Investigators evaluate sacral neuromodulation in nursing home residents

Leo Dreyfuss, MD

In this interview, Leo Dreyfuss, MD, discusses the Neurourology and Urodynamics paper, “Sacral neuromodulation in nursing home residents: Predictors of success and complications in a national cohort of older adults.” Dreyfuss is a urology resident at NewYork-Presbyterian Hospital/Weill Cornell Medical, New York, New York.

Please describe the background for this study.

Overactive bladder is a common problem, particularly for older adults. And for these patients, management can be challenging. They're on many medications, which can have interactions, and they're at particularly high risk for cognitive side effects associated with some anticholinergic medications. And for these reasons, actually, the new OAB guidelines, which were released just a couple of weeks ago, have gone away from this regimented, stepwise approach and introduced a more patient-centered approach, where the clinician can engage in shared decision-making. [The guidelines] actually state that, for patients who are unable or unwilling to try out behavioral or pharmacologic therapy, which are historically the first- and second-line options, clinicians can actually go straight into previously known as third-line therapies, or minimally invasive therapies for overactive bladder is what they're called now, sacral neuromodulation being one of these options. Unfortunately, for clinicians who treat a lot of older adults, there's actually quite limited literature to support the use of these minimally invasive therapies in this population. The reason for this is because most studies that have been performed in these therapies tend to focus on younger individuals who are under the age of 65. This is likely due to some clinician bias or concern for adverse events following these minimally invasive therapies in older adults who we know are at higher risk for complications after invasive procedures. So with this in mind, we thought it would be beneficial to perform this study in a population of nursing home residents. These patients tend to be highly frail, older adults who we think stand to greatly benefit from these therapies.

What were some of the notable findings? Were any of them surprising to you and your coauthors?

Overall, we looked at about 1089 nursing home residents who were included in this study. The mean age was around 78, and about 30% were moderately to severely frail. So right off the bat, this is one of the largest series of older adults who underwent sacral neuromodulation. Of those patients, despite their preoperative comorbidities and characteristics, about 58% went on from test neuromodulation procedure, PNE, or stage 1 permanent tine lead placement, to device implant. Looking at some of the other single-institution retrospective series that have focused on older adults, that rate of 58% is a little bit lower. But it's important to recognize that those studies are single-institution, centers of excellence reports, and this study reflects real-world data across the entire United States. If you compare those findings to other studies that have used claims-based analyses to ask similar questions, the rates are actually higher in this population of nursing home residents. Moving on to one of our other secondary outcomes, device explantation, of the 58% of residents who were implanted, about 10% had an explant or revision procedure within a year after implant. And again, this is quite comparable to other claims-based analyses as well as prospective studies that have focused on younger individuals. So I think these findings overall are reassuring and support the use of neuromodulation in this population. That said, we did find there was a 30-day complication rate of about 40%, which I think jumps out of the page and seems quite high. If you look at the individual complications, the majority of them were urinary tract infections, and a lot of them were sort of minor complications. We also can't necessarily know if all of these complications are directly attributable to the index procedure. In this population of advanced age, highly frail adults, it's possible that there's some expected level of just coincident adverse events unrelated to these procedures. So it's good to keep that in mind. And again, while we don't have access to certain important data such as patient-reported outcomes, this is a limitation of any claims-based analysis. We do think that these data are reassuring and support the use of neuromodulation in a population who may have limited options otherwise.

The success rate of PNE for residents who progressed to device implant was lower than that of Stage 1. Can you elaborate on possible reasons for this difference?

In the study, about two thirds of the residents did undergo PNE and one third underwent Stage 1, and those who underwent PNE were less likely to progress to device implant than Stage 1. While the 2 groups, looking at table 1, were fairly well balanced, those who underwent Stage 1 were more likely to be female, and looking at our primary outcome of device implant on multivariable analysis, female sex was an independent predictor of progression from test period to device implant. And this could be due to some inherent differences between the PNE leads and Stage 1 leads. It's not necessarily a new finding. There's a retrospective study that looked at this outcome and found that patients who underwent PNE were less likely to report subjective symptom improvement compared to stage 1; it's possible that these leads become dislodged or prone to migration, which can result in false negative results. It's also possible that patients who undergo Stage 1, because it's a more invasive procedure, they may be just inherently more invested in the neuromodulation treatment, more likely to report subjective symptoms and progress to device implantation. That said, this is an evolving field. I know there are some emerging technologies that have been recently developed that are meant to improve the performance of PNE performed in the office setting. As those technologies become utilized more often, it'll definitely be important to re-perform these analyses in updated data once those technologies have had a chance to percolate into the field. It'll be interesting to see if anything changes.

One-year explant/revision rates were significantly higher for single-stage procedures vs PNE. What aspects of the single-stage approach do you think might contribute to this finding?

Yes, about 25% of stage 1 procedures were performed with simultaneous device implantation, and about 20% of these residents ultimately progressed to device explant or revision within 1 year. We found that single-stage procedures were an independent predictor of device explant or revision compared to stage 1 or PNE. So there's definitely some potential cost savings associated with single-stage procedures. There was actually an interesting analysis out of Virginia Mason in 2020 that cited some cost savings associated with this approach. However, in that study, they assumed that only 1 in 15 patients would ultimately go on from implant to explant, which is quite a bit different from the 1 in 5 patients who ultimately underwent explantation after single-stage procedures in this study. So I think these findings suggest that for clinicians who treat a lot of older adults with neuromodulation, caution should be exhibited when recommending the single-stage approach. However, I think future studies are needed to look at the potential role of the single-stage approach in younger populations or healthier populations.

Beyond the results presented in this study, are there any additional insights you gained from this study that you believe would be valuable for future research on SNM in older adults with OAB?

Overall, I think this study will allow clinicians to better advise patients in the slightly complex landscape of OAB therapies, particularly as the new OAB guidelines abandon the old stepwise approach in favor of a more patient-centered approach that allows for earlier use of these minimally invasive therapies in the treatment paradigm. Obviously, sacral neuromodulation is a costly procedure. And while cost effectiveness was beyond the scope of this study, I think future studies looking at the cost effectiveness of this procedure in older patients who may have limited life expectancies is important. It's also important that researchers look at patient-reported outcomes and social support as possible factors that may impact these types of studies going forward. That said, we did show that outcomes in this study were comparable to previous claims-based cohort studies looking at similar outcomes in younger populations. And while sacral neuromodulation may not be appropriate for all nursing home residents or all older adults, we think that it may be a good option for certain individuals, pending they have appropriate life expectancy and social support and other factors. And certainly, we would not want to systematically exclude these patients based solely on their chronological age, from this potentially life-improving treatment.

This transcription was edited for clarity.