Abstract:
Coronary heart disease (CHD) refers to a heart diseases caused by narrowing of the
coronary arteries by a build-up of fatty substances(plaque) that obstructs blood flow and oxygen
to the heart muscles and the heart's blood supply is blocked or interrupted in the coronary
arteries. The total deaths of peoples with CHD in Ethiopia reach 47,712 in 2018, where 7.81%
of deaths in Ethiopia were due to CHD. The general objective of the study is to assess best model
selection for survival estimate of CHD patients and to identify determinant factors for CHD
patients. A retrospective cohort study was implemented on CHD patients whose age is ≥ 18
years from June 1/2009 to May 30/ 2019 in University of Gondar referral hospital, Gondar town
in Amhara region, North West Ethiopia. Cox PH model, Parametric PH model and AFT models
are used to identify potential associations between the survival time and the study variables in
survival analysis. The Kaplan-Meier/KM/ estimator were used to estimate the survivor and
hazard functions. The higher value of log likelihood, lower values of the AIC and high value of
coefficient of determination(𝑅2) suggests the best fitted model. Additionally, Cox-Snell residual
plot and LR test (for nested model) are used for model comparison. A total of 302 patients were
included in this study, in which 138 (45.69%) patients were died during the follow up period.
The median follow up period was 457.50 days. Hence, the median survival time was 1429 days.
In this study lognormal AFT model fits the data significantly better than exponential, Weibull,
log logistic and generalized gamma AFT models. While in the parametric PH model Weibull PH
model fit the data significantly better than the exponential PH model. Cox PH model is the best
fitted model than all parametric models to perform the data set for survival analysis of CHD
patients at the time of the study period. The result of Cox PH regression analysis showed that
age of CHD patients, diabetes mellitus, thrombosis, hypertension/high blood pressure/, coronary
artery diseases, chronic kidney diseases, rheumatic heart diseases, congenial heart diseases,
ischemic heart diseases, atherosclerotic heart diseases and tuberculosis/TB/ were significantly
associated with the survival of CHD patients. Therefore, a careful monitoring of patients with
thus diseases & for older patients is necessary in order to improve the survival of CHD patients
and reducing their mortality rate. Mortality rate of CHD patients was very high in the earlier
days of CHD treatment initiation period
