Determinants and clinical outcomes of patients with tetralogy of Fallot lost to cardiology follow-up.

BACKGROUND: Various rates of loss to follow-up (LTFU) were reported in patients with congenital heart disease, but return to follow-up is rarely considered in these analyses. Outcomes of patient LTFU are difficult to assess since patients LTFU no longer attend cardiac care. We leveraged data from the TRIVIA cohort, which combines over 30 years of clinical and administrative data, allowing us to study outcomes even after LTFU.

METHODS: This population-based cohort includes 904 patients with tetralogy of Fallot (TOF) born between 1982 and 2015 in Québec, Canada. Risk factors for LTFU and outcomes were calculated by Cox models and marginal means/rates models. Outcomes of LTFU patients were compared to propensity-score matched non-LTFU patients.

RESULTS: The cumulative risk of experiencing one episode of LTFU was 50.3% at 30 years. However, return to follow-up was frequent and the proportion of patients actively followed was 85.9% at 10 years, 76.4% at 20 years, and 70.6% at 30 years. Factors associated with a reduced risk of LTFU were primary repair with conduit (HR 0.29; 95% CI 0.15-0.58) and transannular patch (HR 0.60; 95% CI 0.46-0.79). LTFU patients had lower rates of cardiac hospitalizations (HR 0.49; 95% CI 0.42-0.56) and cardiac interventions (HR 0.32; 95% CI 0.25-0.42), but similar rate of cardiac mortality (HR 0.95; 95% CI 0.24-3.80).

CONCLUSION: There was a lower proportion of patients LTFU compared to previous studies. Factors associated with lower rates of LTFU were conduits and non-valve sparing surgery. Patients LTFU had lower rates of cardiac procedures and cardiac hospitalizations.