Hypothesis / aims of study
To determine whether post Botox urinary tract infection associates with worse outcome. Botox is increasingly used for female OAB where UTI commonly associates. Given severe morbidity associated with UTI, should Botox be avoided among those at risk?
Study design, materials and methods
1033 consecutive, single centre women with predominant idiopathic refractory urge had 1st Botox injection; 75% of data was prospective. On the day of 1st visit all had had aseptically collected catheter urine analysed with culture/microscopy. Collection was repeated at time of Botox treatment if infection suspected; Positive culture defined as single organism >10 8 CFU/L (cut off of > 10 2 wasn’t used) and > 10 x 10 6 WCC /L, Post treatment, all had 5 days of preventive antibiotic; trimethoprim/sulfamethoxazole or nitrofurantoin. Patients were given pathology request forms and warned they may be symptomatic. All positive cultures were treated. Review occurred at ~ 10 days, ~ 3 months and variably later. Treatment response was initially a 4 and later both 4 and 7 point Global PGI scale (1). (The 2 measures strongly correlate; Spearman 0.795 P<0.001 and associate; P<0.001 (Pearson Chi Sq). Calculated required sample size; 355.
Treatment success, defined as; ‘>= much improved’ was calculated for the whole cohort according to different pre and post-treatment infection conditions and then again only amongst those who had post-treatment positive culture up to 92 days. These were compared to success for the remainder of the cohort in each case.
Pre-treatment patients were divided into those “pre-existing”; (a past history infection (proven/unproven) or a positive-culture at time of treatment) and “new-onset”- with no prior history. Multivariate logistic regression (MVA) for success was performed. Also MVA was conducted for positive-culture up to 92 days.
Results
• Table 1 shows univariable modelling comparing treatment success amongst the entire cohort for various pre-treatment situations. In summary, a positive post-treatment culture by 92 days associates with failure. “New-onset’’ (ie; absent “pre-existing” infection) associates with success only if there is no post-treatment positive culture, where, if there is, failure associates. “Pre-existing” does not associate with failure regardless of the post-treatment infection situation and this was noted for all time periods between 0-200 days post-treatment.
• “New-onset” failure was noted between >32 - <200 days post-treatment
• No ‘’new-onset” had a positive-culture occurring before 35 days. ‘’Pre-existing’’ did.
Of the 192 with post-treatment positive culture <=92 days, 52.6 % (101) had been additionally tested at the time of treatment. Within this group success was compared;
• Of 98 with past infection history; 50.0% (49/98) had success vs 39.4% rest (37/94) (P=0.149)
• “New-onset” success was 35.1% (26/74) compared to all “pre-existing”, 50.8% (60/118) P=0.038
On MVA both a post-treatment positive culture regardless of prior category and also ‘’new-onset’’ infection associated with worse success (Table 2)
The ‘’Pre-existing’’ infection group did not associate when substituted in this model showing: Sig. 0.696, ExpB: 1.100, 95% CI for Exp B: 0.682-1.775
MVA associations with post-treatment positive-culture by 92 days; were age, post-void residual, “pre-existing” infection, inflamed bladder appearance.
All "pre-existing" achieved at least one further positive culture up to 92 days, despite treatment. For both groups, prevalence rose over time. Later interventions limited follow-up.
Interpretation of results
Comparison with other studies suggests the effect of post-Botox infection on outcome is controversial (2,3). Post-Botox positive urine culture associated with worse outcome. Within the subgroupings “New-onset” only associated, where infection onset was delayed > 32 days. This, as well as difficulties detecting and defining infection in OAB may account for differing study findings.