Masood Ahmed Sheikh  ( Department of Urology, Orthopaedic and Medical Institute, Karachi, Pakistan. )
Ahmed Fawad  ( Department of Urology, Ziauddin University, Karachi, Pakistan. )
Khalid Javed Rabbani  ( Department of Urology, Lahore Medical and Dental College, Lahore, Pakistan. )
Syeda Batool Mazhar  ( Department of Gynaecology and Obstetrics, Shaheed Zulfiqar Ali Bhutto Medical University (SZABMU), Islamabad, Pakistan. )
Shahzad Ali  ( Department of Urology, Jinnah Postgraduate Medical Center, Karachi, Pakistan. )
Haleema Yasmin  ( Department of Gynaecology and Obstetrics, Jinnah Postgraduate Medical Centre, Karachi, Pakistan. )
Salman EL-Khalid  ( Department of Urology, The kidney center, Karachi, Pakistan. )
Waqar Azim Niaz  ( Department of Urology, and Transplant Surgery, Quaid e Azam International Hospital, Islamabad, Pakistan. )
Humma Quddusi  ( Department of Gynaecology and Obstetrics, Nishter Medical University, Multan, Pakistan. )
Muhammed Akhtar Anwer  ( Jinnah Postgraduate Medical Center, Karachi, Pakistan. )
Bakhtawar Gul  ( Department of Urology, Institute of Kidney Diseases, Hayatabad, Peshawar, Pakistan. )
Sajid Mumtaz Qazi  ( Department of Urology, Pakistan Institute of Medical Sciences, Islamabad, Pakistan. )

Objective:  To determine the overall prevalence of overactive bladder in Pakistan, and to determine the difference in prevalence in relation to gender.

 

Method: The multicenter study was conducted from February 2017 to October 2018 at 11 institutions across the country, and comprised randomly selected healthy subjects of either gender who were assessed on the basis of symptoms defined by the International Continence Society for overactive bladder. Data was collected using a questionnaire based on the symptoms which was filled for the respondent by designated health workers. Data was analysed using SPSS 23.

 

Results: Of the 1291 respondents, 632(49%) were males with a mean age of 37.8±14.4 years, and 659(51%) were females with a mean age of 38.3±13.7 years. The overall prevalence of overactive bladder was 82(6.4%). Among the males, it was 15(2.4%) and among the females 67(10.2%) (p=0.001). Urgency, frequency and nocturia were reported by 82(6.4%) respondents; 15(1.2%) males and 67(5.2%) females (p=0.001).

 

Conclusion: The prevalence of overactive bladder was found to be low when assessed with strict application.

 

Keywords: Overactive bladder, Prevalence, Urinary symptoms. (JPMA 72: 17; 2022)

 

DOI: https://doi.org/10.47391/JPMA.20-1463

 

Introduction

 

Overactive bladder (OAB) has been defined by the International Continence Society (ICS) as a storage symptom syndrome of the lower urinary tract symptoms (LUTS). It is characterised by urinary urgency with or without urge incontinence, usually with frequency and nocturia, in the absence of confirmed infection or other pathology.¹ It is a prevalent condition in both men and women and has a significant impact on the overall quality of life (QOL), sexual function, sleep and mental health.² OAB is one of the common clinical manifestations of voiding dysfunction which is characterised by involuntary detrusor contractions that may occur spontaneously or may be provoked which the patient is unable to suppress. The diagnosis is usually based on subjective symptoms. However, a large proportion of patients do not report the condition to their physicians, perhaps because of embarrassment or because of the mistaken notion that no effective treatment is available.

An estimated 455 million individuals worldwide experienced OAB in 2008 with numbers expected to increase to 500 million in 2013 (10% increase) and 546 million by 2018 (20.1% increase).³

Several epidemiological studies have been carried out worldwide on OAB whose figures range from 8% in Finland⁴ to as high as 53.1% in Asian women.⁵ The prevalence in a community will differ depending on the understanding of the survey questions asked as well as how severe the respondents feel about these symptoms.

The current study was planned to determine the overall OAB prevalence in Pakistan, and to determine the difference in prevalence with respect to gender.

 

Subjects and Methods

 

The multicenter study was conducted from February 2017 to October 2018 at 10 institutions across the country. After approval was taken from Ethical Review Board and data collection was commenced. The scope of the survey was limited to questionnaire only. OAB prevalence of 6.4% was noted in a pilot survey conducted on 75 subjects in February 2017 prior to calculating the sample size for the current study using the Clopper-Pearson formula⁶ with two-sided 95% confidence interval (CI). The sample was raised from among randomly selected apparently healthy subjects, through Non-probability consecutive sampling, who were either accompanying some patient or who did not come to the medical facility for any medical reasons. Those who came in with any urinary symptoms were excluded.

Based on OAB symptoms defined by the ICS, a questionnaire was developed in the local Urdu language on the pattern of symptom assessment tool for overactive bladder symptom score (OABSS).⁷ The scoring system was not employed, and, instead, direct answers of positive and negative questions were noted. A 4-week recall method was used. The questionnaire was pretested in the pilot study for ease of understanding of the questions. Very minor alterations were needed for the final questionnaire. The ICS symptoms of OAB used in the current study were urinary frequency, nocturia, and urgency or urge incontinence. The survey also included questions on stress incontinence.

Frequency was measured with 3 options: up to seven times, 8-14 times, and 15 times or more.

For nocturia. the options were: ‘never’, ‘once a night’, ‘two times’ and ‘three times or more’.

Urgency, urge incontinence and stress incontinence were graded as ‘never’, ‘less than once a week’, ‘more than once a week’, ‘once a day’, ’2-4 times a day’, and ‘5 or more times a day’.

Verbal consent was taken from all the subjects.

Data was collected using the questionnaire which was filled for the respondent by the researchers.

Frequency was considered abnormal if it was 8 times or more. Nocturia was considered if it was more than 2 times. Urgency response, urge incontinence and stress incontinent were taken as abnormal if any of these occurred at least once a day.

Data was analysed using SPSS 23. Effect modifiers, such as age, gender and urinary/urgency symptoms were classified into groups. Qualitative variables were presented with frequencies and percentages. Students t test was applied for the mean comparison of age after verifying normality through Shapiro-Wilk test. Association of gender and age groups with the occurrence of symptoms were tested using the Chi-square test of independence. P<0.05 was considered statistically significant.

 

Results

 

Of the 1326 subjects approached, 1291(97.3%) forms were correctly filled; 632(49%) males with a mean age of 37.8±14.4 years, and 659(51%) females with a mean age of 38.3±13.7 years. The age difference was not significant in terms of gender (p=0.86). The largest age group was 21-30 years, having 457(39.8%) subjects (Table 1).

 

 

The overall prevalence of overactive bladder was 82(6.4%). Among the males, it was 15(2.4%) and among the females 67(10.2%) (p=0.001).

With regards to the symptoms, urgency, frequency and nocturia were reported by 82(6.4%) respondents; 15(1.2%) males and 67(5.2%) females (p=0.001) (Table 2).

 

 

Urinary urgency was reported >5 times a day by 33(2.6%) subjects; 10(30.3%) males and 23(60.7%) females (p=0.001) (Table 3).

 

 

Urgency in different age groups with gender distribution showed that the symptom increased with advancing age and was maximally seen in those aged >50 years (Table 4). The overall OAB prevalence was 82(6.4%). Among the males, it was 15(2.4%) and among the females 67(10.2%) (p=0.001). Urge incontinence was reported by 127(9.8%) subjects; 15(1.2%) males and 112(8.7%) females.

 

 

Urge incontinence was reported by 135(10.4%) subjects less than once a week, 58(4.5%) had it more than once a week, 55(4.3%) had it once a day, 57(4.4%) had it 2-4 times a day and 15(1.2%) experienced it 5 times a day.

Stress incontinence was reported by 71(5.5%) respondents; 14(1.0%) males and 57(4.5%) females (p=0.001).

 

Discussion

 

To the best of our knowledge, the current study is the first multicenter analysis of OAB symptoms from Pakistan. Epidemiological studies conducted worldwide have demonstrated that the frequency of OAB ranges from 2% to 53%,⁸ depending on the target population and the OAB definition.

A study noted that there are notable inconsistences across epidemiological studies showing OAB prevalence rates from 7% to 26%. These have been attributed to the differences in the questions used for symptom assessment, mode of questionnaire, administration, study population and symptom definitions.^3,4,9 Historically, imprecise definitions of OAB had significantly hindered the epidemiological studies, but since the coding of OAB by the ICS, there has been a significant advancement in this field.¹⁰

The current study strictly applied the ICS definition1 and the questionnaire was administered by medical practitioners, resulting in a lower OAB prevalence.

A study using a computer-assisted telephone interview (CATI) questionnaire9 in the United States defined OAB without urge incontinence as a feeling of urgency 4 times or more in a month and 8 micturations in a day along with patients using other strategies like restricting fluids etc. It showed an overall prevalence of 16% in men and 16.9% in women. An epidemiological study from Japan¹¹ comprising 4,570 respondents showed OAB prevalence of 12.4% (men 14%, women 11%).  It had defined OAB as 8 or more voids per day and one or more urgency episodes per week.

The results of sensitivity analysis in the study¹¹ showed that when threshold for the daily voiding frequency was increased from 5 to 15 times and the urgency frequency was fixed at once a week, the prevalence of OAB decreased from 14% to 2%. Conversely, when the urgency frequency threshold was increased from less than once per week to once a day and the threshold of daily voids was fixed at 8, the prevalence decreased from 21% to 7%. This is consistent with the findings of 6.4% in the current study which took urgency frequency at least once a day and day-time frequency at 8 or more voids.

In the present study, the prevalence of OAB increased with advancing age. The number of elderly population surveyed was, however, smaller as the elderly are reluctant to take part in any survey, take their health condition as their fate and part of the aging process, do not visit hospitals unless in distress and women are especially shy in answering questions related to urgency and incontinence.^8,10,11

A large study on OAB, called the European Prospective Investigation into Cancer and Nutrition (EPIC) study¹² was conducted in five countries, including Canada, Germany, Italy Sweden and the United Kingdom, with over 19,000 participants, and showed an overall prevalence of 11.8%, with similar rates in men and women. Within genders, men had a prevalence of 10.8% and women 12.8% which increased with age in both genders.

In the present study, the overall OAB prevalence was 6.4%; men 1.2% and women 5.2%. If the urgency of a lesser degree was taken as abnormal, the figures would have gone much higher. Additionally, if nocturia had been taken to be positive at one or more times, the prevalence would, again, have been much higher.

Nocturia is one of the most bothersome symptoms. In the EPIC study¹² if frequency of nocturia was taken as one or more voids per night, 48% men and 54.5% women reported the symptom. But if they defined nocturia as 2 or more voids per night, their prevalence would decrease to 20.9% in men and 24% in women. The current study observed that nocturia of one or more voids was seen in 59.7% and at 2 or more voids per night was seen in 27.6% respondents, which is quite similar to the EPIC study.

In the present study, urgency, which is the cardinal symptom of OAB, was reported in 21.6% (men 7.3%; women 14.2%) by the criteria that was employed, but if we define urgency as once a week or more, the prevalence increases to 30.2%. In the epidemiology of LUTS (EpiLUTS) study,² urgency in isolation was present in 15.6% of men and 10.9% of women which differs from the current findings. In Japan11 it was 14% for one or more urgency episodes per week. In one study, it was 15%.¹¹ The current study showed urgency and nocturia in 12.8% (men 3%; women 9.8%). Urgency and frequency were present in 8% (men 1.8%; women 6.1%).

Other Asian epidemiological studies, like the one from Iran8 used ICS definition for a prevalence study of OAB in women. There were 8748 respondents aged 15-55 years. The overall prevalence was 18.2% which increased from 10.9% in those aged 15-29 years to 26.2% in those >50 years. It reported that the prevalence was higher in Iranian women due to the difference in population, collecting tools and different definitions of OAB having been used.

In a South Korean study,¹³ a telephone survey was conducted on 2,000 men and women aged >18 years, using the ICS definition. It reported an overall OAB prevalence of 12.2% (10% men; 14.3% women). Telephone surveys are liable to error because at times the respondent may not have understood the question fully and they are unable to ask for clarification due to time constraints on the phone.

A study in China, Taiwan and South Korea in 201714 comprised 8248 people aged >40 years. Overall prevalence was 20.8% (women 22.1%; men 19.5%) which increased significantly with age from 10.8% to 27.9% at age >60 years.

In the present study, urgency and urge incontinence was 9.8% (men 1.2%; women 8.7%), and wet OAB was reported by 45.5% respondents. A study⁹ reported a prevalence of urge incontinence which increased with age from 2% to 19% in women with a marked increase after 44 years of age, and from 0.3% to 8.9% in men with a marked increase after 64 years age. Across all age groups, OAB without urinary incontinence was more common in men than women. The current study also had urinary incontinence more prevalent in women. In Japan,¹¹ OAB prevalence with and without urgency incontinence (one or more episodes per week) were 6.4% and 6% respectively.

Overall stress incontinence was 5.5% and it was more prevalent in females, which was close to the rates reported in literature.^4,15,16

It is clear that there is still no global agreement on OAB prevalence. Most epidemiological studies done so far have differed on even a range of incidence rates. Not only there are no fixed quantitative defined figures of the frequency of the episodes of urgency, day-time frequency and nocturia, with terms like ‘rarely’, ‘sometimes’, ‘mostly’ and ‘often’ being used, but also in terms of qualitative definitions of the classical symptoms to define the severity of the symptoms, like ‘mild’, ‘moderate’ and ‘severe’. These ultimately have a significant bearing on the results.

 

Conclusion

 

The prevalence of overactive bladder was found to be low when assessed with strict application of the three classical symptoms of the condition.

 

Acknowledgement: We are grateful to the LUTS Research Group, Pakistan.

Disclaimer: The study data was presented at the First Pakistan Colloquium on lower urinary tract symptoms (LUTS), held in Rawalpindi, Pakistan, on July 13-14, 2019.

Conflict of Interest: None.

Source of Funding: None.

 

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