Survival Analysis and Frailty Modelling of Time-to-event Data: an Application to Infant Mortality in Malawi

Introduction : Infant mortality rate is one of the important health and development indicators in a country or community. Malawi, like many countries in the sub Saharan Africa is a country that suffers from the highest rates of infant mortality across the globe. Methods : This study used the most recent survey data, 2015-16 Malawi Demographic and health survey, to identify the factors associated with infant mortality in Malawi by using survival analysis techniques and frailty modelling to control for unobserved heterogeneity. Results : A total number of 4232 infants were analysed for this study and the results showed that children who were the second multiple babies to be born had a higher risk of dying before reaching the age of one year than children who are born single with P-value <0.001, HR=3.26 and 95%CI=(1.639, 5.700). Infants whose mother’s age group 45-49 years had a risk of death 4.63 times higher than infants whose mother’s age group was 15-20 years(P-value<0.001). Furthermore, there were unmeasurable family effects which made infant deaths to cluster in some families. Conclusion : social demographic, environmental and biological factors all have an effect on a child’s survival up to 1 year and the household that a child was born in had some unobservable effects on the child’s survival up to 1 year.