical models.
The conclusions from a profile analysis to identify performance extremes can be affected substantially by the standards and statistical methods used and by the adequacy of risk adjustment. Medically meaningful standards are proposed to replace common statistical standards. Hierarchical regression methods can handle several levels of random variation, make risk adjustments for the providers' case-mix differences, and address the proposed standards. These methods determine probabilities needed to make meaningful profiles of medical units based on standards set by all appropriate parties.
Hospitals, Veterans↗
The effect of medical student teaching on patient satisfaction in a managed care setting.
OBJECTIVE: To measure the effect on patient satisfaction of medical student participation in care and the presence of medical student teaching. DESIGN: Prospective cohort study. SETTING: Eight outpatient internal medicine departments of a university-affiliated HMO in Massachusetts. PATIENTS: Two hundred seven patients seen on teaching days (81 patients who saw a medical student-preceptor dyad and 126 patients who saw the preceptor alone), and 360 patients who saw the preceptor on nonteaching days. Five hundred (88%) of 567 eligible patients responded. MEASUREMENTS AND MAIN RESULTS: Thirteen closed-response items on a written questionnaire, measuring satisfaction with specific dimensions of care and with care as a whole. Visit satisfaction was similar among patients on teaching and nonteaching days. Ninety-one percent of patients seeing a medical student, 93% of patients seeing the preceptor alone on teaching days, and 93% of patients on nonteaching days were satisfied or very satisfied with their visit; less than 2% of patients in each group were dissatisfied with their visit. Satisfaction on all measured dimensions of care was similar for patients seeing a medical student, patients seeing the preceptor alone on teaching days, and patients seeing the preceptor on nonteaching days. CONCLUSIONS: Medical student participation and the presence of medical student teaching had little effect on patient satisfaction. Concerns about patient satisfaction should not prevent managed care organizations from participating in primary care education.
Clinical Clerkship↗
Enrollees' perceptions of participating in the education of medical students at an academically affiliated HMO.
PURPOSE: Little is known about how enrollees in health maintenance organizations (HMOs) perceive the benefits and risks of participating in the education of medical students. This case study elicited the views of enrollees of one academically affiliated HMO about the education of medical students. METHOD: Data from focus groups were used to design two questionnaires that were mailed to 488 adult patients and 298 parents or guardians of pediatric patients. A sample of non-respondents was followed up by telephone. Descriptive analyses were performed on the responses to the questionnaires. RESULTS: Response rates were 46% (adult) and 43% (parent or guardian). More than 75% of the respondents thought the HMO should be involved in teaching, most because teaching contributes to the training of better doctors and increases the skills of teacher-clinicians. Of those who responded, 28% of adults were concerned about risks to confidentiality and 18% were concerned about increased costs for enrollees. Nearly 50% of adults would be uncomfortable with students participating in visits involving "internal" examinations or emotional problems. Of those who responded, 56% of adults and 33% of parents or guardians were uncomfortable about a student's conducting an unsupervised history and physical examination. A total of 52% of adults preferred that the preceptor and student discuss their case in their presence. Respondents who had seen students previously were more comfortable with student activities associated with their care. CONCLUSIONS: The respondents thought the HMO should be involved in teaching, but they had specific concerns about the effects of student participation. Educators in other settings may wish to explore these concerns among their patient populations and develop policies to maximize the "enrollee-friendliness" of medical education in HMOs. While the study provides a first look at how enrollees at one HMO viewed participation in medical students' education, further research is needed at HMOs elsewhere to determine the representativeness of the study's findings.
Adult↗
Fever in pediatric primary care: occurrence, management, and outcomes.
OBJECTIVE: To describe the epidemiology, management, and outcomes of children with fever in pediatric primary care practice. PATIENTS: A cohort of 20 585 children 3 to 36 months of age cared for in 11 pediatric offices of a health maintenance organization between 1991 and 1994. METHODS: Using automated medical records we identified all office visits with temperatures >/=38 degrees C for a random sample of 5000 children, and analyzed diagnoses conferred, laboratory tests performed, and antibiotics prescribed. We also determined the frequency of in-person and telephone follow-up after initial visits for fever. Finally, we reviewed hospital claims data for the entire cohort of 20 585 to identify cases of meningitis, meningococcal sepsis, and death from infection. RESULTS: Among 3819 initial visits of an illness episode, 41% of children had no diagnosed bacterial or specific viral source. Of these, 13% with a temperature of 38 degrees C to 39 degrees C and 36% with a temperature of >/=39 degrees C received laboratory testing. Almost half (43%) received some documented follow-up care in the subsequent 7 days. Among the 26 970 child-years of observation in the entire cohort, 15 children (56 per 100 000 child-years) were treated for bacterial meningitis or meningococcal sepsis. Five had an office visit for fever in the week before hospitalization, but only 1 had documented fever >/=39 degrees C and received neither laboratory testing for occult bacteremia nor treatment with an antibiotic. CONCLUSION: The majority of febrile children in ambulatory settings were diagnosed with a bacterial infection and treated with an antibiotic. Of highly febrile children without a source, 36% received laboratory testing consistent with published expert recommendations, and short-term follow-up was common. Meningitis or death after an office visit for fever without a source was predictably rare. These data suggest that increased testing and/or treatment of febrile children beyond the rates observed here are unlikely to affect population rates of meningitis substantially.
Ambulatory Care↗
Timeliness and quality of care for elderly patients with acute myocardial infarction under health maintenance organization vs fee-for-service insurance.
BACKGROUND: A commonly voiced concern is that health maintenance organizations (HMOs) may withhold or delay the provision of urgent, essential care, especially for vulnerable patients like the elderly. OBJECTIVE: To compare the quality of emergency care provided in Minnesota to elderly patients with acute myocardial infarction (AMI) who are covered by HMO vs fee-for-service (FFS) insurance. METHODS: We reviewed the medical records of 2304 elderly Medicare patients who were admitted with AMI to 20 urban community hospitals in Minnesota (representing 91% of beds in areas served by HMOs) from October 1992 through July 1993 and from July 1995 through April 1996. MAIN OUTCOME MEASURES: Use of emergency transportation and treatment delay (>6 hours from symptom onset); time to electrocardiogram; use of aspirin, thrombolytics, and beta-blockers among eligible patients; and time from hospital arrival to thrombolytic administration (door-to-needle time). RESULTS: Demographic characteristics, severity of symptoms, and comorbidity characteristics were almost identical among HMO (n = 612) and FFS (n = 1692) patients. A cardiologist was involved as a consultant or the attending physician in the care of 80% of HMO patients and 82% of FFS patients (P = .12). The treatment delay, time to electrocardiogram, use of thrombolytic agents, and door-to-needle times were almost identical. However, 56% of HMO patients and 51% of FFS patients used emergency transportation (P = .02); most of this difference was observed for patients with AMIs that occurred at night (60% vs 52%; P = .02). Health maintenance organization patients were somewhat more likely than FFS patients to receive aspirin therapy (88% vs 83%; P = .03) and beta-blocker therapy (73% vs 62%; P = .04); these differences were partly explained by a significantly larger proportion of younger physicians in HMOs who were more likely to order these drug therapies. All differences were consistent across the 3 largest HMOs (1 staff-group model and 2 network model HMOs). Logistic regression analyses controlling for demographic and clinical variables produced similar results, except that the differences in the use of beta-blockers became insignificant. CONCLUSIONS: No indicators of timeliness and quality of care for elderly patients with AMIs were lower under HMO vs FFS insurance coverage in Minnesota. However, two indicators of quality care were slightly but significantly higher in the HMO setting (use of emergency transportation and aspirin therapy). Further research is needed in other states, in different populations, and for different medical conditions.
Adrenergic beta-Antagonists↗
Screening for colorectal cancer with flexible sigmoidoscopy by nonphysician endoscopists.
PURPOSE: Screening with sigmoidoscopy reduces the risk of death from colorectal cancer. Only 30% of eligible patients have undergone sigmoidoscopy, in part because of a limited supply of endoscopists. We evaluated the performance and safety of screening sigmoidoscopic examinations by trained nonphysician endoscopists in comparison with board-certified gastroenterologists. SUBJECTS AND METHODS: Asymptomatic patients 50 years or older without evidence of fecal occult blood and no personal history or family history of a first-degree relative with colorectal cancer under age 55 years were offered sigmoidoscopy. All examinations were performed either by a gastroenterologist or a trained nonphysician endoscopist at a staff model health maintenance organization. Outcomes included the depth of examination, number and histology of polyps, and complications. RESULTS: Nonphysicians performed 2,323 sigmoidoscopic examinations, and physicians performed 1,378 examinations. The mean (+/-SD) depth of sigmoidoscopy examinations performed by nonphysicians was 52 +/- 10 cm compared with 55 +/- 9 cm (P <0.001) in physicians. Nonphysicians detected neoplastic polyps in a greater proportion of patients (7.8%) than physicians (5.8%), but this difference was not significant after adjusting for differences in the age, sex, and family history of the patients (P = 0.35). No major complications occurred. The cost per examination, including the nonphysician training cost, was lower for nonphysicians ($186 per examination) than for physicians ($283 per examination). CONCLUSIONS: Appropriately trained nonphysicians may be capable of performing safe and effective screening for colorectal cancer with flexible sigmoidoscopy. An increased use of nonphysicians to perform sigmoidoscopy may increase the availability and reduce the cost of the procedure.
Aged↗
The public's willingness to discuss their preference for organ donation with family members.
We sought to assess the public's willingness to discuss their preference for organ donation with family members and to identify factors associated with willingness to discuss donation. We categorized individuals (N = 4365) with a preference for donation according to their willingness to discuss donation and used ordinal logistic regression analysis to identify factors related to their level of willingness. About half of those who want to donate have discussed this with a family member. Others were at various stages with respect to their commitment to discuss donation. Those in the more committed stages were more likely than others to have signed an organ donor card, to have seen information about organ donation, to be male, to be white or Hispanic, to know about donation issues, and to be comfortable with the idea of their own death. The decision to donate is ultimately made by family members of a suitable candidate for donation, yet nearly half of those who wish to donate have not made their wishes known. Interventions targeted to individuals at different stages of commitment are needed so that more family members can respond in accordance with their loved one's wishes.
Adolescent↗
The influence of propofol and midazolam/halothane anesthesia on hepatic SvO2 and gastric mucosal pH during cardiopulmonary bypass.
OBJECTIVE: Because propofol is known to reduce vascular resistance, the objective of this study was to compare the indices of hepatosplanchnic circulation and oxygenation during cardiopulmonary bypass (CPB) in patients anesthetized with either propofol or midazolam/halothane. DESIGN: A prospective, randomized, nonblinded study. SETTING: A university hospital. PARTICIPANTS: Twenty patients undergoing cardiac surgery with CPB. INTERVENTIONS: Nine patients were anesthetized with propofol/fentanyl/pancuronium and 11 patients were anesthetized with midazolam/halothane/fentanyl/pancuronium. All patients had a nasogastric tonometer tube and two fiberoptic thermodilution catheters inserted; one in the pulmonary artery and one in the upper right hepatic vein. During bypass, SvO2s were measured from the venous line of the heart-lung machine. MEASUREMENTS AND MAIN RESULTS: Gastric mucosal pH (pHi) was measured prebypass, 30 minutes after the start of CPB, and just before weaning off CPB. Hepatic SvO2 (HSvO2) values were recorded every 5 minutes. The pH gap was less at 30 minutes of hypothermic CPB in the propofol group. In the midazolam/halothane group, the HSvO2 decreased after the start of rewarming, whereas in the propofol group the values remained almost at the prebypass levels. At the end of rewarming, the HSvO2 was almost identical in the two groups. CONCLUSION: Propofol preserved the HSvO2 during CPB and produced a more optimal relationship between the hepatosplanchnic blood flow and oxygen consumption.
Adjuvants, Anesthesia↗
A method for estimating solid organ donor potential by organ procurement region.
OBJECTIVES: This study sought to develop a methodology for estimating potential solid organ donors and measuring donation performance in a geographic region based on readily available data on the hospitals in that region. METHODS: Medical records were reviewed in a stratified random sample of 89 hospitals from 3 regions to attain a baseline of donor potential. Data on a range of hospital characteristics were collected and tested as predictors of donor potential through the use of hierarchical Poisson regression modeling. RESULTS: Five hospital characteristics predicted donor potential: hospital deaths, hospital Medicare case-mix index, total hospital staffed beds, medical school affiliation, and trauma center certification. Regional estimates were attained by aggregating individual hospital estimates. Confidence intervals for these regional estimates indicated that actual donations represented from 28% to 44% of the potential in the regions studied. CONCLUSIONS: This methodology accurately estimates organ donor potential within 3 geographic regions and lays the foundation for evaluating organ donation effectiveness nationwide. Additional research is needed to test the validity of the model in other geographic regions and to further explore organ donor potential in hospitals with fewer than 50 beds.
California↗
Improving the statistical approach to health care provider profiling.
This paper reviews and compares existing statistical methods for profiling health care providers. It recommends improvements that are based on the use of better statistical models and the adoption of more realistic, medically based criteria for judging the performance of health care providers. Unlike most profiling methods, the proposed hierarchical models allow the probability of acceptable provider performance to be calculated; thus, they can answer such questions as, "What is the probability that a given hospital's true mortality rate for cardiac surgery patients exceeded 3.33% last year?" The commonly encountered problems of regression-to-the-mean bias and small caseloads can be handled by using hierarchical models to extract more information from profiling data.
Bayes Theorem↗
[Thromboendarterectomy of chronic thromboembolic pulmonary hypertension].
Chronic thromboembolic pulmonary hypertension has a five year survival rate of less than 10% in patients with a systolic pulmonary artery pressure of 50 mmHg with no convincing effect of medical treatment. The operative mortality from pulmonary thrombendarterectomy in specialised centres has been reduced to 9%, suggesting this treatment as being an option. The results from thrombendarterectomy of two Danish patients are reported. The first patient, a 34 year-old woman was operated at the centre in San Diego with the assistance of a Danish thoracic surgeon. The second, a 60 year-old man was operated at our institution by this surgeon. Following removal of sufficient amount of embolic masses and intimal tissue, the patients were discharged from hospital with a substantial improvement in their clinical status and near normalisation of pulmonary artery pressure, which remained at the latest follow-up (3 to 22 months).
Adult↗
Preoperative renal risk stratification.
BACKGROUND: After cardiac surgery, acute renal failure (ARF) requiring dialysis develops in 1% to 5% of patients and is strongly associated with perioperative morbidity and mortality. Prior studies have attempted to identify predictors of ARF but have had insufficient power to perform multivariable analyses or to develop risk stratification algorithms. METHODS AND RESULTS: We conducted a prospective cohort study of 43 642 patients who underwent coronary artery bypass or valvular heart surgery in 43 Department of Veterans Affairs medical centers between April 1987 and March 1994. Logistic regression analysis was used to identify independent predictors of ARF requiring dialysis. A risk stratification algorithm derived from recursive partitioning was constructed and was validated on an independent sample of 3795 patients operated on between April and December 1994. The overall risk of ARF requiring dialysis was 1.1%. Thirty-day mortality in patients with ARF was 63.7%, compared with 4.3% in patients without ARF. Ten clinical variables related to baseline cardiovascular disease and renal function were independently associated with the risk of ARF. A risk stratification algorithm partitioned patients into low-risk (0.4%), medium-risk (0.9% to 2.8%), and high-risk (> or = 5.0%) groups on the basis of several of these factors and their interactions. CONCLUSIONS: The risk of ARF after cardiac surgery can be accurately quantified on the basis of readily available preoperative data. These findings may be used by physicians and surgeons to provide patients with improved risk estimates and to target high-risk subgroups for interventions aimed at reducing the risk and ameliorating the consequences of this serious complication.
Acute Kidney Injury↗
Trimethoprim-sulfamethoxazole and hypouricemia.
BACKGROUND: Hypouricemia has been reported in a substantial fraction of patients with AIDS and attributed to an HIV-related renal urate transport defect. We tested the alternative hypothesis that hypouricemia was associated with the administration of high-dose trimethoprim-sulfamethoxazole (TMP-SMX). METHODS: Sociodemographic, clinical, and repeated laboratory data on 45 hospitalized patients with Pneumocystis carinii pneumonia (PCP) with and without HIV infection, were abstracted by a blinded reviewer. The primary outcome of interest was the percent change in serum uric acid concentration from baseline to hospital day 5 +/- 1. RESULTS: Subjects who received TMP-SMX were older (mean age 44.8 vs. 37.0, p = 0.02), less likely to be HIV-seropositive (61% vs. 94%, p = 0.01), and more likely to have received glucocorticoid therapy (75% vs. 35%, p = 0.01) than those who received pentamidine, dapsone-trimethoprim, clindamycin-primaquine, sulfadiazine-pyramethamine, or a combination of these agents. The administration of TMP-SMX was associated with a 37% +/- 12% reduction in serum uric acid concentration, adjusting for the effects of age, sex, race, HIV antibody status, renal function, serum sodium, and the use of diuretics and glucocorticoids (p = 0.005). CONCLUSION: Among a diverse cohort of hospitalized patients with PCP, treatment with high-dose TMP-SMX was strongly associated with a reduction in serum uric acid concentration over time.
AIDS-Related Opportunistic Infections↗
Prognostic stratification in critically ill patients with acute renal failure requiring dialysis.
BACKGROUND: Despite the widespread availability of dialytic and intensive care unit technology, the probability of early mortality in critically ill persons with acute renal failure is distressingly high. Previous efforts to predict outcome in this population have been limited by small sample size and the absence of uniform exclusion criteria. Additionally, data obtained decades ago may not apply today owing to changes in case mix. METHODS: The medical records of 132 consecutive patients in the intensive care unit with acute renal failure who required dialysis from 1991 through 1993 were evaluated by a blinded reviewer. RESULTS: The overall in-hospital mortality rate was 70%. Twelve readily available historical, clinical, and laboratory variables were significantly associated with in-hospital mortality. Multivariate logistic regression analysis showed that mechanical ventilation, malignancy, and nonrespiratory organ system failure were independently associated with in-hospital mortality. Using a 95% positivity criterion, this model identified 24% of high-risk patients who died, without misclassification of any survivors. Of those who survived to hospital discharge, 33% were dialysis dependent and 28% were institutionalized long-term. CONCLUSIONS: Among critically ill patients, acute renal failure requiring dialysis is an ominous condition with a high risk of in-hospital mortality. This risk appears to depend largely on comorbid conditions, such as the need for mechanical ventilation and underlying malignancy. While this prognostic model requires prospective validation, it appears to identify a substantial fraction of patients for whom dialysis may be of limited or no benefit.
Acute Kidney Injury↗
The economic impact of multiple-gestation pregnancies and the contribution of assisted-reproduction techniques to their incidence.
BACKGROUND: Although the medical complications associated with multiple-gestation pregnancies have been well documented, little is known about the effects of such pregnancies on the use of health care resources and the associated costs. This is an important issue because of the increasing use of assisted-reproduction techniques, which commonly result in multiple-gestation pregnancies. METHODS: We determined hospital charges and the use of assisted-reproduction techniques (such as induction of ovulation, in vitro fertilization, and gamete intrafallopian transfer) for 13,206 pregnant women (11,986 with singleton pregnancies, 1135 with twin pregnancies, and 85 with more than two fetuses) who were admitted for delivery to Brigham and Women's Hospital, Boston, in 1986 through 1991 and their 14,033 neonates (11,671 singletons, 2144 twins, and 218 resulting from higher-order multiple gestations). RESULTS: After we controlled for variables known to affect hospital charges, the predicted total charges to the family in 1991 for a singleton delivery were $9,845, as compared with $37,947 for twins ($18,974 per baby) and $109,765 for triplets ($36,588 per baby). Assisted-reproduction techniques were used in 2 percent of singleton, 35 percent of twin, and 77 percent of higher-order multiple-gestation pregnancies; such procedures were approximately equally divided between induction of ovulation alone and in vitro fertilization or gamete intrafallopian transfer. CONCLUSIONS: Multiple-gestation pregnancies, a high proportion of which result from the use of assisted-reproduction techniques, dramatically increase hospital charges. If all the multiple gestations resulting from assisted-reproduction techniques, dramatically increase hospital charges. If all the multiple gestations resulting from assisted-reproduction techniques had been singleton pregnancies, the predicted savings to the health care delivery system in the study hospital alone would have been over $3 million per year. Although assisted reproduction provides tremendous benefits to families with infertility, the increased medical risks entailed by multiple-gestation pregnancies and the associated costs cannot be ignored. We suggest that more attention be paid to approaches to infertility that reduce the likelihood of multiple gestation.
Adolescent↗
The accuracy of symptom reporting by patients complaining of palpitations.
PURPOSE: To examine the relationship between patients' reports of palpitations and documented arrhythmias. PATIENTS AND METHODS: Consecutive patients complaining of palpitations and referred for 24-hour ambulatory electrocardiographic monitoring were studied using self-report questionnaires and a structured diagnostic interview. Electrocardiographic results were subsequently analyzed in conjunction with symptom diaries. Positive predictive value was used to estimate the likelihood that a reported symptom coincided with a documented arrhythmia. Sensitivity was calculated as a measure of the likelihood that an arrhythmia would be detected and reported as a symptom. RESULTS: Positive predictive value was inversely related to somatization, hypochondriacal attitudes, and psychiatric symptoms. It was not related to chronicity of palpitations, previously diagnosed heart disease, more extensive medical care utilization, or clinically significant arrhythmias. Patients were generally insensitive to their arrhythmias, failing to note the vast majority. CONCLUSIONS: Somatizing and hypochondriacal patients are not more sensitive to or accurately aware of subtle changes in cardiac activity, but rather may be expressing a response bias toward reporting somatic and psychologic distress in general. Apparently, patients do not learn to discriminate and detect cardiac activity more accurately as a result of having more medical care or suffering longer with their symptoms.
Adult↗