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Biomedical subjects

M D Silverstein

Publications and source records attributed to M D Silverstein.

At least 73 records · Page 4Linked to original sources
PubMed1993

Accuracy of the death certificate in a population-based study of asthmatic patients.

OBJECTIVE: To quantify the reliability of death certificate data concerning asthma. DESIGN: The complete medical records of decedents were reviewed by a physician certified in allergy and pulmonology who determined the cause of death without having access to the original death certificate. Disagreements between the death certificate and the reviewer were adjudicated by an expert panel. SETTING: The community of Rochester, Minn. PATIENTS: The mortality cohort included 339 deaths from a larger cohort of 5241 Rochester residents who received medical treatment for asthma between 1964 and 1983. MAIN OUTCOME MEASURES: Kappa coefficients were used to measure agreement beyond that expected by chance between the reviewer and the death certificate. The sensitivity and specificity of the death certificate diagnosis of asthma were calculated against the standard of the reviewer/panel diagnosis. RESULTS: Death certificates reported asthma as an immediate or underlying cause of death in 22 instances (6%), whereas the reviewer/panel identified asthma in 53 cases (16%). In four cases, the death certificate listed asthma and the panel identified another cause of death. The death certificate had a sensitivity of 42% and a specificity of 99% compared with the reviewer/panel. Agreement between death certificates and the reviewer was not influenced by whether an autopsy was performed. CONCLUSIONS: Death certificate diagnosis of asthma as an underlying cause of death had a low sensitivity but a high specificity. Increases in mortality due to asthma are not likely caused by false-positive diagnoses of asthma as an underlying cause of death. Asthma mortality rates, determined from death certificate data, may indeed underestimate actual asthma-related mortality.

Adolescent↗
PubMed1993

A clinical prediction rule for the diagnosis of ureteral calculi in emergency departments.

OBJECTIVE: To determine: 1) whether a simple clinical prediction rule could identify emergency department patients with ureteral calculi; 2) whether the kidney, ureter, and bladder (KUB) radiograph provides diagnostic information beyond that obtained from the history and physical examination; and 3) whether ureteral calculi can be diagnosed accurately in the emergency department without emergency excretory urography, commonly known as intravenous pyelography (IVP). PATIENTS: Two hundred three patients who underwent emergency KUB and IVP studies for nontraumatic abdominal or flank pain (derivation group) were retrospectively identified from radiology department records; 72 patients were prospectively evaluated in the emergency department for suspected ureteral stones (validation group). MEASUREMENTS: Clinical information included age, gender, characteristics of pain, associated symptoms, presence of fever, history of ureteral calculi, whether a stone was passed, and results of urinalysis and KUB and IVP studies. All KUB and IVP radiographs were independently reviewed by a radiologist blinded to the patient's clinical information and urinalysis results. DESIGN: Stepwise linear discriminant analysis was used to derive a four-item prediction rule from the derivation group and the validation group; the areas under the receiver operating characteristic (ROC) curves and the misclassification rates were compared. RESULTS: The four-item rule (acute onset, flank pain, hematuria, and positive KUB radiograph) correctly classified 83% of patients in the derivation group and 90% in the validation group. The four-item rule had an ROC area of 0.86 in the derivation group and 0.89 in the validation group. The KUB radiograph significantly improved the discriminant ability of the two history items and the urinalysis result. Thirty-three percent of patients were identified to be in a subset with a 96% probability of having a stone. CONCLUSION: These findings, which should be confirmed in another emergency department, suggest that subsets of patients with suspected ureteral calculi may be managed without emergency IVP; this approach thereby reduces the time a patient spends in the emergency department, radiation exposure, expense, and morbidity.

Adolescent↗
PubMed1992

Interobserver variability in medical record review: an epidemiological study of asthma.

Interobserver variability during the data collection for a large retrospective study of asthma was assessed. After extensive training by three physician investigators, two nurses collected study data from existing medical records using an explicit protocol. At four time intervals, samples of records already abstracted by one nurse were reviewed and re-abstracted by another nurse assigned to the project. The unweighted kappa coefficient was used to evaluate observer reliability. Most of the kappa coefficients were > or = 0.6, suggesting good to excellent agreement. Agreement was highest for demographic, clinical and medication variables, while judgement variables had the lowest kappa coefficients. The well known dependence of kappa on the prevalence of the variable studied was evident in these data. We strongly recommend periodic monitoring of observer reliability in any study using more than one individual to collect data to ensure reliable data collection.

Asthma↗
PubMed1992

Venous thromboembolism associated with hip and knee arthroplasty: current prophylactic practices and outcomes.

Joint registry and hospital data bases for 5,024 total hip and total knee arthroplasties done between 1986 and 1988 at the Mayo Clinic were used to study prophylactic measures and frequency of symptomatic deep venous thrombosis and pulmonary embolism. In virtually all patients, graduated compression stockings were used, with or without another type of prophylaxis. Only 44 of 3,115 patients who underwent hip arthroplasty (1.4%) and 32 of 1,909 patients who underwent knee arthroplasty (1.7%) had definite or probable deep venous thrombosis or pulmonary embolism. Death definitely or possibly attributable to pulmonary embolism occurred in 11 patients who underwent hip arthroplasty (0.35%) and 1 patient who underwent knee arthroplasty (0.05%). Although patients with a history of deep venous thrombosis or pulmonary embolism were more likely to receive warfarin than were patients without such a history, the relative risk of symptomatic deep venous thrombosis or pulmonary embolism in patients who underwent hip arthroplasty and received warfarin postoperatively was approximately half that in patients who received other types of prophylaxis. The risk of death from pulmonary embolism was similarly diminished in the group that received warfarin. The lower rates of these complications in the patients who received warfarin support the prophylactic use of this agent after total hip arthroplasty.

Aspirin↗
PubMed1992

Predictors of outcome after percutaneous endoscopic gastrostomy: a community-based study.

Percutaneous endoscopic gastrostomy (PEG) is used to provide nutrition for patients who are unable to eat but have a functionally intact gut. Clinical guidelines for PEG are uncertain and have been derived mainly from referral practices. We performed a population-based cohort study in 97 residents of Olmsted County, Minnesota, referred for PEG between January 1982 and December 1988 to determine complications, duration of tube feeding, and survival. Follow-up continued until death or February 1990. Inpatient and outpatient records were reviewed to determine indications, comorbid conditions, level of consciousness, and limitations in activities of daily living. Outcomes determined after referral for PEG included type and number of complications, tube removal, and survival. Statistical methods used included Kaplan-Meier and proportional hazards regression analyses. PEG placement was successful in 94% of patients. Although complications occurred in 70% of patients, they usually were minor (88%) and most occurred within 3 months. In 24 patients, tubes were removed because eating was resumed. The probability of surviving 30 days, 1.5 years, and 4 years after referral for PEG was 78%, 35%, and 27%, respectively. The major causes of death within and after 30 days were pneumonia, heart disease, and vascular disease of the central nervous system. An increased risk of death after referral for PEG placement was associated with older age, male gender, diabetes, and specific indications for PEG. If validated in other population-based studies, these predictors of survival after referral for PEG placement could be used to identify patients with a low probability of survival who may not benefit from PEG.

Adolescent↗
PubMed1992

Outcomes of patients admitted to a chronic ventilator-dependent unit in an acute-care hospital.

The outcomes in 61 patients admitted to a chronic ventilator-dependent unit (CVDU) at Saint Marys Hospital in Rochester, Minnesota, during an 18-month period are summarized. This unit was designed for patients who could not be weaned from mechanical ventilators after repeated attempts. Most patients had been ventilator dependent for more than 21 days, but some patients were admitted to the CVDU after briefer periods if special circumstances suggested that weaning from mechanical ventilation would be difficult. The unit was organized to provide a multidisciplinary approach to the general medical and respiratory management of these patients, including a physiologic evaluation of the respiratory system to determine the actual cause of ventilator dependence and complete medical, nursing, and psychosocial assessments to help adopt a plan of care and weaning from the ventilator. Of the numerous causes for ventilator dependence in this study group, chronic obstructive pulmonary disease was the most frequent underlying diagnosis. Of the 61 patients admitted to the CVDU, 58 survived, and 53 were liberated from the mechanical ventilator. Ultimately, 35 patients were dismissed directly home from the CVDU. Five of these patients required nocturnal mechanical ventilation. An additional eight patients were dismissed home after rehabilitation. After being weaned from mechanical ventilation, 11 patients were eventually transferred to nursing homes, and 3 additional patients were transferred to a local hospital or physical medicine unit. One patient remains in the CVDU. Thus, the CVDU has successfully liberated patients from ventilator dependence. In addition, because of a decreased need for nursing care, the unit has been cost-effective.

Adult↗
PubMed1992

A community-based study of the epidemiology of asthma. Incidence rates, 1964-1983.

To determine whether the incidence of asthma had increased in Rochester, Minnesota, from January 1, 1964 through December 31, 1983, we used a population-based computer-linked medical diagnosis system to identify individual medical records with diagnosis of asthma or other conditions mimicking asthma. All records were reviewed using explicit predetermined diagnostic criteria; we identified 3,622 incident cases of asthma, including definite asthma (n = 1,547), probable asthma (n = 952), and single wheezing episodes (n = 1,123). The annual age- and sex-adjusted incidence of definite + probable asthma rose from 183 per 100,000 in 1964 to 284 per 100,000 in 1983. This rise was entirely accounted for by increased incidence rates in children and adolescents (age range, 1 to 14 yr); incidence rates for infants younger than 1 yr of age and for adults remained constant. For definite + probable asthma cases, the incidence rates for males were higher than for females from infancy through 9 yr of age and for persons older than 50; incidence rates for females were higher than for males from 15 through 49 yr of age. The median age at onset was 3 yr for males and 8 yr for females. We conclude that asthma begins in early childhood, with a higher incidence and earlier onset in males, and that the increase in incidence rates seen from 1964 to 1983 occurred only in children and in adolescents.

Age Factors↗
PubMed1991

Benign positional vertigo: incidence and prognosis in a population-based study in Olmsted County, Minnesota.

A retrospective review of our population-based medical records linkage system for residents of Olmsted County, Minnesota, revealed 53 patients (34 women and 19 men; mean age, 51 years) with newly diagnosed benign positional vertigo in 1984. The age- and sex-adjusted incidence was 64 per 100,000 population per year (95% confidence interval, 46 to 81 per 100,000). The incidence of benign positional vertigo increased by 38% with each decade of life (95% confidence interval, 23 to 54%). One patient had an initial stroke during follow-up; thus, the relative risk for new stroke associated with benign positional vertigo was 1.62 (95% confidence interval, 0.04 to 8.98) in comparison with the expected occurrence based on incidence rates for an age- and sex-adjusted control population. The observed survival among the 53 Olmsted County residents with benign positional vertigo diagnosed in 1984 was not significantly different from that of an age- and sex-matched general population. Patients with benign positional vertigo seem to have a good prognosis.

Adolescent↗
PubMed1991

Amyotrophic lateral sclerosis and life-sustaining therapy: patients' desires for information, participation in decision making, and life-sustaining therapy.

To identify the wishes of patients with amyotrophic lateral sclerosis (ALS) for information, participation in decision making, and life-sustaining therapy and to determine whether these wishes are stable over time, we conducted a prospective survey (baseline and 6-month follow-up interviews) of 38 consecutive patients with an established diagnosis of ALS at the University of Chicago Motor Neuron Disease Clinic. Demographic data, clinical stage of ALS, illness experience, wishes for information, and desires for participating in decisions about life-sustaining therapy were elicited. Patients readily expressed their wishes for specific information on communication aids and ventilator care for respiratory failure. Demographic, socioeconomic, and clinical characteristics did not predict patients' desires for information and decision making. The preferences for information and participation in decisions were stable during the 6-month study period, whereas preferences for cardiopulmonary resuscitation in two hypothetical circumstances were less stable. Changes were unrelated to demographic or clinical characteristics of the patients. Because many patients with ALS change their preferences for life-sustaining therapy, advance directives for end-of-life care must be reevaluated periodically.

Adult↗
PubMed1990

Testing nicotine gum for ulcerative colitis patients. Experience with single-patient trials.

Epidemiologic studies have documented an association between nonsmoking and ulcerative colitis and case reports have demonstrated that symptoms improve with smoking and worsen with removal of a nicotine source. A double-blind randomized crossover trial for individual ulcerative colitis patients (single-patient trial, or N of 1 clinical trial) was designed to study the safety, patient acceptance, and the effectiveness of nicotine gum in improving patient symptoms and proctoscopic appearance of involved colon. Seven nonsmoking patients chewed up to 10 squares/day (20 mg) of nicotine gum or placebo gum for two weeks. Therapy was crossed-over every two weeks over the eight-week trial. Effectiveness was judged from comparisons between nicotine-gum and placebo-gum periods of patient self-reported symptoms at the conclusion of each two-week period using visual analog scales and proctoscopic appearance using ordered categorical scales. Three of seven patients, all three of whom were former smokers, demonstrated sufficient improvement without adverse effects to warrant institution of nicotine gum into their drug treatment regimens. Three patients demonstrated an uncertain response, despite tolerating the drug, and have not had nicotine gum added to their regimens. One patient could not tolerate the medication and was withdrawn from the study. No serious side effects were noted. We conclude that a randomized trial for an individual patient is a useful method for evaluating treatment regimens for ulcerative colitis and that nicotine gum may be effective therapy for individual patients with ulcerative colitis who demonstrate an objective response with few adverse effects.

Adult↗
PubMed1990

Evaluation and therapy of the patient with fecal occult blood loss: a decision analysis.

We performed a decision analysis to evaluate cost per cancer detected, cost per neoplasm detected, and cost per treatable lesion of two common diagnostic strategies, barium enema-proctoscopy or colonoscopy as the first diagnostic test, for patients with fecal occult blood loss. The prevalence of polyps, cancer, and angiodysplasia, and the colonoscopy success rate were obtained from consecutive colonoscopy records. Costs were estimated from hospital charges; sensitivity and specificity of barium enema and colonoscopy were obtained from the literature. For treatable lesions (cancer, polyps, and angiodysplasia), the colonoscopy first strategy had a higher sensitivity (80% vs. 57%) and a higher specificity (95% vs. 80%) than the barium enema first strategy. Cost effectiveness measures were similar for the two strategies. Colonoscopy as the first diagnostic test had a lower cost per treatable lesion ($2,319 vs. $2,895) and a lower cost per neoplasm detected ($2,694 vs. $2,896), whereas the barium enema first strategy had a lower cost per cancer detected ($10,050 vs. $10,297). The lower cost per treatable lesion of the colonoscopy first strategy was not affected by changes in the prevalence of lesions, test characteristics, costs of tests, or colonoscopy success rate over clinically relevant ranges. The higher cost of colonoscopy was offset by its greater sensitivity and its capacity for biopsy and therapy. Therefore, since the cost per treatable lesion is lower and the sensitivity, specificity, and predictive value is superior, colonoscopy is recommended as the preferred initial test in evaluating a patient with fecal occult blood loss.

Barium Sulfate↗
PubMed1989

Hazard rates for dysplasia and cancer in ulcerative colitis. Results from a surveillance program.

The risk of colon cancer in patients with ulcerative colitis is related to the duration and extent of disease. Prior reports have suggested that patients with onset of disease in childhood have a high risk of cancer. These risk factors were analyzed in 99 patients in a surveillance program of annual colonoscopy to detect mucosal dysplasia. All patients had pancolitis for at least eight years. The mean age at symptom onset was 23.2 years and the mean duration of disease at entry was 17 years. An average of 4.2 tests/patient were performed, and 91% were completely followed through 1985. Cancer risk was expressed as the hazard rate or the annual probability that a patient free of cancer would develop cancer after survival to a given time period. The hazard rate for high-grade dysplasia or cancer in patients with pancolitis measured from symptom onset was 2.5% at 20 years, 4% at 25 years, 7% at 30 years, 13% at 35 years, and 20% at 40 years. Sex was not a significant predictor of cancer, but older age at symptom onset was a predictor of dysplasia and cancer. From these data, the annual hazard rate of developing high-grade dysplasia or cancer can be estimated in patients with pancolitis based on an individual's age at symptom onset and duration of disease.

Age Factors↗
PubMed1989

Decision making in clinical preventive medicine.

The primary care physician can use the framework for decision making outlined in this article to assess the burden of suffering from conditions that occur in the patients in his or her practice, to evaluate the evidence for the effectiveness of diagnostic and therapeutic interventions, and to decide whether specific efficacious preventive maneuvers are likely to be effective when implemented in daily clinical practice.

Cost-Benefit Analysis↗
PubMed1989

The clinical utility of the Ca19-9 radioimmunoassay for the diagnosis of pancreatic cancer presenting as pain or weight loss. A cost-effectiveness analysis.

CA 19-9 is a promising radioimmunoassay for the detection of pancreatic cancer, but its clinical role and cost-effectiveness are not yet known. To investigate these factors, we used clinical decision analysis to study diagnostic strategies for patients with suspected pancreatic cancer presenting as pain or weight loss. Comprehensive diagnostic strategies were developed to reflect current and future patterns of practice utilizing CA19-9 radioimmunoassay (RIA) to yield biopsy-proved cancer or confidently exclude its presence. The performance of the strategies beginning with CA19-9 RIA and ultrasonography were equivalent in positive and negative predictive values over a range of prevalence of pancreatic cancer from 0.02 to 0.15. At higher prevalence, the negative predictive value of the ultrasonography strategy became significantly better. The CA19-9 RIA strategy used fewer noninvasive tests, endoscopic retrograde cholangiopancreatographic procedures, and invasive radiologic studies than did the ultrasonography strategy at each prevalence. The health care costs ranged between $848 and $1413 per patient for the CA19-9 RIA strategy and $1186 and $1848 per patient for the ultrasonography strategy. We conclude that the CA19-9 RIA is a useful, cost-effective initial test for the examination of patients with suspected pancreatic cancer.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1989

Cigarette smoking in Crohn's disease.

Crohn's disease is a chronic disease of unknown etiology. Previous reports have suggested that cigarette smoking may be associated with the development of Crohn's disease. To examine this association, we conducted a case-control study of patients referred to a single practice over a 7-month period. The cigarette-smoking habits of 115 patients with Crohn's disease were compared with the cigarette-smoking exposure of 109 patients with the irritable bowel syndrome. Patients with Crohn's disease were more likely to smoke at the time of symptom onset than were irritable bowel syndrome controls (age and sex adjusted odds ratio 3.71, 95% confidence interval 1.93-7.13). After the diagnosis of Crohn's disease, patients were less likely to quit smoking (odds ratio 0.35, 95% confidence interval 0.18-0.69) than controls. This study demonstrates an association and a temporal relationship between cigarette smoking and Crohn's disease. For the exposure to be considered an etiologic factor for disease, biologic plausibility and pathophysiologic mechanisms require elucidation.

Adult↗
PubMed1988

An ethics consultation service in a teaching hospital. Utilization and evaluation.

A newly established formal ethics consultation service in a university teaching hospital was prospectively evaluated. A physician-ethicist interviewed and examined patients, interviewed family and others as needed, and entered a formal consultation note in the medical record. The requesting physician and the consultant independently completed structured questionnaires. Fifty-one consultation requests were received from 45 physicians from seven departments between July 1, 1986, and June 30, 1987. Seventeen (33%) of 51 patients were in the intensive care unit, and 19 patients (37%) were fully oriented at the time of consultation. Overall, 61% of the patients survived to leave the hospital. The requesting physician sought assistance with withholding or withdrawing life-sustaining treatment in 49% of cases, with resuscitation issues in 37%, and with legal issues in 31%. Assistance with more than one issue was sought in 39 cases (76%). In 36 cases (71%), the requesting physician stated that the consultation was "very important" in patient management, in clarifying ethical issues, or in learning about medical ethics. We conclude that ethics consultation performed by physician-ethicists provides useful, clinically acceptable assistance in a teaching hospital.

Adult↗
PubMed1988

Survival after cardiopulmonary resuscitation in babies of very low birth weight. Is CPR futile therapy?

We conducted a retrospective study of outcome after cardiopulmonary resuscitation (CPR) in babies of very low birth weight. Of 158 such babies (birth weight, less than 1500 g) admitted to a neonatal intensive care unit in 1985, 49 (31 percent) underwent CPR. Low birth weight, low Apgar scores, birth asphyxia, pulmonary interstitial emphysema, hyaline membrane disease, and severe intraventricular hemorrhage were associated with the need for CPR. None of the 38 babies who received CPR in the first three days of life survived. Four of the 11 babies who received CPR after the first 72 hours survived. Three of the four survivors had residual neurologic deficits. Survival rates after CPR in infants of very low birth weight are lower than those in older children or adults. CPR may therefore be considered a nonvalidated therapy in this population. If the results of our study are confirmed, CPR should not be instituted automatically in very-low-birth-weight babies as though it were a validated treatment. Instead, it should be administered upon parents' advance informed consent to experimental treatment.

Apgar Score↗