Chronobiologic Rhythm of Death in Cancer Patients: a Population-Based Study

Abstract Description

Authors (including presenting author) :

Lee SF(1), Wong CS(1)

Affiliation :

(1)Department of Clinical Oncology, Tuen Mun Hospital, New Territory West Cluster, Hospital Authority

Introduction :

Many studies have revealed the circadian pattern of sudden cardiac death. However, only few studies provided data regarding the circadian rhythm in the temporal distribution of cancer death, using single institutional data with small sample sizes.

Objectives :

We aimed to ascertain the temporal distribution of death among cancer patients in Hong Kong. We modeled the time of cancer death and examined if the circadian rhythm existed using state-of-the-art methodology and large sample size.

Methodology :

Data of adult cancer patients between 2008 and 2016 were retrieved from the Clinical Data Analysis and Reporting System, an electronic database operated by the Hospital Authority of Hong Kong. We used parametric and nonparametric methods, including trigonometric regression in the framework of generalized linear models, to assess the presence of circadian rhythms in the time of cancer death among 58,451 patients in public hospitals of Hong Kong.

Result & Outcome :

We found no evidence of unimodal sinusoidal circadian patterns (periodicity) among our cancer patients by using parametric sinusoidal circadian test (Z = -0.04; p = 0.96) and the non-parametric multimode test for one (excess mass = 0.011, p < 0.0001). The highest frequency of death occurred at 06 h 00 min (4.90%) and 20 h 00 min (4.87%) and the lowest frequency at 18 h 00 min (3.66%). The morning and evening peaks showed 1.3 times higher frequency of death than the reference time 00 h 00 min (prevalence ratios for 06 h 00 min and 20 h 00 min = 1.3, 95% confidence interval [CI] 0.8, 2.2). After accounting for the periodicity in the number of cancer patients in a 24-h period, there was no evidence of a biological circadian pattern in the time of cancer death. Therefore, the time of cancer death is a random process possibly associated with the organization of the hospital healthcare provision.