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© The Canadian Journal of Urology™; 23(Supplement 1); February 2016
3
Gender differences in overactive bladder
countries. Multiple studies have also assessed the
treatment options and impact that OAB has on
quality of life.
1,2
Although the overall prevalence of
OAB is similar between the two genders, there are
sex specific differences in the prevalence of various
symptoms within the OAB complex.
3,4
Anatomical and
physiological differences in the lower urinary tract of
males and femalesmay help to explain these variations.
4
Additionally, the underlying mechanisms that cause
the outwardly similar symptomatology in men and
women may be different. This review will focus on
the prevalence data in regards to gender differences
and the differences between men and women in terms
of diagnosis, investigations and treatment of OAB.
5-9
Epidemiology
EPIC study
6,7
This is one of the largest population based surveys
that studied the prevalence of lower urinary tract
symptoms (LUTS) and OAB. Conducted in five
countries including Canada and the United Kingdom,
the EPIC study was a cross sectional telephone survey
of adults aged over 18 years. The study had over 19000
participants and showed an overall OAB prevalence of
11.8% with similar rates in men and women.
The EPIC study showed that the prevalence of
LUTS suggestive of OAB was 10.8% in men and 12.8%
in women. LUTS in general were more common in
women than in men (66.6% versus 62.5%). Looking
specifically at urinary incontinence (UI), women had
a much higher rate of any UI (urge, mixed, stress and
other) than men (13.1% versus 5.4%). These studies
dispel the commonly held misconception that OAB
symptoms affect the older population. Approximately
73%of men and 72%of womenwho participated in the
EPIC study were less than 60 years of age. However,
it appears that the prevalence of OAB symptoms does
increase with age in both genders.
The EPIC study reported urinary incontinence
in 13.1% of women and 5.4% of men. Stress urinary
incontinence was the most common type in women
and other urinary incontinence (urge, mixed) wasmore
common in men.
The EPIC study assessed the prevalence of frequency
in the study population, which largely depends on the
definitionused. ICS defined frequency as the perception
of urinating too often during the daytime.
7
Using this
definition, the EPIC study reports that 31% of men and
25% of women who suffered from OAB symptoms had
frequency. Of these, 75% of men and 60% of women
urinated 8 or fewer times during the day, most of them
falling within the 5-8 voids per day range. Women
were more likely than men (19% versus 12%) to report
frequency of more than 8 times per day. Women were
alsomore likely to be bothered by frequency of urination
than men (66% versus 46%).
The EPIC study used the ICS definition of nocturia
as one or more voids during the night. It was found
that the general prevalence of nocturia is 48.6% inmen
and 54.5% in women. In OAB sufferers, however,
the prevalence is 75% of men and 74% of women
suggesting that nocturia occurs commonly in this
syndrome.
The EPIC study confirmed that most patients
with OAB had a combination of symptoms. Urgency
with or without UI in the absence of frequency or
nocturia was present in only 21% of men and 23% of
women. Approximately 50% of OAB patients had a
combination of two symptoms and approximately
one third of patients reported a combination of three
OAB symptoms.
NOBLE study
8
The National Overactive Bladder Evaluation (NOBLE)
program was developed to estimate the prevalence
of OAB and its burden in the United States. It also
assessed the influence of gender on OAB and its
symptoms. The study also focused on the impact
of OAB on quality of life, sleep and general mental
health. The study showed an overall OAB prevalence
of approximately 16% with no significant differences
between the two sexes (16% in men, 16.9% in women).
The general belief that OAB and urgency symptoms are
more common inwomen thanmen is not supported by
the NOBLE study. However, the manifestation of OAB
symptomclusters, level of bother, urodynamic findings
and responses to treatments may differ significantly
between the two genders.
The NOBLE study discovered that specific OAB
symptoms were more common in women than in
men but with increasing age, especially over the age
of 60 years, symptoms were predominant in men.
Although the overall prevalence of OAB in men and
women was similar, the incidence of OAB with and
without urge incontinence showed significant gender
variation. The NOBLE study demonstrated that in
all age groups, OAB without UI was more common
in men than in women.
The NOBLE study also found an association
between OAB with UI and body mass index (BMI) in
women but not men. Women with BMI > 30 were 2.2
times more likely to have OAB with UI than women
with BMI < 24. Menwho reported a history of prostate
problems had a higher prevalence ratio of OAB with
and without UI.