A semiparametric joint model for terminal trend of quality of life and survival in palliative care research

Zhigang Li, H. R. Frost, Tor D. Tosteson, Lihui Zhao, Lei Liu, Kathleen Lyons, Huaihou Chen, Bernard Cole, David Currow, Marie Bakitas

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Palliative medicine is an interdisciplinary specialty focusing on improving quality of life (QOL) for patients with serious illness and their families. Palliative care programs are available or under development at over 80% of large US hospitals (300+ beds). Palliative care clinical trials present unique analytic challenges relative to evaluating the palliative care treatment efficacy which is to improve patients’ diminishing QOL as disease progresses towards end of life (EOL). A unique feature of palliative care clinical trials is that patients will experience decreasing QOL during the trial despite potentially beneficial treatment. Often longitudinal QOL and survival data are highly correlated which, in the face of censoring, makes it challenging to properly analyze and interpret terminal QOL trend. To address these issues, we propose a novel semiparametric statistical approach to jointly model the terminal trend of QOL and survival data. There are two sub-models in our approach: a semiparametric mixed effects model for longitudinal QOL and a Cox model for survival. We use regression splines method to estimate the nonparametric curves and AIC to select knots. We assess the model performance through simulation to establish a novel modeling approach that could be used in future palliative care research trials. Application of our approach in a recently completed palliative care clinical trial is also presented.

Original languageEnglish
Pages (from-to)4692-4704
Number of pages13
JournalStatistics in medicine
Issue number29
StatePublished - Dec 20 2017


  • end-of-life
  • joint modeling
  • palliative care
  • semiparametric
  • terminal trend


Dive into the research topics of 'A semiparametric joint model for terminal trend of quality of life and survival in palliative care research'. Together they form a unique fingerprint.

Cite this