Research Article

Application of Cox Proportional Hazards Model in Case of Tuberculosis Patients in Selected Addis Ababa Health Centres, Ethiopia

Table 8

Result of test of proportionality assumption containing the variables in Table 7 and their interaction with log time.
(a)

Analysis of maximum likelihood estimates
CovariatesDFParameter estimateStandard errorChi-Square Pr > ChiSq Hazard ratio

Age10.01919 0.02212 0.7526 0.3857 1.019
TBC10.20274 0.95433 0.0451 0.8318 1.225
HIV11.09680 1.13372 0.9359 0.3333 2.995
AgHIV1−0.02914 0.01722 2.8638 0.0906 0.971
Age * log (time)10.00223 0.00561 0.6904 0.6904 1.002
TBC * log (time)1−0.19525 0.23829 0.6714 0.4126 0.823
HIV * log (time)10.31882 0.27050 1.3891 0.2385 1.375
agHIV * log (time)1−0.0001785 0.0001725 1.0712 0.3007 1.000

(b)

Linear hypotheses testing results
Label Wald
Chi-Square
DFPr > ChiSq

Test proportionality2.1579 40.7067