(B-161) Change in Healthcare Use Before and After COVID-19 Using Data From 1.5 Million Individuals in Sweden

Background: Post-infectious sequalae have potential to increase burden on healthcare systems. To understand the consequences of COVID-19 on healthcare use, it is crucial to distinguish between effects directly related to the disease and those stemming from the broader societal impacts of the pandemic.

Objectives: To assess the long-term effect of COVID-19 on number of healthcare contacts in all levels of care.

Methods: In this register-based cohort study, we included all adult (≥18 years) residents in Sweden’s two largest counties, representing 40% of the Swedish population, with registered COVID-19 (index date) during the study inclusion period (31 January 2020 to 9 February 2022). To them, we matched (1:1) controls without registered COVID-19 at index, on sex, birth year, vaccination status, and change in number of healthcare contacts 2018-2019. Individuals with registered COVID-19 were classified as documented cases, while those without were classified as having no recorded infection. We counted the number of healthcare contacts (including telephone contacts) at all levels of care (primary and specialist healthcare) before (13-1 months) and after (3-15 months) the index date. The first 3 months after COVID-19 were omitted in the analysis to exclude the effect of the acute phase. A difference-in-difference (DID) analysis was used to assess the change in number of healthcare contacts as well as diagnosis codes, between the pre and post period and how this differed between individuals with and without registered COVID-19. P-values were adjusted for multiple comparisons.

Results: There were 796,103 matched pairs, comprising 1,476,394 unique individuals. The groups were well-balanced on demographics and comorbidities (SMDs < 0.15). Most individuals with a documented infection had their index date during periods dominated by mixed virus variants (35%, n=276,607) or Omicron (33%, n=264,375). Trends in healthcare contacts were parallel between groups prior to the index date. Post-index, most individuals maintained the same number of contacts as the previous year, but increases were slightly more common among those with registered COVID-19. The DID analysis revealed a mean increase of 0.52 (95%CI 0.49-0.55) contacts following COVID-19, primarily driven by primary healthcare contacts. The largest diagnosis-specific differences were observed for reactions to severe stress and adjustment disorders (ICD-10=F43; DID = 0.03; p < 0.001) and other anxiety disorders (F41; DID = 0.02; p < 0.001).

Conclusions: We demonstrate an increased mean number of healthcare contacts after COVID-19 for individuals with documented COVID-19 compared to individuals without. This could be important information for post-pandemic planning and future pandemic preparedness.