Increased Expression of Anaphylatoxin C5a-Receptor-1 in Neutrophils and Natural Killer Cells of Preterm Infants

Preterm infants are susceptible to infection and their defense against pathogens relies largely on innate immunity. The role of the complement system for the immunological vulnerability of preterm infants is less understood. Anaphylatoxin C5a and its receptors C5aR1 and -2 are known to be involved in sepsis pathogenesis, with C5aR1 mainly exerting pro-inflammatory effects. Our explorative study aimed to determine age-dependent changes in the expression of C5aR1 and C5aR2 in neonatal immune cell subsets. Via flow cytometry, we analyzed the expression pattern of C5a receptors on immune cells isolated from peripheral blood of preterm infants (n = 32) compared to those of their mothers (n = 25). Term infants and healthy adults served as controls. Preterm infants had a higher intracellular expression of C5aR1 on neutrophils than control individuals. We also found a higher expression of C5aR1 on NK cells, particularly on the cytotoxic CD56^dim subset and the CD56^- subset. Immune phenotyping of other leukocyte subpopulations revealed no gestational-age-related differences for the expression of and C5aR2. Elevated expression of C5aR1 on neutrophils and NK cells in preterm infants may contribute to the phenomenon of "immunoparalysis" caused by complement activation or to sustained hyper-inflammatory states. Further functional analyses are needed to elucidate the underlying mechanisms.

Hyperoxia/Hypoxia Exposure Primes a Sustained Pro-Inflammatory Profile of Preterm Infant Macrophages Upon LPS Stimulation

Preterm infants are highly susceptible to sustained lung inflammation, which may be triggered by exposure to multiple environmental cues such as supplemental oxygen (O₂) and infections. We hypothesized that dysregulated macrophage (MФ) activation is a key feature leading to inflammation-mediated development of bronchopulmonary dysplasia (BPD) in preterm infants. Therefore, we aimed to determine age-dependent differences in immune responses of monocyte-derived MФ comparing cord blood samples derived from preterm (n=14) and term (n=19) infants as well as peripheral blood samples from healthy adults (n=17) after lipopolysaccharide (LPS) exposure. Compared to term and adult MФ, LPS-stimulated preterm MФ showed an enhanced and sustained pro-inflammatory immune response determined by transcriptome analysis, cytokine release inducing a RORC upregulation due to T cell polarization of neonatal T cells, and TLR4 surface expression. In addition, a double-hit model was developed to study pulmonary relevant exposure factors by priming MФ with hyperoxia (O₂ = 65%) or hypoxia (O₂ = 3%) followed by lipopolysaccharide (LPS, 100ng/ml). When primed by 65% O₂, subsequent LPS stimulation in preterm MФ led to an exaggerated pro-inflammatory response (e.g. increased HLA-DR expression and cytokine release) compared to LPS stimulation alone. Both, exposure to 65% or 3% O₂ together with subsequent LPS stimulation, resulted in an exaggerated pro-inflammatory response of preterm MФ determined by transcriptome analysis. Downregulation of two major transcriptional factors, early growth response gene (Egr)-2 and growth factor independence 1 (Gfi1), were identified to play a role in the exaggerated pro-inflammatory response of preterm MФ to LPS insult after priming with 65% or 3% O₂. Preterm MФ responses to LPS and hyperoxia/hypoxia suggest their involvement in excessive inflammation due to age-dependent differences, potentially mediated by downregulation of Egr2 and Gfi1 in the developing lung.

Increased Regulatory T Cells Precede the Development of Bronchopulmonary Dysplasia in Preterm Infants

Regulatory T cells (Tregs) are important for the ontogenetic control of immune activation and tissue damage in preterm infants. However, the role of Tregs for the development of bronchopulmonary dysplasia (BPD) is yet unclear. The aim of our study was to characterize CD4+ CD25+ forkhead box protein 3 (FoxP3)+ Tregs in peripheral blood of well-phenotyped preterm infants (n = 382; 23 + 0 – 36 + 6 weeks of gestational age) with a focus on the first 28 days of life and the clinical endpoint BPD (supplemental oxygen for longer than 28 days of age). In a subgroup of preterm infants, we characterized the immunological phenotype of Tregs (n = 23). The suppressive function of Tregs on CD4+CD25- T cells was compared in preterm, term and adult blood. We observed that extreme prematurity was associated with increased Treg frequencies which peaked in the second week of life. Independent of gestational age, increased Treg frequencies were noted to precede the development of BPD. The phenotype of preterm infant Tregs largely differed from adult Tregs and displayed an overall naïve Treg population (CD45RA+/HLA-DR-/Helios+), especially in the first days of life. On day 7 of life, a more activated Treg phenotype pattern (CCR6+, HLA-DR+, and Ki-67+) was observed. Tregs of preterm neonates had a higher immunosuppressive capacity against CD4+CD25- T cells compared to the Treg compartment of term neonates and adults. In conclusion, our data suggest increased frequencies and functions of Tregs in preterm neonates which display a distinct phenotype with dynamic changes in the first weeks of life. Hence, the continued abundance of Tregs may contribute to sustained inflammation preceding the development of BPD. Functional analyses are needed in order to elucidate whether Tregs have potential as future target for diagnostics and therapeutics.

IgG Fc Glycosylation Patterns of Preterm Infants Differ With Gestational Age

Preterm infants acquire reduced amounts of Immunoglobulin G (IgG) via trans-placental transfer as compared to term infants which might explain their high susceptibility for infections. The reduced amount of IgG antibodies also results in a lower amount of anti-inflammatory Fc N-galactosylated and -sialylated IgG antibodies. This reduction or, even more, a qualitative shift in the type of IgG Fc glycosylation might contribute to the increased risk for sustained inflammatory diseases in preterm infants. It was the aim of our explorative study to investigate the IgG Fc glycosylation patterns in preterm infants of different gestational ages compared to term infants and mothers of preterm infants. In plasma samples of preterm infants (n = 38), we investigated IgG concentrations by use of ELISA. Furthermore, we analyzed IgG Fc glycosylation patterns in plasma of preterm infants (n = 86, 23-34 weeks of gestation), term infants (n = 15) and mothers from preterm infants (n = 41) using high performance liquid chromatography. Extremely low gestational age infants (born < 28 weeks of gestation during second trimester) had reduced IgG concentrations and decreased proportions of galactosylated (84.5 vs. 88.4%), sialylated (14.5 vs. 17.9%) and bisecting N-acetylglucosamine-containing (8.4 vs. 10.8%) IgG Fc N-linked glycans as compared to preterm infants born ≥28 weeks of gestation (during third trimester) and term infants. Increased non-galactosylated (agalactosylated, 16.9 vs. 10.6%) IgG Fc N-linked glycans were associated with the development of chronic inflammatory bronchopulmonary dysplasia (BPD). However, mothers of preterm infants born during second or third trimester of pregnancy did not show significant differences in IgG Fc glycosylation patterns. Thus, the IgG Fc glycosylation patterns of preterm infants depend on their gestational age. Although lack of bisecting N-acetylglucosamine has been associated with less inflammatory effector functions, the decreased IgG Fc galactosylation and sialylation with lower gestational age suggest a rather pro-inflammatory pattern. The difference in IgG Fc glycosylation patterns between preterm infants and mothers of preterm infants suggests a selective enrichment of IgG glyco forms in preterm infants, which might contribute to or result of the development of sustained inflammatory diseases like BPD.

Delivery mode and intraventricular hemorrhage risk in very-low-birth-weight infants: Observational data of the German Neonatal Network

BACKGROUND

Very-low-birth-weight infants (VLBWI) are frequently delivered by cesarean section (CS). However, it is unclear at what gestational age the benefits of spontaneous delivery outweigh the perinatal risks, i.e. intraventricular hemorrhage (IVH) or death.

OBJECTIVES

To assess the short-term outcome of VLBWI on IVH according to mode of delivery in a population-based cohort of the German Neonatal Network (GNN).

STUDY DESIGN

A total cohort of 2203 singleton VLBWI with a birth weight <1500g and gestational age between 22 0/7 and 36 6/7 weeks born and discharged between 1st of January 2009 and 31st of December 2015 was available for analysis. VLBWI were stratified into three categories according to mode of delivery: (1) planned cesarean section (n=1381), (2) vaginal delivery (n=632) and (3) emergency cesarean section (n=190). Outcome was assessed in univariate and logistic regression analyses.

RESULTS

Prevalence of IVH was significantly higher in the vaginal delivery (VD) (26.6%) and emergency CS group (31.1%) as compared to planned CS (17.2%), respectively. In a logistic regression analysis including known risk factors for IVH, vaginal delivery (OR 1.725 [1.325-2.202], p≤0.001) and emergency cesarean section (OR 1.916 [1.338-2.746], p≤0.001) were independently associated with IVH risk. In the subgroup of infants >30 weeks of gestation prevalence for IVH was not significantly different in VD and planned CS (5.3% vs. 4.4%).

CONCLUSIONS

Our observational data demonstrate that elective cesarean section is associated with a reduced risk of IVH in preterm infants <30 weeks gestational age when presenting with preterm labor.

Regulatory T cell frequencies are increased in preterm infants with clinical early-onset sepsis

The predisposition of preterm neonates to invasive infection is, as yet, incompletely understood. Regulatory T cells (Tregs ) are potential candidates for the ontogenetic control of immune activation and tissue damage in preterm infants. It was the aim of our study to characterize lymphocyte subsets and in particular CD4(+) CD25(+) forkhead box protein 3 (FoxP3)(+) Tregs in peripheral blood of well-phenotyped preterm infants (n = 117; 23 + 0 - 36 + 6 weeks of gestational age) in the first 3 days of life in comparison to term infants and adults. We demonstrated a negative correlation of Treg frequencies and gestational age. Tregs were increased in blood samples of preterm infants compared to term infants and adults. Notably, we found an increased Treg frequency in preterm infants with clinical early-onset sepsis while cause of preterm delivery, e.g. chorioamnionitis, did not affect Treg frequencies. Our data suggest that Tregs apparently play an important role in maintaining maternal-fetal tolerance, which turns into an increased sepsis risk after preterm delivery. Functional analyses are needed in order to elucidate whether Tregs have potential as future target for diagnostics and therapeutics.

Survival trends of Staphylococcus aureus, Pseudomonas aeruginosa, and Clostridium perfringens in a sandy South Florida beach

The search for alternative indicators of disease-risk from non-enteric pathogens at the beach revealed high densities of targeted bacteria. To explain the high numbers of potential non-enteric pathogens, Staphylococcus aureus and Pseudomonas aeruginosa, in beach sand, we investigated factors affecting their survival and distribution, as well as those of a potential fecal indicator, Clostridium perfringens. Results indicated greater S. aureus and P. aeruginosa survival and proliferation in sterile beach sand, than seawater, with diminished numbers upon exposure to natural micro-predators. C. perfringens remained relatively consistent with initial numbers. Intermediate sand particles (850 μm-2 mm) constituted the major micro-niche; creating implications for beach classification programs. Colonization of sterile sand boxes at the beach by S. aureus and P. aeruginosa confirmed the filtering action (>100×) of beach sand. The use of these potential pathogens in periodic sanitary evaluation of beach sand quality is indicated, regardless of the factors influencing their abundance.

Survival potential of Escherichia coli and Enterococci in subtropical beach sand: implications for water quality managers

Fecal bacteria have traditionally been used as indicator organisms to monitor the quality of recreational waters. Recent work has questioned the robustness of traditional indicators, particularly at seawater bathing beaches. For example, a study of Florida beaches found unexpectedly high abundances of Escherichia coli, fecal coliforms, and enterococci in beach sand. The aim of the present study was to explain these abundances by assessing the survival of E. coli and enterococci in beach sand relative to seawater. We used a combination of quantitative laboratory mesocosm experiments and field observations. Results suggested that E. coli and enterococci exhibited increased survivability and growth in sand relative to seawater. Because fecal bacteria are capable of replicating in sand, at least under controlled laboratory conditions, the results suggest that sand may be an important reservoir of metabolically active fecal organisms. Experiments with "natural" mesocosms (i.e., unsterilized sand or water rich in micropredators and native bacteria) failed to show the same increases in fecal indicators as was found in sterile sand. It is postulated that this was due to predation and competition with indigenous bacteria in these "natural" systems. Nonetheless, high populations of indicators were maintained and recovered from sand over the duration of the experiment as opposed to the die-off noted in water. Indicator bacteria may wash out of sand into shoreline waters during weather and tidal events, thereby decreasing the effectiveness of these indicators as predictors of health risk and complicating the interpretations for water quality managers.

Quality of a family medicine preceptorship is significantly associated with matching into family practice

OBJECTIVES

This study tested whether clinical experiences in family practice are associated with matching into family practice.

METHODS

We conducted a prospective cohort study of 913 medical students who completed the Family Practice Preceptorship (FPP) at the University of Iowa from 1990-1996. Using univariate techniques and logistic regression, we compared the background and experiences of those who matched into family practice with those who chose other specialties.

RESULTS

Twenty-nine percent (n=267) matched into family practice. Positive independent predictors of family practice match were hometown size less than 10,000 (odds ratio [OR] 1.8), anticipating choosing family practice at matriculation (OR 4.2), and liking to help others (OR 4.1). Negative independent predictors included parental income of at least $120,000 (OR .61), desiring to perform technical procedures (OR .51), and liking the scientific method and research (OR .54). The effect of an early summer clinical experience at a community hospital varied depending on the level of student interest in family practice at matriculation. Students who rated the educational value of the FPP as high or very high were significantly more likely to go into family practice (OR 2.9), even after adjusting for all other student characteristics.

CONCLUSIONS

A number of student characteristics and preferences, early clinical experiences, and the perceived quality of a required family medicine preceptorship were significantly and independently associated with students matching into family practice.

Surgeon characteristics associated with mortality and morbidity following carotid endarterectomy

PURPOSE

To identify surgeon characteristics associated with mortality or morbidity, following carotid endarterectomy (CEA).

METHODS

Data on all inpatient discharges from the 284 nonfederal Pennsylvania hospitals were obtained from the Pennsylvania Health Care Cost Containment Council for the period from 1994 to 1995. Physician data were obtained from the Physicians List of the American Medical Association, including name, gender, specialty, year of birth, board certified, and year of licensure. Cases were selected if any of six procedures codes were ICD-9-CM rubric 38.12, indicating CEA.

RESULTS

Among the 12,725 cases studied, in-hospital mortality was 0.7%, nonfatal morbidity was 3.0%, and the total bad outcome rate was 3.7%. Surgeons who performed 1 to 2 CEAs over 2 years had the highest mortality (2.0%) and total bad outcome (9.2%) rates. For surgeons performing three or more cases in 2 years, increased volume was not associated with better outcomes. A greater number of years since the surgeon was licensed was associated with greater mortality (p = 0.001), but not with morbidity or bad outcome rates. In regression analyses that adjusted for patient risk, both years since licensure and specialty predicted surgical mortality rate, but only volume predicted surgical bad outcome rate.

CONCLUSIONS

More years since licensure and very low patient volume are associated with worse patient outcomes following CEA.

Is paracervical block safe and effective? A prospective study of its association with neonatal umbilical artery pH values

BACKGROUND

Paracervical blocks (PCBs) relieve labor pain, but reports of associated complications have caused many physicians to question their safety.

METHODS

We designed a prospective observational study to examine the association between PCBs and umbilical artery hydrogen ion concentration (pH) values. A total of 261 healthy women in labor were recruited from a community hospital. Physicians used 1% lidocaine for the PCBs. We used multivariate linear regression to model predictors of umbilical artery pH at birth.

RESULTS

Of the women studied, 238 (91%) received analgesia during labor (nalbuphine, PCB, pudendal, caudal, or epidural). Of these, 126 (48%) received at least one PCB (191 were given), and 197 (76%) received at least one dose of nalbuphine (237 were given). Univariate analyses showed no significant differences in mean 1-minute Apgar scores, 5-minute Apgar scores, umbilical artery pH, resuscitation with oxygen by mask, or length of newborn stay according to either PCB or nalbuphine exposure. Factors significantly associated with lower umbilical artery pH in a linear regression analysis included longer second stage of labor (-0.032 pH units for each 1-hour increase; 95% confidence interval [CI], -.046 to -.018), pudendal block (-0.022; 95% CI, -.040 to -.004), intrauterine pressure catheter use (-0.029; 95% CI, -0.053 to -.006), nuchal cord (-0.027; 95% CI, -.051 to -.004), and midforceps delivery (-0.080; 95% CI, -.159 to .000). Increasing maternal age and induction with either artificial rupture of membranes or gel were associated with higher umbilical artery pH values.

CONCLUSIONS

After adjusting for other variables, neither PCB nor nalbuphine use were associated with umbilical artery pH at birth. PCBs using 1% lidocaine injected superficially should be considered a safe and effective form of obstetric analgesia. PCBs may be especially useful for women giving birth in hospitals where other obstetric anesthesia services are not readily available.

What clinical information resources are available in family physicians' offices?

BACKGROUND

When faced with questions about patient care, family physicians usually turn to books in their personal libraries for the answers. The resources in these libraries have not been adequately characterized.

METHODS

We recorded the titles of all medical books in the personal libraries of 103 randomly selected family physicians in eastern Iowa. We also noted all clinical information that was posted on walls, bulletin boards, refrigerators, and so forth. Participants were asked to describe their use of other resources such as computers, MEDLINE, reprint files, and "peripheral brains" (personal notebooks of clinical information). For each physician, we recorded how often the resources were used to answer clinical questions during 2 half-day observation periods.

RESULTS

The 103 participants owned a total of 5794 medical books, with 2836 different titles. Each physician kept an average of 56 books in the office. Prescribing references (especially the Physicians' Desk Reference) were most common (owned by 100% of the participants), followed by books on general internal medicine (99%), adult infectious disease (89%), and general pediatrics (83%). Books used to answer clinical questions were more likely to be up to date (copyright date within 5 years) than unused books (74% vs 27%, P <.001). Items posted on walls included drug dosage charts and pediatric immunization schedules. Only 26% of the physicians had computers in their offices.

CONCLUSIONS

Drug-prescribing textbooks were the most common type of book in family physicians' offices, followed by books on general internal medicine and adult infectious diseases. Although many books were relatively old, those used to answer clinical questions were generally current.

Improvement in resource utilization after development of a clinical pathway for patients with pressure ulcers

Clinical pathways are interdisciplinary patient care plans intended to reduce variance and improve quality of care while lowering health care cost. This study was undertaken to determine whether the development of a clinical pathway for care of patients with pressure ulcers can indeed decrease health care costs while preserving quality of care. A clinical pathway for surgical reconstruction of pressure ulcers was developed by standardizing the current practices of our plastic surgeon group. The pathway provided direction in optimal scheduling of physician interventions along with nursing, physical and occupational therapies, and spinal cord rehabilitation interventions. It covered all potential elements of patient care, including laboratory, radiology, dietary services, intravenous fluids, and use of specialty beds. It defined patient outcomes and outlined discharge planning. Pathways were distributed throughout all services caring for patients with pressure ulcers. Patient charts and billing data were reviewed for the 16-month periods before and after initiation of the pathway. No other significant changes in treatment occurred during this time frame. Ninety-seven patient charts were examined (54 before pathway and 43 after pathway implementation). Parameters evaluated included length of stay and total charges (including bed use, medications, laboratory tests, and radiology). Patient readmission rate was also examined. A significant reduction in patient length of stay and total charges was achieved after implementation of the clinical pathway. Reduction was seen not only for patients treated with flaps by plastic surgery but also for patients with pressure ulcers who were not specifically targeted such as those from other services. The readmission rate decreased slightly, although not significantly, after the pathway inception. Total cost saving was almost $11,000 per patient (23 percent). In conclusion, implementation of a clinical pathway, because it standardizes care and reduces variations and duplication of care, can reduce health care cost without impairing quality of care in the treatment of decubitus ulcer patients.

Comparison of pneumatic retinopexy and scleral buckling in the management of primary rhegmatogenous retinal detachment. Southern Wisconsin Pneumatic Retinopexy Study Group

PURPOSE

To compare pneumatic retinopexy and scleral buckling for repair of primary rhegmatogenous retinal detachment with respect to visual outcome, single-procedure reattachment rate, and development of proliferative vitreoretinopathy.

METHODS

A consecutive series of eyes initially treated with pneumatic retinopexy (n = 56) between March 1986 and February 1996 were compared with a selected group of eyes treated with scleral buckling (n = 86) with similar location and distribution of retinal breaks and absence of proliferative vitreoretinopathy. A regression model was developed to adjust for underlying differences between treatment groups, resulting in a cohort of 50 eyes in each group for final comparison. A minimum follow-up of 6 months was obtained.

RESULTS

Single-procedure reattachment rate was significantly higher for scleral buckle eyes (42 of 50 eyes, 84%) than for pneumatic retinopexy eyes (31 of 50 eyes, 62%; P < or = .01). Correspondingly, reoperation rate was significantly higher for pneumatic retinopexy eyes (19 of 50 eyes, 38%) than for scleral buckle eyes (7 of 50 eyes, 14%; P < or = .01). Multiple regression analysis evaluating perioperative factors demonstrated that the use of pneumatic retinopexy was the sole factor predictive of retinal detachment after a single procedure (relative odds = 2.20, P = .02). Final reattachment rate, after reoperations, was 98% (49 of 50 eyes) in each group. Except for nonphakic eyes, final visual outcome and rate of postoperative proliferative vitreoretinopathy development did not differ significantly between the two procedures.

CONCLUSIONS

In phakic eyes, pneumatic retinopexy was associated with a significantly higher reoperation rate than scleral buckling, but resulted in equivalent final visual outcome and reattachment rate after reoperations. If used, it must be incorporated into a strategy in which patient and physician are prepared for a greater chance of reoperation compared to initial management with scleral buckling.

Results of peripheral laser photocoagulation in pars planitis

PURPOSE

To determine the effect of peripheral retinal laser photocoagulation (PLP) on visual acuity, intraocular inflammation, and other ocular findings, including retinal neovascularization in eyes with pars planitis.

METHODS

A retrospective chart review of eyes with pars planitis that had undergone PLP.

RESULTS

Twenty-two eyes in 17 patients with pars planitis had undergone treatment with PLP at 2 centers. The mean age at the time of treatment was 19.3 years. Following treatment, mean follow-up was 16.3 months (range, 6 to 37 months). Mean visual acuity was 20/60 preoperatively and 20/50 postoperatively. This level of improvement was not statistically significant (P > .10), but there was a statistically significant decrease in the use of corticosteroids between the preoperative examination and the last postoperative examination (86% versus 27%, P < .05). There was also a statistically significant decrease in vitritis at the last follow-up (P = .0008) and a decrease in neovascularization of the vitreous base (P = .03) and in clinically apparent cystoid macular edema (P = .02). Epiretinal membranes were noted in 23% of eyes preoperatively and in 45% of eyes postoperatively. Only one of these epiretinal membranes was considered to be visually significant. One eye developed a tonic dilated pupil, which slowly improved.

CONCLUSIONS

Although the long-term natural history of clinical findings in pars planitis is not well documented, PLP appears to decrease the need for corticosteroids while stabilizing visual acuity. It also appears to decrease vitreous inflammation. PLP has few complications and should be considered in patients with pars planitis who are unresponsive or have adverse reactions to corticosteroids.

Use of postoperative information to predict mortality rates for patients who have long stays in the intensive care unit after coronary artery bypass grafting

OBJECTIVE

To derive and evaluate prediction models for patients who had undergone coronary artery bypass grafting (CABG) and had a difficult postoperative course.

DESIGN

Observational.

SETTING

Midwestern hospital specializing in high-risk CABG procedures.

PATIENTS

One hundred eighty-three patients who stayed at least 10 consecutive days in the intensive care unit after a CABG procedure.

OUTCOME MEASURE

Death within 60 days of surgery.

INTERVENTION

None.

RESULTS

The final logistic regression prediction models included the following findings: pulmonary capillary wedge pressure, cardiac index, heart rate, urine output, positive end-expiratory pressure, blood urea nitrogen levels, and the arterial pressure of carbon dioxide. The model was able to stratify patients into four risk groups with observed 60-day mortality rates of 0.0% (n = 107), 21% (n = 39), 55% (n = 20), and 88% (n = 17). Preoperative patient information was not associated with prognosis for these patients.

CONCLUSIONS

The findings suggest that a risk model that is specific for patients who have undergone CABG and is based on postoperative findings may provide useful prognostic information for patients who are having a difficult postoperative course.

Physician extenders for cost-effective management of hypercholesterolemia

OBJECTIVE

Treatment of elevated cholesterol levels reduces morbidity and mortality from coronary heart disease in high-risk patients, but can be costly. The purpose of this study was to determine whether physician extenders emphasizing diet modification and, when necessary, effective and inexpensive drug algorithms can provide more cost-effective therapy than conventional care.

DESIGN

Randomized controlled trial.

SETTING

A Department of Veterans Affairs Medical Center.

PATIENTS

Two hundred forty-seven veterans with type IIa hypercholesterolemia.

INTERVENTIONS

Patients assigned to either a cholesterol treatment program (CTP) or usual health care provided by general internists (UHC). CTP included intensive dietary therapy administered by a registered dietitian utilizing individual and group counseling and drug therapy initiated by physician extenders for those failing to achieve goal low-density lipoprotein (LDL) levels with diet alone. A drug selection algorithm for CTP subjects utilized niacin as initial therapy followed by bile acid sequestrants and lovastatin. Subjects were followed prospectively for 2 years.

MEASUREMENTS

Primary outcome measurements were effectiveness of therapy defined as reductions in LDL cholesterol (LDL-C), and whether goal LDL-C levels were achieved; costs of therapy; and cost-effectiveness defined as the cost per unit reduction in the LDL-C.

MAIN RESULTS

Total program costs were higher for CTP patients than for UHC patients ($659 +/- $43 vs $477 +/- $42 per patient, p < .001). However, at 24 months the patients in CTP were more likely to achieve LDL goal levels (65% vs 44%, p < .005), and also achieved greater reductions in LDL-C 27% +/- 2% vs 14% +/- 2% at 24 months, p < .001). Program costs per unit (mmol/L) reduction in the LDL-C, a measure of cost-effectiveness, was significantly lower for CTP ($758 +/- $58 vs $1,058 +/- $70, p = .002).

CONCLUSIONS

Although more expensive than usual care, the greater effectiveness of physician extenders implementing cholesterol treatment algorithms resulted in more cost-effective therapy.

Are PRO discharge screens associated with postdischarge adverse outcomes?

OBJECTIVE

We evaluate whether patient outcomes may be affected by possible errors in care at discharge as assessed by Peer Review Organizations (PROs).

DATA SOURCES/STUDY SETTING

The three data sources for the study were (1) the generic screen results of a 3 percent random sample of Medicare beneficiaries age 65 years or older who were admitted to California hospitals between 1 July 1987 and 30 June 1988 (n = 20,136 patients); (2) the 1987 and 1988 California Medicare Provided Analysis and Review (MEDPAR) data files; and (3) the American Hospital Association (AHA) 1988 Annual Survey of Hospitals.

STUDY DESIGN

Multivariate logistic regression analysis was used to evaluate the association between the results of generic discharge administered by the PROs and two patient outcomes: mortality and readmission within 30 days. The analysis was adjusted for other patient characteristics recorded on the uniform discharge abstract.

PRINCIPAL FINDINGS

Four discharge screens indicated an increased risk of an adverse outcome-absence of documentation of discharge planning, elevated temperature, abnormal pulse, and unaddressed abnormal test results at discharge. The other three discharge screens examined-abnormal blood pressure, IV fluids or drugs, and wound drainage before discharge-were unrelated to postdischarge adverse outcomes.

CONCLUSIONS

Generic discharge screens based on inadequate discharge planning, abnormal pulse, increased temperature, or unaddressed abnormal tests may be important indicators of substandard care. Other discharge screens apparently do not detect errors in care associated with major consequences for patients.

Telephone contacts do not improve adherence to niacin or bile acid sequestrant therapy

OBJECTIVE

Noxious adverse effects frequently limit patient acceptance of niacin and bile acid sequestrants (BAS), first-line agents in the management of hypercholesterolemia. The purpose of this study was to determine whether telephone contacts from a healthcare professional could improve drug adherence and tolerance in patients prescribed these medications.

PATIENTS AND METHODS

This was a randomized, single-blind trial of telephone contacts vs. no intervention in patients with hyperlipidemia who were prescribed either niacin or BAS in a large, Veterans Affairs, lipid clinic. Patients randomized to telephone contact (n = 81) received weekly calls from a trained healthcare professional during the first month of drug therapy. Counseling regarding adverse effects, and prescriptions to overcome minor adverse effects, were provided as needed to patients during the telephone contact.

RESULTS

Significant differences were not observed between groups in the drug discontinuance rate, adherence assessed by two independent methods, or in the final dosage of medication ingested.

CONCLUSIONS

Telephone contacts do not improve either adherence or tolerance to niacin or BAS. Alternative approaches to enhance acceptance of these medications requires further evaluation.

Postoperative fibrin formation and visual outcome after pars plana vitrectomy

PURPOSE

To determine whether postvitrectomy fibrin formation was associated with visual outcome, a prospective study of patients undergoing pars plana vitrectomy was performed.

METHODS

In 121 patients undergoing vitrectomy at the Medical College of Wisconsin between July 1986 and April 1989, the association of fibrin formation and other perioperative factors with visual outcome was evaluated by univariate and multivariate regression analysis. Poor visual outcome was defined as visual acuity worse than 5/200.

RESULTS

After a median follow-up period of 23 months (range 6 to 51 months), patients with severe fibrin formation experienced a higher rate of poor visual outcome (19 of 26 patients, 73%) than patients with little or no fibrin formation (23 of 95 patients, 24%; P < 0.0001, univariate analysis). After adjusting for a variety of factors with multivariate regression analysis, fibrin formation was not significantly predictive of final visual outcome.

CONCLUSIONS

Factors associated with postvitrectomy fibrin formation may affect visual outcome more than fibrin formation itself.

Physician characteristics affecting referral decisions following an exercise tolerance test

OBJECTIVE

To examine whether physician background and attitudes were altered to the decision to refer a patient with chronic angina to a cardiologist following the results of an exercise tolerance test.

DESIGN

Mailed questionnaire asking family physicians and internists how they would make referral decisions for a patient with classic angina in a detailed case vignette.

PARTICIPANTS

Two hundred sixty-five family physicians and 105 internists.

OUTCOME MEASURES

Physician referral decisions following results of an exercise tolerance test.

RESULTS

Only 15% of the respondents believed that the patient should have been directly referred for cardiac catheterization without conducting an exercise tolerance test previously. Data on the remaining 85% of physicians were analyzed to identify factors influencing referral decisions. These physicians were significantly more likely to refer a patient if they were concerned about a lawsuit (68% vs 53% following a test result suggesting coronary disease and 40% vs 24% following a normal test result). Referral decisions were significantly more likely to be changed on the basis of the test result if the test was administered to determine the need for cardiac catheterization (50% vs 34%) or if the physician was a family practitioner rather than an internist (47% vs 24%). A physician's number of years in practice, experience with patients with angina, and board certification were not associated with referral decisions.

CONCLUSIONS

Many physicians with very different attitudes and backgrounds order diagnostic tests for reasons other than to make referral decisions. This problem appeared to be less prevalent among family physicians than internists, and it may partly be due to fear of lawsuits or lack of knowledge about how the test should be used.

Evaluation of the effectiveness of lipid-lowering therapy (bile acid sequestrants, niacin, psyllium and lovastatin) for treating hypercholesterolemia in veterans

Veterans are frequently older, have more chronic illnesses, and take more medications than subjects volunteering for clinical trials. Because these factors may impair the effectiveness of lipid-lowering drug therapy, the effectiveness of drug therapy in veterans may differ from that measured in randomized controlled trials. In 297 patients with type IIa hyperlipidemia attending a large Veterans Administration Medical Center lipid clinic, adverse effects, compliance, lipid and lipoprotein responses to drug therapy were prospectively monitored. Bile acid sequestrants (4 packets/day) were associated with a high rate of adverse effects, and had the highest drug discontinuance rate (37%) and poorest compliance (73 +/- 3% of the doses prescribed reported ingested) of all agents. Patients aged > 60 years tolerated therapy with bile acid sequestrants less well than did younger veterans (p < 0.01). Niacin (1.5 g/day) also had a high drug discontinuance rate (27%). Lovastatin (20 mg/day) had the lowest drug discontinuance rate (2%) and the highest compliance (90 +/- 2%). Lovastatin also reduced low-density lipoprotein (LDL) cholesterol the most (-21.6 +/- 2.0%), whereas niacin produced the largest increase in high-density lipoprotein (HDL) cholesterol (+/- 14.3 +/- 2.2%); both niacin and lovastatin produced similar reductions in the LDL/HDL ratio. However, psyllium (10.4 g/day) reduced LDL cholesterol by only 2%, and had no effect on the LDL/HDL ratio. Psyllium produced larger LDL cholesterol reductions in patients aged < 60 years than in older patients (p < 0.01). Niacin and lovastatin are effective drugs for hypercholesterolemia management in the Veterans Administration Medical Center setting.(ABSTRACT TRUNCATED AT 250 WORDS)

A measure of mortality risk for elderly patients with acute myocardial infarction

The objective of this study was to derive and validate a simple scoring system that predicts risk of short-term mortality in elderly patients hospitalized with acute myocardial infarction (AMI) and to compare this derived score with the MedisGroups admission severity score. A myocardial infarction severity score (MISS) was derived from a database of clinical information abstracted using MedisGroups and follow-up information on 30-day mortality status. The MISS was validated and compared with the MedisGroups Admission Severity Groups (ASGs) in a separate database. The derivation set included 2,037 Medicare patients 65 years old or older with confirmed AMI who were randomly selected from patients discharged from hospitals in seven states during 1985. The validation set consisted of 6,323 patients from the 1988 MedisGroups comparative database who were at least 65 years of age and had confirmed AMI. Multivariate logistic regression analysis found a set of nine abnormal patient characteristics that independently predict 30-day mortality. There was good agreement between mortality rates predicted by the logistic model and observed mortality rates in the validation population. This regression model was then simplified to an additive score where eight of the characteristics were weighted as one point and one characteristic was weighted as two points. The MISS is the sum of the points for each patient. In the validation dataset, the 1,373 patients with the lowest MISS scores had a mortality rate of 4.6% and the 400 patients with the highest MISS scores had a mortality rate of 64%.(ABSTRACT TRUNCATED AT 250 WORDS)

Progression of nonproliferative diabetic retinopathy and visual outcome after extracapsular cataract extraction and intraocular lens implantation

Twenty-one patients with symmetric nonproliferative retinopathy who underwent extracapsular cataract extraction and intraocular lens implantation were followed up postoperatively for an average (+/- standard deviation) of 18 +/- 7 months to determine the incidence of progression of diabetic retinopathy, the final visual acuity, and factors predictive of progression of retinopathy and final visual acuity. Progression of retinopathy, defined as the development of clinically significant macular edema, an increase in intraretinal hemorrhages or hard exudate, or the development of proliferative diabetic retinopathy, was assessed in both eyes of 19 patients; in two remaining patients, dense preoperative cataract in the fellow eye precluded comparison of retinopathy progression in the operated-on eye to progression in the fellow eye. Overall, retinopathy progressed in 14 of 19 operated-on eyes (74%). Cataract extraction was highly associated with asymmetric progression of nonproliferative retinopathy; it progressed only in the operated-on eye in seven of 19 patients (37%), but in no patients did progression occur in the fellow eye alone (P = .0078). Women had a significantly increased risk of progression of retinopathy in the operated-on eye compared to men (P = .005). Visual acuity improved in 19 of 21 operated-on eyes (86%); however, only 11 eyes (52%) achieved a visual acuity of 20/50 or better and only six eyes (14%) achieved a visual acuity of 20/25 or better. In only five eyes was the final visual acuity in the operated-on eye more than two lines better than the final visual acuity in the fellow eye.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical signs of androgen excess as risk factors for coronary artery disease

Women with androgen excess have been found to have higher triglycerides and lower high-density lipoprotein cholesterol concentrations than nonhirsute women and are presumed to be at increased risk of coronary artery disease. However, definitive data linking androgen excess with coronary artery disease is lacking. We evaluated 102 women coming to coronary artery catheterization for signs and symptoms of androgen excess. Hirsutism was found more commonly in those women with confirmed coronary artery disease (chi 2 = 10.11). Waist:hip ratio (an index of android fat distribution) was associated with hirsutism (by ANOVA, F-test) and with coronary artery disease (t-test). The strongest associations were found in older women (aged greater than or equal to 60). Androgen excess in women may signal risk for coronary artery disease.

The association of waist hip ratio and angiographically determined coronary artery disease

Body fat distribution as measured by the ratio of waist circumference to hip circumference (WHR) is now accepted as an important risk factor for a number of diseases. This study evaluated the association of WHR and coronary artery disease (CAD). Measurements included the subjects' height, weight, waist girth, hip girth, significant CAD on coronary angiography, and cholesterol levels. A history of myocardial infarction, angina, diabetes or hypertension was obtained from subject interviews. The subjects were analyzed in two age groups: younger than age 60 (88 men and 39 women) and age 60 or older (85 men and 63 women). For older women the relative odds of CAD comparing women at the 75th percentile of WHR to women at the 25th percentile was 3.67 (P = 0.003), with a 95 percent confidence interval of 1.57-8.57. The relative odds was reduced to 2.80 after adjusting for all other risk factors. WHR was significantly associated with angiographic evidence of CAD in all women combined after adjusting for age (P = 0.0004), but it was not significantly associated with CAD in younger women or in men. The results suggest that in older women the risk of CAD increases with a greater percentage of body fat in the abdomen.

Risk factors for postvitrectomy fibrin formation

We prospectively studied 194 patients undergoing vitrectomy between July 1988 and April 1989 to determine the incidence of postvitrectomy intraocular fibrin formation and the association of a variety of preoperative and intraoperative variables with the formation of severe postvitrectomy fibrin. Overall, 62 (32%) patients developed postvitrectomy fibrin; 25 (13%) had mild fibrin formation, 13 (6.5%) had moderate fibrin formation, and 24 (12.4%) had severe fibrin formation. By logistic multivariate analysis, preoperative factors that were independently predictive of severe fibrin formation included severe flare (P = .004), the presence of a previously placed scleral buckle (P = .001), and poor preoperative visual acuity (P = .007). Anterior epiretinal membrane dissection was the only intraoperative factor that was independently associated with an increased fibrin risk (P = .0003). A risk score derived from the multivariate analysis effectively categorized patients according to their likelihood of developing severe postvitrectomy fibrin. Results of this study may be useful in designing prophylactic interventions to decrease postvitrectomy fibrin formation.

Efficacy and safety of mercuric oxide in the treatment of bacterial blepharitis

A double-masked, placebo-controlled, randomized study was done to assess the safety and clinical and quantitative microbiologic efficacy of 1% mercuric oxide (yellow) ophthalmic ointment in the treatment of eyelid infections, i.e., bacterial blepharitis. A total of 39 patients with bacterial counts and clinical signs indicative of eyelid infection were treated twice daily for 7 days. Clinical biomicroscopic examination and quantitative microbiologic cultures were done just prior to initiation of treatment and again on days 3 and 7. Statistical analysis revealed a significant improvement in the clinical signs, bacterial count, cure rate, and improvement rate for subjects taking the active medication, compared with those taking the placebo on days 3 and 7. In addition, the medication was well tolerated.

Mechanisms of intraocular pressure elevation after pars plana vitrectomy

A prospective study of 222 consecutive patients undergoing pars plana vitrectomy was done to determine the incidence and mechanisms of postoperative intraocular pressure (IOP) elevation. Within 48 hours of surgery, postoperative IOP increased by at least 5 to 22 mmHg in 136 eyes (61.3%) and to 30 mmHg or more in 79 eyes (35.6%). Presumed mechanisms of open-angle glaucoma included intraocular gas expansion (28.4%), inflammatory trabecular meshwork obstruction (4.5%), silicone oil-related glaucoma (3.6%), and erythroclastic glaucoma (2.2%). Closed-angle mechanisms included pupillary block glaucoma (6.8%) and ciliary body edema (3.6%). Factors which were associated with postvitrectomy pressure elevation included placement of a scleral buckle, either intraoperatively (P = 0.003) or before vitrectomy (P = 0.001), intraoperative scatter endophotocoagulation (P = 0.041), intra-operative lensectomy (P = 0.024), and development of postoperative fibrin membranes (P = 0.038). Surgery was required to lower IOP or relieve pupillary block in 25 eyes (11.3%).

Research collaboration

The complexity and cost of cardiovascular medical care dictate research to deliver high quality and cost-conscious cardiovascular care. This goal is aided by modeling medical decision making. To be useful, the modeling must be based on real data so that the results can serve as a guide to actual practice. It is suggested that a registry of randomized clinical trials and larger data bases in cardiovascular disease and health care delivery be established. The registry would be a resource for those desiring to model decision making. The registry would contain key words allowing retrieval by modelers accessing the registry and would contain contact information for consideration of possible collaborative work. The initiation of such a registry should contain plans for its evaluation to determine whether the registry itself is a cost-effective tool to encourage the needed research.

Quantitative analysis of the exercise tolerance test for determining the severity of coronary artery disease

Results were compiled from the literature on the use of the exercise tolerance test to identify patients with severe coronary artery disease. Pooled estimates of sensitivity and specificity were derived for the ability of the exercise tolerance test to identify three-vessel or left main coronary artery disease. There was great variability among the studies examined in the estimated sensitivity and specificity of a given criterion for severe coronary artery disease. This variability could not be explained by reported variations in study design. The findings suggest that the accuracy of the exercise tolerance test and other tests cannot be properly interpreted without much greater detail presented in the literature on patient selection and test administration.

How physicians use the stress test for the management of angina

The authors examined physicians' reasons for ordering an exercise tolerance test and the influence of the test results on management decisions. Subjects of this study included 265 family physicians in Pennsylvania who completed a questionnaire on the management of a patient with typical chronic stable angina. Eighty-one percent of the respondents reported they would order a noninvasive stress test as a first step in the management of the patient. Of these physicians, 40% would refer the patient to a cardiologist only if the exercise tolerance test were strongly positive, 8% would refer only if it were negative, and 53% would not change their referral decisions on the basis of test results. No more than 57% of the physicians rated as very important any given reason for ordering a noninvasive diagnostic test. The results suggest that a test may be ordered routinely but without a consensus as to why it is ordered and without an effect on clinical management decisions.

The inexact use of Fisher's Exact Test in six major medical journals

We reviewed the use of Fisher's Exact Test in 71 articles published between 1983 and 1987 in six medical journals. Thirty-three of 56 selected articles did not specify use of a one- or two-tailed test, and 12 (36%) of these actually used the one-tailed test. Five (42%) of these 12 articles contained at least one table in which the standard significance level of P less than .05 was no longer met when a two-tailed analysis was run instead. Eleven (65%) of 17 articles with a statistical consultant compared with 10 (28%) of 36 articles without a consultant specified use of a one- or two-sided test. The use of Fisher's Exact Test without specification as a one- or two-tailed version may misrepresent the statistical significance of data. A uniform specification statement should be required for all manuscripts to correct such potential errors in interpretation.

Results of vitrectomy for diabetic traction retinal detachments using the en bloc excision technique

En bloc excision is a technique in which fibrovascular diabetic membranes and the posterior hyaloid are separated from the retina as a single unit. In a consecutive series of 69 eyes with diabetic traction retinal detachment treated with this technique, initial retinal reattachment was accomplished in 100% (69/69) of the eyes. With a minimum of 6 months' follow-up, the retina remained completely attached in 83% (57/69) of eyes, while the macula was attached in 88% (61/69) of eyes. Final visual acuity was 5/200 or better in 71% (49/69) of eyes. While current surgical techniques allow a high rate of anatomic success in the repair of diabetic traction retinal detachment, visual results remain limited by irreversible alterations in retinal function.

Factors associated with severity of symptoms in patients with chronic unexplained muscular aching

Subjects with chronic, diffuse, unexplained muscular aching were recruited--21 from a primary care practice, nine from a rheumatology practice, and two from a pain clinic. No additional criteria were used to select subjects. Subjects with mild or moderate symptoms differed from those with severe symptoms with respect to the following characteristics: the presence of fatigue on awakening, the number of tender points, difficulty in sleeping, and the degree of tenderness in typical fibromyalgia areas as measured by a dolorimeter. These findings suggest that muscular aching is likely to be of greater severity if other symptoms or signs of fibromyalgia are also present.

Intravitreal clearance of tissue plasminogen activator in the rabbit

The clearance of tissue plasminogen activator (t-PA) injected into the midvitreous cavity was studied in the phakic, vitrectomized rabbit eye with and without intravitreal fibrin clots. The quantity and activity of t-PA in the vitreous, serum, and aqueous were determined at ten minutes and at 3, 6, 15, 24, and 48 hours after initial injection by an enzyme-linked immunosorbent assay (ELISA) and a spectrophotometric solid-phase fibrin assay (SOFIA). In eyes without an intravitreal fibrin clot, the estimated half-life for t-PA was 4.3 hours by SOFIA and 5.8 hours by ELISA. In eyes containing a vitreal fibrin clot, the half-life increased to 9.8 hours by SOFIA and 11.9 hours by ELISA. Both of these half-lives were significantly greater than the half-life for eyes without fibrin. Regardless of the presence of fibrin, intravitreal t-PA activity was significantly less than t-PA quantity, suggesting the presence of a t-PA inhibitor. A peak in aqueous t-PA occurred before six hours, indicating that t-PA was cleared in part through the anterior chamber. There was no measurable serum t-PA at any of the sampling times.

A method of quantify confounding in regression analyses applied to data on diet and CHD incidence

We present a method to display the results of linear regression when the independent variables are highly correlated. In this method the sum of squares of regression (SSR) for pairs of variables are partitioned into orthogonal and shared components. A shared component is the reduction in the SSR of one of the variables when the other variable is added to the regression equation. This method shows how the SSR for one variable depends on the other variables present in the regression equation and explains apparent inconsistencies between forward and backward stepwise regression. To demonstrate the potential usefulness of this method we reanalyzed previously reported data on the relationship between coronary heart disease (CHD) and diet. The analysis suggested that carbohydrate and alcohol intake are negatively associated with CHD because they are associated with greater caloric intake. Protein and fat intake are also associated with greater caloric intake, but in addition they are associated with factors that increase the risk of CHD.

Brain metastasis in patients with superior sulcus tumors

During a 20-year period, from 1963 to 1983, 68 patients were treated for carcinoma of the lung presenting in the superior sulcus. Their ages ranged from 41 to 79 years (median, 56 years). Thirty-six patients had squamous cell carcinoma, 13 had adenocarcinoma, 14 had large cell carcinoma, two had small cell carcinoma, and three had clinical diagnosis only. All tumors were considered to be inoperable or unresectable and were treated with external irradiation alone. The 3-year disease-free survival was 25%. Brain metastasis developed in 23 patients (34%); the brain was the first site of metastasis in 16 patients (24%), five of whom eventually developed other sites of metastasis. The cumulative probability of brain metastasis was 53% at 3 years. Brain metastases were seen in ten patients (28%) with squamous cell carcinoma, five patients (38%) with adenocarcinoma, seven patients (50%) with large cell carcinoma, and one patient without a histocytologic diagnosis. The proportion of patients younger than 60 years (19/41, 46%) who developed brain metastasis was significantly greater than that for patients 60 years or older (4/27, 15%) (P less than or equal to 0.01). Nine of 11 patients with metastasis only to the brain died as a consequence of the intracranial disease 1 to 13 months (median, 6 months) after the diagnosis of brain metastases. The other two patients received therapeutic irradiation to the entire brain and survived longer than 5 days after the whole-brain irradiation: one died at 62 months of intercurrent disease, and the other is alive and well 129 months after diagnosis. The high probability of brain metastasis from superior sulcus tumors, regardless of histopathologic type and the frequency with which the brain is the only site of clinical failure, suggest that systematic prophylactic cranial irradiation could reduce the morbidity and perhaps even contribute favorably to the survival of these patients.

Extended-field radiation therapy for prostatic carcinoma with para-aortic lymph node metastasis

The finding of involvement of para-aortic lymph nodes in patients with adenocarcinoma of the prostate has been considered so ominous that further therapy has often only been palliative. What is the proportion of patients with carcinoma of the prostate with regional metastasis limited to the infra-diaphragmatic lymph nodes who might be cured or at least offered long-term progression-free survival by aggressive treatment? From June 1970 through March 1983, 114 patients were treated with curative intent for adenocarcinoma of the prostate, clinical Stage III, at the Medical College of Wisconsin Affiliated Hospitals. Twenty-three of these patients had evidence of metastasis to the para-aortic lymph nodes. These patients were treated aggressively with external radiation therapy to the entire pelvis and para-aortic region. The median dose to the prostate was 70 Gy, the pelvis 54 Gy, and the para-aortic region 50 Gy. The median period of observation after treatment was 53.5 months. The actuarial survival was 90% at 5 years and progression-free survival was 73% at 5 years. The rate of major complications was 4.3%. Although the number of patients is small, the data suggest that extended field radiation therapy can result in prolonged progression-free survival and perhaps cure many patients with juxtaregional dissemination of adenocarcinoma of the prostate.

Measures of the value of a diagnostic test derived from stochastic thresholds

Previous indices for measuring the potential impact of a diagnostic test on a physician's management of a given patient were derived based on a fixed threshold model. The authors adapted these indices to a stochastic threshold model. In the stochastic threshold model the physician's probability of treating the patient is a function of the patient's probability of disease. From this model the authors derived the management value index (the expected effect that the test has on the physician's probability for treating the patient) and the utility value index (the expected benefit to the patient if the diagnostic test is used). Graphs of the indices versus the patient's probability of disease may be useful in teaching appropriate use of diagnostic tests.

Stochastic thresholds

Thresholds have traditionally been represented by a single number; the optimal management of the patient depends on whether his probability of disease is above or below this number. The concept of a threshold as a single number, however, inadequately represents the treatment approach of a group of physicians who do not have all the same threshold or a single physician who is uncertain about the exact value of the threshold. An alternative to a single valued threshold is to consider the threshold as having a probability distribution: for every probability that the patient has the disease there is a probability that the threshold is exceeded. This "stochastic" threshold model contains information about the uncertainty of the threshold estimation. Stochastic thresholds can be useful for testing the sensitivity of a management decision to the patient's probability of disease. They can also be used for comparing the standards of practice of individual physicians or comparing the practice of an individual physician with that of a group.

Prognostic influence of TNM staging and LDH levels in small cell carcinoma of the lung (SCCL)

To better define the prognostic factors influencing the response to therapy and survival in small cell carcinoma of the lung (SCCL), an expanded "TNM" type staging system was developed and investigated in a series of 73 protocol treated patients. Because serum LDH levels at disease presentation have been correlated to disease extent, response to therapy, and treatment outcome in a number of malignancies, including SCCL, these interrelationships were also analyzed in the protocol patients. The TNM system was found to be a more descriptive and specific "shorthand" for denoting sites of involvement and for indicating the body burden of tumor than the traditional limited-extensive disease (LD-ED) system. A clear statistical advantage could not be shown over the LD-ED system for predicting chemotherapy response or survival, although there were trends suggesting the TNM system could divide patients into three prognostic subgroups. Serum LDH proved to be a useful index of disease extent and therapy outcome. LDH levels at presentation were proportionately higher with more extensive tumor, measured by either the LD-ED or TNM staging. High LDH predicted poorer responses to chemotherapy and lower survival within similar stage subgroups compared to patients with normal LDH levels. The negative effect of elevated LDH was independent of hepatic involvement and did not predict subsequent hepatic failure in any consistent way. The SCCL TNM staging system proposed needs further refinement and should be tested with larger patient numbers. LDH, along with other tumor markers recently identified, need to be integrated into the staging system to form an overall prognostic index.

Usefulness of right ventricular diastolic collapse in diagnosing cardiac tamponade and comparison to pulsus paradoxus

To compare the sensitivity, specificity and predictive value of right ventricular (RV) diastolic collapse and pulsus paradoxus as signs of cardiac tamponade, 21 consecutive patients with pericardial effusion and suspected cardiac tamponade underwent prospective hemodynamic and echocardiographic evaluation. Simultaneous hemodynamic and echocardiographic data were obtained in all patients before and after pericardiocentesis. Cardiac tamponade was considered present when there was diastolic equilibration of the intrapericardial, right atrial and pulmonary capillary wedge pressures and elevation of these pressures to more than 10 mm Hg. RV diastolic collapse was 93% sensitive and 100% specific in diagnosing cardiac tamponade, whereas pulsus paradoxus was only 79% sensitive and 40% specific. The positive and negative predictive values of RV diastolic collapse (100% and 83%) were considerably better than pulsus paradoxus (81% and 40%) and demonstrate that RV diastolic collapse is more sensitive, specific and predictive of cardiac tamponade than is pulsus paradoxus. Serial simultaneous hemodynamic and echocardiographic observations at multiple points during pericardiocentesis in a smaller subgroup (5 patients) also suggest that the hemodynamic effects of RV diastolic collapse in cardiac tamponade are mediated by an increase in intrapericardial pressure.

Influence of preoperative irradiation on failures of endometrial carcinoma with high risk of lymph node metastasis

From 1965-1980, 80 patients with adenocarcinoma of the endometrium, FIGO-AJC Stage I, Grade 3 and Stage II received preoperative radiation therapy. Thirty-three patients had Stage I, Grade 3 and 47 had Stage II. All patients were treated with preoperative radiation therapy (intracavitary application, external pelvic irradiation or both) followed by total abdominal hysterectomy and bilateral salpingo-oophorectomy. They were followed from 3-18 years (median, 6.2 years) after the completion of treatment and none was lost to follow-up. Overall 5-year actuarial disease-free survival was 75%. Preoperative external whole pelvic plus intracavitary irradiation gave the best 5-year survival of 83%; there were no failures after 20 months. In comparison to this group, survival for the intracavitary alone group was 64% at 5 years and 54% at 8 years. The 5-year survival of Stage II was 81% compared to 66% of the Stage I, Grade 3 group. Prognostic variables were analyzed and showed that the residual tumor in the specimen at the time of surgery after the preoperative irradiation was significantly correlated to a worse prognosis: patients who were found to have no residual tumor had a 5-year survival rate of 96% compared to 65% of those who were found to have residual tumor (p less than 0.01). Age, stage, methods of preoperative irradiation, dose of external pelvic irradiation or intracavitary application were not statistically significant prognostic factors. The grade of the tumor was suggestive as a prognostic variable. The most common failure site was the para-aortic lymph nodes independent of treatment methods and stage. Four patients developed complications possibly related to the radiation therapy. Our study suggests that preoperative external and intracavitary irradiation reduces the frequency of residual microscopic carcinoma and improves survival for patients with Stage I, Grade 3 and Stage II carcinoma of the endometrium.