Long-term retreatment rates of cerebral aneurysms in a population-level cohort

Background The likelihood of retreatment in patients undergoing procedures for cerebral aneurysms (CAs) has an important role in deciding the optimal treatment type. Existing determinations of retreatment rates, particularly for unruptured CAs, may not represent current clinical practice. Objective To use population-level data to examine a large cohort of patients with treated CAs over a 10-year period to estimate retreatment rates for both ruptured and unruptured CAs and explore the effect of changing treatment practices. Methods We used administrative data from all non-federal hospitalizations in California (2005-2011) and Florida (2005-2014) and identified patients with treated CAs. Surgical clipping (SC) and endovascular treatments (ETs) were defined by corresponding procedure codes and an accompanying code for ruptured or unruptured CA. Retreatment was defined as subsequent SC or ET. Results Among 19 482 patients with treated CAs, ET was performed in 12 007 (62%) patients and SC in 7475 (38%). 9279 (48%) patients underwent treatment for unruptured CAs and 10203 (52%) for ruptured. Retreatment after 90 days occurred in 1624 (8.3%) patients (11.2% vs 3.7%, ET vs SC). Retreatment rates for SC were greater in unruptured than in ruptured aneurysms (4.6% vs 3.1%), but the opposite was true for ET (10.6% vs 11.8%). 85% of retreatments were within 2 years of the index treatment. Retreatment was associated with age (OR=0.99, 95% CI 0.98 to 0.99), female sex (OR=1.5, 95% CI 1.3 to 1.7), Hispanic versus white race (OR=0.86, 95% CI 0.75 to 0.98), and ET versus SC (OR=3.25, 95% CI 2.85 to 3.71). The adjusted 2-year retreatment rate decreased from 2005 to 2012 for patients with unruptured CAs treated with ET (11% to 8%). Conclusions Retreatment rates for CAs treated with ET were greater than those for SC. However, for patients with unruptured CAs treated with ET, we identify a continuous decline in retreatment rate over the past decade.