Seasonal variation of decompensated heart failure admissions and mortality rates in sub-Saharan Africa, Cameroon

Abstract

Background: Epidemiological data of heart failure (HF) decompensation from the northern hemisphere suggests higher rates during winter.

Objectives: We aimed to explore the seasonal variation in decompensated HF admission and mortality rates in a country with equatorial climate.

Methods: We conducted a retrospective cross-sectional study by chart review of the admission, discharge registries and patient files from 2016 to 2018 in the cardiology unit of the Yaoundé Central Hospital, Cameroon. Data was collected on HF morbidity and mortality from the registers and patients' files. Corresponding seasonal climatic data was obtained from the meteorology office of the Cameroonian ministry of transports. Analysis of variance and Chi-square test were respectively used to compare the continuous and categorical data between across seasons. Correlation between continuous data was assess with the Spearman correlation.

Results: Decompensated HF accounted for 636 (36.2%) out 1755 cardiology unit admission and an 18% lethality rate. Decompensated HF admission, mortality and lethality rates were respectively 38.2%, 6.7% and 17.9% higher during the long rainy season (all P values>0.05). We observed a borderline-to-significant inverse linear continuous correlation between monthly temperatures and admission rate (r=-0.301; P=0.070), lethality rate (r=-0.361; P=0.030) and mortality rate (r=-0.385; P=0.020). There was no significant difference of the distribution of precipitating factors between seasons.

Conclusion: Although statistically insignificant, decompensated HF admissions and mortality increase in rainy season where the temperature is lower in an equatorial climate.

Keywords: Cameroon; Cameroun; Decompensation; Décompensation; Heart failure; Insuffisance cardiaque; Seasonal variation; Variation saisonnière.