Risk of new diagnoses and exacerbations of chronic conditions after SARS-CoV-2 infection: a systematic review update

The large number of individuals infected by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) necessitates estimation of the future healthcare burdens. We updated a systematic review examining associations between SARS-CoV-2 infection and the incidence of new diagnoses and exacerbations of chronic conditions. Updated searches were run September 4, 2024 in MEDLINE and EMBASE for observational studies utilizing a control group, addressing confounding by sex and comorbidities, and reporting age-stratified data for ≥1 chronic condition category (n=12) or condition type (n=46) of interest. Two human reviewers screened 50% of identified titles/abstracts, after which DistillerAI acted as second reviewer. Two human reviewers assessed full-texts of relevant studies for eligibility based on a priori criteria. One reviewer extracted data and assessed risk of bias; a second reviewer verified results data and risk of bias assessments. Pooled hazard ratios (HRs) were estimated with inverse-variance weighting, and two reviewers used GRADE to assess certainty in our conclusions of little-to-no association (i.e., HR 0.75 to 1.25), small-to-moderate association (i.e., HR 0.51 to 0.74 or 1.26 to 1.99), or large association (i.e., HR ≤0.50 or ≥2.00). We identified 46 new studies and brought forward 23 studies from the original review. After SARS-CoV-2 infection, there is probably increased risk of new diagnoses for several chronic conditions, especially in adults (18-64 years) and older adults (≥65 years). Most findings are based on data from earlier pandemic periods; their relevance to contemporary populations is uncertain due to differences in vaccination rates, implemented public health measures, and circulating variants of concern.