On Comparing Survival Curves with Right-Censored Data According to the Events Occur at the Beginning, in the Middle and at the End of Study Period

In clinical practice the event of interest does not always occur equally across the study time period. Depending on the disease being investigated, the event that is of interest can occur intensively in different periods of the follow-up time. In such cases, choosing the correct survival comparison test has importance. This study aims to examine and discuss the results of survival comparison tests under some certain circumstances. A simulation study was conducted. We discussed the result of different tests such as Logrank, Gehan-Wilcoxon, Tarone-Ware, Peto-Peto, Modified Peto-Peto tests and tests belonging to Fleming-Harrington test family with (p, q) values; (1, 0), (0.5, 0.5), (1, 1), (0, 1) ve (0.5, 2) by means of Type I error rate that obtained from simulation study, when the event of interest occurred intensively at the beginning of the study, in the middle of the study and at the end of the study time period. As a result of simulation study, Type I error rate of tests is generally lower or higher than the nominal value. In the light of the results, it is proposed to re-examine the tests for cases where events are observed intensively at the beginning, middle and late periods, to carry out new simulation studies and to develop new tests if necessary

EXAMINING TESTS FOR COMPARING SURVIVAL CURVES WITH RIGHT CENSORED DATA

Background and objective: In survival analysis, estimating the survival probability of a population is important, but on the other hand, investigators want to compare the survival experiences of different groups. In such cases, the differences can be illustrated by drawing survival curves, but this will only give a rough idea. Since the data obtained from survival studies contains frequently censored observations some specially designed tests are required in order to compare groups statistically in terms of survival. Methods: In this study, Logrank, Gehan-Wilcoxon, Tarone-Ware, Peto-Peto, Modified Peto-Peto tests and tests belonging to Fleming-Harrington test family with (p, q) values; (1, 0), (0.5, 0.5), (1, 1), (0, 1) ve (0.5, 2) are examined by means of Type I error rate obtained from a simulation study, which is conducted in the cases where the event takes place with equal probability along the follow-up time. Results: As a result of the simulation study, Type I error rate of Logrank test is equal or close to the nominal value. Conclusions: When survival data were generated from lognormal and inverse Gaussian distribution, Type I error rate of Gehan-Wilcoxon, Tarone-Ware, Peto-Peto, Modified Peto-Peto and Fleming-Harrington (1,0) tests were close to the nominal value

Determinants of the changes in positive airway pressure for the retitration in patients with obstructive sleep apnea syndrome

During long-term follow-up of the patients with obstructive sleep apnea syndrome (OSAS) under the positive airway pressure (PAP) therapy, it waits to be explored whether or when routine retitrations are indicated. We prospectively followed up 133 patients for 10 years to define which demographical or polysomnographic factors should be taken into account to determine the need for retitration. Patients were retitrated at 1st, 2nd, 5th, and 10th follow-up years. A change in pressures >= 2cmH(2)O was present in more than half of the patients at 2nd and 5th years. Changes in weight for at least 10 kg showed a significant correlation with the changes in pressures >= 2cmH(2)O (p = 0.023) and >= 3cmH(2)O (p = 0.047) at 2nd year. OSAS-related complaints, nasal or upper airway surgery, or emergence of cardiovascular diseases were not correlated with the changes in pressures. Apnea-hypopnea index (AHI) at diagnostic night was positively correlated with the changes in pressures >= 3cmH(2)O at 1st and 5th years. The percentage of N3 sleep at first titration night showed positive correlation with changes in pressures >= 3cmH(2)O at 2nd and 5th years. The index of periodic leg movements in sleep (PLMS) and PLMS-arousal index at first titration night was positively correlated with any change in pressures at 2nd and 5th years. Our findings showed that vast changes in weight, high AHI at diagnostic night, increased duration of deep NREM sleep and high PLMS and PLMS-arousal indices at first titration night should be noted as important indicators for retitration within the first 5 years of follow-up

Skin prick test results and prevalence of allergic symptoms in workers exposed to toluene

Karabulut, Ismail/0000-0002-1339-5385WOS: 000300203500009Aim: To determine the distribution of allergens and allergic symptoms according to occupation groups in those who were exposed to toluene and presented with allergic rhinitis symptoms. Materials and methods: Of the 2005 patients who were administered an allergy test with the prediagnosis of allergic rhinitis, the files of 138 patients who were exposed to toluene were analyzed retrospectively. Results: The mean age of the patients was 35 10 years. Distributions of symptoms and allergens of 57 patients (41.3%) with negative skin prick test and 81 patients (58.7%) with positive skin prick test were analyzed according to occupation groups. There was no significant difference between the groups in terms of symptoms at baseline except for the symptom of runny nose (P > 0.05). The groups were compared in terms of complaints that started at the age of 16 or later, which was found as 76.5% in the positive group and 91.2% in the negative group. Conclusion: The occupation of the patient must be considered in patients who present with allergic symptoms; in particular, patients with negative skin prick test should be investigated in terms of occupational exposure

Rationale and Design of the Turkish Sleep Apnea Database - TURKAPNE: A National, Multicenter, Observational, Prospective Cohort Study

WOS: 000439590300008PubMed ID: 30083405OBJECTIVES: The primary aim of The Turkish Sleep Apnea Database (TURKAPNE) study is to generate a cross-sectional nationwide database for defining the clinical and polysomnographic characteristics of the patients with obstructive sleep apnea (OSA) in Turkey. MATERIALS AND METHODS: In this ongoing project, all consecutive adults with suspected OSA are recruited from the sleep centers of the university and research hospitals in Turkey. Information on anthropometric data, educational status, driving license, smoking habits, alcohol use, comorbidities, drug use, questionnaires, polysomnographic, and/or cardiorespiratory polygraphic findings are recorded in a systematized Web-based report form. Blood glucose, lipids and other biochemical markers, lung function, and echocardiography measurements are optionally included. Follow-up data regarding treatment modality and compliance is assessed. Cross-sectional and longitudinal associations between OSA phenotypes and metabolic, pulmonary, and cardiovascular comorbidities as well as traffic accidents, and the impact of treatment will be further explored. We target a total sample of 10,000 participants. RESULTS: The study was registered with ClinicalTrials.gov (NCT02784977) in May 2016 and the first patient was recruited in October 2017. A total of 1911 participants from 19 centers have been enrolled in the study by May 31, 2018. CONCLUSION: The TURKAPNE study will contribute to a better understanding of the health-related burden of OSA phenotypes and its association with the comorbidities and adverse outcomes, including traffic accidents in Turkey. The results may also contribute to a more personalized approach and better management of varying OSA phenotypes with concomitant disorders.Turkish Thoracic SocietyThe foundation and infrastructure of the database was supported by grants from the Turkish Thoracic Society with no influence on the design of the study, the analysis of the data, the data collection, drafting of the manuscript, or the decision to publish

Efficacy and Safety of Trastuzumab Emtansine in Her2 Positive Metastatic Breast Cancer: Real-World Experience

Aim The aim of this study is to evaluate the efficacy and toxicity of trastuzumab emtansine (T-DM1) in cases with metastatic breast cancer (mBC) in different lines of treatment. Method Retrospective analysis of T-DM1 results of human epidermal growth factor receptor 2 (Her2) positive 414 cases with mBC from 31 centers in Turkey. Findings Except 2, all of the cases were female with a median age of 47. T-DM1 had been used as second-line therapy in 37.7% of the cases and the median number of T-DM1 cycles was 9. Progression-free survival (PFS) and overall survival (OS) times were different according to the line of treatment. The median OS was found as 43, 41, 46, 23 and 17 months for 1st, 2nd, 3rd, 4th and 5th line, respectively (p = 0.032) while the median PFS was found as 37, 12, 8, 8 and 8 months, respectively (p = 0.0001). Treatment was well tolerated by the patients. The most common grade 3-4 adverse effects were thrombocytopenia (2.7%) and increased serum gamma-glutamyl transferase (2%). Discussion The best of our knowledge this is the largest real-life experience about the safety and efficacy of T-DM1 use in cases with mBC after progression of Her2 targeted treatment. This study suggests and supports that T-DM1 is more effective in earlier lines of treatment and is a reliable option for mBC