Ventriculoperitoneal Shunt Complications in California

BACKGROUND: Risk factors for ventriculoperitoneal (VP) shunt complications have not been assessed with population cohort data since the advent of modern surgical techniques. We examined demographic factors and VP shunt complications in a population-based retrospective cohort study of all nonfederal California hospital admissions between 1990 and 2000. METHODS: We identified all admissions in a statewide administrative hospital discharge database that indicated a VP shunt insertion. Repeat hospital admissions within California generating a discharge diagnosis of surgical shunt complication, defined as a shunt replacement, revision, removal, or exploration, represented the primary outcome of interest. We performed Kaplan-Meier survival analyses and Cox proportional hazards modeling to analyze sex, age, ethnicity, socioeconomic status based on payer status, and type of hydrocephalus in relation to the risk of shunt complications. RESULTS: The annual population incidence of VP shunt placement was 5.5 per 100,000. Among 14,455 individuals with 65,040 person-years of follow-up, the cumulative complication rate at 5 years was 32%. Children demonstrated a higher rate of shunt complications than did adults at 5 years (48 versus 27%, P < 0.0001). The following demographic factors were independently associated with increased risk of shunt complications: male sex (hazard ratio HR, 1.1; 95% confidence interval CI, 1.03-1.2), low socioeconomic status (HR, 1.2; 95% CI, 1.1-1.3), and age younger than 19 years (HR, 1.6; 95% CI, 1.4-1.7). Compared with communicating hydrocephalus, obstructive hydrocephalus was also associated with increased risk of shunt complications (HR, 1.7; 95% CI, 1.5-1.9). CONCLUSION: VP shunt complications are common, especially in children. Further study is needed to explain the associations between demographic factors and elevated shunt complication rates.