- Email: [email protected]
The prevalence of urinary dysfunction in Hong Kong Chinese women
The Prevalence of Urinary Dysfunction Hong Kong Chinese Women
in
G. M. BRIEGER, FRACOG, S. K. YIP, MRCOG, L. Y. HIN, MBChB, AND T. K. H. CHUNG, FRACOG Objective: To determine the prevalence of urinary dysfunction in Hong Kong Chinese women. Methods: A telephone survey was conducted in the territory of Hong Kong. The subjects were a sample of women between the ages of 10 and 90 years. The main outcome determined was the prevalence of urinary dysfunction. Results: We made 3248 calls, resulting in 819 evaluable responses. Stress incontinence was reported by 21% (174) of respondents, urgency or urge incontinence in 15% (1201, urinary frequency in 19% (154), nocturia in 20% (1661, bed-wetting in 4% (311, and voiding difficulties in 13% (109). Stress incontinence occurred as the only symptom in 7% (53), the combination of urgency and frequency in 1% (ll), and mixed symptoms in 6% (52). Four percent required protective underwear or pads, with 2% wearing protective underwear continuously; 4% were incapacitated by their incontinence. Symptoms of urgency, urge incontinence, frequency, and nocturia increased with increasing age, but voiding difficulties and nocturnal enuresis were unrelated to age. Stress incontinence, urgency, urge incontinence, frequency, nocturia, and voiding difficulties increased with increasing parity to para 4. Conclusion: Urinary dysfunction and its patterns appear to be as common and incapacitating in Hong Kong Chinese as they are in other populations. (Obstet Gynecol 1996;88: 2041-4. Copyright 0 2996 by The American College of Obstetricians and Gynecologists.)
The prevalence of urinary dysfunction in randomly selected groups of white women ranges from 8% to 41%.lt2 Questionnaire surveys concerning urinary incontinence report a response rate of 69-89%, with at least 4% of respondents experiencing loss sufficient to necessitate wearing a sanitary napkin or changing underwear several times a day.2-s Previous anecdotal evidence has suggested that Chinese women of low socioeconomic status in Hong Kong “almost never” develop urinary stress incontinence.5 From Hospital,
VOL.
ofOhstetvics
the Depnrtment Chinese University
88, NO.
6, DECEMBER
of Hong
1996
ad Gynecology, Priruze Kong, Hoq Kong.
of Wales
A telephone survey was conducted to determine the prevalence of urinary dysfunction as well as the types of incontinence, the severity of the disorder, its relation to age and parity, and the effects on and attitudes toward the disorder in Hong Kong Chinese women.
Materials and Methods The target population resides in the territory of Hong Kong, which had 2,071,600 females older than 10 years in 1993.h A sample size of greater than 2323 was chosen to produce an error of 2% with a 95% confidence interval, based on the most conservative response rate of 0.41, which had been established in other studies.2-” The telephone questionnaire survey was selected because of the high density of telephones in Hong Kong. At the end of 1994, there were an estimated four million telephones served by 3.1 million exchange lines, representing a density of 66 telephones for every 100 people in Hong Kong7 The total number of residential telephone lines exceeds 1.7 million, with an average of 1.5 lines per household. In 1991, less than 1% of telephone lines were un1isted.s The telephone numbers called were selected by a protocol based on a multi-stage sampling design. First numbers were selected randomly from each of the territory’s three telephone directories in the regions of Hong Kong Island, Kowloon, and the New Territories. Directory page, then line, and then column were each selected randomly for each of the telephone contact numbers by a computer-generated program. Calling status was recorded for each attempted contact: unanswered, business, facsimile, no eligible resident, or uncooperative resident associated with the telephone contact number. Once a contact was made, the research assistants identified themselves by name and informed the contact person that they were conducting an official research project for the Chinese University of Hong Kong. If one or more eligible
0029.7844/96/$15.00
PI1 SOO2Y-7$4~(9(7)00335-3
1041
Table
1.
Number
of Women According
urgency/u1
SI’
Age (Y) <20 20-29 30-39 40-49 50-59 60-69 70 -79 80-89
1 (13%) 9 (4%) 38 (19%) 52 (31%) 36 (42%) 19 (24%) 17 (34%) 2 (20%)
Total
to Age With Urinary
0 16 27 21 19 16 18 3
174 (21%)
Dysfunction* Frequency
(7%) (13%) (13%) (22%) (20%) (35%) (30%)
0 28 (13%) 36 (18%) 31 (19%) 22 (26%) 19 (24%) 16 (31%) 2 (20%)
120 (15%)
154 (19%)
Nocturia’
Voiding
No.
(10%) (14%) (17%) (28%) (41%) (51%) (50%)
3 (38%) 14 (7%) 28 (1491) 30 (18%) 11 (13%) 14 (18%) 9 (18%) 0
8 215 203 167 86 79 51 10
166 (20%)
109 (13%)
819
0 22 28 29 24 32 26 5
SI = stress incontinence; UI = urge incontinence; frequency = seven or more voids per day; nocturia = two or more voids per night; lroiding = incomplete emptying or poor stream. * Each woman may have more than one symptom. ’ Significant correlation (P < .05) using Spearman rank correlation.
respondents resided in the household, a final random selection of one respondent was made from the ordinal order of the age of all eligible respondents. The selected individual was advised of the purpose of the study, and anonymity was assured. The questionnaire was devised using a urinary dysfunction questionnaire derived from the Kings College Urodynamics Questionnaire, using standardized terminology for ease of comparison and translation into Chinese.‘,“’ To assess accuracy, reverse translation was then performed by an independent agent. This questionnaire was validated initially on a group of 50 local Cantonese speakers who were fluent in English, all of whom confirmed that it was easily understood and accurately translated. In this study, incontinence was defined as involuntary loss of urine that is either socially or hygienically unacceptable. Urine loss was not quantified, although the severity of the problem was gauged by whether the woman needed to wear pads or was incapacitated by urinary dysfunction. To determine the prevalence throughout the territory, we included all age groups and regions. The study population was compared with mid-year population projections to determine applicability of the findings to the general population” using Wilcoxon signed-rank test after stratification by age. All data were entered into a data base and analyzed using S-PLUS for Windows, version 3.3 (StatSci Division, Seattle, WA). Spearman rank correlation was used to assess the association between age and urinary dysfunction. The 2 test then was used to test for differences in the frequency of urinary dysfunction among patients of different parity, and also the mean ages of those who sought help from different sources. Finally, generalized additive logistic regression12 was used to investigate the significance of occurrence of urinary symptoms and parity, adjusting for the patient’s age.
1042
Brieger
et al
Urinnry
Dysf~firm-tior~
in Hong
Koq
The study was approved by the clinical ethics committee of the Chinese University Kong.
research of Hong
Red ts Three thousand two hundred forty-eight calls were made, resulting in 819 (25%) evaluable responses. The mean (2 standard deviation) age of the respondents was 41.5 2 16 years (range, 12-89). Thirty-three percent (271) of the respondents were nulliparous and 13% (106) were primiparous; parity ranged from one to nine. Table 1 shows the number of women with urinary dysfunction according to age. Stress incontinence occurred as the only symptom in 7% (53); the combination of urgency and frequency occurred in 1% (11) and mixed symptoms in 6% (52). Bed-wetting was reported by 4% (31). There was an increase in the symptoms of urgency, urge incontinence, frequency, and nocturia with increasing age, as shown in Table 1. Voiding difficulties and nocturnal enuresis were unrelated to age. The occurrence of stress incontinence, urgency and urge incontinence, frequency, nocturia, and voiding difficulties increased with increasing parity to para 4 (Table 2). After adjustment for age using additive logistic regression, stress incontinence (P < ,001) and frequency (P < ,001) were found to be significantly related to parity. Four percent required protective underwear or pads, with 2% wearing protective underwear continuously. Four percent reported that they were incapacitated by their incontinence, as defined by the woman’s own opinion that it interfered significantly with her daily activity. Of the women with urinary dysfunction who sought help, 27% (130) had consulted a general practitioner, 8% (36) a Chinese herbalist, and 15% (70) a specialist medical practitioner for management. Women who
Obstetrics
& Gynecology
Table
2. Number
of Women
According
to Parity
With
Specific
Symptoms* Total
Parity
SI+
Urgency
/ UI’
Frequency’
0 1
14 (5%) 21 (22%)
20 (7%) 12 (11%)
26 (10%) 21 (20%)
2 3 4
54 (28%) 42 (37%) 28 (42%)
23 (12%) 28 (24%) 19 (28%)
38 (20%) 36 (31%) 22 (32%)
5 6
9 (30%) 2 (14%) 4 (33%)
8 (26%) 2 (13%) 6 (50%)
2 (7%) 4 (27%) 3 (25%)
0
2 (25%) 0
2 (25%) 0
7 8 9
0
Nocturia’
Voiding’
tl0.
26 (10%)
22 (8%)
271
21 (20%) 36 (19%)
13 (12%) 27 (14%)
106 191
32 (28%) 25 (37%) 7 (23%)
21 (18%) 16 (24%) 5 (16%)
116 68 31
5 (33%) 9 (75%)
2 (13%) 2 (17%)
15 12
5 (63%) 0
1 (13k) 0
8 1
Abbreviations as in Table 1. * Each woman may have more than one symptom + Significant difference (P < .05) using 2 test.
consulted a Chinese herbalist tended to be older (mean 55.8 years) than those who attended a specialist clinic (mean 44.7 years) or visited a general practitioner (mean 47.6 years) (P < .05). Of those who had not sought help, 5% (23) claimed that they were too embarrassed, 4% (20) had no time, 42% (201) stated that the problem was not severe enough, and 17% (82) did not know that help was available. The remainder declined to give a reason. Comparison using the Wilcoxon signed-rank test between the number of individuals in the survey sample and the expected number of females calculated from the Hong Kong population projections, after stratification by age, showed that despite an under-representation of the population percentages in the age group less than 20 years, the overall goodness of fit between them was good (P = .4) (Table 3).
Discussian In 1977, Zacharin5 reported on the pelvic-floor dissections of 30 Chinese female cadavers aged 12-83 years. He was motivated by observations made by local hospital staff in China and Hong Kong at the time, suggesting that urinary incontinence and genital prolapse were
Table
3. Goodness-of-Fit Statistics
Age
group
Test to Projected Population
for 819 Women Survey population
(VI 420
Projected
population
(females
8 (1%)
X 000)
20-29 30-39
215 (26%) 203 (25%)
384.1 496.9 611.5
40-49 50-59
167 (20%) 86 (11%)
411.2 218.7
(14%) (8%)
60-69 70-79 SO-89
79 (10%) 51 (6%) 10 (1%)
225.2 147.9
(8%) (5%)
P = .4 using
VOL.
88, NO.
Wilcoron
6, DECEMBER
signed-rank
1996
(26%) (17%) (21%)
66.3 (2%) test
seldom encountered in hospital practice. Among his conclusions were that Chinese women of low socioeconomic status “almost never” developed urinary stress incontinence and “rarely” had prolapse.5 These conclusions were not supported by quantitative data concerning the prevalence of urinary dysfunction in Hong Kong; however, the belief that prolapse and stress incontinence are uncommon in this population has prevailed in the Western literature.13 The results of this cross-sectional study suggest that the situation in Hong Kong today is different from that reported by Zacharin5 more than 20 years ago. It also appears to be different from the situation in some provinces in China today.14 Furthermore, this study indicates that urinary dysfunction and its patterns are similar in Hong Kong Chinese as they are in other, primarily white, populations that have been studied. Urodynamic services are now available in Hong Kong in some government hospitals, reflecting a demand that perhaps did not exist 20 years ago. The overall prevalence of stress incontinence of 22%, with 7% having pure stress incontinence-one of the most reliable indicators of an objective diagnosis of genuine stress incontinence’“-is consistent with other is similar, inreports.‘r3 The pattern of incontinence creasing with parity up to 41m3 (the decrease after parity 4 may have been influenced by the small numbers in those groups) and with age, reaching a maximum between the fifth and sixth decades and then decreasing.’ The presence of incontinence in nulliparous women mirrors findings in the Western literature.‘-” The prevalence of urgency, urge incontinence, frequency, nocturia, and voiding difficulties is also substantial, with an increase in nocturia and urgency with age. The relation of age to nocturia is similar to that reported in Western populations.” The proportion of women “incapacitated” by urinary dysfunction resem-
Brieger et al
Urinnry
Dysfunctions
in
Hong
Kong
1043
blcs that reported in Western populations, although the number requiring protection is less.‘,” An attitude change in the Chinese toward Western medicine in Hong Kong has been documented, with a greater reliance on a combination of Western and traditional Chinese medicine rather than on Chinese medicine alone.” Western-style medicine has become much more accessible to the Chinese, with increasing prosperity and the resultant increase in government spending on health care. Nevertheless, the number of women who did not seek help because they felt that their problem was not severe enough or because they were too embarrassed is slightly higher than Western figures.’ These observations, as well as the findings that older women attended Chinese herbalists more often for this condition and that a high proportion of women did not know that help was available, may explain the apparent rarity of stress incontinence reported in Hong Kong circa 1976, given that the observations were made by clinicians working in government hospitals at that time. Telephone surveys are a reliable method for conducting prevalence studies.17 The response rate in Hong Kong to telephone interviews is generally higher than for person-to-person interviews because of security concerns by residents, who are usually reluctant to open the door to strangers.” The telephone survey, however, may have introduced some volunteer bias.‘” The 25% response rate is low; however, this percentage was calculated using a denominator including the total number of calls (all unanswered, business, facsimile, no eligible respondent, and uncooperative responses). It is a cultural characteristic of people in Hong Kong to hang up if an unfamiliar voice is heard on the other end of the line. Furthermore, respondents agreed to participate in the survey before the subject matter was revealed to her. Therefore, the actual bias may not be as great as that suggested by the apparently poor response rate. The percentage of under-representation at the extremes of age less than 20 years reflects children, for whom the findings are probably not applicable; however, the goodness-of-fit test indicated good precision overall. Further research focusing on why the response rate to the telephone survey was lower than expected will determine how applicable these results are to the general Hong Kong population. Nevertheless, the notion that urinary incontinence is rare in Hong Kong Chinese women should, at the very least, be reconsidered.
1. Thomas TN, Plymat urinary incontinence.
Brieger
Address
reprint
requests
to:
G. M. Brieger, FRACOG Dqmtment of Obstetrics and Gynecology Prince of Wales Hospital Chinese UnizJersity of Hong Kong Shatin, New Territories Hong
Kong
Received May 28, 1996. Received in revised form July 30, 1996. Accepted August 22, 1996.
References
1044
2. Jolleys JV. Reported prevalence of urinary incontinence in women in general practice. BMJ 1988;296:1300-2. 3. Sommer P, Bauer T, Nielson KK, Kristensen ES, Hermann GG, Steven K, et al. Voiding patterns and prevalence of urinary incontinence in women. A questionnaire survey. Br J Urol1990;66: 12-5. 4. losif CS, Bekassy 2. Prevalence of genito-urinary symptoms in the late menopause. Acta Obstet Gynecol Stand 1984;63:257-60. 5. Zacharin RF. “A Chinese anatomy”-the pelvic supporting tissues of the Chinese and Occidental female compared and contrasted. Aust N Z J Obstet Cynaecol 1977;17:1-11. 6. Lee SH. Annual departmental report by director of health for the financial year 1992-1993. Hong Kong: Department of Health, 1994. 7. Daryanani R, ed. Hong Kong 1995. Government information services. Hong Kong: Government Printing Department, 1995. 8. Hong Kong Telecommunications Ltd. Annual report 1990-91. Hong Kong: Hong Kong Telecommunications Ltd, 1991. 9. Cardozo L, Cutner A, Wise B. History and examination. In: Basic urogynaecology. Oxford: Oxford University Press, 1993:31-41. 10. Abrams P, Blaivas JG, Stanton SL, Anderson JT. The standardisation of terminology of lower urinary tract function. Br J Obstet Gynaecol 1990;6(suppl):l-16. 11. Demographic and Statistics Section, Census and Statistics Department. Hong Kong population projections 1992-2011. Hong Kong: Hong Kong Government, 1992. 12. Hastie TJ, Tibshirani RJ. Generalized additive models: Some applications. JASA 1987;82:371-86. 13. Mackenzie TM, Chan LW, Yuen PM, Ng CF, Chan PSF. Uterine prolapse and acute renal failure in a Chinese patient. Aust N Z J Obstet Gynaecol 1995;35:461-2. 14. Brieger GM, Yip SK, Fung YM, Chung T. Genital prolapse: A legacy of the West? Aust N Z J Obstet Gynaecol 1996;36:52-4. 15. Haylon BT, Sutherst JR, Frazer MI. Is the investigation of stress incontinence really necessary? Br J Ural 1989;64:147-9. 16. Lee RI’. Perceptions and uses of Chinese medicine among the Chinese in Hong Kong. Cult Med Psychiatry 1980;4:345-75. 17. Lam TH, Kleevens JWL, Wong CM. Doctor-consultation in Hong Kong: A comparison between findings of a telephone interview with the general household survey. Community Med 1988;lO: 175-9. 18. Wong TW, Wong SL, Donnan SPB. Traditional Chinese medicine and Western medicine in Hong Kong: A comparison of the consultation process and side effects. J Hong Kong Med Assoc 1993;45:278-84. 19. Designing research. In: Altman DG. Practical statistics for medical research. London: Chapman and Hall, 1991:74-103.
et al
KR, Blannin J, Meade BMJ 1980;281:1243-5.
Urirwy
Dysfim3iorl
TW.
Prevalence
in Hong Kong
of
Copyright % 1996 by The American College of Obstetricians Gynecologists. Published by Elsevier Science Inc.
Obstetrics
6 Gynecology
and
in
G. M. BRIEGER, FRACOG, S. K. YIP, MRCOG, L. Y. HIN, MBChB, AND T. K. H. CHUNG, FRACOG Objective: To determine the prevalence of urinary dysfunction in Hong Kong Chinese women. Methods: A telephone survey was conducted in the territory of Hong Kong. The subjects were a sample of women between the ages of 10 and 90 years. The main outcome determined was the prevalence of urinary dysfunction. Results: We made 3248 calls, resulting in 819 evaluable responses. Stress incontinence was reported by 21% (174) of respondents, urgency or urge incontinence in 15% (1201, urinary frequency in 19% (154), nocturia in 20% (1661, bed-wetting in 4% (311, and voiding difficulties in 13% (109). Stress incontinence occurred as the only symptom in 7% (53), the combination of urgency and frequency in 1% (ll), and mixed symptoms in 6% (52). Four percent required protective underwear or pads, with 2% wearing protective underwear continuously; 4% were incapacitated by their incontinence. Symptoms of urgency, urge incontinence, frequency, and nocturia increased with increasing age, but voiding difficulties and nocturnal enuresis were unrelated to age. Stress incontinence, urgency, urge incontinence, frequency, nocturia, and voiding difficulties increased with increasing parity to para 4. Conclusion: Urinary dysfunction and its patterns appear to be as common and incapacitating in Hong Kong Chinese as they are in other populations. (Obstet Gynecol 1996;88: 2041-4. Copyright 0 2996 by The American College of Obstetricians and Gynecologists.)
The prevalence of urinary dysfunction in randomly selected groups of white women ranges from 8% to 41%.lt2 Questionnaire surveys concerning urinary incontinence report a response rate of 69-89%, with at least 4% of respondents experiencing loss sufficient to necessitate wearing a sanitary napkin or changing underwear several times a day.2-s Previous anecdotal evidence has suggested that Chinese women of low socioeconomic status in Hong Kong “almost never” develop urinary stress incontinence.5 From Hospital,
VOL.
ofOhstetvics
the Depnrtment Chinese University
88, NO.
6, DECEMBER
of Hong
1996
ad Gynecology, Priruze Kong, Hoq Kong.
of Wales
A telephone survey was conducted to determine the prevalence of urinary dysfunction as well as the types of incontinence, the severity of the disorder, its relation to age and parity, and the effects on and attitudes toward the disorder in Hong Kong Chinese women.
Materials and Methods The target population resides in the territory of Hong Kong, which had 2,071,600 females older than 10 years in 1993.h A sample size of greater than 2323 was chosen to produce an error of 2% with a 95% confidence interval, based on the most conservative response rate of 0.41, which had been established in other studies.2-” The telephone questionnaire survey was selected because of the high density of telephones in Hong Kong. At the end of 1994, there were an estimated four million telephones served by 3.1 million exchange lines, representing a density of 66 telephones for every 100 people in Hong Kong7 The total number of residential telephone lines exceeds 1.7 million, with an average of 1.5 lines per household. In 1991, less than 1% of telephone lines were un1isted.s The telephone numbers called were selected by a protocol based on a multi-stage sampling design. First numbers were selected randomly from each of the territory’s three telephone directories in the regions of Hong Kong Island, Kowloon, and the New Territories. Directory page, then line, and then column were each selected randomly for each of the telephone contact numbers by a computer-generated program. Calling status was recorded for each attempted contact: unanswered, business, facsimile, no eligible resident, or uncooperative resident associated with the telephone contact number. Once a contact was made, the research assistants identified themselves by name and informed the contact person that they were conducting an official research project for the Chinese University of Hong Kong. If one or more eligible
0029.7844/96/$15.00
PI1 SOO2Y-7$4~(9(7)00335-3
1041
Table
1.
Number
of Women According
urgency/u1
SI’
Age (Y) <20 20-29 30-39 40-49 50-59 60-69 70 -79 80-89
1 (13%) 9 (4%) 38 (19%) 52 (31%) 36 (42%) 19 (24%) 17 (34%) 2 (20%)
Total
to Age With Urinary
0 16 27 21 19 16 18 3
174 (21%)
Dysfunction* Frequency
(7%) (13%) (13%) (22%) (20%) (35%) (30%)
0 28 (13%) 36 (18%) 31 (19%) 22 (26%) 19 (24%) 16 (31%) 2 (20%)
120 (15%)
154 (19%)
Nocturia’
Voiding
No.
(10%) (14%) (17%) (28%) (41%) (51%) (50%)
3 (38%) 14 (7%) 28 (1491) 30 (18%) 11 (13%) 14 (18%) 9 (18%) 0
8 215 203 167 86 79 51 10
166 (20%)
109 (13%)
819
0 22 28 29 24 32 26 5
SI = stress incontinence; UI = urge incontinence; frequency = seven or more voids per day; nocturia = two or more voids per night; lroiding = incomplete emptying or poor stream. * Each woman may have more than one symptom. ’ Significant correlation (P < .05) using Spearman rank correlation.
respondents resided in the household, a final random selection of one respondent was made from the ordinal order of the age of all eligible respondents. The selected individual was advised of the purpose of the study, and anonymity was assured. The questionnaire was devised using a urinary dysfunction questionnaire derived from the Kings College Urodynamics Questionnaire, using standardized terminology for ease of comparison and translation into Chinese.‘,“’ To assess accuracy, reverse translation was then performed by an independent agent. This questionnaire was validated initially on a group of 50 local Cantonese speakers who were fluent in English, all of whom confirmed that it was easily understood and accurately translated. In this study, incontinence was defined as involuntary loss of urine that is either socially or hygienically unacceptable. Urine loss was not quantified, although the severity of the problem was gauged by whether the woman needed to wear pads or was incapacitated by urinary dysfunction. To determine the prevalence throughout the territory, we included all age groups and regions. The study population was compared with mid-year population projections to determine applicability of the findings to the general population” using Wilcoxon signed-rank test after stratification by age. All data were entered into a data base and analyzed using S-PLUS for Windows, version 3.3 (StatSci Division, Seattle, WA). Spearman rank correlation was used to assess the association between age and urinary dysfunction. The 2 test then was used to test for differences in the frequency of urinary dysfunction among patients of different parity, and also the mean ages of those who sought help from different sources. Finally, generalized additive logistic regression12 was used to investigate the significance of occurrence of urinary symptoms and parity, adjusting for the patient’s age.
1042
Brieger
et al
Urinnry
Dysf~firm-tior~
in Hong
Koq
The study was approved by the clinical ethics committee of the Chinese University Kong.
research of Hong
Red ts Three thousand two hundred forty-eight calls were made, resulting in 819 (25%) evaluable responses. The mean (2 standard deviation) age of the respondents was 41.5 2 16 years (range, 12-89). Thirty-three percent (271) of the respondents were nulliparous and 13% (106) were primiparous; parity ranged from one to nine. Table 1 shows the number of women with urinary dysfunction according to age. Stress incontinence occurred as the only symptom in 7% (53); the combination of urgency and frequency occurred in 1% (11) and mixed symptoms in 6% (52). Bed-wetting was reported by 4% (31). There was an increase in the symptoms of urgency, urge incontinence, frequency, and nocturia with increasing age, as shown in Table 1. Voiding difficulties and nocturnal enuresis were unrelated to age. The occurrence of stress incontinence, urgency and urge incontinence, frequency, nocturia, and voiding difficulties increased with increasing parity to para 4 (Table 2). After adjustment for age using additive logistic regression, stress incontinence (P < ,001) and frequency (P < ,001) were found to be significantly related to parity. Four percent required protective underwear or pads, with 2% wearing protective underwear continuously. Four percent reported that they were incapacitated by their incontinence, as defined by the woman’s own opinion that it interfered significantly with her daily activity. Of the women with urinary dysfunction who sought help, 27% (130) had consulted a general practitioner, 8% (36) a Chinese herbalist, and 15% (70) a specialist medical practitioner for management. Women who
Obstetrics
& Gynecology
Table
2. Number
of Women
According
to Parity
With
Specific
Symptoms* Total
Parity
SI+
Urgency
/ UI’
Frequency’
0 1
14 (5%) 21 (22%)
20 (7%) 12 (11%)
26 (10%) 21 (20%)
2 3 4
54 (28%) 42 (37%) 28 (42%)
23 (12%) 28 (24%) 19 (28%)
38 (20%) 36 (31%) 22 (32%)
5 6
9 (30%) 2 (14%) 4 (33%)
8 (26%) 2 (13%) 6 (50%)
2 (7%) 4 (27%) 3 (25%)
0
2 (25%) 0
2 (25%) 0
7 8 9
0
Nocturia’
Voiding’
tl0.
26 (10%)
22 (8%)
271
21 (20%) 36 (19%)
13 (12%) 27 (14%)
106 191
32 (28%) 25 (37%) 7 (23%)
21 (18%) 16 (24%) 5 (16%)
116 68 31
5 (33%) 9 (75%)
2 (13%) 2 (17%)
15 12
5 (63%) 0
1 (13k) 0
8 1
Abbreviations as in Table 1. * Each woman may have more than one symptom + Significant difference (P < .05) using 2 test.
consulted a Chinese herbalist tended to be older (mean 55.8 years) than those who attended a specialist clinic (mean 44.7 years) or visited a general practitioner (mean 47.6 years) (P < .05). Of those who had not sought help, 5% (23) claimed that they were too embarrassed, 4% (20) had no time, 42% (201) stated that the problem was not severe enough, and 17% (82) did not know that help was available. The remainder declined to give a reason. Comparison using the Wilcoxon signed-rank test between the number of individuals in the survey sample and the expected number of females calculated from the Hong Kong population projections, after stratification by age, showed that despite an under-representation of the population percentages in the age group less than 20 years, the overall goodness of fit between them was good (P = .4) (Table 3).
Discussian In 1977, Zacharin5 reported on the pelvic-floor dissections of 30 Chinese female cadavers aged 12-83 years. He was motivated by observations made by local hospital staff in China and Hong Kong at the time, suggesting that urinary incontinence and genital prolapse were
Table
3. Goodness-of-Fit Statistics
Age
group
Test to Projected Population
for 819 Women Survey population
(VI 420
Projected
population
(females
8 (1%)
X 000)
20-29 30-39
215 (26%) 203 (25%)
384.1 496.9 611.5
40-49 50-59
167 (20%) 86 (11%)
411.2 218.7
(14%) (8%)
60-69 70-79 SO-89
79 (10%) 51 (6%) 10 (1%)
225.2 147.9
(8%) (5%)
P = .4 using
VOL.
88, NO.
Wilcoron
6, DECEMBER
signed-rank
1996
(26%) (17%) (21%)
66.3 (2%) test
seldom encountered in hospital practice. Among his conclusions were that Chinese women of low socioeconomic status “almost never” developed urinary stress incontinence and “rarely” had prolapse.5 These conclusions were not supported by quantitative data concerning the prevalence of urinary dysfunction in Hong Kong; however, the belief that prolapse and stress incontinence are uncommon in this population has prevailed in the Western literature.13 The results of this cross-sectional study suggest that the situation in Hong Kong today is different from that reported by Zacharin5 more than 20 years ago. It also appears to be different from the situation in some provinces in China today.14 Furthermore, this study indicates that urinary dysfunction and its patterns are similar in Hong Kong Chinese as they are in other, primarily white, populations that have been studied. Urodynamic services are now available in Hong Kong in some government hospitals, reflecting a demand that perhaps did not exist 20 years ago. The overall prevalence of stress incontinence of 22%, with 7% having pure stress incontinence-one of the most reliable indicators of an objective diagnosis of genuine stress incontinence’“-is consistent with other is similar, inreports.‘r3 The pattern of incontinence creasing with parity up to 41m3 (the decrease after parity 4 may have been influenced by the small numbers in those groups) and with age, reaching a maximum between the fifth and sixth decades and then decreasing.’ The presence of incontinence in nulliparous women mirrors findings in the Western literature.‘-” The prevalence of urgency, urge incontinence, frequency, nocturia, and voiding difficulties is also substantial, with an increase in nocturia and urgency with age. The relation of age to nocturia is similar to that reported in Western populations.” The proportion of women “incapacitated” by urinary dysfunction resem-
Brieger et al
Urinnry
Dysfunctions
in
Hong
Kong
1043
blcs that reported in Western populations, although the number requiring protection is less.‘,” An attitude change in the Chinese toward Western medicine in Hong Kong has been documented, with a greater reliance on a combination of Western and traditional Chinese medicine rather than on Chinese medicine alone.” Western-style medicine has become much more accessible to the Chinese, with increasing prosperity and the resultant increase in government spending on health care. Nevertheless, the number of women who did not seek help because they felt that their problem was not severe enough or because they were too embarrassed is slightly higher than Western figures.’ These observations, as well as the findings that older women attended Chinese herbalists more often for this condition and that a high proportion of women did not know that help was available, may explain the apparent rarity of stress incontinence reported in Hong Kong circa 1976, given that the observations were made by clinicians working in government hospitals at that time. Telephone surveys are a reliable method for conducting prevalence studies.17 The response rate in Hong Kong to telephone interviews is generally higher than for person-to-person interviews because of security concerns by residents, who are usually reluctant to open the door to strangers.” The telephone survey, however, may have introduced some volunteer bias.‘” The 25% response rate is low; however, this percentage was calculated using a denominator including the total number of calls (all unanswered, business, facsimile, no eligible respondent, and uncooperative responses). It is a cultural characteristic of people in Hong Kong to hang up if an unfamiliar voice is heard on the other end of the line. Furthermore, respondents agreed to participate in the survey before the subject matter was revealed to her. Therefore, the actual bias may not be as great as that suggested by the apparently poor response rate. The percentage of under-representation at the extremes of age less than 20 years reflects children, for whom the findings are probably not applicable; however, the goodness-of-fit test indicated good precision overall. Further research focusing on why the response rate to the telephone survey was lower than expected will determine how applicable these results are to the general Hong Kong population. Nevertheless, the notion that urinary incontinence is rare in Hong Kong Chinese women should, at the very least, be reconsidered.
1. Thomas TN, Plymat urinary incontinence.
Brieger
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G. M. Brieger, FRACOG Dqmtment of Obstetrics and Gynecology Prince of Wales Hospital Chinese UnizJersity of Hong Kong Shatin, New Territories Hong
Kong
Received May 28, 1996. Received in revised form July 30, 1996. Accepted August 22, 1996.
References
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