Overactive bladder (OAB) and cognitive impairment (CI) are common in the elderly population and often occur concurrently. OAB and urinary incontinence are more severe and carry a higher burden in this population as well, related not only to reduced quality of life but also increased risk of falls and related fractures, urinary tract infections and health care utilization.^1–3 Accordingly, OAB treatment options appropriate for older patients are important.

Anticholinergics, a longtime mainstay of OAB pharmacotherapy, are often problematic in older patients. The Beers Criteria caution against use of this drug class in older patients due to cognitive side effects and polypharmacy risks, and increasing evidence points to a strong association between anticholinergic use and dementia.^4–6 Sacral neuromodulation (SNM) avoids these risks while offering an alternative to other third-line therapies (onabotulinumtoxinA, peripheral tibial nerve stimulation), which require indefinite ongoing procedural visits. However, SNM carries separate concerns in CI patients, predominantly related to device operation. Furthermore, SNM outcome assessment relies heavily on subjective records (eg bladder diaries) that can be unreliable in patients with cognitive dysfunction.

The AUA/SUFU (Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction) OAB Guideline discusses the need for a certain cognitive ability to engage with and maintain therapy, but there are at present no data to guide cognitive thresholds or inform the need for preoperative cognitive assessment for various therapies. Herein we present our preliminary data investigating the role of CI and SNM outcomes and discuss best practice considerations.

Preliminary Data

We recently performed a retrospective review of 510 patients aged 55 and older who underwent test-phase SNM (peripheral nerve evaluation [PNE] or stage 1) for refractory OAB between 2014 and 2021. Using electronic medical record ICD diagnostic codes, we identified 52 (10.1%) patients with a CI diagnosis, including mild CI and/or an active dementia medication. An additional 30 (6.0%) patients were later diagnosed with CI at a median 18.5 months after SNM test-phase.

Patients with CI diagnosis proceeded to permanent SNM implant (demonstrating >50% improvement in symptoms) at similar rates to patients without impairment (76.9% vs 85.4%, p=0.16). Multivariable logistic regression analysis identified PNE, age and baseline B3-agonist use, but not CI, as independent negative predictors of proceeding to implantation. However, on sub-analysis, patients with Alzheimer’s disease were less likely to proceed to permanent implant compared to patients with other CI diagnoses (2 [33%] vs 38 [83%], p=0.11), although event rate was low and not statistically significant. This suggests that SNM response may be poorer with more severe dementia or certain neurocognitive diagnoses. Further research is necessary to better elucidate if severe CI impacts SNM outcomes.

Explant rate was 12.1% and did not differ based on the presence of CI. Overall, the majority of patients discontinued or did not restart anticholinergic OAB medications (64.3%), and few proceeded to intradetrusor chemodenervation (8.3%).

Notably, the study population represents an older cohort with refractory OAB deemed to be appropriate SNM candidates by their treating urologist, suggesting that no obvious CI was noted during evaluation prior to SNM. Despite this, 10% of patients met criteria for CI and this suggests that focused preoperative evaluation of cognition may be helpful. The retrospective methodology is a second study limitation as diagnosis codes incompletely capture CI and lack gradation of dementia severity. It is possible that additional study with more detail regarding CI severity may show that SNM outcomes are impacted as dependent on severity level.

We are currently conducting a prospective observational study investigating the impact of cognitive function on SNM outcomes in older patients. As part of this study, we are performing Montreal Cognitive Assessment (MoCA) examinations on patients aged 60 years and older who are undergoing test-phase SNM for refractory OAB.

As presented at the 2022 AUA meeting, interim analysis of the first 27 patients surprisingly showed that two-thirds of patients met the threshold for CI on MoCA (score <26/30), with median score 24 (range 14–29). Furthermore, just 5 of the 16 patients with a MoCA score suggesting impairment had a formal dementia or CI diagnosis documented in their chart. Initial analysis demonstrates that implant rates and patient-reported outcomes are similar.

Combined, our data demonstrate a high incidence of CI in older patients pursuing SNM for refractory OAB but suggest that CI should not necessarily preclude urologists from offering SNM therapy. Further study is certainly needed to shed light on appropriate cognitive thresholds for successful SNM and to better understand the impact of CI on longer term outcomes.

Best Practice Considerations

Until more comprehensive data are available, we recommend the following best practice considerations when considering SNM for older patients with OAB.

Consider utilizing quick screening tools for CI in at-risk patients

While the impact of CI on SNM outcomes is unclear, CI assessment is beneficial and may allow for additional measures to ensure adequate support, educational resources and guide followup plan. Suggested quick cognitive screening options include the MiniCog (3 minutes), Mini Mental Status Examination (10 minutes) and MoCA (10 minutes).

Evaluate the caregiver/home environment

Some patients with significant CI may be unable to easily adjust SNM settings or keep accurate bladder diary records that are important during the testing phase. However, if patients have involved and motivated caregivers, SNM may still be a reasonable option that can help urologists address the significant impact that urgency urinary incontinence has in this patient population and reduce caregiver burden. In these cases, motivated family members and caregivers can record bladder diaries during the test-phase and manage the device adjustments after implant.

Consider PNE testing phase

Office-based PNE is a convenient, low risk option for test-phase SNM. An advantage in older patients with CI is the ability to avoid possible cognitive risks associated with anesthesia/sedation required for Stage 1 testing. The reported success rates of PNE are traditionally lower compared to Stage 1, although still high.

Ensure close postoperative surveillance

Patients with CI may require more frequent, scheduled followup visits to ensure maintenance of therapeutic benefit and appropriate device use. Further, CI degree can be reassessed in these settings to facilitate plan adjustments as necessary.