Biomedical subjects

Jeffrey Blume

Publications and source records attributed to Jeffrey Blume.

7 recordsLinked to original sources

PubMed2006

Can differences in breast cancer utilities explain disparities in breast cancer care?

BACKGROUND: Black, older, and less affluent women are less likely to receive adjuvant breast cancer therapy than their counterparts. Whereas preference contributes to disparities in other health care scenarios, it is unclear if preference explains differential rates of breast cancer care. OBJECTIVE: To ascertain utilities from women of diverse backgrounds for the different stages of, and treatments for, breast cancer and to determine whether a treatment decision modeled from utilities is associated with socio-demographic characteristics. PARTICIPANTS: A stratified sample (by age and race) of 156 English-speaking women over 25 years old not currently undergoing breast cancer treatment. DESIGN AND MEASUREMENTS: We assessed utilities using standard gamble for 5 breast cancer stages, and time-tradeoff for 3 therapeutic modalities. We incorporated each subject's utilities into a Markov model to determine whether her quality-adjusted life expectancy would be maximized with chemotherapy for a hypothetical, current diagnosis of stage II breast cancer. We used logistic regression to determine whether socio-demographic variables were associated with this optimal strategy. RESULTS: Median utilities for the 8 health states were: stage I disease, 0.91 (interquartile range 0.50 to 1.00); stage II, 0.75 (0.26 to 0.99); stage III, 0.51 (0.25 to 0.94); stage IV (estrogen receptor positive), 0.36 (0 to 0.75); stage IV (estrogen receptor negative), 0.40 (0 to 0.79); chemotherapy 0.50 (0 to 0.92); hormonal therapy 0.58 (0 to 1); and radiation therapy 0.83 (0.10 to 1). Utilities for early stage disease and treatment modalities, but not metastatic disease, varied with socio-demographic characteristics. One hundred and twenty-two of 156 subjects had utilities that maximized quality-adjusted life expectancy given stage II breast cancer with chemotherapy. Age over 50, black race, and low household income were associated with at least 5-fold lower odds of maximizing quality-adjusted life expectancy with chemotherapy, whereas women who were married or had a significant other were 4-fold more likely to maximize quality-adjusted life expectancy with chemotherapy. CONCLUSIONS: Differences in utility for breast cancer health states may partially explain the lower rate of adjuvant therapy for black, older, and less affluent women. Further work must clarify whether these differences result from health preference alone or reflect women's perceptions of sources of disparity, such as access to care, poor communication with providers, limitations in health knowledge or in obtaining social and workplace support during therapy.

Adult↗

PubMed2006

Diagnostic architectural and dynamic features at breast MR imaging: multicenter study.

PURPOSE: To prospectively determine the prevalence and predictive value of three-dimensional (3D) and dynamic breast magnetic resonance (MR) imaging and contrast material kinetic features alone and as part of predictive diagnostic models. MATERIALS AND METHODS: The study protocol was approved by the institutional review board or ethics committees of all participating institutions, and informed consent was obtained from all participants. Although study data collection was performed before HIPAA went into effect, standards that would be compliant with HIPAA were adhered to. Data from the International Breast MR Consortium trial 6883 were used in the analysis. Women underwent 3D (minimum spatial resolution, 0.7 x 1.4 x 3 mm; minimal temporal resolution, 4 minutes) and dynamic two-dimensional (temporal resolution, 15 seconds) MR imaging examinations. Readers rated enhancement shape, enhancement distribution, border architecture, enhancement intensity, presence of rim enhancement or internal septations, and the shape of the contrast material kinetic curve. Regression was performed for each feature individually and after adjustment for associated mammographic findings. Multivariate models were also constructed from multiple architectural and dynamic features. Areas under the receiver operating characteristic curve (Az values) were estimated for all models. RESULTS: There were 995 lesions in 854 women (mean age, 53 years +/- 12 [standard deviation]; range, 18-80 years) for whom pathology data were available. The absence of enhancement was associated with an 88% negative predictive value for cancer. Qualitative characterization of the dynamic enhancement pattern was associated with an Az value of 0.66 across all lesion architectures. Focal mass margins (Az = 0.76) and signal intensity (Az = 0.70) were highly predictive imaging features. Multivariate models were constructed with an Az value of 0.880. CONCLUSION: Architectural and dynamic features are important in breast MR imaging interpretation. Multivariate models involving feature assessment have a diagnostic accuracy superior to that of qualitative characterization of the dynamic enhancement pattern.

Adolescent↗

PubMed2005

Prospective, multireader evaluation of image quality and vascular delineation of multislice CT angiography of the brain.

The aim of this prospective, multireader trial was to investigate image quality and vascular delineation of cranial multislice CT angiography (MSCTA) to identify strengths and weaknesses of the method. Sixty consecutive patients underwent standardized cranial MSCTA. The mean estimated effective dose was 0.96+/-0.11 mSv. Three masked readers independently graded image quality parameters and vascular delineation on a 5-point scale. Vascular attenuation values and dose-length products were assessed quantitatively. Quantitative parameters were evaluated with a proportional odds regression model with bootstrapped standard errors to adjust the relevant standard errors for correlation within subjects and across readers. The non-parametric Wilcoxon sign-rank test was applied for quantitative measurements. Good to excellent ratings were observed regarding image quality parameters and vascular delineation. The delineation of veins was rated higher than that of arteries (OR 2.00). Smaller arterial segments were rated significantly less favorably than larger segments (OR up to 26.98). Moreover, the cavernous sinus, the C2 segment of the ICA and the communicating arteries demonstrated lower scores. Attenuation values were >240 HU and vessel-to-parenchyma ratios >7 in all vessels. Cranial MSCTA achieved high ratings regarding image quality and vascular delineation. Relative weaknesses were found in small arterial subsegments and in vessels in close topographical proximity to bone.

Adolescent↗

PubMed2005

Evaluation of clinical methods for diagnosing bacterial vaginosis.

OBJECTIVE: To determine whether the current clinical criteria for diagnosing bacterial vaginosis can be simplified by using 2 clinical criteria rather than the standard 3 of 4 criteria (Amsel's criteria). METHODS: This was a prospective observational study of 269 women undergoing a vaginal examination in the Women's Primary Care Center, Division of Research, or Colposcopy Clinic at Women & Infants Hospital. All 4 clinical criteria for diagnosing bacterial vaginosis were collected, and Gram stain was used as the gold standard. Sensitivity and specificity were calculated for each individual criterion, combinations of criteria, and a colorimetric pH and amine card. Receiver operating characteristic curve was generated to estimate the preferred pH and percentage of clue cells for diagnosing bacterial vaginosis. RESULTS: The prevalence of bacterial vaginosis in our study population was 38.7%. Vaginal pH was the most sensitive of all the criteria, at 89%, and a positive amine odor was the individual criteria with the highest specificity, at 93%. Similar specificity was seen with combinations of 2 criteria and Amsel's criteria. Receiver operating characteristic curve analysis yielded a preferred pH and percentage of clue cells of 5.0 and 20%, respectively. However, a pH of 4.5 or greater improves sensitivity with minimal loss of specificity. CONCLUSION: The clinical criteria for diagnosing bacterial vaginosis can be simplified to 2 clinical criteria without loss of sensitivity and specificity.

Adult↗

PubMed2004

Randomization in controlled clinical trials: why the flip of a coin is so important.

The randomized controlled trial (RCT) is considered the highest level of medical evidence. In this brief overview, we discuss several key principles of the RCT. First, balance is paramount. Comparison groups must have similar proportions of participants with "important" prognostic and confounding factors. Randomization may or may not achieve this balance; if it does not, statistical adjustments should be used. Second, a statistical analysis should emphasize comparability and not mask dissimilarity. If the trial was indeed randomized, certain analysis techniques, such as an intention to treat analysis, should always be presented. Third, additional bias-reducing techniques, such as concealing treatment assignments from treating physicians and participants (i.e., masking) and using clearly defined exclusion and inclusion criteria, should be used wherever possible.

Humans↗

PubMed2003

A randomized trial of the sleeved cytobrush and the endocervical curette.

OBJECTIVE: To compare endocervical specimens obtained with the endocervical curette to those obtained with the sleeved cytobrush. METHODS: All nonpregnant women undergoing either cervical conization or hysterectomy were eligible for this randomized, split-sample trial. Both endocervical curette and cytobrush sampling were performed on all 62 participants before surgery, with randomization designating the order of the sampling procedures. A pathologist blinded to sampling order reviewed study specimens. The endocervical canals of the surgical specimens were evaluated against endocervical curette and brush samples. Odds ratios (ORs), relative risks (RRs), and risk differences were used to compare the sensitivity and specificity of each procedure in unmatched and matched analyses. RESULTS: There was a significantly higher rate of inadequate specimens in the endocervical curette group (22% versus 2% in the brush group; 95% confidence interval [CI] for the difference: 9%, 31%). Unmatched analysis showed the two tests to be comparable in terms of sensitivity and specificity. Whereas the specificities of both tests were high (100% for the endocervical curette, 88% for the brush; RR 1.13, 95% CI 1.00, 1.28), the sensitivities were poor (44% for the sleeved brush and 32% for the endocervical curette; RR 1.38, 95% CI 0.65, 2.94). Matched analysis showed the sleeved endocervical brush to be a more sensitive sampling method compared with the curette (OR 2.04, 95% CI 0.98, 4.22). Sparse data prevented a matched analysis on the specificity of the two tests. CONCLUSION: Endocervical sampling with the sleeved cytobrush achieves similar sensitivity and specificity to that of traditional endocervical curettage. Given the much greater rate of inadequate specimens when using the endocervical curette, the sleeved cytobrush is a reasonable alternative to this technique.

Adult↗

PubMed2003

What your statistician never told you about P-values.

We provide a non-technical overview of what P-values are and what they are not. To determine how P-values ought to be used, reported, and interpreted, we must first clarify the often-overlooked differences between, and proper usages of, significance testing and hypothesis testing. Several clinical examples are given to illustrate these differences, and failure to distinguish between them is seen to be problematic. Common misinterpretations of P-values are explained. Confidence intervals provide essential information where P-values are deficient in doing so and they therefore play an essential role in reporting and interpreting study results.

Clinical Trials as Topic↗