Orsine Valente

Use of Color Doppler Ultrasonography for the Prediction of Malignancy in Follicular Thyroid Neoplasms Systematic Review and Meta-analysis

Objective. The purpose of this systematic review was to obtain summary estimates of the diagnostic accuracy of color Doppler ultrasonography (CDU) in predicting malignancy in thyroid follicular neoplasms (FNs). Methods. We searched Medical Subject Headings together with the search terms “follicular,” “thyroid,” and “Doppler” in the MEDLINE, Web of Science, and Excerpta Medica databases as well as the Latin American and Caribbean Health Sciences Literature database, after which we performed manual searches of the reference lists to locate additional studies. There were no language restrictions. We included studies that assessed the diagnostic accuracy of CDU in identifying malignancy in thyroid FNs. The assessments of the quality and extraction of data were performed by 3 independent reviewers. Results. We included 4 studies, which collectively evaluated 457 thyroid FNs, 67 of which had been classified as malignant based on the evaluation of surgical biopsy samples. Moderate, rich, predominant, or exclusive internal flow on CDU of thyroid FNs was considered indicative of malignancy. The overall sensitivity of CDU was 85% (95% confidence interval [CI], 74%–93%), with an overall specificity of 86% (95% CI, 82%–89%). The overall prevalence was 14.7%, and the positive and negative predictive values were 51% and 97%, respectively. The positive likelihood ratio was 6.07, and the negative likelihood ratio was 0.18. Conclusions. Predominant internal flow seen on CDU is associated with malignancy of thyroid FNs. Absence of internal flow or predominantly peripheral flow indicates a low probability of thyroid FN malignancy.

Comparative evaluation of digital mammography and film mammography: systematic review and meta-analysis

CONTEXT AND OBJECTIVE Mammography is the best method for breast-cancer screening and is capable of reducing mortality rates. Studies that have assessed the clinical impact of mammography have been carried out using film mammography. Digital mammography has been proposed as a substitute for film mammography given the benefits inherent to digital technology. The aim of this study was to compare the performance of digital and film mammography. DESIGN Systematic review and meta-analysis. METHOD The Medline, Scopus, Embase and Lilacs databases were searched looking for paired studies, cohorts and randomized controlled trials published up to 2009 that compared the performance of digital and film mammography, with regard to cancer detection, recall rates and tumor characteristics. The reference lists of included studies were checked for any relevant citations. RESULTS A total of 11 studies involving 190,322 digital and 638,348 film mammography images were included. The cancer detection rates were significantly higher for digital mammography than for film mammography (risk relative, RR = 1.17; 95% confidence interval, CI = 1.06-1.29; I² = 19%). The advantage of digital mammography seemed greatest among patients between 50 and 60 years of age. There were no significant differences between the two methods regarding patient recall rates or the characteristics of the tumors detected. CONCLUSION The cancer detection rates using digital mammography are slightly higher than the rates using film mammography. There are no significant differences in recall rates between film and digital mammography. The characteristics of the tumors are similar in patients undergoing the two methods.

Síndrome lipodistrófica do HIV: um novo desafio para o endocrinologista

Arq Bras Endocrinol Metab 2007;51/1 CERCA DE 42 MILHÕES DE PESSOAS estão infectadas pelo HIV no mundo (1). A introdução da terapia anti-retroviral de alta potência (highly active antiretroviral therapy — HAART), principalmente em indivíduos jovens e crianças, aumentou muito a expectativa de vida. No entanto, temse observado com maior freqüência uma síndrome caracterizada por redistribuição anormal da gordura corporal, alterações no metabolismo glicêmico, resistência à insulina e dislipidemia, conhecida como síndrome lipodistrófica do HIV (SLHIV). Os pacientes apresentam perda de gordura subcutânea na face, braços, pernas e nádegas e acúmulo de gordura no pescoço e abdômen. Tais alterações podem determinar um significativo risco cardiovascular na população soropositiva sob HAART. Além disso, estudos demonstram redução na qualidade de vida dos pacientes, decorrente das alterações corporais lipodistróficas, limitando a aderência ao tratamento. O surgimento dessa nova entidade nos remete às formas clássicas de lipodistrofia não associadas ao HIV, como as lipodistrofias congênitas ou adquiridas parciais ou generalizadas. Essas condições de baixa prevalência são associadas a complexas anormalidades metabólicas de difícil tratamento. A SLHIV tem uma prevalência entre 30 e 50% (2) e relaciona-se ao uso dos anti-retrovirais (ARV), em especial ao grupo dos inibidores de proteases (IP). O risco de desenvolver essa síndrome aumenta com a duração do tratamento, a idade do paciente e o nível de imunodeficiência. No artigo de Guimarães e cols. (3), publicado neste número dos “Arquivos”, são avaliados dados antropométricos, os perfis lipídico e glicêmico de pacientes infectados pelo HIV, tratados ou não com ARV. Os autores evidenciam, nos pacientes infectados pelo HIV usuários de HAART, aumento dos níveis de triglicérides, colesterol total, glicemia e insulina, caracterizando resistência à insulina. Essas alterações têm muita similaridade com os achados mostrados em uma recente publicação (4), na qual foram estudados 788 adultos infectados pelo HIV sob HAART e avaliados pelos critérios da International Diabetes Foundation (IDF) e do U.S. National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III). A prevalência da síndrome metabólica neste grupo foi de 14% pelos critérios da IDF e 18% pelos critérios da ATP III. Metade dos pacientes apresentava pelo menos duas características da síndrome metabólica, mas não foram classificados como tal porque a medida da cintura ou a razão cintura/quadril não estavam nas faixas da síndrome metabólica definidas por esses critérios. A prevalência de diabetes tipo 2 foi 5 a 9 vezes maior no subgrupo dos pacientes com síndrome metabólica. O mesmo grupo havia mostrado níveis diminuídos de adiponectina em pacientes HIV com lipodistrofia (5). Nesse estudo, adiponectina foi 20% menor nos pacientes com síndrome metabólica. Esse dado não surpreende, já que a obesidade visceral é associada com hipoadiponectinemia. Além disso, esses pacientes com HIV, SM e lipodistrofia apresentam também aumento da proteína C-reativa e hiperleptinemia. A SM estudada nesses pacientes foi mais freqüente naqueles editorial Síndrome Lipodistrófica do HIV: Um Novo Desafio para o Endocrinologista

The oral glucose tolerance test is frequently abnormal in patients with uncontrolled epilepsy.

PURPOSE The clinical efficacy of the ketogenic diet as therapy for patients with difficult-to-treat epilepsy prompted us to investigate the glucose metabolism of these patients under an oral overload of glucose, that is, in the oral glucose tolerance test (OGTT). METHODS Thirty patients (12 males, 18 females; age range: 17-59, mean: 35.1) with difficult-to-treat epilepsy, 23 patients with controlled epilepsy (11 males, 12 females; age range: 14-66, mean: 36.9), and 39 control subjects (18 males, 21 females; age range: 16-58, mean: 33.3) were evaluated with the OGTT. For patients with epilepsy, we also measured C-peptide and glycosylated hemoglobin in the fasting state. Glucose levels lower than 70 mg/dL at any point of the curve were considered to be abnormal. RESULTS All subjects in the control group and the group with controlled epilepsy had a normal OGTT. In contrast, all 30 patients with difficult-to-treat epilepsy had at least one point on the OGTT curve below the normal range (P<0.001), most often 180 and 240 minutes after the oral glucose load (P<0.001). C-peptide levels were significantly lower in the group with difficult-to-treat epilepsy as compared with the group with controlled epilepsy. Fasting glycohemoglobin and insulin levels did not differ between the two patient groups. CONCLUSIONS We suggest that undiagnosed metabolic disturbances in patients with difficult-to-treat epilepsy may somehow contribute to their refractoriness to conventional pharmacological therapy. We propose the hypothesis that calorie-restricted diets aimed at correcting OGTT curves may prove beneficial in treating patients with difficult-to-treat epilepsy. Our hypothesis generates a clear endpoint for the diet, and its demonstration would provide new standards for diet-based antiepileptic regimens. Accordingly, our results may help in understanding the positive consequences of ketogenic or calorie-restricted diets in persons with seizures.

In reply to letter to the editor from S. Y. Chu, S. Y. Kim and J. Lau

We thank Dr Chu, Dr Kim and Dr Lau for their interest and comments regarding our systematic review on maternal body mass index (BMI) and gestational diabetes. Besides the three main aspects they pointed out, our systematic review differed from theirs on other relevant aspects: (i) our critical evaluation of the quality of the included studies on the basis of criteria proposed by acknowledged international reference groups; (ii) the presentation and analysis of heterogeneity of all pooled odds ratios (OR); (iii) subgroup and sensitivity analysis including eight different variables; (iv) the detailed presentation of 21 studies with adjusted OR and the pooled adjusted OR derived from these studies; (v) the evaluation of an additional BMI category (moderate obesity) and (vi) the linear regression graph assessing the mean change in the risk of gestational diabetes mellitus (GDM) for each BMI unit change. We believe that these additions are an important added value to the review, enhancing the validity of the results. In meta-analysis of observational studies, confounding and selection bias are likely to distort results (1–3). We acknowledged these limitations by critically assessing the quality of the primary studies regarding known sources of bias and by examining and reporting of heterogeneity. We also understand that it is critical to separately analyse studies presenting adjusted OR recognizing the value of adjusting in the first place as a way to reduce spurious results. It is true that most of the included studies in our review define severely obese women as those with BMI > 35, while three out of five studies included in Chu’s review used BMI > 40 to define that category. But we deliberately excluded two of these three studies (Callaway 2006 and Grossetti 2004) because the authors reported selective screening for GDM in their populations. We understand that including studies that did not offer screening for GDM to all women, but only to a group selected based on the presence of risk factors, could be an important source of bias. Therefore, we cannot be certain that Chu’s higher pooled OR for severely obese women (their OR = 8.56, 95% confidence intervals 5.07–16.07 vs. our OR = 5.55, 95% confidence intervals 4.27–7.21) is due to their inclusion of more studies that used a higher BMI cut-off or to their inclusion of studies with selective screening for GDM. The two large studies included by Chu et al. (Rosenberg 2003 and Robinson 2005) represent over one-third of their total population (302 247/844 295). We deliberately excluded these two studies as well as other similar studies, because we did not think it is correct to combine different measures of obesity in a single pooled OR. We selected BMI as the only measure to define exposure in order to reduce heterogeneity and because it appears to be reliable and superior to maternal weight for identifying risk for gestational diabetes (4). However, our review included 55 additional studies not included in their original review. Although bigger is not necessarily better, as smaller studies can devote more attention to characterizing confounding factors than larger studies (5), we do not agree with the statement made by Chu et al. that most of our additional studies were based on small populations. In fact, five of our additional studies had over 10 000 participants, seven had populations between 5000 and 10 000, and 31 included between 500 and 4999 women. Additionally, contrary to the information mentioned under their Table 2, we presented the results for all the 70 included studies (not only on 59 cohorts). In the text and supplementary material of our article, we present additional comparisons not made by Chu et al. (therefore not mentioned in their Table 2) such as moderately obese vs. normal women, obese general vs. non-obese general (BMI > 30 vs. BMI < 30) and overweight general vs. nonoverweight general (BMI > 25 vs. BMI < 25) as well as studies that provided only adjusted OR and separate pooled OR for case–control studies. Ultimately, the results from our systematic review reinforce the results obtained by Chu et al., and as they mention, differences in the pooled OR are minor. More importantly, we share Chu’s concern about the public health implications of the escalating problem of obesity worldwide. In our opinion, female obesity is especially worrisome as it can lead to increase in both maternal and perinatal adverse outcomes. However, as it is a modifiable risk factor, the dissemination of information about the significant increase in pregnancy risks caused by high maternal BMI (along with the implementation of lifestyle modification programmes) can contribute to reduce the burden of maternal obesity. obesity reviews doi: 10.1111/j.1467-789X.2009.00578.x