# A qualitative burden of disease study in patients with invasive Escherichia coli disease aged ≥ 60 years in the United States

## TL;DR

This study explores the physical, social, and psychological impacts of invasive Escherichia coli disease in older U.S. patients and how well standard quality of life tools capture these effects.

## Contribution

The study provides new qualitative insights into the HRQoL impacts of IED in older adults and identifies gaps in generic HRQoL instruments.

## Key findings

- IED significantly affects daily routines, movement, sleep, and causes exhaustion and pain.
- Most HRQoL impacts were captured by SF-36 and EQ-5D, but some IED-specific impacts were not.
- Patients frequently reported neurological and mental impacts not measured by standard tools.

## Abstract

Invasive Escherichia coli disease (IED) comprises a diverse range of severe infections caused by E. coli, mainly affecting neonates and older adults, and is associated with severe and sometimes fatal outcomes. This study aimed to evaluate signs and symptoms associated with IED, and to assess the impact of IED on health-related quality of life (HRQoL) among older patients. Furthermore, we examined how generic patient-reported outcomes questionnaires capture experiences of patients with IED.

A cross-sectional qualitative study consisting of semi-structured interviews was conducted. Participants aged ≥ 60 years who met the IED clinical case definition were enrolled within 2 weeks after the disease episode and asked to describe IED signs and symptoms and HRQoL impact through open-ended questions. The interview transcripts were analyzed using NVivo 12 and a conceptual model was built. The concepts for impacts identified by participants with IED were then compared with the concepts routinely assessed by two generic HRQoL instruments: the 36-Item Short Form Survey (SF-36) and EuroQol 5-Dimension (EQ-5D).

Of 80 patients screened, 43 met inclusion criteria and 16 consented to participate in the study. The interviews showed that IED affected daily routines and activities (n = 13), ability to move and sleep (both n = 11), and caused exhaustion (n = 10) as well as constant pain (n = 9). Most HRQoL impacts identified were also measured in SF-36 and EQ-5D, but concepts specific for patients with IED, not measured in SF-36 and EQ-5D, were also recognized.

IED was shown to cause substantial physical, social, and psychological impacts in patients. This burden was especially apparent in review of patient self-reports for concepts that are part of generic HRQoL instruments (SF-36, EQ-5D), and patients also frequently reported neurological/mental impacts. Further, this study provides valuable qualitative data that may be useful for future research in developing a disease-specific instrument for the assessment of HRQoL in patients with IED.

The online version contains supplementary material available at 10.1186/s12879-025-11628-5.