BackgroundThe UK Department for Work and Pensions (DWP) administers Universal Credit (UC) – the main UK benefit for people in- and out-of-work. UC is being rolled out nationally from 2013 to 2024. Citizens Advice (CA) is an independent charity that provides advice and support to people making a claim for UC. The aim of this study is to understand who is seeking advice from CA when making a UC claim and how the types of people seeking advice are changing as the rollout of UC continues.MethodsCo-developed with Citizens Advice Newcastle and Citizens Advice Northumberland we performed longitudinal analysis of national data from Citizens Advice for England and Wales on the health (mental health and limiting long term conditions) and socio-demographic of 1,003,411 observations for people seeking advice with claiming UC over four financial years (2017/18 to 2020/21). We summarised population characteristics and estimated the differences between the four financial years using population-weighted t-tests. Findings were discussed with three people with lived experience of seeking advice to claim UC to help frame our interpretation and policy recommendations.ResultsWhen comparing 2017/18 to 2018/19, there was a significantly higher proportion of people with limiting long term conditions seeking advice with claiming UC than those without (+ 2.40%, 95%CI: 1.31-3.50%). However, as the rollout continued between 2018/29 and 2019/20 (-6.75%, 95%CI: -9.62%--3.88%) and between 2019/20 and 2020/21 (-2.09%, 95%CI: -2.54%--1.64%), there were significantly higher proportions of those without a limiting long term condition seeking advice than with. When comparing 2018/19 to 2019/20 and 2019/20 to 2020/21, there was a significant increase in the proportion of self-employed compared to unemployed people seeking advice with claiming UC (5.64%, 95%CI: 3.79-7.49%) and (2.26%, 95%CI: 1.29-3.23%) respectively.ConclusionAs the rollout for UC continues, it is important to understand how changes in eligibility for UC may impact on those who need help with applying for UC. Ensuring that the advice process and application process is responsive to a range of people with different needs can help to reduce the likelihood that the process of claiming UC will exacerbate health inequalities.