Hypothesis / aims of study
Vesical dysfunction is well documented in HTLV-1 infected patients. Anticholinergic drugs are widely used to treat overactive bladder symptoms, but the frequence of adverse events such as constipation, dry mouth, visual and mental disturbances, and even urinary retention, limit the use of these medications. HTLV-1 infected patients usually have sicca syndrome symptoms and constipation due to neuro-immune-inflammatory reasons. This fact restrains the adherence of the HTLV-1 infected patients to the anticholinergic drugs. We have previously shown, in an open label study, parasacral transcutaneous electrical nerve stimulation (PTENS) improve the urinary symptoms in HTLV-1 infected patients. We hypothesized that this kind of treatment could be as effective as anticholinergics in controlling overactive bladder symptoms in HTLV-1 infected patients with more tolerable profile of adverse events.
The aim of this study is to compare the efficacy of treatment with parasacral transcutaneous electrical nerve stimulation (PTENS) with oral darifenacin for overactive bladder (OAB) in HTLV 1 infected patients.
Study design, materials and methods
Proof-of-concept randomized clinical trial carried out at the HTLV-1 Outpatient Clinic. All the patients are participants of a major cohort study enrolling exclusively HTLV-1 patients and they are evaluated by a multidisciplinary team twice a year. Overactive bladder was defined according to ICS criteria as the presence of urinary urgence with or without incontinence, usually accompanied by increased daytime frequency and/or nocturia, in the absence of urinary tract infection or other detectable disease. Sociodemographic and clinical data were collected and enregistered in an online data base platform (RedCap). Overactive Bladder Symptoms Score questionnaire was applied before and after treatment to evaluate each group of treatment: group1 (G1 – Darifenacin) and group 2 (G2 – PTENS). Patients in the G1 received Darifenacin 15mg daily for 2 months and patients in G2 were treated with PTENS (10Hz, 500µs) sessions 3 times a week up to a total of 20 sessions. Sample size calculation was performed considering α = 0.05 and power of 80%. Estimate response in each group was 60% and 50% for G an G2, respectively. Random sequences were generated by SPSS statistical package. Statistical analyses were carried out using SPSS package software, version 29 (IBM Inc).
Results
Forty-six patients were enrolled to participate in the study. One refused to participate due to the side effects of the medication and 3 refused physiotherapeutic treatment due to the impossibility of attending the 3 days a week proposed for treatment. Six patients abandoned treatment with Darifenacin due to adverse events and 1 abandoned treatment with PTENS due to unacceptability of the diagnosis. Demographic, socio-economic and general characteristics of the 2 groups are presented on table 1. There was no difference regarding age, female sex prevalence, social income, schooling and OABSS at admission. There was a predominance of Afro-Americans in both groups, but more self-declared black people was significantly prevalent in G2. As observed in table 2, the initial median (interquartile range – IQR) OABSS was 11.19 (9.5 – 14.0) in G1 and 10.67 (8.0 – 12.7) in G2. After treatment, it was observed that OABSS were 6.29 (3.7 – 9.8) in G1 and 5.79 (4.2 – 8.2) in G2. There was no statistically significant difference between the two groups - P = 0.794. The analysis of each symptom compounding OABSS could demonstrate there was a reduction in daytime frequency, nocturia, urgency and incontinence after therapy (P < 0.05).
Interpretation of results
In the present study, we investigated the effect of parasacral transcutaneous electrical nerve stimulation and drug therapy (Darifenacin) in the treatment of OAB of patients with HTLV-1. To our knowledge, no previous studies have compared the therapeutic effects of Darifenacin and PTNS in patients with HTLV-1. The results showed significant differences before and after treatment in the groups in relation to all variables related to the severity of urinary symptoms, regardless of the form of treatment.
Our study has shown that both proposed treatments were effective in the treatment of OAB, reinforcing the hypothesis that transcutaneous nerve stimulation of the parasacral region reduces the symptoms of overactive bladder as much as darifenacin.
Regarding electrostimulation, studies on PTENS have been promising in the treatment of OAB Syndrome and it is a technique characterized as simple, non-invasive and without major side effects, which facilitates the acceptance of the therapy by the patients. Although PTENS therapy has demonstrated good results, these are restricted only to women, young people and children, with no neurogenic cause in most of them, evidencing the scarcity of studies in elderly individuals, with neurogenic bladder and infected with HTLV-1, who could benefit from the same technique. Based on this, the present protocol can reinforce with the literature on the effect of transcutaneous electrical nerve stimulation applied in the parasacral region on urinary symptoms.