Additionally, time-varying covariates are included into the model using an approach buy SYN-117 based on fractional polynomials. The different methods of this article are then applied to a dataset consisting of four studies conducted by the German Breast Cancer Study Group (GBSG). The occurrence of the first isolated locoregional recurrence (ILRR) is studied. The results contribute to the debate on the role of the ILRR with respect to the course of the breast cancer disease and the resulting prognosis.

Results: We have investigated different modelling strategies for the transition

hazard after ILRR or in general after an intermediate event. Including time-dependent structures altered the resulting hazard functions considerably and it was shown that this time-dependent structure has to be taken into account in the case of our breast cancer dataset. The results indicate that an early recurrence increases the risk of death. A late ILRR increases the hazard function much less and after the successful removal of the second tumour the risk of death is almost the same as before the recurrence. With respect to distant disease, the appearance of the ILRR only slightly increases the risk of death if the

recurrence was treated successfully.

Conclusions: It is important to realize that there are several modelling strategies for the intermediate event and that each BAY 80-6946 manufacturer of these strategies Caspase inhibitor has restrictions and may lead to different results. Especially in the medical literature considering breast cancer development, the time-dependency is often neglected in the statistical analyses. We show that the time-varying variables cannot be neglected in the case of ILRR and that fractional polynomials are a useful

tool for finding the functional form of these time-varying variables.”
“BACKGROUND: There is little information on the recovery of Mycobacterium tuberculosis complex from sputum samples collected in the field for bacteriological examination.

SETTING: Tribal areas in the State of Madhya Pradesh, in central India.

METHODS: Sputum specimens collected from subjects with chest symptoms in a disease prevalence survey were refrigerated until transportation to the laboratory. The specimens were processed for microscopy and culture. The samples were grouped based on the delay in processing for culture from the day of collection into three groups: 0-3, 4-7 and >= 8 days, and the recovery of M. tuberculosis complex in these groups was analysed. The statistical analysis was performed using chi(2) test.

RESULTS: Of the 3651 processed specimens, 114 were positive for M. tuberculosis complex by culture and 96 by smear microscopy. The differences in the proportion of ‘smear-positive, culture-positive’, ‘smear-positive, culture-negative’ and ‘smear-negative, culture-positive’ samples between the three groups were not significant.