PROS1 and hyperinsulinemic hypoglycemia, familial, 4: The difference between the proportion of those with protein S deficiency in the ART group (n = 9/61; 14.8%) and those in the HIV ART-naïve group (n = 15/58; 25.9%) was statistically significant (χ2 = 16.9, p < 0.0001).