BACKGROUND - Hippus is a prominent, repetitive oscillation of the pupils. Although regarded by some as a normal variant of pupillary unrest, the clinical importance of hippus has not been investigated systematically in hospitalized patients.
METHODS - We conducted a retrospective cohort study of 117 hospitalized patients demonstrating hippus. To mitigate observer bias, 486 control patients were selected using 2 adjacent admissions by the same attending physician before and after each index case. The primary outcomes were mortality during the admission and within 30 days of discharge.
RESULTS - Patients with bedside hippus were more likely to die within 30 days of observation (P <.00005). Independent risk factors for death by 30 days were altered mental status (odds ratio [OR] 4.11; 95% confidence interval [CI], 2.05-8.25, P <.001), hippus (OR 2.99; 95% CI, 1.46-6.11, P = .003), cirrhosis (P = .029), and renal disease (P = .054); angiotensin-system inhibitors were protective (P = .012). Patients with hippus were more likely to have altered mental status (OR 11.23; 95% CI, 6.27-20.09, P <.001), a history of trauma (OR 3.76; 95% CI, 1.65-8.59, P = .002), cirrhosis (P = .038), renal disease (P = .051), and a history of using iron supplements (P = .016).
CONCLUSION - The recognition of hippus in hospitalized patients is a clinically important predictor of early mortality.