Long-term health outcomes of Shiga toxin-producing Escherichia coli O157 (STEC O157) infection and STEC-associated haemolytic uraemic syndrome (STEC-HUS), Wales, 1990-2020.

Background: Information on sequelae of Shiga toxin-producing Escherichia coli (STEC) O157 infection is limited to follow-up of paediatric haemolytic uraemic syndrome (HUS) cases. We investigate recorded long-term health outcomes experienced by individuals exposed to STEC O157 and STEC-HUS up to three decades on.

Methods: We compared acute or new onset of chronic outcomes in individuals ≥ 1 year after STEC O157 or STEC-HUS to unexposed general population comparators between 01/01/1990-01/01/2019. The unexposed were their age- and sex-equivalents (4:1 matching ratio) and assigned the same study entry date. Outcomes were identified in primary and secondary care and categorised as kidney, neurological, cardiac, gastrointestinal, respiratory, or endocrine. Hazard ratios (HRs) and 95% confidence intervals (95% CI) were calculated using Cox regression.

Results: Of 1,245 individuals with STEC O157, 65 developed HUS (5.2%). Individuals with STEC O157 were more likely to experience kidney (adjusted (a)HR: 1.9, 95% CI: 1.1-3.3), gastrointestinal (aHR: 1.7, 95% CI: 1.1-2.5) and respiratory (aHR: 1.4, 95% CI: 1.2-1.6) outcomes compared to the unexposed, on average between 3.4-11 years after exposure. Gastrointestinal (HR: 7.7, 95% CI: 2.6-23), kidney (HR: 5.5, 95% CI: 1.6-19), cardiac (HR: 5.1, 95% CI: 1.1-23) and respiratory (HR: 1.9, 95% CI: 1.1-3.1) outcomes were more common in the STEC-HUS cohort and occurred sooner, on average after 2.7-4.8 years.

Conclusions: Long-term complications were nearly twice as likely in the STEC O157 cohort, and as many as eight times more likely following STEC-HUS. We recommend that those exposed to STEC be monitored for at least five years for late-emerging kidney and extrarenal complications.