Joint Modeling of Longitudinal Changes of Respiratory Rate, Pulse Rate and Oxygen Saturation with Time to Convalescence among Pneumonia Patients: A comparison of separate and joint models

Abstract Background: Globally, pneumonia is the first infectious disease which is the leading cause of children under age five morbidity and mortality with 98% of deaths in developing countries.Objective: The study aimed to identify the determinant factors that jointly affect the longitudinal measures of pneumonia (respiratory rate, pulse rate and oxygen saturation) and time to convalescence or recovery of under five admitted pneumonia patients at Felege Hiwot Referral Hospital, Bahir Dar, Ethiopia.Methods:A prospective cohort study design was used on 101 sampled under five admitted pneumonia patients from December 2019 to February 2020. The study was conducted using joint model of longitudinal outcomes and survival outcomes.Results: The significant values of shared parameters in the survival sub model shows that the use of joint modeling of multivariate longitudinal outcomes with the time to event outcome is the best model compared to separate models. The estimated values of the association parameters for \({\gamma }\_1,\) \({\gamma }\_2 \text{a}\text{n}\text{d} {\gamma }\)_3 were -0.297, -0.121 and 0.5452 respectively and indicates that; respiratory rate and pulse rate were negatively related with recovery time, whereas oxygen saturation was positively associated with recovery time. As age of patients increased by one month, the average respiratory rate and pulse rate were significantly decreased by 0.3759 bpm and 1.1012 bpm respectively keeping other variables constant, but age has no information about oxygen saturation.Conclusion: Residence, birth order, severity and visit were found as determinants of the longitudinal measures of pneumonia and time to recovery of under-five admitted pneumonia patients jointly. To improve child survival, the community should be responsible for post ponding child birth and marriage.