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Biomedical subjects

B L Strom

Publications and source records attributed to B L Strom.

At least 163 records · Page 9Linked to original sources
PubMed1986

Duration of warfarin anticoagulant therapy and the probabilities of recurrent thromboembolism and hemorrhage.

To determine the association of duration of warfarin anticoagulant therapy after hospitalization for venous thromboembolism with the probability of recurrent thromboembolism and with the risks of hemorrhage, medical records of 2,422 patients hospitalized in 1970 through 1980 with pulmonary embolism, thrombophlebitis, or both were reviewed. Multivariate life-table analyses were performed for 370 patients who had positive results of venography or pulmonary angiography, or who had lung scanning evidence of a "high probability" of pulmonary embolism and no history of the disease. For these patients, warfarin therapy for more than six weeks was not associated with a lower risk of recurrent thromboembolism when compared with warfarin therapy for one through six weeks (risk of recurrence for seven to 26 weeks of treatment 0.8; 95 percent confidence limits 0.3 and 2.5; risk of recurrence for more than 26 weeks of treatment 1.1; 95 percent confidence limits 0.4 and 3.1). The longer the warfarin therapy, the higher the risk of medically important complications from therapy. From one week through five years, the probability of major hemorrhage increased almost linearly: 10 percent for 12 weeks, 18 percent at one year, 26 percent at two years, and 41 percent at five years. This study suggests that intensive, long-term warfarin anticoagulation, in patients with a first episode of venous thromboembolism and no predisposing condition, is associated with more toxicity than efficacy and should be abandoned.

Actuarial Analysis↗
PubMed1986

Oral contraceptives and other risk factors for gallbladder disease.

Prior studies of the association between oral contraceptives (OCs) and gallbladder disease (GBD) have yielded conflicting results. To clarify this association, a retrospective (historical) cohort study was performed on a very large data base including 1980 and 1981 Medicaid billing data from the states of Michigan and Minnesota in which 138,943 users of OCs were compared with 341,478 nonusers. The crude relative risk (RR) and 95% confidence interval (CI) for symptomatic GBD resulting in medical care was 1.14 (CI 1.09 to 1.20), with a clear dose-response (P less than 0.001). Age markedly modified the effect of OCs on GBD. The RR (CI) decreased from 3.1 (2.7 to 3.6) in women 15 to 19 years old to 1.2 (0.9 to 1.5) in women 40 to 44 years old, providing an explanation for previously conflicting reports. The effects of a number of other risk factors on GBD, some which have been controversial, were also confirmed. Adjustment for these did not change the results. In conclusion, OCs are risk factors for GBD, although the risk is of sufficient magnitude to be of potential clinical importance only in young women.

Adolescent↗
PubMed1986

Does gallbladder removal protect against subsequent myocardial infarction?

It has been suggested that gallbladder removal may protect against subsequent development of myocardial infarction because of increased gastrointestinal cholesterol excretion resulting from increased enterohepatic cycling. To test this hypothesis, the authors used data from two large case-control studies of myocardial infarction--one conducted in 1976-1979 in 155 US hospitals and one conducted in 1980-1983 in 78 US hospitals. First, 550 female myocardial infarction cases were compared to 1,658 controls. Simultaneously adjusting for possible confounding variables using logistic regression, the odds ratio for development of a myocardial infarction subsequent to cholecystectomy was 0.8 (95% confidence interval, 0.5-1.1). Second, 1,511 male myocardial infarction cases were compared to 3,837 controls. With similar adjustments, the odds ratio was 0.8 (95% confidence interval, 0.5-1.2). The risk did not decline as the interval following cholecystectomy increased. The present data are compatible with a protective effect of cholecystectomy on the risk of subsequent myocardial infarction, but they are not conclusive.

Adult↗
PubMed1985

Post-marketing studies of drug efficacy: why?

In order to quantify the need for post-marketing studies of drug efficacy, the 100 drug uses (i.e., drug-indication pairs) that were most common in 1978 were reviewed. Of the 100 most common drug uses, 31 were not Food and Drug Administration (FDA)-approved at the time of initial marketing and 18 had not become FDA-approved, even subsequently. In 13, the use was based on the drug's secondary effect rather than on the primary effects investigated before marketing. The efficacy of all was subject to modification by incompletely explored factors, including other drugs, patient age, other illnesses, pregnancy, etc. Specific examples are provided of important modifiers of the efficacy of these drugs that were not investigated prior to marketing. Thus, despite the existence of sufficient data for the regulatory process to permit the marketing of these commonly used drugs, considerable gaps remain in the information needed for their optimal clinical use. Post-marketing studies of drug efficacy will be needed to fill these gaps.

Drug Labeling↗
PubMed1985

Discriminant scorecard for diagnosis of invasive pulmonary aspergillosis in patients with acute leukemia.

Invasive pulmonary aspergillosis, a serious opportunistic infection in adult patients with acute leukemia, is difficult to diagnose antemortem. To identify patients with invasive pulmonary aspergillosis without reliance on invasive diagnostic procedures, a discriminant scorecard for invasive pulmonary aspergillosis based on clinical parameters was evaluated in a three-phase study. In phase I, the records of 62 patients, including 15 with invasive pulmonary aspergillosis, were reviewed. Eleven clinical parameters distinguished patients with invasive pulmonary aspergillosis from control subjects. These parameters were combined into a discriminant scorecard. In phase II, the discriminant scorecard was validated by a blinded, retrospective review of 94 consecutive admissions. The discriminant scorecard score was highly associated with the clinical outcome (p less than 0.0005). The sensitivity of the discriminant scorecard was calculated as a range from 62.9 to 92.8 percent and the specificity as a range from 87.5 to 98.3 percent. In phase III, the clinical utility of the discriminant scorecard was determined by its prospective application to 49 consecutive patient admissions. The discriminant scorecard identified patients with invasive pulmonary aspergillosis at an average of 4.1 days prior to clinical recognition of the disease and initiation of amphotericin B therapy. The discriminant scorecard outperformed a complex function based on multiple linear regressions, was easy to use, and did not require difficult calculations. Thus, for this patient population, the discriminant scorecard was an accurate, useful noninvasive screening test for invasive pulmonary aspergillosis. The scorecard allows more rapid clinical identification of patients with this infection and could lead to improved patient survival through earlier diagnostic and therapeutic intervention.

Acute Disease↗
PubMed1985

No evidence of association between methyldopa and biliary carcinoma.

Cancer of the bile ducts is rare and little is known about its risk factors. Recently, an association between methyldopa therapy and biliary carcinoma was reported in a retrospective case-control study. If this association were real, it would represent a significant health hazard, because methyldopa is widely prescribed. Using analysis of covariance to study the relationship between biliary tract cancer rates (obtained from 11 cancer registries in the US, Canada, Europe, and Asia) and per capita methyldopa sales (obtained from its manufacturer), this possible association was re-examined. For the rates of all biliary tract cancers combined, using both three- and ten-year lag periods between drug sales and disease, there were no associations between methyldopa and biliary carcinoma. When the rates for the biliary tract cancer sites were examined separately, one small positive regression coefficient was observed with extrahepatic biliary tract cancer, using the ten-year lag period only (p = 0.03). Since the majority of biliary tract cancers are extrahepatic in origin, it is likely that most of the cancers coded as 'biliary tract cancer, part unspecified' are actually extrahepatic. Also, the magnitude of the slope is very small, contrary to what one would expect with a common drug exposure and an uncommon disease. For these reasons, we believe that the negative results obtained with the combined rates for biliary tract cancer are more meaningful than the results obtained for each cancer site separately. In conclusion, our data do not support the presence of an association between methyldopa and biliary tract cancer.

Biliary Tract Neoplasms↗
PubMed1985

Invasive pulmonary aspergillosis in adult acute leukemia: clinical clues to its diagnosis.

Invasive pulmonary aspergillosis, a leading cause of morbidity and mortality in patients with acute leukemia, is difficult to diagnose antemortem because its signs and symptoms are ill-defined. To refine the clinical description of this infection, we reviewed our experience with 15 pathologically documented cases of invasive pulmonary aspergillosis in a population of 60 patients treated for acute leukemia. Findings occurring significantly more often (P less than or equal to .001) among cases than controls included pleuritic chest pain; acute sinus tenderness, and nasal discharge, epistaxis and eschar; rales; development of multilobar infiltrates after the 14th hospital day; and presence of nodular or cavitary infiltrates. In addition, patients with invasive pulmonary aspergillosis had a significantly prolonged duration of granulocytopenia, more febrile days and febrile episodes without a fever diagnosis and more febrile days on antibiotics (P less than or equal to .001 in all). This complex of findings should improve the clinician's ability to diagnose invasive pulmonary aspergillosis in patients with acute leukemia.

Acute Disease↗
PubMed1985

Cancer of the gallbladder in Bolivia: suggestions concerning etiology.

In order to investigate the very high incidence of gallbladder cancer in Bolivia, a series of patients with gallbladder cancer and/or cholelithiasis from a hospital in La Paz was compared to a series of patients with cholelithiasis from Philadelphia. Each group demonstrated a similar female predilection. Bolivian patients with gallbladder cancer were older than patients with cholelithiasis who, in turn, were older than the general population (p less than 0.001). Racial differences demonstrated previously were confirmed. Bolivian gallstones were uniformly cholesterol in type, in contrast to the US series, in which 27% of patients had black pigment stones. Bile specimens obtained from Bolivian patients with cholelithiasis had a lower concentration of bile salts, phospholipids, and cholesterol than bile specimens from US cholelithiasis patients (p less than 0.01, less than 0.001, and less than 0.001, respectively). These biochemical differences may help to explain the differing incidence of cholelithiasis and gallbladder cancer in the US and Bolivia.

Bile↗
PubMed1985

International variations in epidemiology of cancers of the extrahepatic biliary tract.

Previous studies of the descriptive epidemiology of biliary tract cancers have not differentiated among different types of biliary tract cancer because until recently the International Classification of Diseases (ICD) did not classify them separately. Recent versions of the ICD now distinguish cancers of the gallbladder, extrahepatic bile ducts, and ampulla of Vater. In order to describe more precisely the distribution of these three cancers, we obtained data from nine cancer registries throughout the world which used the eighth or ninth revision of the ICD. Sex-specific, age-adjusted disease rates were calculated for each disease. Log-linear models were used to evaluate the association of age and sex with the risk of acquiring each disease and to assess whether the risk of acquiring disease or the age and sex distribution of the three diseases varied by geographic location. Gallbladder cancer was the most common of the three diseases and occurred more frequently in females. Extrahepatic bile duct cancer was the next most common disease and occurred equally in both sexes. Cancer of the ampulla of Vater was the least common and was more common in males. The incidence of each of the diseases increased with age. The age and sex distributions of the different diseases different among the nine registries. Thus these three neoplasms differ in their descriptive epidemiology and should therefore be considered separately in clinical practice and in future investigations.

Adult↗
PubMed1984

Post-marketing studies of drug efficacy: how?

This report reviews the 100 most recently approved drugs in order to quantify the frequency with which post-marketing studies of drug efficacy can be performed experimentally and non-experimentally. These drugs represent 131 potential drug uses. Of them, the absolute efficacy of 89 (68 percent) could be evaluated from clinical observations. Of the remaining 42, six (14 percent) could be studied experimentally or non-experimentally, six (14 percent) only experimentally, one (2 percent) only non-experimentally, and 29 (69 percent) by neither technique. Answers to all questions of relative efficacy required formal research. Of these, 94 (72 percent) could be studied using either experimental or non-experimental techniques. The remaining 37 (28 percent) could be studied experimentally only. Thus, clinical observations and non-experimental research can contribute a large proportion of the information about drug efficacy still needed after marketing.

Drug Therapy↗
PubMed1984

Prolonged granulocytopenia: the major risk factor for invasive pulmonary aspergillosis in patients with acute leukemia.

A case-control study of patients with acute leukemia was done to identify significant risk factors for invasive pulmonary aspergillosis by reviewing the medical histories of 15 cases of pathologically proven invasive pulmonary aspergillosis and 45 controls. A history of lung or sinus disease, smoking, and multiple recurrences of leukemia did not increase the risk of invasive pulmonary aspergillosis. Cases and controls received similar chemotherapeutic regimens, and exposure to aminoglycosides, carbenicillin, trimethoprim-sulfamethoxazole, or corticosteroids was not significantly associated with development of invasive pulmonary aspergillosis. Among the factors tested, only granulocytopenia was associated with development of invasive pulmonary aspergillosis. Early in the course of granulocytopenia, patients developed signs of invasive pulmonary aspergillosis at a rate of approximately 1% per day. As the duration of granulocytopenia increased, the rate increased, approximating 4.3% per day between the 24th and 36th days. Of the 13 patients remaining granulocytopenic at 28 days, 7 had developed signs of invasive pulmonary aspergillosis. For patients with acute leukemia, granulocytopenia persisting longer than three weeks is the major risk factor for developing invasive pulmonary aspergillosis.

Acute Disease↗
PubMed1983

The epidemiology of cancer of the extra-hepatic biliary tract in Bolivia.

Data on patients with cancer of the gall bladder and cancer of the extra-hepatic bile ducts were obtained from the tumour registry in La Paz, Bolivia. Incidence rates were calculated using the Bolivian census data and compared to US incidence data from the Third National Cancer Survey. The age and population standardized incidence rates for cancer of the gall bladder in Bolivia were 5.3/100,000 males/year and 10.3/100,000 females/year. Comparable US rates were 1.0/100,000 males/year and 2.1/100,000 females/year. The age and population standardized incidence rates for cancer of the extra-hepatic bile ducts in Bolivia were 1.1/100,000 males/year and 4.1/100,000 females/year. Comparable US rates were 1.6/100,000 males/year and 1.0/100,000 females/year respectively. Both diseases occurred at younger ages in Bolivia than in the US and both showed marked racial variation. Differences in disease incidence between Bolivia and the US could not be fully explained by differences in age, sex, or racial distributions. Studies designed to investigate the causes of this remarkable variation in disease incidence could provide important clues to disease aetiology.

Adolescent↗