Kevin Cheung

Calcitonin Measurement in the Evaluation of Thyroid Nodules in the United States: A Cost-Effectiveness and Decision Analysis

CONTEXT European studies have shown that the use of routine calcitonin screening for detection of medullary thyroid cancer (MTC) in patients with thyroid nodules increases the detection of occult MTC and may improve patient outcomes. Calcitonin screening for MTC has not been recommended in recent U.S. practice guidelines. OBJECTIVE Our objective was to determine the cost-effectiveness (C/E) of routine calcitonin screening in adult patients with thyroid nodules in the United States. SETTINGS/SUBJECTS A decision model was developed for a hypothetical group of adult patients presenting for evaluation of thyroid nodules in the United States. Patients were screened using current American Thyroid Association guidelines only, or American Thyroid Association guidelines with routine serum calcitonin screening. Input data were obtained from the literature, the Surveillance Epidemiology and End Results and Healthcare Cost and Utilization Projects Nationwide Inpatient Sample databases, and the Medicare Reimbursement Schedule. Sensitivity analyses were performed for a number of input variables. MAIN OUTCOME MEASURES C/E, measured in dollars per life years saved (LYS), was calculated. RESULTS Addition of calcitonin screening to current American Thyroid Association guidelines for the evaluation of thyroid nodules would cost

A Meta-analysis of Preoperative Localization Techniques for Patients with Primary Hyperparathyroidism

11,793 per LYS (

Rvb1-Rvb2: essential ATP-dependent helicases for critical complexes.

10,941-

Clinical Outcomes of 5358 Patients Undergoing Direct Open Bypass or Endovascular Treatment for Aortoiliac Occlusive Disease: A Systematic Review and Meta-Analysis

12,646). When extrapolated to the national level, calcitonin screening for MTC in the United States would yield an additional 113,000 life years at a cost increase of 5.3%. Calcitonin screening C/E is sensitive to patient age and gender, and to changes in disease prevalence, specificity of fine needle aspiration and calcitonin testing, calcitonin screening level, costs of testing, and length of follow-up. CONCLUSION Routine serum calcitonin screening in patients undergoing evaluation for thyroid nodules appears to be cost effective in the United States, with C/E comparable to the measurement of thyroid stimulating hormone, colonoscopy, and mammography screening.

The Clp Chaperones and Proteases of the Human Malaria Parasite Plasmodium falciparum

BackgroundReported accuracy of preoperative localization imaging for primary hyperparathyroidism (pHPT) varies. The purpose of this study is to determine the accuracy of ultrasound, sestamibi-single photon emission computed tomography (SPECT), and four-dimensional computed tomography (4D-CT) as preoperative localization strategies.MethodsA meta-analysis was performed of studies investigating the accuracy of ultrasound, sestamibi-SPECT, and 4D-CT for preoperative localization in pHPT. Electronic databases were systematically searched, and two independent reviewers reviewed results using specific criteria. Study quality was assessed using a validated measure for diagnostic imaging studies. Study heterogeneity and pooled results were calculated.Results43 studies met criteria for inclusion, and data were available for extraction in 19 ultrasound, 9 sestamibi-SPECT, and 4 4D-CT studies. Ultrasound had pooled sensitivity and positive predictive value (PPV) of 76.1% (95% CI 70.4–81.4%) and 93.2% (90.7–95.3%), respectively. Sestamibi-SPECT had pooled sensitivity and PPV of 78.9% (64–90.6%) and 90.7% (83.5–96.0%), respectively. Only two 4D-CT studies investigated patients undergoing initial parathyroidectomy. Results suggested sensitivity and PPV of 89.4% and 93.5%, respectively.ConclusionsUltrasound and sestamibi-SPECT are similar in ability to preoperatively localize abnormal parathyroid glands in pHPT. Accuracy may be improved with 4D-CT; however, further investigation is required. Choice of preoperative imaging strategy depends on numerous patient, institutional, and economic factors of which the surgeon must be aware.

Would scan, but which scan? A cost-utility analysis to optimize preoperative imaging for primary hyperparathyroidism

Rvb1 and Rvb2 are highly conserved, essential AAA+ helicases found in a wide range of eukaryotes. The versatility of these helicases and their central role in the biology of the cell is evident from their involvement in a wide array of critical cellular complexes. Rvb1 and Rvb2 are components of the chromatin-remodeling complexes INO80, Swr-C, and BAF. They are also members of the histone acetyltransferase Tip60 complex, and the recently identified R2TP complex present in Saccharomyces cerevisiae and Homo sapiens; a complex that is involved in small nucleolar ribonucleoprotein (snoRNP) assembly. Furthermore, in humans, Rvb1 and Rvb2 have been identified in the URI prefoldin-like complex. In Drosophila, the Polycomb Repressive complex 1 contains Rvb2, but not Rvb1, and the Brahma complex contains Rvb1 and not Rvb2. Both of these complexes are involved in the regulation of growth and development genes in Drosophila. Rvbs are therefore crucial factors in various cellular processes. Their importance in chromatin remodeling, transcription regulation, DNA damage repair, telomerase assembly, mitotic spindle formation, and snoRNP biogenesis is discussed in this review.

Pharyngeal flap versus sphincter pharyngoplasty for the treatment of velopharyngeal insufficiency: a meta-analysis.

Purpose To examine clinical outcomes of endovascular and open bypass treatment for aortoiliac occlusive disease (AIOD). Methods Multiple databases were systematically searched to identify studies on open and endovascular treatment for AIOD published from 1989 to 2010. Studies were independently reviewed for eligibility criteria. Study selection and assessment of methodological quality were performed by two independent reviewers. Assuming between-study heterogeneity due to biases inherent to observational studies, a random effects model (DerSimonian-Laird method) was used for calculation of weighted proportions. Pooled weighted proportions or weighted means are reported. Twenty-nine open bypass studies (3733 patients) and 28 endovascular treatment studies (1625 patients) were analyzed. Results Weighted mean patient age was 60.4 years for open bypass and 60.8 years for endovascular treatment. Poor preoperative runoff was greater in the open bypass group (50.0% vs. 24.6%, p<0.001). Mean length of hospital stay (LOS) was 13 days for open bypass vs. 4 days for endovascular treatment procedures (p<0.001). The open bypass group experienced more complications (18.0% vs. 13.4%, p<0.001) and greater 30-day mortality (2.6% vs. 0.7%, p<0.001). At 1, 3, and 5 years, pooled primary patency rates were greater in the open bypass group vs. the endovascular cohort (94.8% vs. 86.0%, 86.0% vs. 80.0%, 82.7% vs. 71.4%, respectively; all p<0.001); the same was true for secondary patency [95.7% vs. 90.0% (p=0.002), 91.5 vs. 86.5% (p<0.001), and 91.0% vs. 82.5% (p<0.001), respectively]. Conclusion Although this study was limited by a paucity of randomized control trials, these results demonstrate superior durability for open bypass, although with longer LOS and increased risk for complications and mortality, when compared to the endovascular approach.

To stimulate or withdraw? A cost-utility analysis of recombinant human thyrotropin versus thyroxine withdrawal for radioiodine ablation in patients with low-risk differentiated thyroid cancer in the United States.

The Clp chaperones and proteases play an important role in protein homeostasis in the cell. They are highly conserved across prokaryotes and found also in the mitochondria of eukaryotes and the chloroplasts of plants. They function mainly in the disaggregation, unfolding and degradation of native as well as misfolded proteins. Here, we provide a comprehensive analysis of the Clp chaperones and proteases in the human malaria parasite Plasmodium falciparum. The parasite contains four Clp ATPases, which we term PfClpB1, PfClpB2, PfClpC and PfClpM. One PfClpP, the proteolytic subunit, and one PfClpR, which is an inactive version of the protease, were also identified. Expression of all Clp chaperones and proteases was confirmed in blood-stage parasites. The proteins were localized to the apicoplast, a non-photosynthetic organelle that accommodates several important metabolic pathways in P. falciparum, with the exception of PfClpB2 (also known as Hsp101), which was found in the parasitophorous vacuole. Both PfClpP and PfClpR form mostly homoheptameric rings as observed by size-exclusion chromatography, analytical ultracentrifugation and electron microscopy. The X-ray structure of PfClpP showed the protein as a compacted tetradecamer similar to that observed for Streptococcus pneumoniae and Mycobacterium tuberculosis ClpPs. Our data suggest the presence of a ClpCRP complex in the apicoplast of P. falciparum.

To Supplement or Not to Supplement: A Cost-Utility Analysis of Calcium and Vitamin D Repletion in Patients After Thyroidectomy

BACKGROUND Minimally invasive parathyroidectomy for primary hyperparathyroidism depends on accurate preoperative localization. This study examines the cost-utility of sestamibi in combination with single photon emission computed tomography (sestamibi-SPECT); ultrasound; and 4-dimensional computed tomography (4D-CT). METHODS A decision tree was constructed for patients undergoing initial parathyroidectomy. Patients were randomized to 1 of 5 preoperative localization protocols: (1) ultrasound; (2) sestamibi-SPECT; (3) 4D-CT; (4) sestamibi-SPECT and ultrasound; and (5) sestamibi-SPECT and ultrasound and 4D-CT, if discordant (sestamibi-SPECT and ultrasound ± 4D-CT). From a societal perspective, all relevant costs were included. Input data were obtained from literature and Medicare. The incremental cost-utility ratio was determined in dollars per quality-adjusted life years (

Surgeon Volume Trumps Specialty: Outcomes From 3596 Pediatric Cholecystectomies

/QALY). Sensitivity analyses were performed. RESULTS In the base-case, ultrasound was least expensive, with a cost of