Is a bladder function test indicated for a patient with recurrent overactive bladder (OAB) symptoms, despite initial success with Vesicare (Solifenacin) and failure of Betmiga (Mirabegron), with a history of Diabetes Mellitus (DM) and significant mobility issues?

Bladder Function Test for Recurrent OAB with Diabetes and Mobility Issues

Urodynamic testing is indicated for this patient with recurrent OAB symptoms, diabetes mellitus, and mobility limitations who has failed multiple pharmacological therapies. 1

Rationale for Urodynamic Testing

The 2024 AUA/SUFU guidelines specifically support urodynamic testing in this case for several key reasons:

1. Treatment Failure: The patient has experienced recurrence of OAB symptoms despite initial success with solifenacin 10mg and subsequent failure of mirabegron (Betmiga), indicating an inadequate response to standard pharmacological management 1

2. Diabetes Mellitus: The patient has long-standing diabetes, which is specifically mentioned in guidelines as a condition warranting PVR assessment and potential urodynamic evaluation 1

3. Mobility Limitations: The patient uses a wheelchair and has difficulty walking, which may complicate voiding dynamics and contribute to the clinical picture 1

4. Post-void Residual: The ultrasound shows a post-void residual of 60cc, which while not severely elevated, should be monitored in the context of diabetes and mobility issues 1

Diagnostic Considerations

Current Findings Support Further Testing

• Ultrasound shows normal kidneys and bladder with no hydronephrosis, calculi, or growth
• Pre-void volume of 259cc and post-void residual of 60cc
• Good flow reported clinically, but no objective measurement provided
• Failed response to both antimuscarinic (solifenacin) and beta-3 agonist (mirabegron) therapies

What Urodynamic Testing Will Provide

• Differentiation between detrusor overactivity and other causes of symptoms 1
• Assessment of detrusor contractility, which is particularly important in diabetic patients who may have impaired detrusor function 1
• Evaluation for possible neurogenic lower urinary tract dysfunction related to diabetic neuropathy 1
• Quantification of bladder capacity, compliance, and voiding pressures 1

Specific Urodynamic Findings to Anticipate

In patients with diabetes and OAB symptoms, urodynamic studies commonly reveal:

• Detrusor overactivity (present in approximately 48% of diabetic patients) 1
• Impaired detrusor contractility (present in approximately 30% of diabetic patients) 1
• Poor bladder compliance (present in approximately 15% of diabetic patients) 1
• Altered bladder sensation, which may present as delayed first sensation 1

Clinical Implications of Testing

The results of urodynamic testing will guide the next steps in management:

• If significant detrusor overactivity is confirmed: Consider third-line therapies such as intradetrusor onabotulinumtoxinA or neuromodulation therapies 2
• If impaired detrusor contractility is identified: Adjust treatment approach to avoid worsening retention 1
• If mixed findings are present: Tailor therapy to address the predominant dysfunction 1

Potential Pitfalls and Caveats

• Urodynamic testing should be performed by experienced clinicians familiar with interpreting results in the context of diabetes and mobility limitations
• A single urodynamic study may not capture the full spectrum of bladder dysfunction, particularly if symptoms are variable
• The patient's mobility limitations may affect positioning during testing and should be accommodated
• Results should be interpreted in the context of the patient's symptoms and quality of life impact 3

In conclusion, given the patient's recurrent OAB symptoms despite multiple medication trials, presence of diabetes mellitus, mobility limitations, and the need to guide next therapeutic steps, urodynamic testing is clearly indicated according to current guidelines 1.