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Keywords:

  • prevalence;
  • lower urinary tract symptoms;
  • overactive bladder;
  • urinary incontinence;
  • bladder outlet obstruction

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. ACKNOWLEDGEMENTS
  8. CONFLICT OF INTEREST
  9. REFERENCES
  10. Supporting Information

Study Type – Symptom prevalence (prospective cohort)

Level of Evidence 1b

What’s known on the subject? and What does the study add?

Few prevalence studies used current ICS LUTS symptom definitions and to our knowledge no studies exist that estimate total worldwide prevalence of reported LUTS symptoms. One of the primary goals of this analysis was to estimate current and future worldwide prevalence of LUTS among adults. Our estimation model suggests that LUTS are highly prevalent worldwide, with an increasing burden predicted over time.

OBJECTIVE

• To estimate and predict worldwide and regional prevalence of lower urinary tract symptoms (LUTS), overactive bladder (OAB), urinary incontinence (UI) and LUTS suggestive of bladder outlet obstruction (LUTS/BOO) in 2008, 2013 and 2018 based on current International Continence Society symptom definitions in adults aged ≥20 years.

PATIENTS AND METHODS

• Numbers and prevalence of individuals affected by each condition were calculated with an estimation model using gender- and age-stratified prevalence data from the EPIC study along with gender- and age-stratified worldwide and regional population estimates from the US Census Bureau International Data Base.

RESULTS

• An estimated 45.2%, 10.7%, 8.2% and 21.5% of the 2008 worldwide population (4.3 billion) was affected by at least one LUTS, OAB, UI and LUTS/BOO, respectively. By 2018, an estimated 2.3 billion individuals will be affected by at least one LUTS (18.4% increase), 546 million by OAB (20.1%), 423 million by UI (21.6%) and 1.1 billion by LUTS/BOO (18.5%).

• The regional burden of these conditions is estimated to be greatest in Asia, with numbers of affected individuals expected to increase most in the developing regions of Africa (30.1–31.1% increase across conditions, 2008–2018), South America (20.5–24.7%) and Asia (19.7–24.4%).

CONCLUSIONS

• This model suggests that LUTS, OAB, UI and LUTS/BOO are highly prevalent conditions worldwide. Numbers of affected individuals are projected to increase with time, with the greatest increase in burden anticipated in developing regions.

• There are important worldwide public-health and clinical management implications to be considered over the next decade to effectively prevent and manage these conditions.


Abbreviations
LUTS

lower urinary tract symptoms

OAB

overactive bladder

UI

urinary incontinence

LUTS/BOO

LUTS suggestive of bladder outlet obstruction

ICS

International Continence Society

IDB

US Census Bureau International Data Base

INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. ACKNOWLEDGEMENTS
  8. CONFLICT OF INTEREST
  9. REFERENCES
  10. Supporting Information

Lower urinary tract symptoms (LUTS), overactive bladder (OAB), urinary incontinence (UI) and LUTS suggestive of bladder outlet obstruction (LUTS/BOO) are prevalent conditions [1,2] and many individuals experience bothersome symptoms that impair their health-related quality of life [3–5]. These conditions are also highly stigmatized [6] and are associated with a substantial economic and human burden [7–9]. According to current (2002) International Continence Society (ICS) definitions, LUTS can be divided into storage (increased daytime frequency, nocturia of at least one episode/night, urgency and UI), voiding (slow or intermittent stream during micturition, splitting or spraying of the urine stream, straining, hesitation, terminal dribble) and postmicturition symptoms (feeling of incomplete emptying and postmicturition dribble) [10].

The prevalence of LUTS, OAB, UI and LUTS/BOO increases with advancing age [1,11–13], and worldwide prevalence is expected to increase, based on the predicted aging of the worldwide population [14]. There are, however, notable inconsistencies across epidemiological studies in reported prevalence rates; for example, reported prevalence rates for male and female populations range from 13%[15] to 67%[16] for LUTS; 7%[17] to 26%[18] for OAB and 4%[19] to 50%[20] for UI. These inconsistencies have been attributed to differences between studies in the questions used for symptom assessment, mode of questionnaire administration, study population and symptom definitions [1,21,22]. Few prevalence studies have used current ICS symptom definitions for LUTS, OAB, UI and LUTS/BOO [23]. Moreover, to our knowledge, no studies have used these definitions to estimate total numbers or overall prevalence of individuals affected by these conditions worldwide.

The primary goal of this analysis was to estimate current and future worldwide prevalence of LUTS, OAB, UI and LUTS/BOO in adults aged ≥20 years using current ICS definitions. A second objective was to estimate the current and future overall prevalence in major geographic regions (i.e. Africa, Asia, Europe, North America and South America). The worldwide and regional numbers and prevalence of affected individuals were estimated for each condition using prevalence data from the EPIC study [1], a large population-based, cross-sectional telephone survey that assessed the prevalence of LUTS, OAB, UI and LUTS/BOO in 19 165 men and women in five countries, and worldwide and regional population estimates from the US Census Bureau International Data Base (IDB) [14].

METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. ACKNOWLEDGEMENTS
  8. CONFLICT OF INTEREST
  9. REFERENCES
  10. Supporting Information

Details of the EPIC survey study were reported previously [1]. Briefly, the EPIC study assessed the prevalence of LUTS, OAB, UI and LUTS/BOO in 19 165 men and women in Canada, Germany, Italy, Sweden and the UK between April and December 2005. Participants were ≥18 years of age and were randomly selected to ensure representation of the general population in their respective country. Prevalence of LUTS, OAB, UI and LUTS/BOO was determined via responses to a computer-assisted telephone interview.

In the present analysis, worldwide and regional numbers of individuals affected by LUTS, OAB, UI and LUTS/BOO were estimated for 2008 and predicted for 2013 and 2018 using gender- and age-specific prevalence data from the EPIC study [1] (including only data for respondents aged ≥20 years stratified into 5-year age groups; see Supplementary material, Table S1) and gender- and age-specific population estimates from the IDB [14] (also stratified into 5-year age groups; see Supplementary material, Table S2). Overall worldwide and regional numbers of individuals affected by each condition were estimated via summation of male and female population estimates. Worldwide and regional prevalence rates were calculated for each condition by dividing the estimated number of affected individuals by the general population (IDB) estimate. Because the ICS definition for nocturia (at least one episode/night) is broad and may capture the normal clinical spectrum [1,24], a more conservative definition of nocturia (at least two episodes/night) was used in worldwide and regional estimates of individuals experiencing at least one LUTS and at least one storage LUTS; ICS guidelines were followed in defining all other LUTS. Worldwide and regional LUTS/BOO estimates were calculated based on the presence of ICS-defined voiding LUTS indicative of BOO. All calculations were made using non-rounded EPIC study and/or IDB source data but the results are presented as rounded figures. No formal statistical analysis was conducted to assess temporal or regional differences in estimates of prevalence rates and numbers of affected individuals. Assumptions made in this estimation model were that the prevalence values determined in countries assessed in the original EPIC study are not, on average, different from prevalence in other locations or worldwide, and that the age- and gender-specific prevalence of these conditions will not change between 2008 and 2018.

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. ACKNOWLEDGEMENTS
  8. CONFLICT OF INTEREST
  9. REFERENCES
  10. Supporting Information

Assuming that the gender- and age-stratified prevalence of LUTS, OAB, UI and LUTS/BOO (as reported in the EPIC study [1]) remain stable over time, this estimation model predicts that worldwide numbers and prevalence of individuals affected by LUTS, OAB, UI and LUTS/BOO will increase between 2008 and 2018. This can be attributed to population growth and overall aging of the worldwide general population. The IDB population estimates forecast that the worldwide population ≥20 years of age will increase by 16.9% between 2008 (4.3 billion) and 2018 (5.0 billion), with an 11% increase between 2008 and 2018 in the proportion of individuals aged ≥45 years (40.4% to 44.9%).

The IBD estimates that in 2008, approximately 465 million individuals ≥20 years of age were residing in Africa, 2.6 billion in Asia, 572 million in Europe, 360 million in North America and 247 million in South America. Similar to worldwide estimates, the numbers and prevalence of individuals affected by LUTS, OAB, UI and LUTS/BOO are expected to increase between 2008 and 2018 in each region because of population growth and overall aging of the general population. However, there is considerable variation between regions in the estimated increase of the general population. Africa is projected to have the greatest population increase (29.3%), followed by South America (18.6%), Asia (17.8%), North America (13.9%) and Europe, (0.8%). The growth of the aging population is also expected to differ across regions, with the greatest increase in Asia (16.1% increase between 2008 and 2018 in the proportion of individuals aged ≥45 years), followed by South America (13.5%), Europe (8.0%), North America (6.7%) and Africa (2.4%).

Proportions of men and women in worldwide and regional populations are estimated to change ≤0.5% between 2008 and 2018.

Estimated worldwide numbers of individuals aged ≥20 years experiencing LUTS are shown by symptom category type, gender and year in Table 1. Approximately 1.9 billion individuals in the 2008 worldwide population were estimated as experiencing any LUTS, with numbers of affected individuals projected to increase by 9.3% to 2.1 billion in 2013 and by 18.4% to 2.3 billion in 2018. The worldwide prevalence of LUTS is anticipated to increase from 45.2% in 2008 to 45.8% by 2018. The prevalence of LUTS is estimated as being greater in women than men in 2008 (46.3% vs 44.1%, respectively), 2013 (46.5% vs 44.4%) and 2018 (46.8% vs 44.7%).

Table 1.  Estimated worldwide number of individuals with LUTS by type, gender and year
ConditionMale populationFemale populationTotal population
200820132018200820132018200820132018
  • *

    Nocturia defined as at least one episode/night.

  • Nocturia defined as at least two episodes/night.

  • ‡Participants reporting both urgency UI and stress UI symptoms were classified as having mixed UI. Those who reported UI without symptoms of urgency UI or stress UI were categorized as having other UI.

  • §

    §Indicator of LUTS suggestive of bladder outlet obstruction in the present analysis. LUTS, lower urinary tract symptoms; OAB, overactive bladder; UI, urinary incontinence.

Any LUTS*1 259 424 8771 377 756 2391 494 129 4311 382 747 5581 508 619 1021 632 626 6782 642 172 4352 886 375 3413 126 756 109
Any LUTS932 947 0201 020 763 2571 107 206 981995 968 8191 086 969 4341 176 252 5021 928 915 8392 107 732 6912 283 459 483
Storage LUTS         
 Any storage LUTS*1 049 604 9051 151 554 0801 253 722 1071 252 107 3261 367 719 6501 482 792 2902 301 712 2312 519 273 7292 736 514 397
 Any storage LUTS597 219 718655 873 843715 093 706761 920 081833 875 985905 668 5681 359 139 7991 489 749 8281 620 762 275
 Nocturia ≥1 time/night942 162 9431 035 519 5161 130 404 4161 100 002 3391 203 619 7771 307 753 3362 042 165 2822 239 139 2932 438 157 752
 Nocturia ≥2 times/night387 875 072427 555 413468 789 610464 940 904510 905 415558 338 637852 815 976938 460 8281 027 128 247
 Urgency204 975 873226 043 985247 478 322249 837 613274 366 611298 569 985454 813 487500 410 596546 048 307
 Frequency126 696 352139 367 165152 325 169160 947 117174 399 799186 877 992287 643 469313 766 964339 203 161
 Any UI97 926 056109 245 296120 578 611250 205 314276 439 685302 919 365348 131 370385 684 981423 497 976
  Mixed UI 11 008 01512 307 13713 655 24542 645 80647 578 01052 682 70653 653 82159 885 14666 337 951
  Stress UI10 378 899 11 658 46613 064 025127 568 529140 670 362153 534 055137 947 428152 328 829166 598 080
  Urgency UI22 008 07724 673 12127 442 74927 268 01230 096 69932 937 46649 276 09054 769 82060 380 215
  Other UI54 722 57160 811 31466 632 88953 006 91558 405 02664 128 218107 729 486119 216 340130 761 108
Voiding LUTS         
 Any voiding LUTS§514 768 768563 516 317612 034 508402 617 124439 325 111475 263 932917 385 8921 002 841 4281 087 298 441
 Intermittency164 269 137180 990 603198 176 329148 382 880162 253 590175 999 877312 652 017343 244 193374 176 206
 Slow stream156 320 309173 766 759193 589 613122 766 573134 771 536146 998 916279 086 882308 538 296340 588 530
 Straining132 186 270145 246 389158 023 19783 353 09790 734 40298 184 808215 539 367235 980 791256 208 005
 Terminal dribble288 892 001315 397 622341 268 312210 911 393229 398 652246 978 098499 803 393544 796 274588 246 410
Post-micturition LUTS         
 Any post-micturition LUTS332 189 247364 739 378397 357 370297 620 365324 360 340350 599 698629 809 613689 099 717747 957 069
 Incomplete emptying262 522 471288 484 165314 632 596257 979 864280 958 427303 568 531520 502 335569 442 592618 201 127
 Other post-micturition incontinence107 544 267 118 200 573128 976 03164 037 01870 068 48676 044 295171 581 285188 269 059205 020 326
OAB syndrome204 975 873226 043 985247 478 322249 837 613274 366 611298 569 985454 813 486500 410 597546 048 307

Storage symptoms, the most common LUTS subtype, are estimated to affect 1.4 billion individuals in 2008, 1.5 billion in 2013 (9.6% increase) and 1.6 billion in 2018 (19.2% increase from 2008); the prevalence of storage symptoms is estimated to increase from 31.8% in 2008 to 32.5% in 2018. Numbers of individuals experiencing voiding and postmicturition LUTS in 2008 (917 million and 630 million, respectively) are estimated to increase 9.3% and 9.4% by 2013 and by 18.5% and 18.8% by 2018, respectively. The prevalence of voiding LUTS is anticipated to increase from 21.5% in 2008 to 21.8% in 2018 and the prevalence of postmicturition LUTS is expected to increase from 14.7% in 2008 to 15.0% in 2018. Women are estimated to have a higher prevalence of at least one storage LUTS than men (35.4% vs 28.2% in 2008, 35.7% vs 28.5% in 2013, 36.0% vs 28.9% in 2018, respectively). Conversely, a lower prevalence is estimated in women versus men for at least one voiding LUTS (18.7% vs 24.3% in 2008, 18.8% vs 24.5% in 2013, 18.9% vs 24.7% in 2018, respectively) and at least one postmicturition LUTS (13.8% vs 15.7% in 2008, 13.9% vs 15.9% in 2013, 13.9% vs 16.1% in 2018).

Estimated numbers of individuals affected by LUTS in 2008, 2013 and 2018 are greatest in the region of Asia, followed by Europe, Africa, North America and South America (Fig. 1A). These values are expected to increase most rapidly between 2008 and 2018 in the developing regions of Africa (30.1%), South America (20.5%) and Asia (19.7%), with a relatively small predicted increase in Europe (2.5%). The 2008 and 2018 prevalence of LUTS is estimated as being similar across regions, with the highest values in Europe (47.6% and 48.4%, respectively; 1.8% increase over time), followed by North America (46.3% and 47.0%; 1.5% increase), Asia (44.8% and 45.5%; 1.6% increase), South America (44.8% and 45.5%; 1.6% increase) and Africa (43.9% and 44.2%; 0.7% increase).

image

Figure 1. Estimated numbers of individuals in major world regions affected by (A) any lower urinary tract symptom (LUTS; nocturia defined as at least two episodes/night), (B) overactive bladder (OAB), (C) urinary incontinence (UI) and (D) LUTS suggestive of bladder outlet obstruction (LUTS/BOO) in 2008, 2013 and 2018.*Percentage increase in the number of affected individuals from 2008 to 2013. Percentage increase in the number of affected individuals from 2008 to 2018.

Download figure to PowerPoint

Estimated worldwide numbers of individuals aged ≥20 years experiencing OAB are shown by gender and year in Table 1. An estimated 455 million individuals worldwide experienced OAB in 2008, with numbers of affected individuals anticipated to increase to 500 million by 2013 (10.0% increase) and to 546 million by 2018 (20.1% increase). Worldwide prevalence is anticipated to increase from 10.7% in 2008 to 10.9% by 2018. The prevalence of OAB worldwide is estimated as being greater in women versus men in 2008 (11.6% vs 9.7%, respectively), 2013 (11.7% vs 9.8%) and 2018 (11.9% vs 10.0%).

As with LUTS, both the 2008 and 2018 burden of OAB is estimated as being greatest in Asia, followed by Europe, Africa, North America and South America (Fig. 1B), with the greatest increases in numbers of affected individuals projected in the developing regions of Africa, South America and Asia (31.1%, 22.4% and 22.1% increase, respectively, from 2008 to 2018). The 2008 and 2018 prevalence of OAB is estimated as being similar across regions, with the highest values in Europe (11.9% in 2008 and 12.3% in 2018), followed by North America (11.2% and 11.6%), South America (10.5% and 10.8%), Asia (10.5% and 10.8%) and Africa (9.9% at both time points).

Estimated worldwide numbers of individuals aged ≥20 years experiencing UI are shown by UI type, gender and year in Table 1. Approximately 348 million individuals worldwide in 2008 experienced any UI, with numbers of affected individuals projected to increase 10.8% to 386 million by 2013 and 21.6% to 423 million by 2018. The worldwide prevalence of UI is anticipated to increase from 8.2% in 2008 to 8.5% by 2018. Stress UI is predicted to be the most common UI type worldwide through 2018 because of its high prevalence in women (5.9% in women vs 0.49% in men in 2008, 6.0% vs 0.51% in 2013, 6.1% vs 0.53% in 2018). Worldwide numbers of stress UI are projected to increase by 10.4% to 152 million by 2013 and by 20.8% to 167 million by 2018, with the overall prevalence anticipated to increase from 3.2% to 3.3% between 2008 and 2018. Numbers of patients affected by urgency UI are expected to increase from 49 million in 2008 to 55 million in 2013 (11.1% increase) and to 60 million in 2018 (22.5% increase), which corresponds to an increase in prevalence from 1.15% to 1.21%. Numbers of individuals affected by urgency UI are estimated to be similar in men and women. Mixed UI affected an estimated 54 million individuals in 2008, which is expected to increase to 60 million in 2013 (11.6% increase) and to 66 million in 2018 (23.6% increase); the prevalence of mixed UI is anticipated to increase from 1.26% in 2008 to 1.33% in 2018. Mixed UI is predicted to affect more women than men (probably because of the greater occurrence of stress UI in women). Finally, an estimated 108 million individuals in the 2008 population were affected by an ‘other’ type of UI (i.e. UI without symptoms of urgency UI or stress UI). This value is expected to increase by 10.7% to 119 million by 2013 and by 21.4% to 131 million by 2018, corresponding to an increase in prevalence from 2.5% in 2008 to 2.6% in 2018, with similar numbers of men and women affected.

Similar to LUTS and OAB, the regional burden of UI is expected to be greatest in Asia, followed by Europe, Africa, North America and South America (Fig. 1C), with the developing regions of Africa, South America and Asia showing the greatest increase in affected individuals between 2008 and 2018 (30.8%, 24.7% and 24.4%, respectively). The prevalence of UI in both 2008 and 2018 is estimated as being similar across regions, with the highest values in Europe (9.6% in 2008 and 10.0% in 2018), followed by North America (8.9% and 9.2%), South America (8.0% and 8.4%), Asia (7.9% and 8.3%) and Africa (7.2% and 7.3%).

Estimated worldwide numbers of individuals aged ≥20 years experiencing LUTS/BOO (defined as the presence of any voiding symptom) are shown by gender and year in Table 1. An estimated 917 million individuals worldwide experienced LUTS/BOO in 2008, with numbers of affected individuals projected to increase by 9.3% to 1.0 billion in 2013 and by 18.5% to 1.1 billion in 2018. The worldwide prevalence of LUTS/BOO is anticipated to increase from 21.5% in 2008 to 21.8% by 2018. The prevalence of LUTS/BOO is estimated as being greater in the men versus women population in 2008 (24.3% vs 18.7%, respectively), 2013 (24.5% vs 18.8%) and 2018 (24.7% vs 18.9%).

The 2008 and 2018 burden of LUTS/BOO is estimated as being greatest in Asia, followed by Europe, Africa, North America and South America (Fig. 1D), with the greatest increases between 2008 and 2018 in numbers of affected individuals projected in the developing regions of Africa (30.2%), South America (20.6%) and Asia (19.7%). The 2008 and 2018 prevalence of LUTS/BOO is estimated as being similar across regions, with the highest values in Europe (22.5% in 2008 and 23.0% in 2018), followed by North America (22.0% and 22.4%), Asia (21.3% and 21.7%), South America (21.2% and 21.6%) and Africa (20.9% and 21.0%).

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. ACKNOWLEDGEMENTS
  8. CONFLICT OF INTEREST
  9. REFERENCES
  10. Supporting Information

This is the first analysis to estimate current (2008) and future worldwide and regional prevalence of LUTS, OAB, UI and LUTS/BOO based on current ICS symptom definitions. Using gender- and age-specific prevalence data from the EPIC study and population estimates from the IDB, our model estimates that LUTS, OAB, UI and LUTS/BOO were highly prevalent in the 2008 worldwide population (45.2%, 10.7%, 8.2% and 21.5% respectively), and that the numbers of individuals affected by each of these conditions are expected to increase by approximately 20% by 2018. Individual LUTS, estimated as being the most common across all time points, included nocturia, postmicturition symptoms, incomplete emptying, terminal dribble and urgency. Regional numbers of individuals affected by these conditions are also predicted to increase between 2008 and 2018, with the greatest increases expected in the developing regions of Africa (30.1–31.1% increase across conditions), South America (20.5–24.7%) and Asia (19.7–24.4%). Increases in worldwide and regional prevalence are also predicted for all conditions by 2018; although these increases appear to be small, they translate into a substantial number of affected individuals given the size of the worldwide and regional general populations.

Reported increases in numbers of affected individuals are the result of IDB predictions of population growth and overall aging in worldwide and regional general populations. For Africa, these increases are primarily attributed to the substantial size growth (29.3%) that is predicted within its general population between 2008 and 2018, with little overall population aging expected. For Europe, these increases are largely driven by the overall aging of the general population (8.0% increase in the number of individuals aged ≥45 years between 2008 and 2018). For Asia and South America, increases in numbers and prevalence of affected individuals are similarly affected by the size growth (17.8% and 18.6%, respectively) and overall aging (16.1% and 13.5% increase in numbers of individuals ≥45 years of age, respectively).

The use of gender- and age-specific prevalence values from the EPIC study is a major strength of this analysis. The EPIC study is a landmark epidemiological study because it is the first large, multinational, population-based study to simultaneously assess the prevalence of LUTS, OAB and UI based on current ICS symptom definitions [1]. Consistent with other epidemiological studies [2,11,25], the EPIC study showed that LUTS, OAB, UI and LUTS/BOO are highly prevalent, and that prevalence increases with age [1].

There are very few published studies on the prevalence of LUTS in some regions of the world, which requires an assumption to be made for the model to estimate numbers of individuals reporting LUTS. This model assumes that the prevalence rates reported in the EPIC study are representative of worldwide LUTS prevalence; the use of EPIC prevalence rates is a conservative estimation for several reasons. The gender- and age-specific LUTS, OAB, UI and LUTS/BOO prevalence values from the EPIC study represent the ‘average’ prevalence across countries weighted by size [1]. These values reflect neither the highest nor lowest prevalence values reported in other population-based epidemiological studies. The prevalence of OAB and UI in EPIC was on the lower end of the range seen in the literature. The overall prevalence of LUTS in EPIC was on the higher side, which was primarily driven by the prevalence of nocturia when defined as at least episode/night [1]. However, our model uses a more stringent definition of nocturia (at least two episodes/night). Hence, the model prevalence of any LUTS (46.5% for men and 48.1% for women) is a more conservative estimate. Notably, many published studies did not use the current LUTS ICS definitions, which could account for some of the variability in the prevalence rates among countries.

Based on the less stringent ICS definition of nocturia, our model estimates that 2.6 billion individuals in the worldwide population (61.9%) experienced at least one LUTS in 2008, with a projected increase of 18.3% to 3.1 billion (62.7%) in 2018. The large difference in these estimates versus those derived from the more stringent at least two episodes/night nocturia definition – 1.9 billion (45.2%) in 2008 to 2.3 billion (45.8%) in 2018 – suggest that experiencing one micturition per night may be part of the normal clinical spectrum [26]. Possible exceptions to the ‘underestimation’ potential of our model are the estimates for worldwide number and prevalence of individuals affected by ‘other’ UI, which may be overestimated in comparison with urgency, stress and mixed IU estimates. The EPIC study reported that 21% of women and 54% of men with UI could be classified as experiencing ‘other’ UI [1], whereas other epidemiological studies have classified only 2% to 10% of individuals with UI as experiencing ‘other’ UI [27–29].

The already high and increasing burden of LUTS, OAB, UI and LUTS/BOO predicted by our estimation model has significant implications for public health and clinical practice. These conditions are under-reported, underdiagnosed and undertreated [5,30,31]; and are associated with significant direct and indirect costs [7–9]. Using values from a recently published economic model evaluating the direct healthcare costs attributed to OAB [8] and estimated worldwide numbers of individuals affected by OAB in the present analysis, we can extrapolate that the average worldwide annual direct cost of OAB was €1.2 trillion to €2.7 trillion in 2008 and can be expected to increase to €1.4 trillion to €3.2 trillion by 2018. Many individuals with LUTS, OAB, UI and LUTS/BOO experience symptom bother and reduced health-related quality of life [3–5]. In particular, urgency UI is reported as being bothersome by many patients with OAB [25]; urgency UI and mixed UI appear to have a greater impact on health-related quality of life compared with stress UI [32]. Notably, individuals experiencing LUTS may have one or multiple symptom types at any given time [2,8,13]; affected individuals are more likely to experience symptom bother as the number of LUTS increases [26]. However, not all individuals who report the presence of LUTS experience symptom bother or require treatment. For example, in the original EPIC study, only 54% of men and 53% of women with OAB considered their symptoms bothersome, although a greater percentages of men (77%) and women (67%) in this population reported symptom bother when UI was also present [5].

Considering this information as a whole, we believe that there is a clear and urgent need to improve the awareness, prevention, diagnosis and management of these conditions. International and national programmes that increase public awareness, educate clinicians and at-risk or affected populations, and implement public campaigns designed to diminish or eliminate social stigma will be a significant step toward reaching this objective. Such public-health programmes will need to be adapted by region because countries often differ in their healthcare resources, treatment guidelines and social perceptions. Additional prevalence research can provide further support for these programmes and valuable information on how to best customize their objectives, methodologies and goals, especially in the developing regions of Africa and South America where there are a paucity of LUTS, OAB, UI and LUTS/BOO prevalence data to assist with public healthcare planning.

A potential limitation of our study is that the prevalence results are approximations and not true values. Also, the LUTS, OAB, UI and LUTS/BOO prevalence and population burden estimates do not reflect a homogeneous population of individuals bothered by and seeking treatment because of their symptoms. Another potential limitation is the model assumption that the gender- and age-specific LUTS, OAB, UI and LUTS/BOO prevalence reported in the EPIC study are not, on average, different from the prevalence regionally or worldwide. As discussed, country-specific variation in LUTS prevalence was observed in the EPIC study [1]. Country-specific variability in UI prevalence (4.3–16.2%) was similarly observed in a population-based study evaluating male UI prevalence across four countries [33]. However, the impact of this limitation may be minimal given that the gender- and age-specific LUTS, OAB, UI and LUTS/BOO prevalence rates reported in EPIC are conservative compared with those from other epidemiological studies. Another potential limitation is the model assumption that the age- and gender-specific prevalence of LUTS, OAB, UI and LUTS/BOO will not change between 2008 and 2018. This is also most likely a conservative assumption because IDB population estimates forecast that the worldwide population ≥20 years of age will increase [14]. Finally, potential limitations of the original EPIC study also apply to this analysis, namely that self-reports were used to assess symptoms (i.e. the analysis does not reflect numbers of individuals diagnosed with or bothered by these conditions) and that the results of the self-report may have been influenced by the mode of questionnaire administration [1].

Our estimation model results suggest that LUTS, OAB, UI and LUTS/BOO are highly prevalent worldwide, with an increasing burden predicted over time. The burden is expected to increase to the greatest extent in the developing regions of Africa, South America and Asia. Although our results are only approximations, we hope that these data will provide support for the development of international and national education and intervention programmes to improve the awareness, social acceptance, prevention, diagnosis and management of these conditions.

ACKNOWLEDGEMENTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. ACKNOWLEDGEMENTS
  8. CONFLICT OF INTEREST
  9. REFERENCES
  10. Supporting Information

This study was funded by Pfizer Inc. Statistical validation was provided by Alexa Parliyan, Jagadeesh Bosula and Hardik Panchal. Editorial support was provided by Tracy J. Wetter at Complete Healthcare Communications, Inc.

CONFLICT OF INTEREST

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. ACKNOWLEDGEMENTS
  8. CONFLICT OF INTEREST
  9. REFERENCES
  10. Supporting Information

Debra E. Irwin is a study investigator funded by Pfizer; Zoe S. Kopp and Barnabie Agatep are employees of Pfizer; Ian Milsom is a paid consultant and study investigator funded by Pfizer; Paul Abrams has received funding from and is a study investigator funded by Pfizer. Source of Funding: Pfizer.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. ACKNOWLEDGEMENTS
  8. CONFLICT OF INTEREST
  9. REFERENCES
  10. Supporting Information

Supporting Information

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. ACKNOWLEDGEMENTS
  8. CONFLICT OF INTEREST
  9. REFERENCES
  10. Supporting Information

TABLE S1 Age- and Gender-Specific Prevalence Estimates of LUTS, OAB, UI, and LUTS/BOO From the EPIC Study.

TABLE S2 Worldwide and Regional Population Estimates from the United States Census Bureau International Data Base.[14]

FilenameFormatSizeDescription
BJU_9993_sm_Tab_S1-S2.doc215KSupporting info item

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