causes and risk of death using verbal autopsy in the ibadan study of ageing

1. Abstract

1.1 Background: The documentation of death is inadequate in many developing countries due to poor coverage of vital registration. In order to fill this gap, Verbal Autopsy (VA) has often been employed as a method of determining the cause of death.

1.2 Method: A survey of the causes of death in a cohort of elderly persons (aged ≥ 65 years) over a 39-month period was conducted using Verbal Autopsy (VA). VA was conducted using a questionnaire designed by the World Health Organization (WHO) and the International Network of Demographic Evaluation of Populations and Their Health (INDEPTH), adapted for local understanding. The questionnaire was administered to household members with adequate knowledge of the circumstances of death in the cohort. Two physicians, with knowledge of local terms of illness and the living conditions of subjects, reviewed each VA form independently to assign one or more causes of death, and subsequently met to reach consensus for cases where there were differences of opinion. If consensus could not be reached, the cause of death was regarded as indeterminate.  Assignment of causes of death was based on the 9th edition of the International Classification of Diseases (ICD-9), which is the official classification of morbidity and mortality in the country.

1.3 Result: There were 268 deaths out of the 2149 elderly persons in the study cohort, giving a mortality rate of 33.3 per 1000 person years, with gender specific rates of 35.29 per 1000 person years for males and 31.48 per 1000 person years for females. Infective causes (malaria fever, diarrhoeal disease and febrile illness of unknown cause) accounted for 13.1 deaths per 1000 person years, followed by hypertension/cardiovascular accident and asthma/respiratory pathology which accounted for 6.8 and 4.6 per 1000 person years, respectively. Multivariate logistic analysis reveals that belonging to low to average socioeconomic class (OR=1.4, 95%CI=1.3-2.8, p=0.009); significantly increased the likelihood of dying at follow up while engaging in moderate intensity physical activities (OR= 0.7, 95%CI=0.5-1.0, p=0.049 ) reduced it.

1.4 Conclusion: Infections constituted the predominant causes of death among these elderly people and belonging to low to moderate economic status increased the risk of dying.