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Survival analyses are heavily used to analyze data in which the time to event is of interest. The purpose of this paper is to introduce some fundamental concepts for survival analyses in medical studies. We comprehensively review current survival methodologies, such as the nonparametric Kaplan-Meier method used to estimate survival probability, the log-rank test, one of the most popular tests for comparing survival curves, and the Cox proportional hazard model, which is used for building the relationship between survival time and specific risk factors. More advanced methods, such as time-dependent receiver operating characteristic, restricted mean survival time, and time-dependent covariates are also introduced. This tutorial is aimed toward covering the basics of survival analysis. We used a neurosurgical case series of surgically treated brain metastases from non-small cell lung cancer patients as an example. The survival time was defined from the date of craniotomy to the date of patient death. This work is an attempt to encourage more investigators/medical practitioners to use survival analyses appropriately in medical research. We highlight some statistical issues, make recommendations, and provide more advanced survival modeling in this aspect. [ABSTRACT FROM AUTHOR]

This study assessed the quality of life (QoL) and pregnancy outcomes among infertile women undergoing in vitro fertilization (IVF) treatment to investigate the association between QoL and IVF pregnancy outcomes. This study included 686 women with 1205 embryo transfers (ETs). QoL was measured using the fertility quality of life (FertiQoL) tool before ET. FertiQoL comprises two modules: a Core module (including mind/body, emotional, relational, and social domains) and a Treatment module (covering treatment environment and tolerability domains). The FertiQol total and subscale scores were computed and scored in the range of 0–100 (higher scores indicate better QoL). Multivariate generalized estimating equation analyses were carried out to assess the association between QoL and IVF pregnancy outcomes, with adjustment for time-varying factors across multiple ETs for a given person. The lowest score in the core module was for the emotional domain (62.0), and that in the Treatment module was for the tolerability domain (59.4). QoL scores were significantly and positively associated with pregnancy outcomes (i.e., ongoing pregnancy, live birth); with a one unit increase in the emotional domain score, the probabilities of ongoing pregnancy and live birth significantly increased by 2.4% and 2.6%, respectively (p < 0.05). This study evaluated the prospective association between QoL and IVF pregnancy outcomes among infertile women. The results highlight the importance of developing clinical strategies to improve QoL among infertile women undergoing IVF treatment, which may further improve the pregnancy rates of this population. [ABSTRACT FROM AUTHOR]

Background We investigated whether prior stain use before admission for a first-attack AP would reduce the severity and mortality rate of a first-attack of AP with a dose–response relationship. Methods We conducted a retrospective cohort study from a tertiary medical center's database in Taiwan. We evaluated the dose–response relationship between statin use and the first-attack of AP by defining the daily dose (DDD). The cumulative DDD (cDDD) was calculated as the sum of the dispensed DDD of any specific statin. The outcome measures in our study included the hospital mortality rate, duration of hospitalization, Ranson's score, computed tomography severity index (CTSI), and C-reactive protein (CRP) level. Results In our study, we enrolled 31 patients in statin group and 63 matched patients in control group. In the univariate analysis there was no significant difference between them with regard to the outcomes except the CTSI and serum calcium concentration. According to multivariate analysis the serum calcium concentration was significantly higher in the statin group, and the CTSI was lower in the statin group. In subgroup analysis we divided the statin group into two groups according to the cDDDs (< 365 days and > 365 days) and the results showed no significance in the demographic data, overall mortality rate, hospitalization days, CRP level, Ranson's score, or CTSI. Conclusion Our study rejected the hypothesis that statins have beneficial effects on the clinical outcomes of patients with a first-attack of AP. However we demonstrated that statins have a positive effect on the CTSI. [ABSTRACT FROM AUTHOR]

Abstract: Quantitative imaging has emerged as a leading priority on the imaging research agenda, yet clinical radiology has traditionally maintained a skeptical attitude toward numerical measurement in diagnostic interpretation. To gauge the extent to which quantitative reporting has been incorporated into routine clinical radiology practice, and to offer preliminary baseline data against which the evolution of quantitative imaging can be measured, we obtained all clinical computed tomography (CT) and magnetic resonance imaging (MRI) reports from two randomly selected weekdays in 2011 at a single mixed academic-community practice and evaluated those reports for the presence of quantitative descriptors. We found that 44% of all reports contained at least one “quantitative metric” (QM), defined as any numerical descriptor of a physical property other than quantity, but only 2% of reports contained an “advanced quantitative metric” (AQM), defined as a numerical parameter reporting on lesion function or composition, excluding simple size and distance measurements. Possible reasons for the slow translation of AQMs into routine clinical radiology reporting include perceptions that the primary clinical question may be qualitative in nature or that a qualitative answer may be sufficient; concern that quantitative approaches may obscure important qualitative information, may not be adequately validated, or may not allow sufficient expression of uncertainty; the feeling that “gestalt” interpretation may be superior to quantitative paradigms; and practical workflow limitations. We suggest that quantitative imaging techniques will evolve primarily as dedicated instruments for answering specific clinical questions requiring precise and standardized interpretation. Validation in real-world settings, ease of use, and reimbursement economics will all play a role in determining the rate of translation of AQMs into broad practice. [Copyright &y& Elsevier]

Background & Aims We investigated the rate of relapse of hepatitis B virus (HBV) infection after entecavir therapy for chronic hepatitis B and the association between level of hepatitis B surface antigen (HBsAg) and relapse. Methods In a retrospective study, we analyzed data from 252 patients with chronic HBV infection who were treated with entecavir and met the Asian Pacific Association for the Study of the Liver treatment stopping rules (mean time, 164 ± 45 weeks) from January 2007 through June 2011 in Taiwan. Eighty-three were hepatitis B e antigen (HBeAg)-positive, and 169 were HBeAg-negative. Patients had regular post-treatment follow-up examinations for at least 12 months. Virologic relapse was defined on the basis of serum HBV DNA >2000 IU/mL after entecavir therapy. Clinical relapse was defined as a level of alanine aminotransferase >2-fold the upper limit of normal and HBV DNA >2000 IU/mL. Results Two years after therapy ended, 42% of HBeAg-positive patients had a virologic relapse, and 37.6% had a clinical relapse; 3 years after therapy ended, these rates were 64.3% and 51.6% for HBeAg-negative patients, respectively. On the basis of Cox regression analysis, factors independently associated with virologic and clinical relapse included old age, HBV genotype C, and higher baseline levels of HBsAg for HBeAg-positive patients and old age and higher end-of-treatment levels of HBsAg for HBeAg-negative patients. In HBeAg-positive patients, risk of HBV relapse increased with age ≥40 years and HBsAg level ≥1000 IU/mL at baseline ( P < .001). In HBeAg-negative patients, the combination of age (<55 years) and HBsAg level (<150 IU/mL) at the end of treatment was associated with a lower rate of virologic relapse (4.5% of HBeAg-negative patients had viral relapse at year 3). The decrease in level of HBsAg from month 12 of treatment until the end of treatment was greater in patients who did lose HBsAg after entecavir therapy compared with those who did not. Conclusions The combination of age and level of HBsAg is associated with relapse of HBV infection after treatment with entecavir. HBsAg levels might be used to guide the timing of cessation of entecavir treatment in patients with chronic HBV infection. [ABSTRACT FROM AUTHOR]

The association between human epidermal growth factor receptor-2 (HER2) amplification and brain metastasis (BM) in patients having colorectal cancer (CRC) has been suggested but not yet established. This study investigated the expression patterns of HER2, its association with BM, and its prognostic value in patients having CRC. We retrospectively identified 99 patients having metastatic CRC (mCRC) and BM (the BM cohort) and compared them with a cohort of 249 patients having mCRC and without BM (the stage IV cohort) by propensity score matching. Immunohistochemical studies of HER2 on all available paraffin-embedded tumour samples, either from the primary tumour, the metastasis (brain and/or extracranial sites) or both, were performed and analysed. HER2 fluorescent in situ hybridisation was applied when necessary. The expression of HER2 was compared and correlated with survival. HER2 amplifications were detected in 16 (18.4%) of 87 and 9 (3.6%) of 249 patients who had specimens available in the BM and stage IV cohorts, respectively (P <.001). After propensity score matching, HER2 amplification was significantly associated with BM (odds ratio: 5.38, P =.003). HER2 heterogeneity was frequently observed not only at the single tumour level but also in paired tumour samples. A marginally significant longer survival since BM was found in patients having HER2-amplified mCRC than in those without (P =.07). HER2 amplification was significantly associated with BM in patients having mCRC and might have prognostic value for survival since BM. Given the heterogeneity of HER2 expression, the testing of HER2 status on available tissues from both primary and metastatic tumours should be encouraged. • Propensity score matching examined HER2 amplification and brain metastases. • High frequency of HER2 amplification in patients having metastatic colorectal cancer and brain metastasis was demonstrated. • Intra-patient heterogeneities of HER2 amplification were observed. [ABSTRACT FROM AUTHOR]

Introduction: The effect of using closed suction drainage system with the proximal femoral nail antirotation (PFNA) system fixation on outcomes in treating intertrochanteric fractures (ITFs) is still unknown. This prospective randomized controlled trial aimed to examine whether routine drainage is useful for PFNA fixation in ITFs.Methods: A total of 80 patients with acute ITFs were treated with closed or mini-open reduction with PFNA fixation at the National Cheng Kung University Hospital and 60 eligible patients were randomized for whether to receive suction drainage. In clinical outcomes, the visual analog scale (VAS), morphine equivalent dosage, injured thigh width, body temperature, wound condition and wound infection were measured on postoperative day 1, 2, 4, 10, and 90. In laboratory outcomes, we evaluated hemoglobin and hematocrit levels postoperatively at different time points. Blood transfusion and total blood loss (TBL) were measured by Mercuriali's formula in millimeter.Results: The results revealed that the amount of blood transfusion received by the drained group (543.3 mL) was more than that by the undrained group (367.8 mL; p = 0.0074), and similarly, TBL in the drained group (750.1 mL) was more than that in the undrained group (537.4 mL; p = 0.0067). Regarding clinical and laboratory outcomes, compared with the undrained group, the drained group had a higher VAS score on postoperative day 2 (p = 0.0216). No difference was observed between the 2 groups for morphine equivalent dosage, thigh swelling, wound infection and hematoma, hospitalization period, or total number of complications at every time point after index procedure.Conclusions: Blood transfusion requirement and TBL were higher in the drained group than in the undrained group of PFNA fixation for ITFs. In addition, the closed drainage system may have manifested no short-term benefit for wound condition postoperatively. [ABSTRACT FROM AUTHOR]

Objective: To determine whether kidney stone history is associated with adverse outcomes after percutaneous coronary intervention (PCI). Kidney stone formers have an increased risk of developing coronary artery disease; however, whether these patients have worse cardiac outcomes is unknown.Materials and Methods: We identified adult patients who underwent first-time PCI in Vanderbilt University Medical Center (VUMC) Synthetic Derivative from 2008 to 2016 (n = 11,289) and in a nationwide database of Taiwan (NHIRD) from 2005 to 2012 (n = 155,762). Odds ratios (ORs) of 30-day in-hospital mortality and hazard ratios (HRs) of 1-year and 3-year adverse outcomes associated with kidney stone history were estimated using a propensity score approach.Results: Overall, 294 and 12,286 stone formers undergoing PCI were identified in the VUMC and NHIRD, respectively. After matching, stone formers at VUMC were at higher risks of 30-day in-hospital mortality (OR 2.79, 95% CI 1.15-6.69) and 1-year (HR 1.59, 95% CI 1.13-2.24) and 3-year (HR 1.36, 95% CI 1.02-1.81) myocardial infarction. In the NHIRD, kidney stone history was associated with 1-year (HR 1.12, 95% CI 1.03-1.21) and 3-year (HR 1.14, 95% CI 1.06-1.22) myocardial infarction. In a sensitivity analysis, stone formers undergoing kidney stone surgery were marginally associated with 30-day in-hospital mortality (OR 1.21, 95% CI 0.99-1.48) and were associated with 3-year myocardial infarction (HR 1.13, 95% CI 1.02-1.25).Conclusion: Kidney stone history is associated with poorer cardiac outcomes after PCI. Improving secondary cardiac prevention strategies after PCI may be necessary for patients with a history of kidney stone disease. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To evaluate whether semi-quantitative analysis of high temporal resolution dynamic contrast-enhanced MRI (DCE-MRI) acquired early in treatment can predict the response of locally advanced breast cancer (LABC) to neoadjuvant chemotherapy (NAC). Materials and Methods: As part of an IRB-approved prospective study, 21 patients with LABC provided informed consent and underwent high temporal resolution 3T DCE-MRI before and after 1cycle of NAC. Using measurements performed by two radiologists, the following parameters were extracted for lesions at both examinations: lesion size (short and long axes, in both early and late phases of enhancement), radiologist's subjective assessment of lesion enhancement, and percentages of voxels within the lesion demonstrating progressive, plateau, or washout kinetics. The latter data were calculated using two filters, one selecting for voxels enhancing ≥50% over baseline and one for voxels enhancing ≥100% over baseline. Pretreatment imaging parameters and parameter changes following cycle 1 of NAC were evaluated for their ability to discriminate patients with an eventual pathological complete response (pCR). Results: All 21 patients completed NAC followed by surgery, with 9 patients achieving a pCR. No pretreatment imaging parameters were predictive of pCR. However, change after cycle 1 of NAC in percentage of voxels demonstrating washout kinetics with a 100% enhancement filter discriminated patients with an eventual pCR with an area under the receiver operating characteristic curve (AUC) of 0.77. Changes in other parameters, including lesion size, did not predict pCR. Conclusion: Semi-quantitative analysis of high temporal resolution DCE-MRI in patients with LABC can discriminate patients with an eventual pCR after one cycle of NAC. [Copyright &y& Elsevier]