Apparent lack of seasonal variation in implantation rates after in-vitro fertilization

It has been suggested that seasonal variation in endometrial receptivity may occur in women, which could affect the likely success of in-vitro fertilization (IVF) treatment. We therefore studied implantation rates (fetal sacs as a proportion of embryos transferred) as an indirect index of receptivity in a narrowly defined population of women under 40 years old with normal ovulatory cycles and normal uterus and men with normal sperm function. A total of 577 cycles of IVF treatment were undertaken using a standard protocol of pituitary desensitization and ovarian stimulation during the 3 years 1990-1992. Results were compared between calendar months and 3-month seasons. The overall implantation rate was 14.9% of embryos, and the clinical pregnancy rate was 30.3% of cycles reaching egg collection. There were no significant differences in the monthly rates of eggs collected, fertilization and cleavage, or embryos transferred. Implantation rates varied to a greater extent but analysis of variance showed no seasonal variation. These findings do not support a seasonal variation in ovarian responsiveness or endometrial receptivity when stimulated for IVF treatment, but larger studies are needed for firm conclusions to be drawn.

Correlation of polymorphic expression of CYP2D6 mRNA in bladder mucosa and tumor tissue to in vivo debrisoquine hydroxylase activity

Debrisoquine hydroxylase activity has been attributed to CYP2D6 and poor metabolizers of debrisoquine have a reduced relative risk of developing aggressive bladder cancer. Production of a proximate carcinogen could occur in liver or bladder mucosa. However, it is not known if CYP2D6 is expressed in human bladder mucosa. In vivo whole body debrisoquine hydroxylase activity was measured as the debrisoquine recovery ratio (DBRR) following single dose oral administration of debrisoquine (10 mg) in 10 normal subjects and 20 patients with bladder cancer prior to diagnostic cystoscopy. Semi-quantitative PCR was used to measure mRNA for CYP2D6 in bladder tissue obtained at cystoscopy. Of the 30 subjects, three were phenotypically and genotypically poor metabolizers. Among the extensive metabolizers, there were extensive intersubject variations in DBRR. A 10-fold variation in CYP2D6 mRNA levels was observed in bladder tissue. There was a highly significant association between DBRR and CYP2D6 mRNA expression (r2 = 0.702, P < 0.001). These results demonstrate the presence of CYP2D6 mRNA in bladder mucosa. Furthermore, they are consistent with debrisoquine hydroxylation being mediated by CYP2D6 and suggest that differences in mRNA concentration are rate limiting for enzyme activity and that bladder mucosal regulation reflects total body regulation for this enzyme. The expression of CYP2D6 in bladder mucosa suggests that this enzyme could be involved in the local production of a proximate carcinogen in this tissue and contribute to the pathogenesis of bladder cancer in man.

Expression of dihydropyridine resistance differs in porcine bronchial and tracheal smooth muscle

Voltage-dependent and receptor-operated Ca2+ entry mechanisms have been demonstrated in airway smooth muscle, but their relative importance for maintenance of contraction is unknown. Blockade of voltage-dependent Ca2+ channels (VDC) has produced inconsistent relaxation. We postulated regional variations in Ca2+ handling by airway smooth muscle cells and compared the efficacy of dihydropyridine VDC blockers in tracheas and bronchi. Porcine tracheal smooth muscle strips and bronchial rings were mounted in tissue baths filled with physiological solutions and isometric tension was measured. Tissues were precontracted with carbachol or KCl, and relaxation dose-response curves to nifedipine, Mn2+, or Cd2+ were obtained. Relaxation responses to nifedipine were significantly different in carbachol-contracted tracheas and bronchi. Whereas carbachol-contracted tracheal muscle completely relaxed with 10(-6) M nifedipine, bronchial smooth muscle relaxed < 50%. In contrast, KCl-contracted bronchial muscle was completely relaxed by nifedipine. The nonspecific Ca2+ channel blockers Mn2+ and Cd2+ produced similar relaxation responses in each tissue. Thus VDC are the predominant mechanism for Ca2+ entry in porcine tracheal smooth muscle, but a dihydropyridine-insensitive pathway is functionally important in carbachol-contracted porcine bronchi. Regional variation may account for apparent inconsistencies between previous studies.

Prevalence of known diabetes in a multiethnic community

AIMS

To describe the prevalence of known diabetes in an area of New Zealand with a large Pacific Islands and Maori population.

METHOD

A cross sectional door to door census with identification of those with known diabetes was conducted between April and October 1992. The data was validated by comparison with available local general practice diabetes registers and data from a repeat visit to a randomly selected 5% of houses.

RESULTS

Interviews were completed at 92.7% of the 5081 households, containing 22,651 residents (1417 European, 5606 Maori, 14,802 Pacific Islands). The Pacific Islands population was 40% larger than that predicted from the 1991 census. The age adjusted prevalence of known diabetes in adults (aged > or = 20 years) was 2.8% (95% CI 1.9-3.9) in Europeans, 6.9% (95% CI 6.0-7.9) in Maori and 4.6% (95% CI 4.1-5.1) in Pacific Islands people. The greatest differences in prevalence were found in those aged 40-59 years. Interviews at 185/280 houses revisited showed that 13% of households had moved completely in the 2-8 months between visits. Comparison between participating general practice registers and the door to door survey database showed that 11.2% (26/232) of diabetic individuals were missed by the door to door survey, and 23.7% (55/232) were not on the register of the named general practitioner.

CONCLUSIONS

The prevalence of known diabetes in the community is much higher than that in the workforce. Differences between Maori and Pacific Islands people may be due to more undiagnosed diabetes or a lower risk of diabetes in the latter.

Why are children hospitalized? The role of non-clinical factors in pediatric hospitalizations

OBJECTIVE

Pediatric medical discharge rates vary widely across hospital service areas, beyond differences explained by chance or disease incidence alone. This study examines the relationship between the characteristics of local medical services and the likelihood of hospitalization.

DESIGN

Small area and population-based regression analysis.

SETTING

The 72 hospital service areas of Maine, New Hampshire, and Vermont.

STUDY POPULATION

The 589,290 (1989) children of Maine, New Hampshire, and Vermont < 15 years of age with 120,806 discharges during 1985 through 1989.

MEASUREMENT AND MAIN RESULTS

Using logistic regression and controlling for community income, we found that children residing in zip codes with high per capita bed supply (4.0/1000) had 9% more discharges (odds ratio: 1.09; 99% confidence interval: 1.07, 1.11) compared with children in areas with low per capita bed supply (1.9/1000). Children living 30 minutes from the nearest hospital had 15% fewer medical discharges (odds ratio: 0.849; confidence interval: 0.830, 0.867) than those living in a zip code with a hospital. Residence in one of the three academic medical center hospital service areas resulted in 32% fewer discharges (odds ratio: 0.68; confidence interval: 0.66, 0.70). Similar and statistically significant (P < .01) results were noted for the most common nonperinatal diagnostic categories: asthma/bronchitis (diagnostic related group = 98) and gastroenteritis (diagnostic related group = 184). No effect was noted for femur fracture, a condition for which admission rates equal disease incidence.

CONCLUSIONS

The supply and character of medical care are important influences on the likelihood of hospitalization for pediatric medical conditions for which outpatient alternatives are available.

Cost-effectiveness of streptokinase for acute myocardial infarction: A combined meta-analysis and decision analysis of the effects of infarct location and of likelihood of infarction

OBJECTIVE

To determine the effects of infarct location and of the likelihood of infarction on the cost-effectiveness of intravenous streptokinase (IVSK) for suspected acute myocardial infarction (AMI).

DESIGN

A meta-analysis of short-term survival was combined with a simple decision tree to determine marginal cost-effectiveness ratios for different infarct locations and different likelihoods of AMI (pMI).

SETTING

Six randomized trials comparing IVSK with conservative treatment.

PATIENTS

31,940 patients with onset of symptoms of AMI from four to 24 hours earlier and, with the exception of one trial, electrocardiographic abnormalities. Patients with contraindications to thrombolytic treatment such as uncontrolled hypertension were excluded.

MAIN RESULTS

If AMI is certain, treatment with IVSK has marginal cost-effectiveness ratios for each additional life saved of $9,900, $56,600, and $28,400, respectively, for patients with anterior, inferior, and other locations of AMI. If pMI is 50% treatment with IVSK has marginal cost-effectiveness ratios for each additional life saved of $22,700, $131,800, and $63,100, respectively, for patients with anterior, inferior, and other locations of AMI.

CONCLUSIONS

The marginal cost-effectiveness ratio for IVSK therapy of inferior infarction is six times that for anterior infarction and rises steeply as the presence of AMI becomes less certain. Assuming society is willing to pay $250,000 per life saved, IVSK therapy should be given if the chance of acute anterior infarction exceeds 7%, if the chance of inferior infarction exceeds 32%, or if the chance of infarction in other locations exceeds 17%. In patients with suspected acute myocardial infarction, IVSK saves lives and is a reasonable use of societal resources.

A decision analysis of alternative treatment strategies for clinically localized prostate cancer. Prostate Patient Outcomes Research Team

OBJECTIVE

To model the impact of initial therapy on outcomes for men with localized (clinical stage A or B) prostatic carcinoma.

DESIGN

A decision analysis modeling three strategies: radical prostatectomy, external-beam radiation therapy, and watchful waiting, with delayed hormonal therapy if metastatic disease develops. We modeled the main benefit of treatment as a reduction in the chance of death or disutility from metastatic disease. These benefits were offset in the model by the risks of treatment-related morbidity and mortality. The model was used to analyze expected outcomes by tumor grade (well, moderately, and poorly differentiated) for men 60 to 75 years of age.

DATA

Probabilities and rates for important clinical events, obtained through review of the literature for prostatic carcinoma and analysis of Medicare claims data.

MAIN RESULTS

Several patterns emerged within the range of uncertainty about the risks and benefits of treatment for prostatic carcinoma. In patients with well-differentiated tumor grades, based on clinical staging, treatment at best offers limited benefit in terms of quality-adjusted life expectancy and may result in harm to the patient. Among patients with moderately or poorly differentiated tumors, if we use the most optimistic assumptions about treatment efficacy, then patients aged 60 to 65 years would benefit from either radical prostatectomy or external-beam radiation therapy, compared with watchful waiting. However, in most other cases, treatment offers less than a 1-year improvement in quality-adjusted life expectancy or decreases the quality-adjusted life expectancy compared with watchful waiting. Invasive treatment generally appears to be harmful for patients older than 70 years.

CONCLUSIONS

Radical prostatectomy and radiation therapy may benefit selected groups of patients with localized prostate cancer, particularly younger patients with higher-grade tumors. However, our model shows that in most cases the potential benefits of therapy are small enough that the choice of therapy is sensitive to the patient's preferences for various outcomes and discounting. The choice of watchful waiting is a reasonable alternative to invasive treatment for many men with localized prostatic carcinoma.

Studying outcomes and hospital utilization in the elderly. The advantages of a merged data base for Medicare and Veterans Affairs hospitals

That veterans aged 65 years and older are eligible to receive care either in the Veteran Affairs (VA) health care system or in the private sector under Medicare confounds the analysis of veterans' health services utilization and outcomes in two ways. First, changes in eligibility or financial barriers to access with regard to either system influence veterans' decisions about where to seek needed care. Second, analyses of VA care for elderly veterans that rely solely on VA data sources underestimate both overall utilization and treatment complications. Similarly, failure to consider the contribution of health care delivery in the VA system may confound analyses of health care utilization by the Medicare-eligible population. To study the magnitude of such confounding influences, we linked the Medicare and VA health care administrative databases for residents of New England and New York. Results indicated that, for ten surgical procedures commonly performed in the elderly, as well as for hospitalizations resulting from acute myocardial infarction and hip fracture, VA patients receive from 17.6% to 37.4% of hospital care outside the VA system. Private hospitalizations account for 5.5% to 19.5% of the care received by veterans within 6 months after an initial episode of care in a VA hospital. It was also found that initial hospitalizations for study conditions in the VA accounted for 3.6% of all such hospitalizations among elderly Medicare-eligible men. Although overall hospital utilization appears to be underestimated in VA data sources, it was found that ascertaining mortality from sources available within the VA produced excellent results when compared with deaths recorded in the Medicare enrollment files. A national, merged VA-Medicare data base is feasible and would enhance the validity of analyses of health care delivery both for elderly veterans and for the Medicare population.

The accuracy of Medicare's hospital claims data: progress has been made, but problems remain

BACKGROUND

Health care databases provide a widely used source of data for health care research, but their accuracy remains uncertain. We analyzed data from the 1985 National DRG Validation Study, which carefully reabstracted and reassigned ICD-9-CM diagnosis and procedure codes from a national sample of 7050 medical records, to determine whether coding accuracy had improved since the Institute of Medicine studies of the 1970s and to assess the current coding accuracy of specific diagnoses and procedures.

METHODS

We defined agreement as the proportion of all reabstracted records that had the same principal diagnosis or procedure coded on both the original (hospital) record and on the reabstracted record. We also evaluated coding accuracy in 1985 using the concepts of diagnostic test evaluation.

RESULTS

Overall, the percentage of agreement between the principal diagnosis on the reabstracted record and the original hospital record, when analyzed at the third digit, improved from 73.2% in 1977 to 78.2% in 1985. However, analysis of the 1985 data demonstrated that the accuracy of diagnosis and procedure coding varies substantially across conditions.

CONCLUSIONS

Although some diagnoses and all major surgical procedures that we examined were accurately coded, the variability in the accuracy of diagnosis coding poses a problem that must be overcome if claims-based research is to achieve its full potential.

Is coronary-care-unit admission restricted for elderly patients? A multicenter study

BACKGROUND

To investigate whether elderly patients are more likely to experience restricted access to high technology medical care, we examined the impact of age on the likelihood of coronary care unit (CCU) admission for patients with acute myocardial infarction.

METHODS

As part of a prospective investigation of emergency room triage for patients with suspected cardiac ischemia, we studied 4223 patients presenting to six hospitals. Because CCU admission is the accepted standard of care for acute infarction, we defined nonadmission to the CCU as a restriction of access to care. We used a logistic regression model to control for gender, hospital, and CCU occupancy at the time of admission and examined the relationship between age and CCU nonadmission.

RESULTS

Patients 75 years or older with acute myocardial infarction were 2.5 times more likely not to be admitted to the CCU than younger patients (RR 2.5, 95% CI 1.64, 3.85). Coronary unit admission was restricted even when the physician's admitting diagnosis was "myocardial infarction" (RR 7.1, 95% CI 2.1, 25.0) or "rule-out myocardial infarction" (RR 1.5, 95% CI 1.1, 2.1). Observed differences in clinical presentation or severity of illness between older and younger patients did not account for these findings.

CONCLUSION

Our findings suggest that physicians may intentionally restrict access to coronary care for elderly patients with acute myocardial infarction.

Ethical issues in caring for the patient with advanced cancer

The patient in the advanced stages of cancer presents many challenges for the nurse caregiver. To care for the patient effectively as the end of life approaches requires a shift in focus from cure or treatment of the disease to the management of the associated symptoms. This is the primary goal of palliative care, a unique approach to meeting the needs of this vulnerable patient group. The clinical issues that are common in the care of the patient with advanced cancer may raise specific ethical concerns for the nurse. Managing the symptoms with the goal of palliative care in mind will help to frame these concerns more clearly. Communicating with patients and families on an ongoing basis in a clear and sensitive manner will help to ensure that patients' decisions are known and respected. Nurses need to be prepared to assist in these difficult situations. A nursing ethics group is one method that has been found to be effective in developing nurses' expertise in this area.

Ethics committees in health care institutions in the New York City metropolitan region: a report of two nursing surveys

Two surveys were conducted independently to ascertain whether health care institutions in the New York City metropolitan region currently have ethics committees and to gather information related to their functioning and use by nurses. Comparable findings in the overlapping samples suggest that approximately one-third of surveyed institutions do not have interdisciplinary ethics committees. Where the committees do exist, they may not be adequate to address nurses' ethical concerns.

Automated critiquing of medical decision trees

The authors developed a decision tree-critiquing program (called BUNYAN) that identifies potential modeling errors in medical decision trees. The program's critiques are based on the structure of a decision problem, obtained from an abstract description specifying only the basic semantic categories of the model's components. A taxonomy of node and branch types supplies the primitive building blocks for representing decision trees. Bunyan detects potential problems in a model by matching general pattern expressions that refer to these primitives. A small set of general principles justifies critiquing rules that detect four categories of potential structural problems: impossible strategies, dominated strategies, unaccountable violations of symmetry, and omission of apparently reasonable strategies. Although critiquing based on structure alone has clear limitations, principled structural analysis constitutes the core of a methodology for reasoning about decision models.