Relationship between multimorbidity, SARS-COV-2 infection and long COVID: a cross-sectional population-based French...

Understanding the risks of COVID-19-related consequences for vulnerable groups such as people with multimorbidity is crucial to better tailor health care and public health measures. The main objective of this study was to explore the association between multimorbidity and WHO-defined post-COVID condition (PCC), while also considering the association with SARS-COV-2 infection given that the infection is a prerequisite of PCC.

This population-representative cross-sectional study was conducted in the general adult population in mainland France between 29 August and 31 December 2022 (N = 1813). The analyses of the association between multimorbidity (defined as disease count and most prevalent dyads/triads) and PCC or SAR-COV-2 infection were adjusted for age, sex, socioeconomic variables and number of infections (for PCC only) using adjusted Poisson regression with robust variance.

The study population had a mean age (SD) of 53 (± 18.5) years, while 53.6% were women. The likelihood of SARS-COV-2 infection increased with disease count but was only significant for ≥ 4 diseases. Five dyads and one triad presented a higher risk; almost all included anxiety. The likelihood of PCC increased with disease count, prevalence ratios (PRs) (95% CI) for 1, 2-3 and ≥ 4 diseases versus 0 were 1.90 (1.16-3.13), 3.32 (2.07-5.35) and 5.65 (3.41-9.38), respectively, and for 19 of 26 most prevalent dyads and the triad. The association was strongest for cardiac rhythm disorder and either low back pain (PR (95%CI) 4.17 (2.03-8.53)) or anxiety (PR (95%CI) 3.73 (1.98-7.01)).

Multimorbidity, most frequently in combination with anxiety or low back pain, presented a significant association with PCC beyond that of SARS-CoV-2 infection underscoring the importance of implementing strategies to prevent and manage persistent symptoms in vulnerable groups.