Mapping 2-Year Psychiatric and Neurologic Risks After Infections Across Body Systems and Age Groups.

Abstract

Importance Infections are associated with postacute psychiatric and neurologic disorders, but whether risks generalize across infections affecting different body systems and how they vary by age remain unclear. Objective To map risks of 14 psychiatric and neurologic disorders among patients hospitalized with infections across 10 body systems and 4 age groups. Design, Setting, and Participants This was a retrospective multicohort study using propensity score matching of patients hospitalized between 2014 and 2018, with a 2-year follow-up. Patient data were taken from 62 health care organizations within the TriNetX US Collaborative Network. Included were cohorts of individuals hospitalized with an infection compared with each other, with individuals hospitalized for noninfectious causes, and with the general population. Data were analyzed from May 2024 to March 2026. Exposure Hospitalization with an infection. Main Outcomes and Measures Thirteen neurologic or psychiatric disorders (plus a composite category of cognitive deficits) diagnosed between 1 month and 2 years after hospital admission. Measures included the ratio of restricted mean time lost (RMTL), absolute risk difference, and infection specificity per outcome via network meta-analysis. Results Among 1 062 722 matched pairs of individuals (mean [SD] age, 48.4 [23.6] years; 547 328 female [51.5%]), infections were associated with a greater risk of most disorders. When compared with hospitalization for other causes, RMTL ratios exceeded 1 in 116 of 140 infection-disorder tests; the highest relative risk was observed for encephalitis (eg, among cardiac infections, median RMTL ratio, 6.54; 95% CI, 3.78-11.31; P = 2.0 × 10-11), and the highest absolute risk difference was for cognitive deficits (eg, among cardiac infections, risk difference, 12.37%; 19.08% [95% CI, 18.51-19.65] vs 6.71% [95% CI, 6.36-7.07]). Similar patterns were observed (though with higher RMTL ratios) when patients hospitalized with infections were compared with the general population. Although children also faced increased risks of psychiatric and neurologic disorders after infections, absolute risk differences were significantly lower than those in adults. In 45 head-to-head comparisons (median [IQR] sample, 30 766 [11 856-104 336]), infectious encephalitides were the leading risk factor for 7 of 14 disorders and among the top 3 for 12 of 14 disorders. Other infectious risk factors were disorder specific. Conclusions and Relevance Results of this multicohort study suggest that patients hospitalized with infections across all body systems had an associated increase in psychiatric and neurologic diagnoses over the subsequent 2 years, particularly in adults. Infectious encephalitides carried the greatest associated excess risk. Taken together with the existing literature, these findings identify infections as important risk factors for brain health conditions.