The 5-year survival rate is a good prognostic indicator for patients with Gastric cancer that is usually estimated based on Kaplan-Meier. In situations where censored observations are too many, this method produces biased estimations. This study aimed to compare estimations of Kaplan-Meier and Weighted Kaplan-Meier as an alternative method to deal with the problem of heavy-censoring. Data from 330 patients with Gastric cancer who had undergone surgery at Iran Cancer Institute from 1995- 1999 were analyzed. The Survival Time of these patients was determined after surgery, and the 5-year survival rate for these patients was evaluated based on Kaplan-Meier and Weighted Kaplan-Meier methods. A total of 239 (72.4%) patients passed away by the end of the study and 91 (27.6%) patients were censored. The mean and median of survival time for these patients were 24.86±23.73 and 16.33 months, respectively. The one-year, two-year, three-year, four-year, and five-year survival rates of these patients with standard error estimation based on Kaplan-Meier were 0.66 (0.0264), 0.42 (0.0284), 0.31 (0.0274), 0.26 (0.0264) and 0.21 (0.0256) months, respectively. The estimations of Weighted Kaplan-Meier for these patients were 0.62 (0.0251), 0.35 (0.0237), 0.24 (0.0211), 0.17 (0.0172), and 0.10 (0.0125) months, consecutively. In cases where censoring assumption is not made, and the study has many censored observations, estimations obtained from the Kaplan-Meier are biased and are estimated higher than its real amount. But Weighted Kaplan-Meier decreases bias of survival probabilities by providing appropriate weights and presents more accurate understanding.

Regarding the importance of housing in life, the investigation of various aspects of this issue such as housing price Estimation, identifying its affective factors and combination of price and its changes over the time; is necessary. To achieve these goals, housing price in Mashhad has been estimated by using Kaplan Meier model both in apartment and in the villas. To meet this objective, 1000 examples of Housing and apartment’s price during 2010 and 2011 were extracted from khorasan newspaper ads. Data was scattered on the map, by Geographic information system (GIS) and its results was analyzed by SPSS software and Kaplan Meier model. The results of Kaplan Meier model showed that the difference in prices of villas and apartments based on the number of every house rooms is significant and the probability of villas prices are less than apartment prices according to the number of rooms, was confirmed. In addition of the 3 variables which entered in the equation, the variable of ' ' infrastructure level' ' is the highest coefficient Equal to 1/196.Subsequently, the variable of "old building" has a coefficient equal to 0.973.After that, the variable of "land extent" with a coefficient equal to 0.996 is located in the second stage. Then the variable of "Age of Building" with a coefficient equal to.973 stands in the third stage. Also the spatial distribution of apartment and villa prices in the city of Mashhad indicated that the most expensive areas are mainly developed Regions or areas with high access (to holy shrine).

BACKGROUND AND OBJECTIVES: Cytomegalovirus (CMV) infection is one of the most frequent infectious complications, which results in renal transplant failure. In this study, we aimed to evaluate the demographic characteristics and risk factors associated with the incidence period of CMV infection after renal transplant.METHODS: This cross-sectional study was conducted in renal transplant recipients during 2010-2015 in kidney transplant unit of Shahid Beheshti Hospital of Babol, Iran. The evaluated demographics included body mass index (BMI), smoking status, type of underlying disease leading to end-stage renal disease, hepatitis B, hepatitis C, and type of dialysis. Data analysis was performed using Kaplan-Meier estimator, log-rank test, and Cox regression.FINDINGS: In total, 242 patients received renal transplant, among whom 73 (30.2%) cases had CMV infection with median and mean survival of 41 and 48.09±23.50, respectively. In this study, there was no correlation between demographic variables (e.g., gender, place of residence, marital status, educational level, BMI, smoking status, hepatitis B, and type of dialysis) and incidence period of CMV. However, a significant relationship was observed between the incidence period of CMV and age (mean: 45 years, P=0.04), as well as etiology of ESRD urology (P=0.03).CONCLUSION: The prevalence of CMV infection is reported to be high in elderly patients with history of urologic diseases. Therefore, performing short-term follow-ups four months after transplantation, with emphasis on the first two months is recommended.

Background: Duration of breastfeeding is an important health indicator of mother and child. There are various indirect epidemiological methods available to estimate the duration of breastfeeding from cross sectional data. Objective: To estimate the distribution of duration of breastfeeding at national level cross sectional data and compare various available technique. The impact of the sampling frame (ascertain of the individual understudy) is also evaluated. Method: National Family Health Survey (NFHS-IV) data is used. Duration of breastfeeding of only those children who were born before 60 months from survey date were included in the study. The technique of Current Status Data, Life Table Analysis, and Kaplan Meier (KM) estimator is applied to assess the distribution of duration of breastfeeding. Result: The mean estimate is 32. 84, 33. 14 and 33. 64 months by Kaplan Maier Estimator, Current Status Data and Life Table Analysis respectively. The Current Status and Life Table method are better than Kaplan Meier Estimator as it is doesn’ t based on recall data and heaping present in the data. Conclusion: One must be very cautions while estimating the various epidemiological parameters from cross section data set. The assumptions of the methodology as per data available should be evaluate. If such data is not available, the available methodology may be modified. Regression analysis based on Current Status data technique may be used to assess the impact of various clinical and epidemiological factors (such as nutrition of mother, health status of mother etc. ) on duration of breastfeeding.