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Biomedical subjects

M E Cowen

Publications and source records attributed to M E Cowen.

At least 19 recordsLinked to original sources
PubMed2000

Assessing quality of life in men with clinically localized prostate cancer: development of a new instrument for use in multiple settings.

BACKGROUND: Quality of life in prostate cancer patients with clinically localized disease has become the focus of increasing attention over the past decade. However, few instruments have been developed and validated to assess quality of life specifically in this patient population. OBJECTIVE: The purpose of this investigation was to create a comprehensive, multi-scale quality of life instrument that can be tailored to the needs of the clinician/investigator in multiple settings. DESIGN, SUBJECTS, AND MEASURES: Patients diagnosed with clinically localized prostate cancer were mailed a questionnaire consisting of new and previously validated quality of life items and ancillary scales. Data from returned questionnaires were analyzed and used to create a multiscale instrument that assesses the effects of treatment and disease on urinary, sexual, and bowel domains, supplemented by a scale assessing anxiety over disease course/effectiveness of treatment. The instrument was then mailed to a second sample of prostate cancer patients once and then again two weeks later to assess test retest reliability. To assess feasibility in clinical settings, the instrument was self-administered to a third patient sample during a urology clinic visit. RESULTS: All scales exhibited good internal consistency and test retest reliability, convergent and discriminant validity, and significant correlations with disease specific, generic health-related, and global measures of quality of life. Men with greater physiologic impairment reported more limitations in role activities and more bother. Scales were also able to differentiate patients undergoing different therapies. All scales exhibited negligible correlations with a measure of socially desirable responding. Additionally, the instrument proved feasible when used as a self-administered questionnaire in a clinical setting. CONCLUSIONS: The current instrument possesses brief multi-item scales that can be successfully self-administered in multiple settings. The instrument is flexible, relatively quick, psychometrically reliable and valid, and permits a more comprehensive assessment of patients' quality of life.

Aged↗
PubMed1999

Methods for analyzing referral patterns.

OBJECTIVE: To develop a sound method to identify patient and physician characteristics that influence specialty referrals. DESIGN: A retrospective cohort analysis of medical claims data from 1996 supplemented with surveys of primary care physicians. SETTING: A 600-member independent practice association in southeastern Michigan that provided care for 90,000 members of an HMO. PATIENTS: Five cohorts, each of 2,000 to 6,000 patients with diagnoses that could be referred to cardiologists, ophthalmologists, pulmonologists, orthopedists, or general surgeons. MAIN RESULTS: The referral rates for the different cohorts ranged from 1% to 7%. The discriminatory ability of the multivariate logistic models (c-statistic) ranged from 0.66 to 0.79. The likelihood of referral was associated with the patient's diagnoses and medications and with the referring physician's age, years out of medical school, satisfaction with the specialty being referred to, and the importance of making or confirming a diagnosis. CONCLUSIONS: Because these methods were not difficult to implement and the results were credible, we believe that other organizations should be able to use them.

Cohort Studies↗
PubMed1999

Serial prostate specific antigen screening for prostate cancer: a computer model evaluates competing strategies.

PURPOSE: We compare prostate specific antigen (PSA) screening strategies in terms of expected years of life saved with screening, number of screens, number of false-positive screens and rates of over diagnosis, defined as detection by PSA screening of patients who would never have been diagnosed without screening. MATERIALS AND METHODS: A computer model of disease progression, clinical diagnosis, PSA growth and PSA screening was used. Under baseline conditions, when screening is not considered, the model replicates clinical diagnosis and disease mortality rates recorded by the Surveillance, Epidemiology and End Results Program of the National Cancer Institute in the mid 1980s. RESULTS: Biannual screening with PSA greater than 4.0 ng./ml. was projected to reduce the number of screens and false-positive tests by almost 50% relative to annual screening while retaining 93% of years of life saved. With annual screening use of an age specific bound for PSA to consider a test positive instead of the standard 4.0 ng./ml. was projected to reduce false-positive screens by 27% and over diagnosis by a third while retaining almost 95% of years of life saved. Sensitivity analyses did not change the relative efficacy of biannual screening. CONCLUSIONS: Under the model assumptions biannual PSA screening is a cost-effective alternative to annual PSA screening for prostate cancer. With annual screening use of an age specific bound for PSA positivity appears to reduce false-positive results and over diagnosis rates sharply relative to a bound of 4 ng./ml. while retaining most of the survival benefits.

Adult↗
PubMed1999

Telephone interviews vs. workstation sessions for acquiring quality of life data.

Patient quality of life data can be acquired in a variety of ways, including over the telephone and through computerized questionnaires. However, if the method of collection produces different results, medical decisions regarding appropriate and cost-effective care may be influenced by collection method. We conducted an experiment where subjects had two quality of life measures, the time trade-off and rating scale utilities, assessed both in telephone interivews and via computer touchscreens. The order of telephone and touchscreen was randomized. We found that rating scale utilities were similar whether obtained via the telephone or via touchscreen regardless of which was done first. However, patients who had their time trade-off utilities assessed over the telephone first did not provide as consistent responses as those elicited first via touchscreen (p = 0.01). Caution is suggested when considering eliciting time trade-off over the telephone with subjects who have not had time trade-off elicited previously.

Analysis of Variance↗
PubMed1998

Preoperative predictors of cost in Medicare-age patients undergoing coronary artery bypass grafting.

BACKGROUND: Identification of preoperative factors that contribute to the cost of coronary artery bypass grafting could aid in predicting the procedure's expense. In this study, 30 sociodemographic and clinical preoperative factors were examined with "survival analysis" techniques to determine characteristics related to total hospital cost. METHODS: Characteristics of all patients age 65 or older undergoing isolated coronary artery bypass grafting from July 1993 to April 1995 (n = 757) were recorded. Software was developed within the hospital's Transitions Systems, Inc, database to calculate the outcome variable of total cost. Nonparametric methods were used for the univariate analysis of the data, and the Cox proportional hazards model was used for the multivariable analysis, censoring 25 patients who died in the hospital. RESULTS: Median hospital cost from the day of the operation until discharge was $15,198. Median length of stay after the operation was 6 days. Multivariable analysis revealed that age, preoperative renal failure, history of cerebrovascular accident, low ejection fraction, and surgical urgency were independent predictors of total cost. CONCLUSIONS: This study, using an accurate representation of true hospital cost and a modeling technique that accounts for the confounding effect of in-hospital death on cost, provides a template for analysis of cost in other patient groups.

Age Factors↗
PubMed1998

Casemix adjustment of managed care claims data using the clinical classification for health policy research method.

OBJECTIVES: The objective of this study was to explore the use of the Clinical Classification for Health Policy Research (CCHPR) as a casemix adjustment method for examining physician practice patterns. METHODS: The data source was 2 years of administrative claims from an 86,000 member health maintenance organization in southeastern Michigan. The CCHPR version 2 algorithm, which is in the public domain, was used to assign each claim to one of 260 clinical categories. CCHPR and age-sex categories were used as explanatory variables in multiple linear regression models with approved claims payments in dollars as the outcome variable. Regressions were performed retrospectively for 1994 and 1995, and with 1994 claims' history to predict 1995 utilization. Similar regressions were performed with age-sex categories alone, and also with the ambulatory diagnostic groups. RESULTS: The adjusted R2 value of the retrospective regression models for total approved dollars was 0.42 for both study years when CCHPR categories were used. In contrast, age-sex explanatory variables alone achieved an R2 of 0.02. CONCLUSIONS: The CCHPR method appears to be a promising tool to understand variability in physician resource utilization in managed care.

Adult↗
PubMed1997

Survival estimates for patients with abnormal swallowing studies.

OBJECTIVE: To better understand the life expectancy of patients who have an abnormal videofluoroscopic swallowing study. DESIGN: Retrospective cohort study. The common starting point was the time of the severely abnormal swallowing study. Hospital charts were reviewed for clinical variables of potential prognostic significance by reviewers blinded to the outcome of interest, survival time. SETTING: A university-affiliated, community teaching hospital. PATIENTS: One hundred forty-nine hospitalized patients who were deemed nonoral feeders based on their swallowing study. Patients excluded were those with head, neck, or esophageal cancer, or those undergoing a thoracotomy procedure. MEASUREMENTS AND MAIN RESULTS: Clinical and demographic variables and time until death or censoring were measured. Overall 1-year mortality was 62%. Multivariable Cox proportional hazards analyses identified four variables that independently predicted death: advanced age, reduced serum albumin concentration, disorientation to person, and higher Charlson comorbidity score. Eighty patients (54%) subsequently underwent placement of a percutaneous endoscopic gastrostomy (PEG) tube after their swallowing study. CONCLUSIONS: Mortality is high in patients with severely abnormal swallowing studies. Common clinical variables can be used to identify groups of patients with particularly poor prognoses. This information may help guide discussions regarding possible PEG placement.

Aged↗
PubMed1997

A decision analysis for treatment of clinically localized prostate cancer.

OBJECTIVE: To determine the preferred treatment of clinically localized prostate cancer. DESIGN: Cancer grade, patient age, and comorbidities are considered in a Markov model with Monte Carlo sensitivity analyses. Large and recent pooled analyses and patient-derived utilities are included. RESULTS: Principal findings suggest benefit for radical prostatectomy relative to watchful waiting for men under 70 years of age with low to moderate comorbidity. Men older than 70 with high comorbidity and disease of low to moderate grade do better with watchful waiting. CONCLUSIONS: Cohort-level sensitivity analyses suggest a quality-based treatment benefit for radical prostatectomy for younger men and treatment harm for older men. Tailored patient and clinician decisions remain necessary, especially for men older than 70 in good health but with aggressive cancers.

Adenocarcinoma↗
PubMed1997

Spontaneous pneumothorax in a patient with an azygos lobe.

The association between a spontaneous pneumothorax and an azygos lobe is surprisingly rare. A case is reported in which surgical management was difficult; it is suggested that thoracotomy is preferable to video-assisted thoracoscopic surgery in this situation. It is possible that the presence of an azygos lobe might protect against the subsequent development of a spontaneous pneumothorax, and the possible mechanism of this is discussed.

Adult↗
PubMed1996

A national survey of attitudes regarding participation in prostate carcinoma testing.

BACKGROUND: The prevalence of prostate carcinoma testing is rapidly changing. Little is known about the frequency of testing in the non-Medicare population in the United States. The current study was conducted for a better understanding of who is being tested and some of the reasons why. METHODS: A randomized national telephone survey was administered to 800 men by the George H. Gallup International Institute. Questions in the survey were evaluated for their association with participation in prostate carcinoma testing reported by the men interviewed. RESULTS: Participation in prostate carcinoma testing approximated the frequency of colon carcinoma testing Eighty-six percent of the men surveyed believed that prostate carcinoma is a serious malignancy, and 78% believed that it could be cured often if detected early. Multivariate logistic regression models identified six factors that increased the likelihood of men in the survey being tested: white race, willingness to be tested, previous conversation with a physician or health professional, having had serum cholesterol tested, having been tested for colon carcinoma, and belonging to successively advanced age groups. CONCLUSIONS: Prostate carcinoma testing is commonly performed in men older than 40 years. Physician counsel and patient prevention consciousness appear to be the major influences when a patient decides to be tested. If early detection is considered beneficial, special efforts would be needed to reach the nonwhite population.

Adult↗
PubMed1996

A guide for planning community-oriented health care: the health sector resource allocation model.

The objective of this study was to demonstrate the value of a planning model for the design and evaluation of community health services. The health status of Washtenaw County, Michigan was modeled. Data were obtained from the Michigan Department of Public Health, Medstat Systems, and the medical literature for 32 diseases or conditions, representing approximately 85% of causes of death and 56% of medical payments (excluding medication costs). An expanded life-table approach was used for 16 age-and sex-matched cohorts exposed to a disease attack rate, access-to-care rate, case fatality rate, morbidity, and costs. Rates can be modified to reflect changes due to treatment, secular trends, or prevention programs. Two alternative delivery methods were considered to show the potential impact of reducing cardiovascular deaths (worksite initiative), or increasing utilization of services (lay health promotion) on county health status and costs over time. Deaths, bed days, and annual medical payments were the main outcome measurements. Cardiovascular and cancer conditions are and will be the primary causes of death in this population. The most important causes of bed days are musculoskeletal conditions, chronic obstructive pulmonary disease, accidents, strokes, and depression. The major health-care payments are for angina pectoris and/or other cardiac conditions, musculoskeletal conditions, accidents, prenatal care, and/or childbirth, and depression. The two alternative scenarios illustrate how reductions in mortality are not necessarily equated with similar improvements in morbidity or costs. This model presents an overview of the current and projected health status of a community. With such a planning tool, a community can better understand the impact of potential prevention or intervention programs, and help design its health-care system within the constraints of available resources.

Cause of Death↗
PubMed1995

Time-related effects of enzymatic disaggregation on model human lung carcinomas.

Enzyme cocktails used to prepare tumor cell suspensions may influence yield, viability, and cytology, thus time-related cocktail effects on model human lung carcinomas were examined. A549, NCI-H125, and NCI-H460 carcinomas were completely disaggregated at 25 degrees C over 2 h with either (mg/ml) collagenase/DNAase (C/D, 1/0.1), collagenase/hyaluronidase/DNAse (C/H/D, 1/0, 1/0.1), or polymyxa protease/DNAse (PP/D, 3/0.1). Trypan blue viabilities, total yields, viable yields, and flow cytometric percent tumor cells (TC) were measured every 20-30 min (n = 4-7 per tumor type). The final percentages of TC, mononuclear cells (MN), polymorphonuclear cells (PMN), lymphocytes, and necrotic cells were determined by cytology (n = 4-5 per tumor type). The time-dependent measurements showed that 1) disaggregation was progressive and complete with all cocktails; 2) viability was stable or increasing with all cocktails; 3) percent TC was stable for all cocktails, but lower for PP/D than C/D in final suspensions; and 4) PP/D gave lower final total yields, higher final viabilities, but the same final viable yields as the C cocktails, suggesting selective elimination of dead cells by PP/D. Final cytology measurements showed that PP/D gave a lower percent MN and a higher percent PMN than C cocktails. Cocktail effects may importantly influence cell suspension properties.

Animals↗
PubMed1994

Dose-related doxorubicin effect in an orthotopic secondary lung cancer screen.

Lung cancer is the leading cause of cancer-related death of both sexes in the United States and promises to be a major problem in the world community for decades. We are developing an orthotopic (organ specific) secondary screening system to measure the uptake and efficacy of new lung cancer agents. The elements of the system are: (1) orthotopic growth of a model human lung cancer (NCI-H460 large cell carcinoma) in the right caudal lobe of the nude rat; (2) 1-hr ex vivo pulmonary perfusion treatment of the tumor-bearing lungs; and (3) soft agar clonogenic assay of the enzymatically disaggregated tumor cells. This study characterizes dose-response aspects of the system. Perfusion of tumor-bearing lungs with 0, 1, 10, and 100 micrograms/ml doxorubicin resulted in a dose-related reduction in surviving fraction from 1.01 +/- 0.41 to 0.019 +/- 0.006 (P < 0.05) without significant treatment-related increases in lung weight or perfusion pressure. Tumor and lung drug levels were also dose-related, with lung levels exceeding tumor levels at all doses. The tumor drug level at the 100 micrograms/ml dose was 62 +/- 16 ng/mg. There was a strong negative correlation between the measured tumor drug level and surviving fraction in the clonogenic assay (R2 = 0.47, P = 0.0005). This new screening system is capable of demonstrating dose-related uptake and tumoricidal activity of doxorubicin on an orthotopic, model human large cell lung carcinoma. It may be useful for the secondary screening of agents active against human lung cancer.

Animals↗
PubMed1994

A Markov model of the natural history of prostate cancer.

The objective of this study was to lay a foundation for future cost-benefit analyses evaluating the public health impact of treatment and screening protocols for prostate cancer. Specifically we wanted to define the relative impact on cancer-specific mortality rates of the individual epidemiological components: pathological incidences by age groups, cancer progression rates, and the effect of competing causes of death, assuming expectant management (i.e. no definitive treatment). A biological model of prostate cancer incidence and progression was converted into a standard Markov tree where competing causes of death could occur. Weighted averages of progression rates were obtained from clinical studies. Separate cohorts of 30 year old black and white men were followed for 50 years. The model yielded cancer-specific mortality rates, overall mortality rates, and pathologic prevalences for both white and black males, consistent with the literature. Sensitivity analyses showed that of all the parameters studied, the pathological incidence of cancer in men under 50 years of age had the greatest impact on the cancer-specific mortality rates. Also important was the annual probability of progression of A1 lesions. However the other parameters including pathological incidence in older males, and progression from locally-extensive to metastatic lesions had much smaller effects. In summary, this model correlates the clinical literature with the epidemiology of prostate cancer and can be used for further decision analyses. We recommend that future research be done to more precisely quantify the pathological incidence of prostate cancer in men under 50-60 years of age. More certainty is also needed before generalizing the results of relatively small A1 series to millions of men, since A1 progression rates critically affect the eventual cancer-specific mortality. Enough uncertainty remains at this point however, that we cannot advocate widespread screening for prostate cancer until its merit be demonstrated either by the definitive long term study, or by examination of costs and quality-of-life-adjusted benefits.

Adult↗
PubMed1992

Mucin gel formed by tumorigenic squamous lung carcinoma cells has Le(a)-X oligosaccharides and excludes antibodies from underlying cells.

Cells of cloned lines of human squamous lung carcinomas elaborate large glycoproteins that are associated with their tumorigenic potential. Two groups of clones (called Le(a)-X-positive and Le(a)-X-negative) were studied that either do or do not express the Le(a)-X oligosaccharide associated with large glycoproteins and mucins secreted by these clones. Le(a)-X-positive cells elaborate a mucin gel complex associated with their apical surfaces, which appears as a mosaic of extracellular plates. Clones of this type are tumorigenic in nude rodents when injected s.c. or when introduced into the lungs via intrabronchial aerosol. By contrast, the Le(a)-X-negative clones do not form extracellular plates and are not tumorigenic in the lungs or subcutaneously. We demonstrate that the extracellular plates of Le(a)-X-positive cells exclude antibodies from interacting with the underlying squamous lung carcinoma cells and may therefore exert an immunoprotective effect. In support of this possibility it was found that: (a) There is a substantial inflammatory cell infiltrate associated with regressing nodules of Le(a)-X-negative cells in nude rodent lung and subcutaneous nodules, while there is no observable infiltration associated with progressing Le(a)-X-positive tumors. (b) In the brain (an immunoprivileged site) tumors develop and progress when either Le(a)-X-negative or -positive cells are introduced.

Animals↗
PubMed1992

Lung tolerance to hyperthermia by in vivo perfusion.

In vivo isolated lung perfusion is a novel technique for targeting anticancer therapy to the lung while avoiding systemic toxicity as normal lung toxicity from the antitumour therapy becomes the limiting factor. This study was performed to investigate the effects of hyperthermia on lung function in an intact animal model in which both acute and subacute toxicity could be monitored. Dogs underwent in vivo isolated lung perfusion. A control group was perfused to a lung temperature of 37 degrees C (group 1) and two other groups were treated in an identical manner except that the perfusion temperature was 43 degrees-44.8 degrees C in group 2 and greater than 45 degrees C in group 3. An assessment of lung injury was performed pre-perfusion, immediately post-perfusion and 2 weeks post-perfusion by measurement of extravascular lung water (Qev), serotonin uptake and wet weight to dry weight ratio. Our findings showed that the lung was tolerant to hyperthermia up to about 44 degrees C for 1 h. Analysis of 4 animals who survived perfusion above 3/44.0 degrees C showed a highly significant decrease in serotonin uptake between pre- and post-perfusion values (82.4 +/- 1.2 vs 40.4 +/- 3.9, P less than 0.02); at 2 weeks serotonin uptake had returned to normal in all 3 dogs. Fulminating pulmonary oedema developed at temperatures over 45 degrees C. Serotonin uptake may be a sensitive predictor of thermal lung injury.

Animals↗