Int Urogynecol J DOI 10.1007/s00192-015-2626-8
ORIGINAL ARTICLE
Prevalence, risk factors and the bother of lower urinary tract symptoms in China: a population-based survey Yuliang Wang & Hao Hu & Kexin Xu & Xiaofeng Wang & Yanqun Na & Xiaoping Kang
Received: 3 September 2014 / Accepted: 4 January 2015 # The International Urogynecological Association 2015
Abstract Introduction and hypothesis Lower urinary tract symptoms (LUTS) consist of storage, voiding and postmicturition symptoms and cause discomfort in approximately 15.8 to 82.0 % of adults worldwide. Despite the wide range in prevalence rates, certain potential risk factors for LUTS have been identified, advanced age being the most noted one. However, the true extent of symptom discomfort among the affected population may be underestimated because of the considerable underreporting of the problem. The objective of this study was to evaluate the prevalence, risk factors and discomfort caused by LUTS in China. Methods This population-based, cross-sectional survey was conducted in five geographical regions of China. A stratified, clustered, systematic sample of individuals aged ≥18 years was selected to answer demographic questionnaires and the International Consultation on Incontinence Questionnaire Male/Female Lower Urinary Tract Symptoms Long Form. Results A total of 3,023 participants (1,551 men; 1,472 women) were included in this study, and 61.2 % (61.2 % men; 61.1 % women) reported at least one LUTS. The prevalence
Electronic supplementary material The online version of this article (doi:10.1007/s00192-015-2626-8) contains supplementary material, which is available to authorized users Y. Wang : H. Hu : K. Xu (*) : X. Wang : Y. Na Urology Department, Peking University People’s Hospital, No. 11 Xizhimen South Street, Xicheng District, 100044 Beijing, People’s Republic of China e-mail: [email protected] Y. Wang School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China X. Kang Department of Clinical Epidemiology and Biostatistics, Peking University, Beijing, China
of storage symptoms (59.8 % men; 60.5 % women) was greater than that of voiding (23.6 % men; 8.8 % women) plus postmicturition symptoms (14.6 % men; 6.3 % women). Nocturia (58.2 % men; 56.9 % women) was the most common specific LUTS. Advanced age, alcohol consumption and smoking were risk factors for LUTS among participants of both sexes. Enlarged prostate, diabetes mellitus and lower education levels correlated positively with LUTS in men, whereas higher parity and hypertension correlated positively with LUTS in women. Subjects with LUTS had great discomfort. Nocturia was the least bothersome symptom in both sexes, whereas nocturnal enuresis and urge urinary incontinence were the most bothersome in men and women respectively. Conclusions Lower urinary tract symptoms are highly prevalent in China and many known risk factors are associated with these bothersome symptoms. However, the perception of the extent of symptom discomfort differed between sexes, and it may not correspond with symptom prevalence. Thus, an appropriate symptom discomfort assessment tool is needed to identify the clinically relevant conditions that warrant treatment. Keywords Lower urinary tract symptoms . Prevalence . Risk factor . Symptom bother
Introduction Lower urinary tract symptoms (LUTS) consist of storage, voiding and postmicturition symptoms and cause discomfort in approximately 15.8 to 82.0 % of adults worldwide [1–6]. Despite the wide range in prevalence rates, certain potential risk factors for LUTS have been identified, advanced age being the most noted one [7, 8]. However, the true extent of
Int Urogynecol J
symptom discomfort among the affected population may be underestimated because of the considerable underreporting of the problem. Epidemiological studies are crucial for identifying the characteristics of LUTS, thus contributing to raising public awareness of the considerable healthcare burden posed by these conditions. The prevalence, risk factors and bother of LUTS have been assessed in numerous studies, but most of these studies only focused on certain specific symptoms, such as urinary incontinence (UI), symptoms related to benign prostatic hyperplasia (BPH), or overactive bladder (OAB), rather than LUTS in the general population, and many of published works were also limited by sex or age groups, or did not apply the current International Continence Society (ICS) definitions [2, 5, 9, 10]. Additionally, lack of universal symptom discomfort assessment tools makes comparisons of studies more challenging. Recent studies have extensively explored the variation of LUTS with regard to race/ethnicity [11, 12]; however, research on this subject in Asia is relatively scarce compared with the USA and Europe. To date, no large epidemiological studies of LUTS have been conducted among a population of both sexes and all adult age groups in China. Therefore, we aimed to establish the prevalence of LUTS, examine the potential risk factors and discomfort caused by LUTS in a population-based sample of men and women aged ≥18 years in China using the current ICS definitions [1].
Materials and methods A population-based, cross-sectional survey over a period of 4 months (October 2012 to January 2013) was conducted among adults aged ≥18 years in five geographical regions of China: Northeast China, North China, Northwest China, Central China and South China. Face-to-face interviews were carried out using stratified, clustered, systematic sampling with questionnaires on demographic data, prevalence and symptom discomfort. This study has been approved by the ethics committees of Peking University People’s Hospital and conforms to the provisions of the Declaration of Helsinki revised in Tokyo in 2008. Written informed consent was obtained from all participants. Questionnaires The study questionnaires were divided into two parts: part 1 included data on sociodemographic characteristics, obstetric history and past medical history. Part 2 comprised the Chinese version of the International Consultation on Incontinence Questionnaire Male/Female Lower Urinary Tract Symptoms Long Form (ICIQ-MLUTS LF/ICIQ-FLUTS LF) supplied by the ICIQ study group and validated by previous studies for
evaluating male/female LUTS [13, 14]. The questionnaire covered the occurrence and discomfort of LUTS over the past 4 weeks. The response options for the occurrence were on a five-point Likert scale, i.e. Bnever^, Boccasionally^, Bsometimes^, Bmost of the time^ and Ball of the time^, except for urinary frequency and nocturia, which were ranked by number of micturitions. Each question was followed immediately by a symptom scale for rating the extent of discomfort (scored from 0 [best] to 10 [worst]). Additionally, the two questions regarding terminal dribble and postmicturition dribble included in the ICIQ-MLUTS LF, but not in ICIQ-FLUTS LF, were also applied to the female participants surveyed. Definitions of a case The current ICS definitions were used for urgency, nocturnal enuresis, urge urinary incontinence (UUI), stress urinary incontinence (SUI), mixed urinary incontinence, hesitancy, intermittency, slow stream, straining, terminal dribble, postmicturition dribble and incomplete emptying [1]. Frequency was defined as >8 micturitions/24 h, considered an objective indicator and used in most previous studies [9]. Unless otherwise noted, nocturia was defined as the act of waking at night once or more to void. For comparison with previous work, when specified, a secondary analysis of nocturia was conducted with the threshold of two or more voids per night. Participants who reported UI without symptoms of UUI or SUI were regarded as having other UI. The prevalence of any LUTS was defined by the symptom frequency threshold at least Bsometimes^ in the five-point Likert scales from ICIQMLUTS LF/ICIQ-FLUTS LF. Sample size and sampling procedure The sample size was calculated based on the conservative expected prevalence of 15 % for LUTS, derived from previous studies [2–5]. The formula was as follows: pq n0 ¼ z 2 2 d
where, n0 z p q d
estimated sample size linked to 95 % confidence interval, α=0.05, z=1.96 expected prevalence of LUTS, 15 % was used expected non-prevalence, q=1-p relative desired precision, allowing within 10 % of the range for p, d=0.1p
With an expected response rate of 55 % and an expanded sample size of 120 %, the sample size was adjusted using n= 1.2n0: 0.60=4,750.
Int Urogynecol J
A three-stage sampling was used to select the study sample of the general population. In the first stage, China was stratified into five geographical regions: Northeast, North, Northwest, Central and South, and one city that could be representative of the geographic and economic developing status in each region was selected: Changchun, Beijing, Xi’an, Wuhan and Guangzhou. In the second stage, one township or one street district (cluster), with a stable population and a gross domestic product per capita at the average level of the corresponding city, was randomly selected from each city and a sampling quota was allocated using the probability proportional to size (PPS) procedure. Systematic sampling was adopted in the final stage where the sample interval was determined by the ratio of the total number of households in clusters to the expected number of sampling units (≈15). The first household was randomly selected, and thereafter, every 15th household was approached according to the house number until the quota was achieved. Within a given household, an individual aged ≥18 years and with the most recent birthday (last-birthday selection method) was randomly selected to fill in the questionnaires on demographic data and ICIQ-MLUTS LF (male only)/ICIQ-FLUTS LF (female only) independently. The uniformly trained investigators in this survey were familiar with local cultures and dialects and offered the necessary guidelines if the participants had difficulty understanding any of the questions in the questionnaires. Statistical analysis Descriptive statistics were used to characterize the demographics and the prevalence of LUTS. Continuous variables are presented as means and standard deviations (±SD) and were compared using the t test or analysis of variance. Categorical variables are presented as percentages and were compared using the Chi-squared test. The multivariable logistic regression analysis was used to control for a potential confounding effect and determine risk factors associated with LUTS. Results are presented as numbers and percentages of participants with 95 % confidence intervals. To represent the general population of Chinese adults, all calculations were weighted by age (10-year groups) and sex distribution on the basis of the sixth nationwide population census of China in 2010. All statistical analyses were performed using SPSS software, version 17.0 (IBM, Armonk, NY, USA). P values
ORIGINAL ARTICLE
Prevalence, risk factors and the bother of lower urinary tract symptoms in China: a population-based survey Yuliang Wang & Hao Hu & Kexin Xu & Xiaofeng Wang & Yanqun Na & Xiaoping Kang
Received: 3 September 2014 / Accepted: 4 January 2015 # The International Urogynecological Association 2015
Abstract Introduction and hypothesis Lower urinary tract symptoms (LUTS) consist of storage, voiding and postmicturition symptoms and cause discomfort in approximately 15.8 to 82.0 % of adults worldwide. Despite the wide range in prevalence rates, certain potential risk factors for LUTS have been identified, advanced age being the most noted one. However, the true extent of symptom discomfort among the affected population may be underestimated because of the considerable underreporting of the problem. The objective of this study was to evaluate the prevalence, risk factors and discomfort caused by LUTS in China. Methods This population-based, cross-sectional survey was conducted in five geographical regions of China. A stratified, clustered, systematic sample of individuals aged ≥18 years was selected to answer demographic questionnaires and the International Consultation on Incontinence Questionnaire Male/Female Lower Urinary Tract Symptoms Long Form. Results A total of 3,023 participants (1,551 men; 1,472 women) were included in this study, and 61.2 % (61.2 % men; 61.1 % women) reported at least one LUTS. The prevalence
Electronic supplementary material The online version of this article (doi:10.1007/s00192-015-2626-8) contains supplementary material, which is available to authorized users Y. Wang : H. Hu : K. Xu (*) : X. Wang : Y. Na Urology Department, Peking University People’s Hospital, No. 11 Xizhimen South Street, Xicheng District, 100044 Beijing, People’s Republic of China e-mail: [email protected] Y. Wang School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China X. Kang Department of Clinical Epidemiology and Biostatistics, Peking University, Beijing, China
of storage symptoms (59.8 % men; 60.5 % women) was greater than that of voiding (23.6 % men; 8.8 % women) plus postmicturition symptoms (14.6 % men; 6.3 % women). Nocturia (58.2 % men; 56.9 % women) was the most common specific LUTS. Advanced age, alcohol consumption and smoking were risk factors for LUTS among participants of both sexes. Enlarged prostate, diabetes mellitus and lower education levels correlated positively with LUTS in men, whereas higher parity and hypertension correlated positively with LUTS in women. Subjects with LUTS had great discomfort. Nocturia was the least bothersome symptom in both sexes, whereas nocturnal enuresis and urge urinary incontinence were the most bothersome in men and women respectively. Conclusions Lower urinary tract symptoms are highly prevalent in China and many known risk factors are associated with these bothersome symptoms. However, the perception of the extent of symptom discomfort differed between sexes, and it may not correspond with symptom prevalence. Thus, an appropriate symptom discomfort assessment tool is needed to identify the clinically relevant conditions that warrant treatment. Keywords Lower urinary tract symptoms . Prevalence . Risk factor . Symptom bother
Introduction Lower urinary tract symptoms (LUTS) consist of storage, voiding and postmicturition symptoms and cause discomfort in approximately 15.8 to 82.0 % of adults worldwide [1–6]. Despite the wide range in prevalence rates, certain potential risk factors for LUTS have been identified, advanced age being the most noted one [7, 8]. However, the true extent of
Int Urogynecol J
symptom discomfort among the affected population may be underestimated because of the considerable underreporting of the problem. Epidemiological studies are crucial for identifying the characteristics of LUTS, thus contributing to raising public awareness of the considerable healthcare burden posed by these conditions. The prevalence, risk factors and bother of LUTS have been assessed in numerous studies, but most of these studies only focused on certain specific symptoms, such as urinary incontinence (UI), symptoms related to benign prostatic hyperplasia (BPH), or overactive bladder (OAB), rather than LUTS in the general population, and many of published works were also limited by sex or age groups, or did not apply the current International Continence Society (ICS) definitions [2, 5, 9, 10]. Additionally, lack of universal symptom discomfort assessment tools makes comparisons of studies more challenging. Recent studies have extensively explored the variation of LUTS with regard to race/ethnicity [11, 12]; however, research on this subject in Asia is relatively scarce compared with the USA and Europe. To date, no large epidemiological studies of LUTS have been conducted among a population of both sexes and all adult age groups in China. Therefore, we aimed to establish the prevalence of LUTS, examine the potential risk factors and discomfort caused by LUTS in a population-based sample of men and women aged ≥18 years in China using the current ICS definitions [1].
Materials and methods A population-based, cross-sectional survey over a period of 4 months (October 2012 to January 2013) was conducted among adults aged ≥18 years in five geographical regions of China: Northeast China, North China, Northwest China, Central China and South China. Face-to-face interviews were carried out using stratified, clustered, systematic sampling with questionnaires on demographic data, prevalence and symptom discomfort. This study has been approved by the ethics committees of Peking University People’s Hospital and conforms to the provisions of the Declaration of Helsinki revised in Tokyo in 2008. Written informed consent was obtained from all participants. Questionnaires The study questionnaires were divided into two parts: part 1 included data on sociodemographic characteristics, obstetric history and past medical history. Part 2 comprised the Chinese version of the International Consultation on Incontinence Questionnaire Male/Female Lower Urinary Tract Symptoms Long Form (ICIQ-MLUTS LF/ICIQ-FLUTS LF) supplied by the ICIQ study group and validated by previous studies for
evaluating male/female LUTS [13, 14]. The questionnaire covered the occurrence and discomfort of LUTS over the past 4 weeks. The response options for the occurrence were on a five-point Likert scale, i.e. Bnever^, Boccasionally^, Bsometimes^, Bmost of the time^ and Ball of the time^, except for urinary frequency and nocturia, which were ranked by number of micturitions. Each question was followed immediately by a symptom scale for rating the extent of discomfort (scored from 0 [best] to 10 [worst]). Additionally, the two questions regarding terminal dribble and postmicturition dribble included in the ICIQ-MLUTS LF, but not in ICIQ-FLUTS LF, were also applied to the female participants surveyed. Definitions of a case The current ICS definitions were used for urgency, nocturnal enuresis, urge urinary incontinence (UUI), stress urinary incontinence (SUI), mixed urinary incontinence, hesitancy, intermittency, slow stream, straining, terminal dribble, postmicturition dribble and incomplete emptying [1]. Frequency was defined as >8 micturitions/24 h, considered an objective indicator and used in most previous studies [9]. Unless otherwise noted, nocturia was defined as the act of waking at night once or more to void. For comparison with previous work, when specified, a secondary analysis of nocturia was conducted with the threshold of two or more voids per night. Participants who reported UI without symptoms of UUI or SUI were regarded as having other UI. The prevalence of any LUTS was defined by the symptom frequency threshold at least Bsometimes^ in the five-point Likert scales from ICIQMLUTS LF/ICIQ-FLUTS LF. Sample size and sampling procedure The sample size was calculated based on the conservative expected prevalence of 15 % for LUTS, derived from previous studies [2–5]. The formula was as follows: pq n0 ¼ z 2 2 d
where, n0 z p q d
estimated sample size linked to 95 % confidence interval, α=0.05, z=1.96 expected prevalence of LUTS, 15 % was used expected non-prevalence, q=1-p relative desired precision, allowing within 10 % of the range for p, d=0.1p
With an expected response rate of 55 % and an expanded sample size of 120 %, the sample size was adjusted using n= 1.2n0: 0.60=4,750.
Int Urogynecol J
A three-stage sampling was used to select the study sample of the general population. In the first stage, China was stratified into five geographical regions: Northeast, North, Northwest, Central and South, and one city that could be representative of the geographic and economic developing status in each region was selected: Changchun, Beijing, Xi’an, Wuhan and Guangzhou. In the second stage, one township or one street district (cluster), with a stable population and a gross domestic product per capita at the average level of the corresponding city, was randomly selected from each city and a sampling quota was allocated using the probability proportional to size (PPS) procedure. Systematic sampling was adopted in the final stage where the sample interval was determined by the ratio of the total number of households in clusters to the expected number of sampling units (≈15). The first household was randomly selected, and thereafter, every 15th household was approached according to the house number until the quota was achieved. Within a given household, an individual aged ≥18 years and with the most recent birthday (last-birthday selection method) was randomly selected to fill in the questionnaires on demographic data and ICIQ-MLUTS LF (male only)/ICIQ-FLUTS LF (female only) independently. The uniformly trained investigators in this survey were familiar with local cultures and dialects and offered the necessary guidelines if the participants had difficulty understanding any of the questions in the questionnaires. Statistical analysis Descriptive statistics were used to characterize the demographics and the prevalence of LUTS. Continuous variables are presented as means and standard deviations (±SD) and were compared using the t test or analysis of variance. Categorical variables are presented as percentages and were compared using the Chi-squared test. The multivariable logistic regression analysis was used to control for a potential confounding effect and determine risk factors associated with LUTS. Results are presented as numbers and percentages of participants with 95 % confidence intervals. To represent the general population of Chinese adults, all calculations were weighted by age (10-year groups) and sex distribution on the basis of the sixth nationwide population census of China in 2010. All statistical analyses were performed using SPSS software, version 17.0 (IBM, Armonk, NY, USA). P values
