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Adequacy of a single visit for classification of hypertensive status in a Nigerian civil servant population
N Markovic1, I N Olomu, C H Bunker
1Graduate School of Public Health, University of Pittsburgh, PA 15261.
Insights
Classifying hypertension using a single blood pressure reading or a single visit average is adequate for cross-cultural comparisons. This study found good agreement across different measurement methods in a Nigerian urban population.
Area of Science:
- Cardiovascular Health
- Epidemiology
- Public Health
Background:
- Concerns exist regarding the accuracy of classifying hypertension based on single blood pressure readings or single-visit averages.
- The appropriateness of these classifications for cross-cultural hypertension rate comparisons is questioned.
Purpose of the Study:
- To investigate the variability in hypertension classification using different blood pressure measurement strategies.
- To assess the adequacy of single-visit blood pressure averages for cross-cultural hypertension comparisons.
Main Methods:
- Compared hypertension status determined by: 1) single reading, 2) average of second/third readings at first visit, 3) average of second/third readings across three visits.
- Calculated Kappa statistic, sensitivity, and specificity for 804 Nigerian civil servants.
- Compared findings with other published studies on blood pressure measurement variability.
Main Results:
- Observed good to excellent agreement between single reading, first visit average, and three-visit average for the entire population.
- Sensitivity and specificity measures were acceptable across the population.
- No significant distinctions in agreement were found based on sex or socioeconomic status.
Conclusions:
- Repeated blood pressure measurements showed no greater variability compared to studies in developed and developing countries.
- A single-visit average of blood pressure determinations is adequate for classifying hypertension in this urban working population.
- This method is suitable for comparisons with hypertension rates in Westernized populations.
Background:
Concern has been expressed regarding the adequacy of classifying individuals as hypertensive based upon a single blood pressure determination and/or the average of readings taken at a single visit and the appropriateness of these determinations in cross-cultural comparisons of rates of hypertension.
Methods:
This analysis investigated the potential classification variability by comparing hypertensive status determined by 1) a single reading, 2) an average of the second and third determination at the first visit, and 3) an average of the second and 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, Benin City, 1992. Data were also compared to other published studies for variability in hypertension classification with repeated blood pressure determinations.
Results:
Good to excellent agreement was observed for the entire population between the single blood pressure determination, the average of the first visit, and the average of three visits. Sensitivity and specificity measures were also acceptable for the entire population. Further analysis by sex and staff status (a measure of socioeconomic status) found no apparent distinctions between the groups.
Conclusion:
Contrasting the data with other published studies, conducted in both developed and developing countries, we note no greater variability in repeated blood pressure measurements, and conclude that the average of blood pressure determinations at a single visit in this working urban population is adequate for determining hypertensive status for comparisons with hypertension rates in Westernized populations.