CRP and obstructive sleep apnea syndrome: Using a linear regression model (Figure 4), the change in serum level of hs-CRP (Δhs-CRP) following a 6 month-nCPAP therapy was found to be positively correlated with the baseline hs-CRP level for both normotensive OSAHS patients (p < 0.0001; r = 0.89) and hypertensive ones (p = 0.02; r = 0.68).