Assessing the risk of early-onset dementia within 5 years of cancer diagnosis

ObjectiveTo evaluate risk of early-onset dementia (EOD) after diagnosis of cancer among Medicaid beneficiaries. DesignLongitudinal observational study of Medicaid enrollment, inpatient, and outpatient claims data from 26 states and Washington, DC, 2001-2019. MethodsBeneficiaries aged 18-64 with [≥]6 months of enrollment were matched 1:1 on cancer status (lung, colon, breast, prostate) by age, sex, race, year and state. We estimated the weighted cumulative incidence functions of EOD at 1, 2, and 5 years after cancer diagnosis using the Aalen-Johansen estimator to account for the competing risk of death and cluster stratified analyses to account for matching. We calculated the corresponding risk differences (RD) and 95% confidence intervals (CI) using the 2.5th and 97.5th percentile of point estimates from 500 bootstrap resamples. ResultsThe 5-year risk of EOD was 4.7% (95%CI: 4.5,5.0) and 4.7% (95%CI: 4.4, 4.9) among those with and without lung cancer, respectively (RD:0.08; 95%CI: -0.27,0.42). The 5-year risk of EOD was 4.1% (95%CI: 3.8, 4.4) and 3.9% (95%CI:3.7,4.3) among those with and without colon cancer, respectively, (RD 0.18; 95%CI: -0.25,0.55). The 5-year risk of EOD was 3.0% (95%CI: 2.8,3.1) and 2.9% (95%CI: 2.7,3.0) among those with and without breast cancer, respectively, (RD 0.10; 95%CI: -0.14,0.43). The 5-year risk of EOD was 4.6% (95%CI: 4.3,4.9) and 5.3% (95%CI: 4.9,5.7) among those with and without prostate cancer, respectively; those with prostate cancer had a lower EOD risk (RD -0.66; 95%CI: -1.2,-0.16). ConclusionsEOD incidence peaked at 4-5% among beneficiaries with and without cancer. Diagnosis of lung, colon, breast and prostate cancers were not strongly associated with EOD within 5 years. Additional work is needed to identify risk factors for EOD.