Some aspects of the pattern of systemic hypertension in the adult population of Gassim, Saudi Arabia: age distribution of the subsets of hypertensives.

As part of our studies in prevent nephrology, we have recorded causal blood pressure during a total population cross-sectional survey of the Faizia East Primary Health District of Buraidah (FEPHD), capital of Gassim region of Saudi Arabia. Out of 5671 subjects whose blood pressure could be recorded, 2222 were above 19 years of age and constituted our adult population. For this report, hypertension have been defined as equal to and greater than 140/90 mm Hg. Total hypertensive population had been divided into three subsets, based on this basic definition, namely combined systolic and diastlic hypertension (S/DHPN), isolated systolic hypertension (ISHPN) and isolated diastolic hypertension (IDHPN), a format which is not generally clear in previous studies on the subject. The overall prevalence of systemic hypertension was found to be 23.58%, which is lower than the figure of 36% for USA (pre-primary prevention intensive campaign). It is assumed that all the three subsets mentioned above have been used in calculating the latter. Although males tended to be more hypertensive than females (OR = 1.22; Chi Square = 3.89; P = 0.05; C.I.: 1.00 < OR < 1.49), the marginal difference (25.7% vs 22.10%) was largely due to the IDHPN subset (OR = 1.73; Chi Square = 4.48; P = 0.034; C.I.: 1.01 < OR < 2.96). In both the S/DHPN and ISHPN: statistical significance was not achieved. Significantly, ISHPN subset constituted the bulk--56.68%--of the hypertensive population while IDHPN constituted the least--11.64%. When analysed into 10-year-age cohorts, ISHPN showed the steepest rise in prevalence with age. Rather suprisingly, the IDHPN did not rise with advancing age while the S/DHPN slope was in between the two. We are unable to identify this pattern in our literature search on the subject. We cannot assess its significance by this study, but we wonder whether or not it carries any prognostic significance in terms of target organ damage. It is possible that this pattern may be peculiar to the sub-region but it certainly is not spurious and in our view deserves further scrutiny. We wish to suggest that clear definition of the three subsets of hypertensive population should be mandatory when defining prevalence. This may provide some further clues in the prognosis and pathogenesis of target organ damage.