# Definitions and Scope of Complicated UTI — IDSA 2022

## Definition of Complicated UTI

The IDSA guideline defines **complicated urinary tract infection (cUTI)** based on observable clinical signs indicating that the infection has extended beyond the bladder, rather than relying solely on host risk factors. This represents a shift from traditional definitions that automatically classified certain populations (e.g., men, patients with diabetes, immunocompromised patients) as having complicated disease.

### Clinical Features of Complicated UTI

A cUTI is characterized by any of the following:

- **Systemic symptoms:** Fever, chills, rigors, flank pain, costovertebral angle (CVA) tenderness
- **Urinary tract devices:** Indwelling urinary catheters, ureteral stents, nephrostomy tubes
- **Obstruction or retention:** Urinary calculi (stones), severe benign prostatic hyperplasia (BPH)
- **Bacteremia with a urinary source:** Positive blood cultures with a urinary tract pathogen

### Uncomplicated UTI (for Distinction)

An uncomplicated UTI is limited to the lower urinary tract (bladder) without systemic signs. Both men and women can experience uncomplicated UTI under this updated framework.

## Scope of the Guideline

### Clinical Questions Addressed

The guideline addresses three primary clinical questions:

1. **Empiric antibiotic selection:** In patients with cUTI, which classes of empiric antibiotic therapy should initially be prioritized?
2. **IV-to-oral transition:** In patients with cUTI treated initially with parenteral therapy, when should transition to oral antibiotics occur?
3. **Treatment duration:** What is the optimal duration of antibiotic therapy for cUTI?

### Population

- **Included:** Adults (women and men) with cUTI in both inpatient and outpatient settings, including acute pyelonephritis
- **Included:** Patients with and without Gram-negative bacteremia from a urinary source

### Exclusions

The guideline recommendations may not fully apply to the following populations, who may require individualized management:

- Pregnant or lactating patients
- Patients with indwelling urinary catheters (may need individualized plans)
- Severe sepsis or septic shock
- Immunocompromising conditions (e.g., organ transplant, active chemotherapy)
- Severe chronic kidney disease
- Renal abscesses or perinephric abscesses
- Chronic pyelonephritis
- Recent urologic procedures
- Complete urinary tract obstruction
- Bacterial prostatitis, epididymitis, or orchitis
- Fungal UTI

### Note on Prostatitis

Men with febrile, bacteremic UTI in whom acute bacterial prostatitis is suspected may benefit from a longer treatment duration (10-14 days), although optimal evidence for this subgroup is lacking.

## Agents Not Recommended for Complicated UTI

The following agents should **not** be used for complicated UTI due to inadequate tissue penetration for infections extending beyond the bladder:

- **Nitrofurantoin:** Achieves high bladder concentrations but poor renal/tissue penetration; appropriate only for uncomplicated cystitis
- **Oral fosfomycin (single-dose):** Insufficient evidence to support use in cUTI; approved only for uncomplicated cystitis

## Limitations

- This is the first IDSA guideline specifically addressing complicated UTI management, and evidence for some subpopulations remains limited.
- Imaging indications for suspected cUTI are not addressed in these recommendations (a future clinical question).
- The definition of complicated UTI remains debated across guidelines and clinical trial populations.
- Recommendations are based primarily on studies of community-acquired gram-negative uropathogens; healthcare-associated or multidrug-resistant infections may require different approaches informed by local resistance data.
