Joint Modeling of Longitudinal Pulse Rate and Time-to-Default from Treatment of Congestive Heart Failure Patients

Background: Globally, heart failure is a rapidly growing public health problem with an estimated prevalence of > 37.7 million. It is a shared chronic phase of cardiac functional loss secondary to many etiologies. Objective: The main purpose of this study was to investigate the risk of longitudinal change in pulse rate on time to default from treatment among congestive heart failure patients. Methods: Hospital-based retrospective studies were conducted among 302 congestive heart failure patients who were 15 years old or older and who were on treatment follow-up from the 1 February 2016 to 31 December 2018 in Felege-Hiwot Referral Hospital, Bahir Dar, Ethiopia. Data were entered using SPSS version 23 and analyzed using SAS and R software. First, data were analyzed using linear mixed model and survival models separately, and then the joint models of both sub-models were analyzed using joint model analysis. Results: Out of the total of 302 respondents, 34.1% of the respondents defaulted from treatment. About 55.2% male respondents are defaulting and the remaining were censored. The results for separate and joint models were quite similar to each other but not identical. However, the estimated association parameter (α) in the joint model is (HR = 1.0311, 95% CI: 1.0033, 1.0597, P = 0.0278), providing there is evidence of a positive significant relationship between the survival and the longitudinal sub-models. Thus, defaulting is more likely to occur in patients with higher pulse rates. A patient, who are male, New York Heart Association class IV, had low left ventricular ejection fraction and comorbid with hypertensive, chronic kidney disease, pneumonia were risk factors of pulse rate change and defaulting from treatment of congestive heart failure patients. Conclusion: The joint model was preferred for simultaneous analyses of repeated measurement and survival data. Thus, the longitudinal measure pulse rate had a positive significant effect on time to default from treatment of patients.