Is the grading system of the severity of the OSAHS used presently rational or not?: from the view of incidence of hypertension in different severity groups

The grading system of the severity of obstructive sleep apnea hypopnea syndrome (OSAHS) used presently showed that the severe OSAHS had an extensive range of apnea hypopnea index (AHI) (≥30, even over 100). So this grading system is not rational. From Jan 1999 to June 2011, there were 2,618 patients complaining of snoring took the polysomnography. The patients were divided into 11 groups according to their AHI. Frequencies of OSAHS with hypertension in each group were tested using crosstabs. The incidence of hypertension was increased as the increasing of AHI. Crosstab analysis showed that there were four cutoff points of AHI (5, 30, 50, 100). There was a significant difference in the incidence of hypertension between the groups of AHI more than the cutoff point and AHI less than the cutoff point. So from the view of hypertension in each group, we recommend that the AHI <5 should be considered as normal or simple snorer, AHI = 5–30 as mild degree of OSAHS, AHI = 30–50 as moderate degree of OSAHS, AHI = 50–100 as severe degree of OSAHS, and AHI ≥100 as profound degree of OSAHS.