Laser Acupuncture Alleviates Symptoms and Improves Quality of Life in Women with Overactive Bladder: A Double-Blind, Pilot Randomized Controlled Trial

Objective The aim of this study was to investigate the clinical efficacy of laser acupuncture for the treatment of women with overactive bladder (OAB) in Taiwan. Methods A double-blind randomized controlled trial was conducted on female patients with OAB symptoms referred from gynecologists, and subjects were divided into two groups using blocked randomization. LaserPan (RJ-Laser, Germany) was applied to seven selected acupuncture points. The subjects received laser acupuncture 3 times per week for 3 weeks, 9 sessions in total. Basic patient data, Overactive Bladder Symptom Score (OABSS), Incontinence Impact Questionnaire (IIQ-7), and Urogenital Distress Inventory (UDI-6) scores were recorded prior to first treatment and at the end of 3rd, 6th, and 9th treatments. Results Thirty patients were enrolled, and twenty-seven patients completed all treatments in this study. The OABSS total score of the experimental group decreased significantly by 3.13 (p ≤ 0.001), 4.60 (p ≤ 0.001), and 3.79 (p ≤ 0.001) after 3rd, 6th, and 9th treatments, respectively, compared with that of the control group. The IIQ-7 score declined significantly from baseline by 4.57 (p=0.003) and 3.63 (p=0.023) after 3rd and 6th treatments, respectively, compared with that of the control group. Similarly, the UDI-6 score of the experimental group exhibited a significant decrease from baseline by 1.90 (p=0.042) and 2.25 (p=0.025) after 6th and 9th interventions, respectively, compared with that of the control group. Conclusions This study demonstrates that laser acupuncture can alleviate OAB symptoms and improve quality of life. This noninvasive device could be an effective therapy for women with OAB.


Introduction
According to International Continence Society, the overactive bladder (OAB) syndrome was defined in 2002 as "urgency, with or without urgency incontinence, usually with frequency and nocturia," in the absence of proven infection or other obvious pathology [1]. In general, females suffered more from OAB syndrome than males in the world but the contributing factors remain to be elucidated [2]. According to statistics in different countries, the prevalence of OAB among females ranges from 6.0 to 17.4% [2,3] and increases with age [4]. OAB has become a major women health issue worldwide. In Taiwan, the age-adjusted prevalence of OAB is 16% in men and 18.3% in women, respectively [5].
OAB poses significant financial impact in the US with medical costs ranging from USD 656 to 860 per patient annually [6]. In a US population-based survey of 2009, the total cost of disease-specific OAB was estimated at USD 24.9 to 36.5 billion [7]. Various methods for treating OAB have been developed. Conventional first-line interventions in the management of OAB include behavioral interventions such as fluid intake management, bladder training, and pelvic muscle exercises [8].
Traditional Chinese medicine (TCM) has for many years utilized herbal medicine, acupuncture, and moxibustion to treat lower urinary tract symptoms (LUTS) [13][14][15]. Some systematic reviews have concluded that acupuncture can improve OAB symptoms and enhance performance in objective urodynamic tests. However, both pain and hematoma limit the acceptance of acupuncture treatment [16,17].
Laser acupuncture, belonging to the category of Low-Level Laser Therapy (LLLT), is commonly believed to be a safe and noninvasive treatment with no obvious side effect [18]. However, the therapeutic effect of laser acupuncture on women with OAB has not yet been examined. This study is a double-blind, pilot randomized controlled trial for assessing the efficacy of laser acupuncture on women with OAB in Taiwan. According to prior research assessing the efficacy of moxibustion on patients with OAB [14], it was estimated that 14 people would be required for each arm to reach 90% statistical power. Whitehead et al. [19] also recommended pilot trial sample size per treatment arm of 15 for standardized effect size. Therefore, 30 participants were recruited for this clinical trial.

Materials and Methods
The recruited patients who met the inclusion criteria completed the urodynamic test (to rule out neurogenic bladder), per vaginal examination and initial screening (to rule out major surgery indication) by an experienced gynecologist. All participants started the trial after understanding thoroughly the study and signing informed consent forms.
The inclusion criteria were as follows: (1) Female at least 20 years old with differential diagnosis performed by a gynecologist prior to being referred to the Chinese Medicine Outpatient Clinic (2) Good health in general with no other major medical conditions and willing to sign the consent as well as responding to evaluation scales (3) Moderate to severe OAB symptoms with total scores of OABSS > 6 and the score of 3 rd question of OABSS > 2 (4) Discontinuation of antimuscarinic and β3-adrenoceptor agonists for at least 2 weeks ensuring drug effect being washed out The exclusion criteria were as follows: (  [20] into the experimental group receiving verum laser treatment (n = 15) and the control group receiving sham laser treatment (n = 15). All subjects receive laser acupuncture 3 times per week for 3 weeks, 9 sessions in total, with minor modifications according to clinical practice. Basic patient data, OABSS, UDI-6, and IIQ-7 scores were recorded prior to 1 st treatment and at the end of 3 rd , 6 th , and 9 th treatments. Adverse effects during the clinical trial were also recorded. The flowchart of this study is shown in Figure 1.
Neither patients nor investigators were informed of the grouping. Therefore, this study was a prospective doubleblind randomized controlled trial.

Outcome Measurements. Primary outcomes included
Overactive Bladder Symptom Score (OABSS), whereas secondary outcomes included scores obtained using 1 p't loss to follow-up due to fall accident. Incontinence Impact Questionnaire-Short Form (IIQ-7) and Urogenital Distress Inventory (UDI-6). OABSS was developed for assessing symptom improvement and treatment efficacy in daily clinical practice [21]. OABSS comprising four symptom items (daytime frequency, nighttime frequency, urgency, and urgency incontinence), 15 points in total, translated into Chinese and validated in Taiwan [22,23] was selected to be the primary outcome measurement in this study. Highly sensitive to treatment-related changes in OAB symptoms, OABSS can be an alternative to a bladder diary for symptom and efficacy assessment in daily clinical practice [21]. Both UDI-6 and IIQ-7 (Chinese version) which showed correlation with daytime urinary frequency and incontinent episodes [24] were employed to evaluate how OAB symptoms impact patients' quality of life (QoL).

Statistical Analysis.
Analysis was performed using SPSS software (IBM Corp. Released 2015. IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp.). Values of p < 0.05 were considered to be statistically significant. Generalized estimating equation (GEE) was utilized to assess improvement ratios on scores of OABSS, UDI-6, and IIQ-7. Independent samples T test, Chi-square test, and nonparametric test (Mann-Whitney U test) were conducted to analyze baseline characteristics and raw data between the two groups.

Results
From early 2019, 40 patients referred from a gynecologist were screened and 30 were enrolled as participants. They were then randomly assigned to receive verum laser acupuncture (n � 15) or sham laser acupuncture (n � 15). Of them, 27 (90%) finished treatment; one patient in the experimental group dropped out because of schedule conflict and two patients in the control group discontinued the trial due to progressed OAB symptoms and hip fracture in a fall accident, respectively. The baseline characteristics were similar between the two groups (Table 1). A table of raw data from the three questionnaires showed the trend of score declining in time dependent manner between two groups calculated by nonparametric test (Table 2).
According to the logic calculus of GEE, data of the three subjects who did not complete the trial were still included in the statistics. The time point subtracted baseline intragroup and the slope between two groups were calculated using the generalized estimating equation (GEE) approach for the following results. p value < 0.05 represents the significant difference of the slopes between two groups.

Changes in OAB Symptoms.
In primary outcome measurement, the OABSS total score of the experimental group decreased significantly by 3.13 (p ≤ 0.001) after the 3 rd treatment compared with that of the control group. The difference in score of OABSS from baseline between the experimental group and control group changed was 4.60 (p ≤ 0.001) after the 6 th treatment and 3.79 (p ≤ 0.001) after the 9 th treatment (Table 3(a), Figure 3(a)).

Changes in QoL of Participants.
After the 3 rd treatment, the UDI-6 score of the experimental group declined slightly (0.87), showing no significant change compared with that of the control group but exhibited a marked decrease from baseline after 6 th and 9 th interventions (−1.90; p � 0.042 and −2.25; p � 0.025, respectively) (Table 3(b)). For IIQ-7, the score of the experimental group exhibited a significant improvement from baseline after 3 rd and 6 th treatments (−4.57; p � 0.003 and −3.62; p � 0.023, respectively) compared with that of the control group, but only a slight insignificant decrease (−3.42; p � 0.073) from baseline after the 9 th treatment (Table 3(c)). The GEE results are shown in Figures 3(b) and 3(c).

Daytime Urinary Frequency, Urgency, Nocturia, and
Urgency Incontinence. In view of urgency being the core OAB symptom, the question "how often do you have a sudden desire to urinate, which is difficult to defer" was taken from OABSS to assess specifically severity of urgency. The results showed the experimental group had marked decrease in urgency of statistical significance after 6 th and 9 th treatments (−1.88; p � 0.001 and −1.26; p � 0.030, respectively) compared with the control group (Table 4(a), Figure 4(a)). In addition, the symptoms of nocturia and urgency incontinence also improved significantly after laser acupuncture treatment (Tables 4(b) and 4(c); Figures 4(b) and 4(c)). There is no significant difference in daytime urinary frequency between the two groups (Table 4(d), Figure 4(d)).

Discussion
According to the American Urological Association (AUA) and the Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction (SUFU) OAB Guidelines, OAB therapy starts with dietary and behavioral modification and progresses to pharmacotherapy as well as third-line therapies including neuromodulation, PTNS, and so on. However, the guidelines highlight that each patient should not be required to go through each line of treatment in the order specified [8]. In view of the above-mentioned facts, many alternative treatments such as acupuncture, extracorporeal magnetic stimulation, Erbium: YAG laser treatment, elastomer roller perineal stimulation and, moxibustion have been developed and validated [14,[25][26][27]. To our knowledge, this is the first clinical trial assessing the therapeutic effect of laser acupuncture on patients with OAB.
In this study, patients with moderate to severe symptoms (OABSS > 6) and urgency more than once a week (Q3, 3 rd question of OABSS > 2) were enrolled, and the OABSS total scores were 8.7 and 8.5 (p � 0.76) in the experimental and control group, respectively, prior to treatment. After 3 rd , 6 th , and 9 th treatments, the OABSS total score decreased significantly in the experimental group in comparison with that in the control group, indicating that laser acupuncture can ameliorate moderate to severe OAB symptoms. Furthermore, the symptoms of urgency (Q3 of OABSS) and nocturia (Q2, 2 nd question of OABSS) improved significantly after 3 rd , 6 th , and 9 th treatments, with urgency incontinence (Q4, 4 th question of OABSS) improving after 9 th treatment, while daytime frequency (Q1, 1 st question of OABSS) showed an insignificant trend of decrease.
UDI-6 and IIQ-7 (Chinese version) are secondary outcome measurements in this study assessing the impact of OAB symptoms on patients' QoL. The IIQ-7 score improved significantly from baseline after 3 rd and 6 th treatments in the experimental group compared that in the control group, but the difference in improvement after the 9 th treatment between the two groups was insignificant (Table 3(c); Figure 3(c)). Such results can be attributed to related placebo effect in long-term treatment. The UDI-6 scale focuses on how troubling OAB symptoms are, especially urinary incontinence. The present findings revealed significant improvement in UDI-6 score in the experimental group after 6 th and 9 th interventions (Table 3(b); Figure 3(b)), which was consistent with the results obtained for Q4 of OABSS.
Acupuncture has been applied as OAB treatment for years. Previous research on OAB in females revealed that acupuncture could even be comparable to anticholinergics (tolterodine tartrate) in reducing the frequency of daytime urinary, incontinence, and nocturia and increase volume voided per micturition [28]. Moreover, other reviews suggested that acupuncture could reduce the frequency of urination, incontinence, and nocturia and increase the volume of urination [16,17]. In view of related adverse effects such as pain, hematoma, and granuloma [16,17], noninvasive laser acupuncture treatment may be a better option than needle acupuncture.
Laser acupuncture, a kind of LLLT has been used for more than 40 years in treating veterinary or human disease [29]. Being noninvasive and with minimal adverse effects, laser acupuncture has been promoted as a safer pain-free alternative to needle acupuncture. However, the mechanism, effectiveness, and indication of laser acupuncture are still unknown [18]. Until now, it remains a challenge to select appropriate parameters including wavelength, power output, energy dosage, and frequency in a specific situation due to heterogeneity among therapeutic theories and individuals' skin pigment, thickness, and location on the body [30]. In this study, selected acupoints were assumed to correspond to meridians, and the frequencies thus applied followed the Reininger Meridian Frequencies. The seven selected acupuncture points (KI3, SP6, CV4, CV6, GV20, BL33, and BL34) are commonly used in treating OAB, urinary incontinence, and LUTS according to TCM theory and the therapeutic effects have been demonstrated in many modern studies [16,17]. We took these clinical trial papers and reviews as reference for selecting acupuncture points. Due to the characteristics of patient's posture changeable and short treatment time in laser acupuncture, the seven selected acupuncture points located in different parts of body can be stimulated in the same session. The reasons for selecting these acupuncture points concluded in Table 5 and the results of our clinical trial showed that these acupuncture points applied with Reininger Meridian Frequencies provide an effective treatment for women with OAB.
To explain the possible mechanism from the neurological point of view, BL33 and BL34 are, respectively, located in the 3 rd and 4 th sacral foramen at the lumbosacral region, and sacral spinal nerves S2-S4 together form the pudendal nerve which innervates external urethral sphincter. SNS is an invasive therapeutic technique with electrodes placed in the S3-S4 sacral foramen to produce long-term electric stimulation of the sacral nerves for restoring normal voiding habits. The most well-accepted hypothesized mechanism for such effect is stimulation of the alpha myelinated afferent fibers and unmyelinated C fibers in the S3 and S4 pelvic, pelvic splanchnic nerve roots, and pudendal nerve roots that affect the micturition reflex [10,35]. In our opinion, sacral neuromodulation theory may explain the possible mechanism of the stimulation of BL33 and BL34. Moreover, clinically available neuromodulation therapies for OAB target not only the sacral nerve roots but also the posterior tibial nerve and dorsal genital nerve for stimulation   , and IIQ-7 (c) scores at 3 rd , 6 th , and 9 th treatments between experimental group and control group. Visits 1, 2, and 3 represent 3 rd , 6 th , and 9 th treatments, respectively. * p < 0.05, * * p < 0.01, * * * p < 0.001.  [12]. PTNS delivers retrograde stimulation to the sacral complex through electrodes placed near the posterior tibial nerve at locations similar to acupuncture points KI3 and SP6. However, the mechanism of laser acupuncture may be different from electrical stimulation provided by PTNS. As a consequence, we suppose the mechanism of these two acupuncture points may share some common pathways that needle acupuncture, laser acupuncture, and PTNS can reach.
In addition, several studies used moxibustion on Conception Vessel meridian 3, 4, or 6 (CV3, CV4, or CV6) to alleviate OAB and other LUTS [14]. The speculative mechanism of moxibustion on CV meridian involves direct or indirect regulation of the autonomic nervous system (ANS) [36] but the exact principle behind is still unknown. Whether laser acupuncture achieves therapeutic effect through similar neurological mechanism or other theories, such as Qi or  , and daytime urinary frequency (Q1) (d) between experimental group and control group. Visits 1, 2, and 3 represent 3 rd , 6 th , and 9 th treatments, respectively. * p < 0.05, * * p < 0.01, * * * p < 0.001. The acupuncture points frequently used in LUTS are BL31 to BL35. They are located above the sacral foramen lie over the first to fourth sacral nerve roots, respectively. These acupuncture points correspond to the segmental innervation of bladder's parasympathetic nerve. A RCTpublished in JAMA confirmed the effect of electroacupuncture involving the lumbosacral region for women with SUI.
Sacral nerve stimulation. [31] KI3 and SP6 (lower leg) According to TCM theory, OAB and LUTS are due to Zang-Fu organ imbalance of kidney, spleen, and liver. KI3 (kidney meridian) and SP6 (spleen meridian) are commonly used to adjust Yin-Yang balance in OAB and LUTS and have been included in several studies.
Posterior tibial nerve stimulation. [28,32] CV4 and CV6 (lower abdomen) In TCM theory, bladder dysfunction is due to insufficiency of Yang Qi. Conception Vessel meridian is suggested as a treatment option as several studies used moxibustion or acupuncture on CV3, CV4, or CV6 to alleviate OAB and other LUTS.
Autonomic nervous system regulation. [14,33] GV20 (head) GV20, one of the most important acupoints of the government vessel, is commonly used in neurology and psychiatry. Stimulation at GV20 will increase cerebral perfusion in the cerebral cortex, stabilize emotions, and reduce sympathetic activity in stress response. Studies have reported stimulating GV20 can lift fallen Yang Qi in accordance with TCM theory; therefore, we selected GV20 to calm emotions and lift patient's Yang Qi.
Increasing the cerebral perfusion in the cerebral cortex for mood stabilization. meridian theories, remains to be further studied. The speculative mechanism of laser acupuncture is shown in Figure 5.

Limitations.
There are several validated questionnaires for OAB assessment being developed to evaluate the validity and reliability [23,37]. However, these subjective assessment scales lack objective data. In recent years, many studies have reported that the nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), C-reactive protein (CRP), prostaglandins, and cytokines may be used as potential biomarkers of OAB but none of these meets the criteria for becoming an isolated OAB marker [38]. A potential biomarker, such as NGF, may be selected to be one of the secondary outcomes in future research.
Unlike traditional questionnaire with the same minimum and maximum score, OABSS assesses different items using different maximal scores (2, 3, 5, and 5 for daytime frequency, nighttime frequency, urgency, and urgency incontinence, respectively.). However, the frequency score of OABSS, ranging from 0 to 2, is too narrow to reflect the real situation of daytime urination frequency. For future research, it should be calculated using the number of urinations recorded in the 3-day bladder diary.
Constrained by limited research funding and resources, this study demonstrated only the short-term effect of laser acupuncture without a long-term follow-up. A long-term and multiple-center clinical trial is warranted for further evaluation.

Conclusion
To date, this is the first clinical trial evaluating the effects of laser acupuncture on OAB in women. The present results demonstrate that laser acupuncture can alleviate OAB symptoms and improve QoL of female suffering from OAB. Laser acupuncture may be a safe and effective intervention for treating OAB symptoms.

Data Availability
The data supporting the findings of this study are available from the corresponding author upon request.