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Academic Appointments


Research & Scholarship

Current Research and Scholarly Interests


1. Investigation of the epidemiology of diabetic ketoacidosis (DKA) at a public hospital. All cases of DKA at SCVMC occurring over the past 5 years have been identified. Of the 480 cases of DKA, about 1/3 are in Type II diabetics, and 2/3 in Type I diabetics. We are exploring the causes of DKA in the two groups.

2. Rebound hyperkalemia in thyrotoxic periodic paralysis (TPP). Of 27 cases of TPP presenting to SCVMC over the past 10 years, approximately 1/3 develop hyperkalemia after treatment of their hypokalemia with potassium. We are exploring the causes of this rebound hyperkalemia.

Teaching

2013-14 Courses


Publications

Journal Articles


  • Needle in a Haystack NEW ENGLAND JOURNAL OF MEDICINE Kapoor, R., Moseley, R. H., Kapoor, J. R., Crapo, L. M., Saint, S. 2009; 360 (6): 616-621
  • Screening pregnant women for autoimmune thyroid disease: a cost-effectiveness analysis EUROPEAN JOURNAL OF ENDOCRINOLOGY Dosiou, C., Sanders, G. D., Araki, S. S., Crapo, L. M. 2008; 158 (6): 841-851

    Abstract

    Untreated maternal hypothyroidism during pregnancy can have adverse consequences on maternal health and child intelligence quotient (IQ). Our objective was to examine the cost-effectiveness of screening pregnant women for autoimmune thyroid disease.We developed a state-transition Markov model and performed a cost-effectiveness analysis of screening pregnant US women, aged 15-45 years, with no known history of thyroid disease, in the first trimester.Three strategies were compared: 1) no screening, 2) one-time screening using anti-thyroid peroxidase (anti-TPO) antibodies, and 3) one-time screening using TSH. Screening tests were added to the laboratory tests of the first prenatal visit. Abnormal screening tests were followed by further testing and subsequent thyroxine treatment of hypothyroid women.Screening pregnant women in the first trimester using TSH was cost-saving compared with no screening. Screening using anti-TPO antibodies was cost-effective compared with TSH screening with an incremental cost-effectiveness ratio of $15,182 per quality-adjusted life year. Screening using TSH remained cost-saving across a wide range of ages at screening, costs of treatment, and probabilities of adverse outcomes. The cost-effectiveness of anti-TPO screening compared with TSH screening was mostly influenced by the probability of diagnosing hypothyroidism in unscreened subjects or subjects with a normal screening test. Screening remained highly cost-effective in scenarios where we assumed no improvement of child IQ outcomes by levothyroxine treatment.Screening all pregnant women for autoimmune thyroid disease in the first trimester is cost-effective compared with not screening.

    View details for DOI 10.1530/EJE-07-0882

    View details for Web of Science ID 000256812800009

    View details for PubMedID 18505905

  • The treatment of subclinical hypothyroidism is seldom necessary JOURNAL OF CLINICAL ENDOCRINOLOGY & METABOLISM Chu, J. W., Crapo, L. M. 2001; 86 (10): 4591-4599

    View details for Web of Science ID 000171755400004

    View details for PubMedID 11600508

  • The epidemiology of thyroid disease and implications for screening ENDOCRINOLOGY AND METABOLISM CLINICS OF NORTH AMERICA Wang, C., Crapo, L. M. 1997; 26 (1): 189-?

    Abstract

    The burden of thyroid disease in the general population is enormous. As many as 50% of people in the community have microscopic nodules, 3.5% have occult papillary carcinoma, 15% have palpable goiters, 10% demonstrate an abnormal thyroid-stimulating hormone level, and 5% of women have overt hypothyroidism or hyperthyroidism. Despite this high prevalence of thyroid disease, screening for these disorders is not recommended by any major health agency. This article explores the epidemiologic issues surrounding this complex problem by analyzing prevalence, incidence, and mortality data from a worldwide variety of sources.

    View details for Web of Science ID A1997WN28100012

    View details for PubMedID 9074859

  • The biochemical diagnosis of hypercortisolism. The Endocrinologist Crapo LM., Miller J 1994: 7-16
  • THE MEDICAL-TREATMENT OF CUSHINGS-SYNDROME ENDOCRINE REVIEWS Miller, J. W., Crapo, L. 1993; 14 (4): 443-458

    View details for Web of Science ID A1993LR90200003

    View details for PubMedID 7693447

  • MONITORING THERAPY IN PATIENTS TAKING LEVOTHYROXINE ANNALS OF INTERNAL MEDICINE Helfand, M., Crapo, L. M. 1990; 113 (6): 450-454

    Abstract

    To evaluate the use of thyroid function tests to monitor therapy in patients taking levothyroxine.Studies published between 1966 and January 1990 were identified through computer searches and references of identified studies.Studies that included a careful description of the patients under study, well-defined interventions, and a meaningful criterion standard were emphasized.Data from different studies were combined to estimate the probability of positive and negative test results in well-defined clinical situations. Informal methods of synthesizing evidence were used when combining data from different studies was not justified.The sensitive thyrotropin (TSH) test is the preferred method to monitor therapy because it agrees with physiologic measures of thyroid hormone effect. Among clinically euthyroid patients who take 100 to 150 micrograms/d of levothyroxine, the probability that the sensitive thyrotropin will be undetectable is close to 50%. These patients are most likely to benefit from testing. Patients who take over 250 micrograms/d are almost certain to have undetectable sensitive thyrotropin levels; in these patients, the dose may be lowered without testing.Adequate long-term studies are needed to determine the role of biochemical testing in monitoring therapy. Current evidence suggests that the sensitive thyrotropin test should be used to monitor therapy. Clinically euthyroid patients taking lower dosages of levothyroxine are most likely to benefit from testing.

    View details for Web of Science ID A1990DY95800008

    View details for PubMedID 2143640

  • SCREENING FOR THYROID-DISEASE ANNALS OF INTERNAL MEDICINE Helfand, M., Crapo, L. M. 1990; 112 (11): 840-849

    Abstract

    To evaluate the usefulness of screening for thyroid dysfunction in various clinical settings.Review and synthesis of the literature.Screening in the community detects new overt thyrotoxicosis or hypothyroidism in approximately 0.5% of the general population. The yield is best among women over 40 years of age (1%) and is lowest among young men (0%). Case-finding (testing clinic patients who are seeing a physician for unrelated reasons) has a better yield and is less expensive than screening in the community. Patients hospitalized with acute illnesses do not benefit from routine thyroid function testing. However, patients who are admitted to specialized geriatric units because of general disability, failure to thrive, and other indications may benefit. In various studies, from 2% to 5% of patients admitted to geriatric units have treatable thyroid disease. The serum total thyroxine, free thyroxine index, free thyroxine, and sensitive thyrotropin assay are all effective as initial tests for screening. The sensitive thyrotropin assay is less cost-effective than the other choices.Case-finding in some women over 40 years of age can be useful. Patients admitted to specialized geriatric units may also benefit from routine testing. Thyroid function tests are not indicated for community screening programs or for patients hospitalized with acute medical or psychiatric illnesses.

    View details for Web of Science ID A1990DE90300008

    View details for PubMedID 2111649

  • THE CUSHING SYNDROME - AN UPDATE ON DIAGNOSTIC-TESTS ANNALS OF INTERNAL MEDICINE Kaye, T. B., Crapo, L. 1990; 112 (6): 434-444

    Abstract

    Review and evaluation of diagnostic tests for the Cushing syndrome based on reports published since 1978.Studies published in the English literature from 1978 through 1989 were identified using Index Medicus and cross searching of bibliographies.Studies of five or more patients for general analysis and smaller studies and case reports when pertinent. To develop criteria for the corticotropin-release hormone (CRH) stimulation test, only studies reporting individual patient data were analyzed.No new test is clearly better than existing tests in establishing a definitive diagnosis. Among tests to determine cause, the CRH stimulation test, by newly developed criteria, has a 91% sensitivity (95% CI, 85% to 95%) and a 95% specificity (CI, 82% to 99%), and the overnight high-dose dexamethasone suppression test has an 89% sensitivity (CI, 80% to 94%) and a 100% specificity (CI, 84% to 100%) for the pituitary Cushing syndrome. Magnetic resonance imaging has greater sensitivity for detecting adrenocorticotropin (ACTH)-producing pituitary adenomas than computed tomography. Inferior petrosal sinus sampling can correctly identify a pituitary cause in 88% (CI, 79% to 94%) of cases.Diagnosis is still best established by using 24-hour urine free cortisol measurements or low-dose dexamethasone suppression testing. The CRH stimulation test is an outpatient alternative to determine cause, and the over-night high-dose dexamethasone test may become the test of choice along with plasma ACTH measurements by radioimmunoassay in the initial evaluation of cause. Magnetic resonance imaging should be used to evaluate the pituitary Cushing syndrome, and inferior petrosal sinus sampling is most useful in problematic cases with uncertain cause.

    View details for Web of Science ID A1990CT10000007

    View details for PubMedID 2178536

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