Seasonality of stroke: Winter admissions and mortality excess: A Thailand National Stroke Population Database Study

Nicole Lorking, Adrian Wood, Somsak Tiamkao, Allan B. Clark, Kannikar Kongbunkiat, Joao H. Bettencourt-Silva, Kittisak Sawanyawisuth, Narongrit Kasemsap, Mamas A. Mamas, Phyo K. Myint* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


We examined the existence and potential burden of seasonality of stroke admissions and mortality within a tropical climate using cohort data collected between 1 st November 2003 and 31 st October 2012.

Patients and methods
In a prospective cohort of hospitalised stroke patients from the catchment of ∼75% of the Thai population (n = 569,307; mean SD age = 64(14.5)), incident stroke admissions, in-hospital mortality, prolonged hospitalisations, and stroke related complications by season were determined. Rates of incident stroke admissions by month and season were plotted. Winter excess indexes for study outcomes expressed as a percentage were calculated. Using logistic regression we examined the association between winter admission and in-hospital mortality (non-winter admission as reference) adjusting for age, sex, stroke type, year of admission, and presence of pre-existing comorbidities.

We observed a winter excess in mortality during hospitalisation (+10.3%) and prolonged length of stay (+7.3%). Respective winter excess indexes for dyslipidaemias, arrhythmias, anaemia, and alcohol related disorders in patients that died during hospitalisation were +1.4%, +6.2%, +0.2%, +1.5%. In these patients, respective winter excess indexes for post-stroke complications of pneumonia and sepsis were +6.7% and +3.2%. In fully adjusted analyses, winter admission (compared to non-winter admission) was associated with increased odds of in-hospital mortality (OR (95% CI) = 1.023 (1.006-1.040)).

We provide robust evidence for the existence of an excess in winter stroke admissions and subsequent in-hospital deaths within a tropical region.
Original languageEnglish
Article number106261
Pages (from-to)106261
Number of pages7
JournalClinical Neurology and Neurosurgery
Early online date2 Oct 2020
Publication statusPublished - Dec 2020

Bibliographical note

We wish to thank the administrative staff of Insurance Schemes who prepared the anonymised data sets. We are grateful to Tiberiu A Pana for assistance in generating the figures.

Sources of funding
ADW was funded by the Special Educational Scholarship award by the Department of Medicine for the Elderly, NHS Grampian [grant number ES798]. ST was funded by the Thai Neurological Society to study the database of the National Health Security Organization (NHSO).


  • stroke
  • seasonality
  • mortality excess
  • Thailand
  • cohort study
  • Stroke
  • Cohort study
  • Seasonality
  • Mortality excess


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