A trend analysis of the burden of cataract in Trinidad and Tobago from 1990 to 2021 using joinpoint regression and age-period-cohort models

To study the burden of cataract in Trinidad and Tobago from 1990 to 2021 using cataract disability adjusted life years (DALYs) and prevalence data. National age prevalence and cataract DALY numbers, crude prevalence and DALY rates, age-standardised prevalence rates and DALY rates from 1990 to 2021 for Trinidad and Tobago, were extracted from the Global Burden of Disease Study 2021. Trend analysis was conducted using a joinpoint regression model, an age-period-cohort (APC) model, and a Bayesian age-period-cohort (BAPC) analysis model. The three methods showed comparable results. There was an overall increase in cataract prevalence and DALYs numbers over the period. A further breakdown by age groups, showed a direct relationship between age and both measures. Joinpoint regression models showed a significant (P < 0.05) decrease in both age-standardised prevalence rates (571.13 in 1990 to 508.52 in 2021) and age-standardised DALY rates (from 42.07 in 1990 to 29.09 in 2021). The joinpoint models also identified an overlap in the period of most significant decline for the DALYs and prevalence data. Additionally, the APC models identified that age and cohort effects on the burden of cataract were also significant (P < 0.001). The trend analysis showed that while cataract prevalence and DALY numbers increased over the period, age-standardised prevalence and DALY rates decreased. Age and cohort effects were significant.