CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 1, February 2012
AFRICA
49
antihypertensive medications are beneficial for patients with
prehypertension. However, it is evident that lifestyle modifica-
tion (e.g. weight loss, reduced sodium intake and regular physi-
cal activity) can be very successful in reducing blood pressure
levels. Therefore, the JNC7 report states that all patients with
prehypertension should be ‘firmly and unambiguously advised
to practice lifestyle modification’.
3
Several limitations of the study require consideration. First,
analyses were based on cross-sectional studies, in which the
inherent limitations may have affected our findings. Second, this
meta-analysis was performed on a limited number of articles
(
n
=
22), which may have been too small to generate sufficient
statistical power for conducting meta-regression analyses. The
possibility of residual confounding or bias cannot be excluded.
In the meta-regression models, age was not included due to
insufficient data, and characteristics of residents (e.g. rural or
urban) could not be assessed from the majority of publications.
These factors may have played an important role in the vari-
ability of the estimates of prevalence. In addition, considering
the disagreement on quality criteria for assessing cross-sectional
studies, we did not include assessment of the methodological
quality of the studies.
Conclusion
We conducted a meta-analysis of prehypertension prevalence
studies, and a meta-regression to investigate the sources of vari-
ability across estimates of prevalence. In our study, we found
that the overall pooled prevalence of prehypertension worldwide
was 38%. This result may be an underestimate since a positive
correlation between sample size and prevalence was observed.
The prevalence among males was higher than that in females
(41 vs 34%), and non-Asians, particularly the black African
population, were more likely to be prehypertensive than Asian
individuals. The year of inception of the survey was the only
source of heterogeneity we found on meta-regression analysis.
Further research with sufficient data is expected.
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