ADEQUACY OF A SINGLE VISIT FOR CLASSIFICATION OF HYPERTENSIVE STATUS IN A NIGERIAN CIVIL-SERVANT POPULATION

Background. Concern has been expressed regarding the adequacy of class ifying individuals as hypertensive based upon a single blood pressure determination and/or the average of readings taken at a single visit a nd the appropriateness of these determinations in cross-cultural compa risons of rates of hypertension.Methods. This analysis investigated th e potential classification variability by comparing hypertensive statu s determined by 1) a single reading, 2) an average of the second and t hird determination at a first visit, and 3) an average of the second a nd third determinations obtained at each of three visits according to a standardized protocol. Kappa statistic, sensitivity and specificity were calculated to assess the agreement of hypertension classification for 804 subjects in the Health Survey in Nigerian Civil Servants, Ben in City, 1992. Data were also compared to other published studies for variability in hypertension classification with repeated blood pressur e determinations. Results. Good to excellent agreement was observed fo r the entire population between the single blood pressure determinatio n, the average of the first visit, and the average of three visits. Se nsitivity a nd specificity measures were also acceptable for the entir e population. Further analysis by sex and staff status (a measure of s ocioeconomic status) found no apparent distinctions between the groups . Conclusion. Contrasting the data with other published studies, condu cted in both developed and developing countries, we note no greater va riability in repeated blood pressure measurements, and conclude that t he average of blood pressure determinations at a single visit in this working urban population is adequate for determining hypertensive stat us for comparisons with hypertension rates in Westernized populations.