PSS Health: como calcular tamanho de amostra para testes de comparação de médias de dois grupos / PSS Health: how to calculate sample sizes for mean comparison tests between two groups

Dando continuidade à série de artigos que pretendem orientar o usuário na utilização da ferramenta PSS Health para o planejamento de uma pesquisa, esta edição apresenta um passo a passo de como realizar o cálculo e de quais informações são necessárias para comparar médias: de dois grupos dependentes ou independentes, de dois grupos independentes com duas medidas repetidas (deltas), e com duas ou mais medidas repetidas. Todos os exemplos também são ilustrados e disponibilizados em vídeos no canal da Unidade de Bioestatística.

Following the series of articles aiming to guide users in using the PSS Health tool for research planning, this issue presents a step-by-step guide on how to calculate and what information is needed to compare means between 2 dependent or independent groups, 2 independent groups with 2 repeated measures (deltas), and 2 independent groups with 2 or more repeated measures. All examples are accompanied by figures and available in video on the Biostatistics Unit's channel.

Why do some trauma patients die while others survive? A matched-pair analysis based on data from Trauma Register DGU® / 中华创伤杂志(英文版)

PURPOSE@#The mortality rate for severely injured patients with the injury severity score (ISS) ≥16 has decreased in Germany. There is robust evidence that mortality is influenced not only by the acute trauma itself but also by physical health, age and sex. The aim of this study was to identify other possible influences on the mortality of severely injured patients.@*METHODS@#In a matched-pair analysis of data from Trauma Register DGU®, non-surviving patients from Germany between 2009 and 2014 with an ISS≥16 were compared with surviving matching partners. Matching was performed on the basis of age, sex, physical health, injury pattern, trauma mechanism, conscious state at the scene of the accident based on the Glasgow coma scale, and the presence of shock on arrival at the emergency room.@*RESULTS@#We matched two homogeneous groups, each of which consisted of 657 patients (535 male, average age 37 years). There was no significant difference in the vital parameters at the scene of the accident, the length of the pre-hospital phase, the type of transport (ground or air), pre-hospital fluid management and amounts, ISS, initial care level, the length of the emergency room stay, the care received at night or from on-call personnel during the weekend, the use of abdominal sonographic imaging, the type of X-ray imaging used, and the percentage of patients who developed sepsis. We found a significant difference in the new injury severity score, the frequency of multi-organ failure, hemoglobine at admission, base excess and international normalized ratio in the emergency room, the type of accident (fall or road traffic accident), the pre-hospital intubation rate, reanimation, in-hospital fluid management, the frequency of transfusion, tomography (whole-body computed tomography), and the necessity of emergency intervention.@*CONCLUSION@#Previously postulated factors such as the level of care and the length of the emergency room stay did not appear to have a significant influence in this study. Further studies should be conducted to analyse the identified factors with a view to optimising the treatment of severely injured patients. Our study shows that there are significant factors that can predict or influence the mortality of severely injured patients.

Comparison of supine and prone miniaturized percutaneous nephrolithotomy in the treatment of lower pole, middle pole and renal pelvic stones: A matched pair analysis

ABSTRACT Purpose We aimed to compare the outcomes of supine and prone miniaturized percutaneous nephrolithotomy (m-PNL) in the treatment of lower pole, middle pole and renal pelvic stones. Materials and Methods 54 patients who performed supine m-PNL between January 2017 and March 2018 and 498 patients who performed prone m-PNL between April 2015 and January 2018 were included in the study. Of the 498 patients, 108 matching 1: 2 in terms of age, gender, body mass index, American Association of Anesthesiology score, stone size, stone localization and hydronephrosis according to the supine m-PNL group were selected as prone m-PNL group. The patients with solitary kidney, upper pole stone, urinary system anomaly or skeletal malformation and pediatric patients (<18 years old) were excluded from the study. The success was defined as 'complete stone clearance' and was determined according to the 1st month computed tomography. Results The operation time and fluoroscopy time in supine m-PNL was significantly shorter than prone m-PNL group (58.1±45.9 vs. 80.1±40.0 min and 3.0±1.7 min vs. 4.9±4.5 min, p=0.025 and p=0.01, respectively). When post-operative complications were compared according to the modified Clavien-Dindo classification, overall and subgroup complication rates were comparable between groups. There was no significant difference between the groups in terms of the success rates (supine m-PNL; 72.2%, prone m-PNL; 71.3%, p=0.902). Conclusions Supine m-PNL procedure is more advantageous in terms of operation time and fluoroscopy time in the treatment of lower pole, middle pole and renal pelvic stones.

Milk Reverts the Effects of an Enamel Erosive but Healthy Diet

Objective: To determine the erosive effects of popular fruits and vegetables on enamel, and the potential counter effects of milks. Material and Methods: Ten popular fruits and vegetables were individually blended in a juicer to form a fruit or vegetable juice. The labial surfaces (three for each treatment group) were then immersed for thirty minutes in a fresh juice of one of ten products: strawberry, spinach, pineapple, grapefruit, green pepper, pickle, orange, apple, tomato, and carrot. In a second experiment, human enamel was treated with Coca-Cola for 30 minutes, followed by a variety of milks: Skim, 2%, Whole, Chocolate, Lactaid, Almond, and Silk Soy. Three teeth were used for each treatments and enamel microhardness of each sample was measured at baseline, after erosive exposure, and after the 30-minute variable treatment. Results: All fruits and vegetables showed differences between the pre- and posttreatment microhardness values. For the second experiment, tested milks result in significant increases (p<0.05) in enamel microhardness. Paired-t test was used for all comparisons. A thirty-minute exposure to the juices of all fruits and vegetables examined in the study significantly changed the microhardness of enamel, with grapefruit and pickle having potentially the most erosive effect on enamel. Diets that are high in fruits and vegetables can predispose to enamel erosion. For the second experiment, filtered water, ACT fluoride rinse, and varying milks all result in remineralization of enamel. Conclusion: Eroded enamel exposed to milk demonstrated a significant greater gain of enamel microhardness as compared to filtered water.

Prognostic significance of normal-sized ovary in advanced serous epithelial ovarian cancer / 부인종양

OBJECTIVE: We compared survival outcomes of advanced serous type epithelial ovarian cancer (EOC) patients with normal-sized ovaries and enlarged-ovarian tumors by propensity score matching analysis. METHODS: The medical records of EOC patients treated at Samsung Medical Center between 2002 and 2015 were reviewed retrospectively. We investigated EOC patients with high grade serous type histology and International Federation of Gynecology and Obstetrics (FIGO) stage IIIB, IIIC, or IV who underwent primary debulking surgery (PDS) and adjuvant chemotherapy to identify patients with normal-sized ovaries. Propensity score matching was performed to compare patients with normal-sized ovaries to patients with enlarged-ovarian tumors (ratio, 1:3) according to age, FIGO stage, initial cancer antigen (CA)-125 level, and residual disease status after PDS. RESULTS: Of the 419 EOC patients, 48 patients had normal-sized ovary. Patients with enlarged-ovarian tumor were younger (54.0±10.3 vs. 58.4±9.2 years, p=0.005) than those with normal-sized ovary, and there was a statistically significant difference in residual disease status between the 2 groups. In total cohort with a median follow-up period of 43 months (range, 3–164 months), inferior overall survival (OS) was shown in the normal-sized ovary group (median OS, 71.2 vs. 41.4 months; p=0.003). After propensity score matching, the group with normal-sized ovary showed inferior OS compared to the group with enlarged-ovarian tumor (median OS, 72.1 vs. 41.4 months; p=0.031). In multivariate analysis for OS, normal-sized ovary remained a significant factor. CONCLUSION: Normal-sized ovary was associated with poor OS compared with the common presentation of enlarged ovaries in EOC, independent of CA-125 level or residual disease.

Safety and Efficacy of 6.2 mm Patellar Button in Resurfacing Less than 20 mm Thin Patella: A Matched Pair Analysis

PURPOSE: Restoring the native patellar thickness after patellar resurfacing provides optimal function of the knee after arthroplasty and minimises complications related to the patellofemoral articulation. The aim of this study was to assess the usefulness of a thin patellar button (6.2 mm) in patients with a patella thickness of less than 20 mm during total knee arthroplasty. MATERIALS AND METHODS: This is a retrospective case control study. A total of 54 female patients with an intraoperative patellar thickness of < 20 mm, resurfaced with a patellar button of 6.2 mm in thickness were identified (group 1). They were matched with 54 patients with a patellar thickness of 20–23 mm, resurfaced with a patellar button of 8 mm (group 2), based on age, sex, body mass index, and deformity. A clinical and radiological evaluation was done at a minimum 2-year follow-up. RESULTS: The preoperative mean patellar thickness was 18.94±1.07 mm and was restored to 19.06±0.79 mm in group 1, as compared to 21.63±0.99 mm and 21.72±0.99 mm in group 2. The mean postoperative range of motion was 122.22°±9.25° in group 1 and 123.52°±8.72° in group 2 (p=0.13). No patellar bone or button related complications were observed in any patient in either group. CONCLUSIONS: The 6.2 mm thin patella is useful to restore the native thickness in patients with a patellar thickness of less than 20 mm without risk of button fracture, loosening or overstuffing.

Violência urbana e política pública de prevenção: avaliação do Programa Fica Vivo! no estado de Minas Gerais, Brasil / Urban violence and public prevention policy: assessment of Program "Fica Vivo" (is alive), in the State of Minas Gerais, Brazil / Violencia urbana y política pública de prevención: evaluación del Programa "Fica Vivo" en el Estado de Minas Gerais, Brasil

A violência urbana no Brasil tem assumido proporções elevadas nos últimos anos. Somente em 2014, quase 60 mil pessoas foram vítimas de homicídios no Brasil, posicionando o país entre os mais violentos do mundo. O objetivo deste texto é apresentar os resultados da avaliação da implementação do Programa Fica Vivo! na cidade de Belo Horizonte, ao longo de 15 anos de execução. De maneira geral, pode-se dizer que o programa cumpriu sua finalidade e logrou êxito em reverter a tendência de crescimento das taxas de homicídio. A metodologia adotada para avaliar os impactos do Programa Fica Vivo! permitiu aferir os efeitos das políticas de prevenção e controle dos homicídios.

Urban violence in Brazil has reached high proportions in recent years. Only in 2014, almost 60 thousand people were victims of homicide in Brazil, positioning the country among the most violent in the world. The goal of this research note is to present the evaluation of the implementation of the Fica Vivo Program in the city of Belo Horizonte over 15 years of execution. In general, it can be said that the program has fulfilled its objective and has succeeded in reversing the growth trend of homicide rates. The methodology adopted to evaluate the impacts of the Fica Vivo Program allowed to assess the effects of policies of prevention and control of homicide.

La violencia urbana en Brasil ha asumido proporciones elevadas en los últimos años. Solo en 2014, casi sesenta mil personas fueron víctimas de homicidios en Brasil, lo que posicionó al país entre los más violentos del mundo. El objetivo de este artículo es mostrar el resultado de la evaluación de la implementación del programa Fica Vivo en la ciudad de Belo Horizonte a lo largo de sus 15 años de ejecución. En general, se puede decir que el programa ha cumplido su objetivo y que fue exitoso al revertir la tendencia de crecimiento de las tasas de homicidio. La metodología adoptada para evaluar los impactos del programa Fica Vivo permitió evaluar los efectos de las políticas de prevención y control de los homicidios.

Óbitos e feridos graves por acidentes de trânsito em Goiânia, Brasil - 2013: magnitude e fatores associados / Muertes y heridos graves por accidentes de tránsito en Goiânia, Brasil - 2013: magnitud y factores associados / Deaths and serious injuries due to traffic accidents in Goiânia, Brazil - 2013: the magnitude and associated factors

Objetivo: identificar a magnitude e fatores associados ao óbito e lesões graves entre vítimas de acidentes de trânsito ocorridos na área urbana de Goiânia, Brasil. Métodos: estudo transversal com linkage entre registros do Sistema de Informações sobre Mortalidade (SIM), Sistema de Informações Hospitalares do Sistema Único de Saúde (SIH/SUS) e ocorrências de acidentes de trânsito, no período de janeiro a junho de 2013; utilizou-se a regressão de Poisson. Resultados: entre 9.795 vítimas identificadas, houve 155 óbitos e 1.225 feridos graves; ciclistas (razão de incidência [RI]=2,26; IC95% 1,19;4,30) e pedestres (RI=2,12; IC95% 1,26;3,58) tiveram maior risco de morte, enquanto o risco de lesões graves foi superior entre motociclistas (RI=2,38; IC95% 2,01;2,83), ciclistas (RI=2,35; IC95% 1,76;3,13) e pedestres (RI=2,83; IC95% 2,27;3,53). Conclusão: o estudo revelou número de óbitos e feridos graves mais próximo do real e identificou grupos vulneráveis, possível alvo para o planejamento de ações de segurança no trânsito.

Objetivo: identificar la magnitud y factores asociados a muerte y lesiones graves entre víctimas de accidentes de tránsito ocurridos en el área urbana de Goiânia, Brasil. Métodos: estudio transversal con enlace entre registros del Sistema de Información sobre Mortalidad (SIM), Sistema de Información Hospitalaria del Sistema Único de Salud (SIH / SUS), ocurrencias de accidentes de tránsito, entre enero-junio 2013; utilizamos regresión de Poisson. Resultados: entre 9.795 víctimas, hubo 155 muertes y 1.225 heridos graves; ciclistas (razón de incidencia [RI = 2,26], IC95% 1,19, 4,30) y peatones (RI = 2,12, IC95% 1,26, 3,58) tuvieron mayor riesgo de muerte, mientras que el riesgo de lesiones graves fue superior entre motociclistas (RI=2,38; IC95% 2,01;2,83), ciclistas (RI=2,35; IC95% 1,76;3,13) y peatones (RI=2,83; IC95% 2,27;3,53). Conclusión: el estudio reveló un número de muertes y heridos graves más cerca de lo real e identificó grupos vulnerables para la planificación de acciones de seguridad de tránsito.

Objective: to identify the magnitude and factors associated with death and serious injuries among victims of traffic accidents in the urban area of Goiânia, Brazil. Methods: cross-sectional study with linkage between records of the Mortality Information System (SIM) Hospital Information System of the Brazilian National Health System (SIH/SUS) and occurrences of traffic accidents, from January to June 2013; Poisson regression was used. Results: among 9,795 identified victims, there were 155 deaths and 1,225 serious injuries; cyclists (Incidence ratio [IR]=2.26; 95%CI 1.19;4.30) and pedestrians (IR=2.12; 95%CI 1.26;3.58) had an increased risk of death, while the risk of serious injuries was higher among motorcyclists (IR=2.38; 95%CI 2.01;2.83), cyclists (IR=2.35; 95%CI 1.76;3.13) and pedestrians (IR=2.83; 95%CI 2.27;3.53). Conclusion: the study revealed a number of deaths and serious injuries, closer to the real and identified vulnerable groups to plan traffic safety actions.

Comparing the effect of a desensitizing material and a self-etch adhesive on dentin sensitivity after periodontal surgery: a randomized clinical trial

OBJECTIVES: This double-blind randomized placebo-controlled clinical trial evaluated the ability of a desensitizing agent and a self-etch adhesive on cervical dentin sensitivity (CDS) after periodontal surgery. MATERIALS AND METHODS: Ninety hypersensitive teeth of 13 subjects were included in the study. After periodontal surgery, the teeth of each posterior sextant treated with one of the following materials: G1: Clearfil S³ Bond (Kuraray Dental), G2: Gluma Desensitizer (Heraeus Kulzer), and G3: placebo (water). The sensitivity was assessed using evaporative stimuli before treatment (baseline, T0), 1 day after treatment (T1), after 1 week (T2), and after 1 month (T3) according to visual analog scale (VAS). RESULTS: Following the treatment, all the 3 groups showed significant reduction of CDS in T1 compared to T0. Reduction of CDS between T1 and T2 was observed only in G1 but there was no significant difference between T2 and T3 in this group. Although we observed a significant difference in T3 compared to T1 and T2 in G2 and G3, comparison of treatment groups in each assessment time showed a significant difference only in T3. According to paired comparison, this was due to the difference between G2 and G3. CONCLUSIONS: Dentin sensitivity following periodontal surgery will decrease spontaneously over time, but treating the sensitive teeth with Gluma Desensitizer and Clearfil S³ Bond can have some benefits.

Comparison of Two Different Segmentation Methods on Planar Lung Perfusion Scan with Reference to Quantitative Value on SPECT/CT / 대한핵의학회잡지

PURPOSE: Until now, there was no single standardized regional segmentation method of planar lung perfusion scan.We compared planar scan based two segmentation methods, which are frequently used in the Society of Nuclear Medicine, with reference to the lung perfusion single photon emission computed tomography (SPECT)/computed tomography (CT) derived values in lung cancer patients.METHODS: Fifty-five lung cancer patients (male:female, 37:18; age, 67.8 ± 10.7 years) were evaluated. The patients underwent planar scan and SPECT/CT after injection of technetium-99 m macroaggregated albumin (Tc-99 m-MAA). The % uptake and predicted postoperative percentage forced expiratory volume in 1 s (ppoFEV1%) derived from both posterior oblique (PO) and anterior posterior (AP) methods were compared with SPECT/CT derived parameters. Concordance analysis, paired comparison, reproducibility analysis and spearman correlation analysis were conducted.RESULTS: The % uptake derived from PO method showed higher concordance with SPECT/CT derived % uptake in every lobe compared to AP method. Both methods showed significantly different lobar distribution of%uptake compared to SPECT/CT. For the target region, ppoFEV1% measured from PO method showed higher concordance with SPECT/CT, but lower reproducibility compared to AP method. Preliminary data revealed that every method significantly correlated with actual postoperative FEV1%, with SPECT/CT showing the best correlation.CONCLUSIONS: The PO method derived values showed better concordance with SPECT/CT compared to the AP method. Both PO and AP methods showed significantly different lobar distribution compared to SPECT/CT. In clinical practice such difference according to different methods and lobes should be considered for more accurate postoperative lung function prediction.

Effects of Electrical Automatic Massage of Whole Body at Bedtime on Sleep and Fatigue

OBJECTIVES: To investigate the effect of electrical automatic massage (EAM) at bedtime on sleep quality and fatigue. METHODS: We recruited consecutively 35 adults (23 male, 48.7±8.07 y) who complained of poor sleep (Pittsburgh Sleep Quality Index≥5) and fatigue (Chalder Fatigue Scale≥4). This is a cross over study including two consecutive sleep studies with or without EAM. The EAM session includes preset ‘sleep mode’, which last 30 minutes covering whole body. Participants were seated in the commercially available massage chair (REX-L®) under the calm and dim light condition immediately before polysomnography. Participants reported perceived sleep latency, sleep duration, and fatigue using visual analogue scale following morning. RESULTS: Polysomnography parameters and subjective reports were compared between sleep with EAM and sleep without EAM. Paired comparison on average revealed sleep structure improvement N1 (13.6→10.9%) and N2 sleep (59.3→57.2%) decreased, and N3 sleep increased (3.0→6.4%), as well as sleep latency (10.3→5.6 min). Improvement in arousal index (17.1→13.0/h) and apnea-hypopnea index (9.1→7.0/h) were also seen following sleep after EAM. Sleep efficiency and total sleep time were not changed by EAM. Participants subjective reports also indicated better sleep on EAM; more lengthened sleep (306→330 minutes) and more relieved fatigue significantly after EAM. CONCLUSIONS: This study demonstrated that muscle relaxation through EAM at bedtime may improve the sleep and alleviate fatigue. It suggests that EAM may be one of alternatives to promote sleep quality. Further studies in a clinical setting are warranted to support this finding.

Optimizing the reconstruction filter in cone-beam CT to improve periodontal ligament space visualization: An in vitro study

PURPOSE: Evaluation of alveolar bone is important in the diagnosis of dental diseases. The periodontal ligament space is difficult to clearly depict in cone-beam computed tomography images because the reconstruction filter conditions during image processing cause image blurring, resulting in decreased spatial resolution. We examined different reconstruction filters to assess their ability to improve spatial resolution and allow for a clearer visualization of the periodontal ligament space. MATERIALS AND METHODS: Cone-beam computed tomography projections of 2 skull phantoms were reconstructed using 6 reconstruction conditions and then compared using the Thurstone paired comparison method. Physical evaluations, including the modulation transfer function and the Wiener spectrum, as well as an assessment of space visibility, were undertaken using experimental phantoms. RESULTS: Image reconstruction using a modified Shepp-Logan filter resulted in better sensory, physical, and quantitative evaluations. The reconstruction conditions substantially improved the spatial resolution and visualization of the periodontal ligament space. The difference in sensitivity was obtained by altering the reconstruction filter. CONCLUSION: Modifying the characteristics of a reconstruction filter can generate significant improvement in assessments of the periodontal ligament space. A high-frequency enhancement filter improves the visualization of thin structures and will be useful when accurate assessment of the periodontal ligament space is necessary.

Disability Weights Measurement for 228 Causes of Disease in the Korean Burden of Disease Study 2012

Disability weight for each disease plays a key role in combining years lived with disability and years of life lost in disability adjusted life year. For the Korean Burden of Disease 2012 study, we have conducted a re-estimation of disability weights for causes of disease by adapting the methodology of a recent Global Burden of Disease study. Our study was conducted through a self-administered web-based survey using a paired comparison (PC) as the main valuation method. A total of 496 physicians and medical college students who were attending in third or fourth grade of a regular course conducted the survey. We applied a probit regression on the PC data and computed the predicted probabilities of each cause of disease from the coefficient estimates of the probit regression. We used 'being dead (1)' and 'full health (0)' as anchor points to rescale the predicted probability of each cause of disease on a scale of 0 to 1. By this method, disability weights for a total of 228 causes of disease were estimated. There was a fairly high correlation between the disability weights of overlapping causes of disease from this study and a previous South Korean study despite the differences in valuation methods and time periods. In conclusion, we have shown that disability weights can be estimated based on a PC by including 'full health' and 'being dead' as anchor points without resorting to a person trade-off. Through developments in the methodology of disability weights estimation from this study, disability weights can be easily estimated and continuously revised.

Comparison beetwen open and laparoscopic radical cistectomy in a latin american reference center: perioperative and oncological results

ABSTRACTObjectives:To evaluate the differences of peri-operatory and oncological outcomes between Laparoscopic Radical Cystectomy and Open Radical Cystectomy in our center.Materials and Methods:Overall, 50 patients were included in this non randomized match-pair analysis: 25 patients who had undergone Laparoscopic Radical Cystectomy for invasive bladder cancer (Group-1) and 25 patients with similar characteristics who had undergone Open Radical Cystectomy (Group-2). The patients were operated from January 2005 to December 2012 in a single Institution.Results:Mean operative time for groups 1 and 2 were 350 and 280 minutes (p=0.03) respectively. Mean blood loss was 330 mL for group 1 and 580 mL for group 2 (p=0.04). Intraoperative transfusion rate was 0% and 36% for groups 1 and 2 respectively (p=0.005). Perioperative complication rate was similar between groups. Mean time to oral intake was 2 days for group 1 and 3 days for group 2 (p=0.08). Median hospital stay was 7 days for group 1 and 13 for group 2 (p=0.04). There were no differences in positive surgical margins and overall survival, between groups.Conclusions:In a reference center with pelvic laparoscopic expertise, Laparoscopic Radical Cystectomy may be considered a safe procedure with similar complication rate of Open Radical Cystectomy. Laparoscopic Radical Cystectomy is more time consuming, with reduced bleeding and transfusion rate. Hospital stay seems to be shorter. Oncologically no difference was observed in our mid-term follow-up.

Validity of bag urine culture for predicting urinary tract infections in febrile infants: a paired comparison of urine collection methods / 소아과

PURPOSE: Catheter urine (CATH-U) and suprapubic aspiration (SPA) are reliable urine collection methods for confirming urinary tract infections (UTI) in infants. However, noninvasive and easily accessible collecting bag urine (CBU) is widely used, despite its high contamination rate. This study investigated the validity of CBU cultures for diagnosing UTIs, using CATH-U culture results as the gold standard. METHODS: We retrospectively analyzed 210 infants, 2- to 24-month-old, who presented to a tertiary care hospital's pediatrics department between September 2008 and August 2013. We reviewed the results of CBU and CATH-U cultures from the same infants. RESULTS: CBU results, relative to CATH-U culture results (> or =104 colony-forming units [CFU]/mL) were widely variable, ranging from no growth to > or =105 CFU/mL. A CBU cutoff value of > or =105 CFU/mL resulted in false-positive and false-negative rates of 18% and 24%, respectively. The probability of a UTI increased when the CBU bacterial count was > or =105/mL for all infants, both uncircumcised male infants and female infants (likelihood ratios [LRs], 4.16, 4.11, and 4.11, respectively). UTIs could not be excluded for female infants with a CBU bacterial density of 104-105 (LR, 1.40). The LRs for predicting UTIs based on a positive dipstick test and a positive urinalysis were 4.19 and 3.11, respectively. CONCLUSION: The validity of obtaining urine sample from a sterile bag remains questionable. Inconclusive culture results from CBU should be confirmed with a more reliable method.

T test as a parametric statistic / 대한마취과학회지

In statistic tests, the probability distribution of the statistics is important. When samples are drawn from population N (micro, sigma2) with a sample size of n, the distribution of the sample mean X should be a normal distribution N (micro, sigma2/n). Under the null hypothesis micro = micro0, the distribution of statistics z=X-micro0/sigma/radical(n) should be standardized as a normal distribution. When the variance of the population is not known, replacement with the sample variance s2 is possible. In this case, the statistics X-micro0/s/radical(n) follows a t distribution (n-1 degrees of freedom). An independent-group t test can be carried out for a comparison of means between two independent groups, with a paired t test for paired data. As the t test is a parametric test, samples should meet certain preconditions, such as normality, equal variances and independence.

Drusini's and Takei's Methods for Age Estimation in Korean Adults / 대한법의학회지

Estimation of an individual's age has received considerable attention in forensic science. Several methods have been described, and abundant results have been obtained and evaluated. Among the numerous methods for dental age prediction in adults, the progressive diminution of the coronal pulp cavity and dental attrition have been primarily used. Although the reliability of age estimation methods using teeth has been demonstrated, correlation between methods has not been reported. Therefore, the aim of this study was to evaluate concurrence between Drusini's methods. We reanalyzed the age of 107 patients (64 male, 43 female) using Drusini's method. The ages had been previously estimated as ranging from 24 to 69 years using Takei's method. Our results revealed a strong correlation between the two methods (r=0.762) and suggest both methods to be suitable for application in Korean individuals younger than 50 years old. A previous study has shown Takei's and Drusini's methods to be reliable for forensic purposes. The strong correlation between the two methods in the present study suggests that it would be reasonable to use the most appropriate method for age estimation dependent on oral state.

The Influence of Alcoholic Liver Disease on Serum PIVKA-II Levels in Patients without Hepatocellular Carcinoma

BACKGROUND/AIMS: Prothrombin induced by vitamin K deficiency or antagonist II (PIVKA-II) is a widely used diagnostic marker for hepatocellular carcinoma (HCC). We evaluated the correlation between alcoholic liver disease (ALD) and serum PIVKA-II levels in chronic liver disease (CLD) patients. METHODS: We retrospectively reviewed the medical records of 2,528 CLD patients without HCC. Among these patients, 76 exhibited serum high PIVKA-II levels of >125 mAU/mL (group 1). We categorized 76 control patients matched by age, sex, and the presence of liver cirrhosis from the remaining patients who were negative for serum PIVKA-II (group 2). RESULTS: Group 1 revealed increased antibiotic usage (23.7% vs 2.6%, p<0.001) and incidence of ALD (60.5% vs 14.5%, p<0.001) as well as elevated aspartate aminotransferase (52.5 IU/L vs 30.5 IU/L, p=0.025) and gamma glutamyl transpeptidase (67.5 IU/L vs 36.5 IU/L, p=0.005) levels compared with group 2. Further, group 1 was significantly associated with a worse Child-Pugh class than group 2. In the multivariate analysis, ALD (odds ratio [OR], 7.151; p<0.001) and antibiotic usage (OR, 5.846; p<0.001) were significantly associated with positive PIVKA-II levels. CONCLUSIONS: Our study suggests that ALD and antibiotics usage may be confounding factors when interpreting high serum PIVKA-II levels in patients without HCC. Therefore, serum PIVKA-II levels in patients with ALD or in patients administered antibiotics should be interpreted with caution.

The Influence of Alcoholic Liver Disease on Serum PIVKA-II Levels in Patients without Hepatocellular Carcinoma

BACKGROUND/AIMS: Prothrombin induced by vitamin K deficiency or antagonist II (PIVKA-II) is a widely used diagnostic marker for hepatocellular carcinoma (HCC). We evaluated the correlation between alcoholic liver disease (ALD) and serum PIVKA-II levels in chronic liver disease (CLD) patients. METHODS: We retrospectively reviewed the medical records of 2,528 CLD patients without HCC. Among these patients, 76 exhibited serum high PIVKA-II levels of >125 mAU/mL (group 1). We categorized 76 control patients matched by age, sex, and the presence of liver cirrhosis from the remaining patients who were negative for serum PIVKA-II (group 2). RESULTS: Group 1 revealed increased antibiotic usage (23.7% vs 2.6%, p<0.001) and incidence of ALD (60.5% vs 14.5%, p<0.001) as well as elevated aspartate aminotransferase (52.5 IU/L vs 30.5 IU/L, p=0.025) and gamma glutamyl transpeptidase (67.5 IU/L vs 36.5 IU/L, p=0.005) levels compared with group 2. Further, group 1 was significantly associated with a worse Child-Pugh class than group 2. In the multivariate analysis, ALD (odds ratio [OR], 7.151; p<0.001) and antibiotic usage (OR, 5.846; p<0.001) were significantly associated with positive PIVKA-II levels. CONCLUSIONS: Our study suggests that ALD and antibiotics usage may be confounding factors when interpreting high serum PIVKA-II levels in patients without HCC. Therefore, serum PIVKA-II levels in patients with ALD or in patients administered antibiotics should be interpreted with caution.