Hypothesis / aims of study
OnabotulinumtoxinA (BTX-A) injections are commonly used third-line therapies for treatment of overactive bladder (OAB). The most common side effects, urinary retention and urinary tract infections (UTIs), may deter some providers from performing this treatment in the elderly, even though rate of OAB increases with age with associated increased morbidity and decreased quality of life. We examine the rate of complications and efficacy in patients 80 years or greater versus patients between the ages of 50-70 years receiving intradetrusor BTX-A for the treatment of OAB.
Study design, materials and methods
A retrospective case series of patients who underwent BTX-A injection at a tertiary care center from January 2007 through September 2017 was conducted. Patients were stratified into an “elderly” cohort, greater than 80 years old (EC), and a comparator “younger” cohort (YC) 50-70 years. Demographics, clinical characteristics, post-BTX-A complications including 30 day rehospitalization, urinary tract infections, and symptomatic urinary retention requiring self- catheterization, and patient-reported satisfaction following treatment were collected. Statistical analyses included chi-square and t-tests for patient characteristics and univariable and multivariable logistic regression models for outcomes.
Results
The EC consisted of 62 patients (48%) with a mean age of 84 years, ranging from 80-94 years, versus the YC of 68 patients (52%) with a mean age of 59 years, ranging from 50-70 years, for a total of 130 patients (Table 1). Among EC patients, 76% had comorbid conditions (47% moderate to severe), and in the YC, 65% had comorbidities (31% moderate to severe) (p = 0.24). Complication rates between both groups were 23% for the EC and 16% for the YC (p = 0.36) (Table 2). Among the EC, 11% developed difficulty voiding require clean intermittent catheter (CIC) use versus 4% in the YC (p = 0.14). UTI was seen in 6% of the EC and 7% of the YC (p = 0.84). When examining the characteristics of the patients in the YC who developed difficulty voiding requiring CIC, all 3 of these patients (4%) had a history of a prior incontinence surgery. In total, 14 patients in the YC had an incontinence procedure. 3 of these 14 patients required (CIC), compared to 0 of the 54 patients who did not have an incontinence procedure (p= 0.005). All three patients in the YC who required CIC had a diagnosis of OAB wet and none of them had a pre-existing neurological condition. 2 patients received 100 units of BTX-A while one received 200 units of BTX-A. In the EC, 7 patients had urinary retention (11%). 3 were male and 4 were female. All of these patients had a diagnosis of OAB-wet. 2 of them had a prior neurological condition (cauda-equina syndrome). 5 of these patients received 100 units of BTX-A and 2 received 200 units of BTX-A. With respect to efficacy, 47% of the EC reported satisfaction after their final treatment, versus 53% of the YC (p = 0.31).
Interpretation of results
The rates of our patients developing difficulty voiding post operatively requiring CIC is comparable to published data based on aged matched cohorts. Furthermore, the UTI rate of 6% in the EC and 7% in the YC is also similar to other published series. In our YC, it is notable that the three patients who required CIC post operatively also had a prior anti-incontinence procedure and that none of the patients in that cohort who did not have an anti-incontinence procedure required postoperative CIC. We examined the incidence of other pelvic surgeries in the EC and could not make a similar interpretation. The use of 100 units of BTX-A vs 200 units of BTX-A was also surgeon dependent.