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Comparisons of cox semi-parametric and parametric shared frailty models: application for under-five children survival
Haile Mekonnen Fenta1,2,3, Ding-Geng Chen4,5, Temesgen T Zewotir6
1Department of Statistics, University of Pretoria, Pretoria, South Africa. hailemekonnen@gmail.com.
Insights
Under-five child mortality in sub-Saharan Africa is influenced by various factors. Improved water access, clean fuel, and maternal age significantly reduce child deaths, while rural residence increases risk.
Area of Science:
- Demography
- Public Health
- Survival Analysis
Background:
- Under-five child mortality in sub-Saharan Africa (sSA) remains a critical issue.
- Limited research exists on disparities in mortality determinants across sSA countries and districts.
- Child survival is influenced by numerous known and unknown covariates, varying by region.
Purpose of the Study:
- To assess under-five child mortality time and associated risk factors in sSA.
- To compare the performance of semiparametric and parametric frailty models in analyzing child survival data.
- To identify key determinants of under-five mortality across sSA administrative districts.
Main Methods:
- Utilized Demographic and Health Survey (DHS) data from 33 sSA countries.
- Employed semiparametric and parametric frailty models with various frailty distributions.
- Modeled under-five survival time across administrative districts within the selected sSA countries.
Main Results:
- Analyzed 330,373 children, with 6.02% experiencing under-five mortality.
- Significant country-level and district-level variances impacted child survival.
- Maternal age (25-49 years), urban residence, improved water access, and clean cooking fuel were associated with reduced mortality risk.
Conclusions:
- The exponential shared frailty hazard model with lognormal frailty distribution outperformed the Cox semiparametric model.
- Key risk factors identified include place of residence, wealth, media exposure, birth order, birth interval, water access, and cooking fuel type.
- These findings highlight modifiable factors crucial for reducing under-five mortality in sSA.
Background:
The under-five child mortality in sub-Saharan African (sSA) countries is a persistent problem with limited effort being made to explore the determinants of disparities across countries and their lower administrative districts. A child's survival may depend on several known and unknown covariates and vary across the study areas. The main objective of this study is to assess the time to death of under-five children and its associated risk factors by comparing the performance of semiparametric and parametric frailty models across sSA regions.
Methods:
We used a dataset from the Demographic and Health Survey (DHS) across 33 sSA countries. The semiparametric and parametric models with different frailty distributions were used to model the under-five survival time of children across the administrative districts of 33 sSA countries.
Results:
A total of 330,373 under-five children were included in the study, of whom 19,893 (6.02%) died before reaching their 5th birthday. Unobserved country-level variance [Formula: see text] and district-level variance (0.183) effects considerably impacted the survival time of under-five children in sSA countries. Under-five children born to mothers aged 25-29 and 30-49 were 16% and 20% less likely to die compared to children born to mothers younger than 24 years. Moreover, children born in rural areas were 8.3% more likely to die than those who were born in urban areas. Children who were born from mothers with better access to improved water sources and clean fuel were 9% and 11% less likely to die than their counterparts, respectively.
Conclusions:
The exponential shared frailty hazard model with lognormal frailty distribution demonstrated better performance compared to the Cox semiparametric model for identifying risk factors for under-five children across sSA countries. Place of residence, wealth index, media exposure, birth order, birth interval, access to improved water, and use of clean fuels for cooking were the significant risk factors on time to death of under-five children in sSA.
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