Subset of Patients Hospitalized With cUTI May Qualify for Outpatient Care

Roughly 1 in 5 patients hospitalized for complicated urinary tract infection (cUTI) and treated with intravenous (IV) antibiotics may be eligible for outpatient care, and mean hospital stays ranged from 7.2 to 15.5 days across 5 patient clusters, according to 2 posters presented at IDWeek 2026 in Washington, DC.^1,2 Serena P. Koenig, MPH, MD, of Brigham and Women’s Hospital and Harvard Medical School, presented both posters.

Roughly 1 in 5 Patients With cUTI May Be Outpatient-Eligible

Koenig and colleagues developed a rule-based classification to separate patients who could be treated as outpatients from those who require inpatient care.¹ They identified 8190 adults hospitalized for cUTI with a positive urine culture who received IV antibiotics, using Mass General Brigham electronic health record data from January 2019 to August 2025.

The team built the classification by reviewing structured data and clinical notes from 30 randomly selected patients, then refined it using literature and expert input. Patients were considered outpatient-eligible only if they met every criterion:

• A quick Sequential Organ Failure Assessment (qSOFA) score below 2
• Clinical stability, defined as no life-threatening condition with risk of deterioration and no need for critical or intensive care
• No sepsis
• No moderate-to-severe acute kidney injury or immunosuppression
• No bacteremia
• Ability to tolerate oral medications
• No signs of conditions that may require surgery, such as urinary obstruction or abscess

Between 20% and 30% of patients were classified as outpatient-eligible, and the remainder were classified as inpatient-required. Clinical stability and absence of sepsis were the criteria met least often in the 30-patient sample, at 56.7% and 50.0%, respectively. The classification was built from records at a single health system, and the authors said results from a larger sample are expected.

“Approximately one in five patients hospitalized for cUTI and treated with IV antibiotics may be outpatient-eligible, highlighting the need for effective oral therapies to reduce avoidable hospitalizations,” the authors concluded.

Length of Stay Varies Widely Across 5 Patient Clusters

A second analysis used latent class analysis, a statistical method that groups patients by shared characteristics, to identify clusters among 7344 US adults hospitalized for cUTI who received an IV carbapenem within 1 day before to 3 days after admission.² Data came from Optum’s de-identified Market Clarity data and spanned January 2019 to June 2025. The model identified 5 clusters:

• Cluster 1 had the greatest comorbidity burden and the highest proportion of catheter-associated urinary tract infection.
• Cluster 2 included the oldest patients, with moderate comorbidity, a high proportion with sepsis, and a low proportion with pyelonephritis.
• Cluster 3 had younger patients with moderate comorbidity, a high proportion of females, and high proportions of both sepsis and pyelonephritis.
• Cluster 4 included older patients with low comorbidity, a moderate proportion with sepsis, and a low proportion with pyelonephritis.
• Cluster 5 had younger patients with low comorbidity and a high proportion with pyelonephritis.

Antibiotic resistance risk was high in Cluster 1, moderate in Clusters 2 and 3, and low in Clusters 4 and 5. Mean length of stay (LOS) was longest in Cluster 1 at 15.5 days (95% CI, 13.6-17.4), followed by Cluster 2 at 13.3 days (95% CI, 11.5-15.2) and Cluster 4 at 11.6 days (95% CI, 8.6-14.6). Clusters 3 and 5, the younger and lower-comorbidity groups, had the shortest mean stays: 7.7 days (95% CI, 7.0-8.4) and 7.2 days (95% CI, 6.0-8.4), respectively.

Patients varied widely in resistance risk and LOS, and resistance risk was highest in the clusters with the most comorbidity and the longest stays.

“Substantial heterogeneity exists among US patients hospitalized with cUTI receiving IV carbapenem, with marked differences in antibiotic resistance risk and LOS across clinically distinct subgroups,” the authors concluded. “Antibiotic resistance risk was highest in clusters with highest comorbidity and longest LOS. These findings suggest LOS may be prolonged by the need for IV therapy for highly resistant infections and highlight a potential unmet need for effective oral therapies.”

GSK funded both studies, and several authors are GSK employees or hold GSK stock.^1,2 Analysis Group Inc, a consulting firm, received GSK funding to conduct the studies. Brigham and Women’s Hospital received funding from Analysis Group for both studies, and Mass General Brigham received funding from Analysis Group for the rule-based classification study.

References

1. Koenig SP, Edgecomb A, Joshi K, et al. Rule-based classification to determine outpatient-eligible versus inpatient-required among patients hospitalized for complicated urinary tract infection. Presented at: IDWeek 2026; October 21-24, 2026; Washington, DC. Accessed October 19, 2026. Poster 287.

2. Koenig SP, Joshi K, Joshi AV, et al. Distinct patient profiles among hospitalized patients with complicated urinary tract infection treated with intravenous carbapenems: a machine learning approach. Presented at: IDWeek 2026; October 21-24, 2026; Washington, DC. Accessed October 19, 2026. Poster 286.