benign prostatic hyperplasia ( bph ) is a pathological term with no universally accepted epidemiologic definition .
lower urinary tract symptoms ( luts ) due to bph are a common problem , particularly in older men .
the prevalence of luts / bph increases with age , affecting more than 70% of men older than 70 years .
the socioeconomic burden of bph is tremendous , costing over $ 3 billion every year . as life expectancy increases , so does this burden .
the prevalence of bph or luts has been studied in many nationwide surveys from various regions including europe , the united states , and korea . however , for the incidence of luts , not many reports have been published , and no study has reported the incidence of luts / bph previously in korea .
the health insurance review & assessment ( hira ) service is a nationwide healthcare system in korea , including health insurance and medical aid , covering all citizens .
therefore , the incidence of luts / bph as well as treatment patterns can be determined from it without follow - up loss .
herein , we investigated the incidence of luts / bph and treatment patterns for patients who were diagnosed in a year with 3 years of follow - up using a nationwide korean database . medication - free rate at 1 year after the surgery was also assessed .
after the approval of institutional review board ( h-1202 - 065 - 398 ) , we extracted the data of patients who were diagnosed of bph in the year of 2008 and their follow - up visits for 3 years from hira database . the diagnosis of bph was defined as 2 or more records of reimbursement with the international classification of diseases , 10th revision ( icd-10 ) diagnosis code of n40.0 used as a primary or secondary diagnosis .
the first diagnosis was defined as an index diagnosis and patients with an index diagnosis of 2008 were traced for 3 years .
patients diagnosed with bph within the previous 12 months before the index diagnosis were excluded .
patients diagnosed with prostate cancer ( icd-10 , c61 ) within the 12 months after the index diagnosis or having claims suggesting a prior prostatic surgery , prostate cancers , inflammatory diseases of the prostate , neurological diseases or conditions that could affect luts were also excluded ( table 1 ) .
incidence was calculated as the number of new cases identified in 2008 divided by the number of at - risk individuals .
age , mean and median numbers of office visits and the tier of hospital where the index diagnosis was made were identified . to determine treatment patterns , patient status was determined every 3 months as medication , no medication , or surgery status .
medication status was defined as having a prescription record for 25% of the 3 months .
surgery was assigned as having a record of the following procedures : transurethral resection of the prostate ( turp , r3975 ) , photoselective vaporization of the prostate ( pvp , r3976 ) , holmium laser enucleation of prostate ( holep , r3977 ) , open prostatectomy ( r3950 ) , and thermal therapy ( r3516 ) .
alfuzosin , doxazosin , tamsulosin , terazosin , and silodosin were categorized as alpha - blockers .
oxybutynin , propiverine , fesoterodine , solifenacin , and tolterodine were categorized as anticholinergics . for those who underwent surgery once during the 3 years of follow - up
, preoperative medication status was assessed 1 month prior to the surgery . for those who were taking medication 1 month prior to the surgery ,
the patient status such as medication , no medication and surgery were assessed as categorical variables .
( ibm co. , armonk , ny , usa ) was used for all analyses , and a p - value < 0.05 was considered statistically significant .
after the approval of institutional review board ( h-1202 - 065 - 398 ) , we extracted the data of patients who were diagnosed of bph in the year of 2008 and their follow - up visits for 3 years from hira database . the diagnosis of bph was defined as 2 or more records of reimbursement with the international classification of diseases , 10th revision ( icd-10 ) diagnosis code of n40.0 used as a primary or secondary diagnosis .
the first diagnosis was defined as an index diagnosis and patients with an index diagnosis of 2008 were traced for 3 years .
patients diagnosed with bph within the previous 12 months before the index diagnosis were excluded .
patients diagnosed with prostate cancer ( icd-10 , c61 ) within the 12 months after the index diagnosis or having claims suggesting a prior prostatic surgery , prostate cancers , inflammatory diseases of the prostate , neurological diseases or conditions that could affect luts were also excluded ( table 1 ) .
incidence was calculated as the number of new cases identified in 2008 divided by the number of at - risk individuals .
age , mean and median numbers of office visits and the tier of hospital where the index diagnosis was made were identified . to determine treatment patterns , patient status was determined every 3 months as medication , no medication , or surgery status .
medication status was defined as having a prescription record for 25% of the 3 months .
surgery was assigned as having a record of the following procedures : transurethral resection of the prostate ( turp , r3975 ) , photoselective vaporization of the prostate ( pvp , r3976 ) , holmium laser enucleation of prostate ( holep , r3977 ) , open prostatectomy ( r3950 ) , and thermal therapy ( r3516 ) .
alfuzosin , doxazosin , tamsulosin , terazosin , and silodosin were categorized as alpha - blockers .
oxybutynin , propiverine , fesoterodine , solifenacin , and tolterodine were categorized as anticholinergics . for those who underwent surgery once during the 3 years of follow - up
, preoperative medication status was assessed 1 month prior to the surgery . for those who were taking medication 1 month prior to the surgery
the patient status such as medication , no medication and surgery were assessed as categorical variables .
21.0 ( ibm co. , armonk , ny , usa ) was used for all analyses , and a p - value < 0.05 was considered statistically significant .
a total of 386,873 men were identified and included in the bph cohort of 2008 .
the incidence of bph was 2,105 per 100,000 men , and increased with age ( fig .
mean age was 59.7 years . for index patients who were diagnosed with bph in 2008 ,
27.1% of patients received medication for more than 9 months , 17.6% of patients took medication for more than a year . for the surgical treatment ,
7,955 patients ( 2.1% ) underwent surgery , including 252 patients who underwent surgery twice or more . the treatment rate increased with age until the age of 70 years ( fig .
turp was the most commonly performed surgical procedure , followed by pvp and thermal therapy ( fig .
as our cohort comprised patients diagnosed with bph in 2008 and followed up until 2011 , holep constituted only 2% of bph surgeries , as it has only been performed after 2010 .
although the symptom severity was not assessed , older patients were more likely to receive treatment , with an or of 1.56 for each additional decade ( 95% confidence interval , 1.551.58 ; p<0.001 ) . to assess medication free - rate ,
patients taking medication at 1 month preoperatively were assessed and traced until 3 years after the surgery ( fig .
were the most common type of medication used , followed by 5-alpha reductase inhibitors . medication - free rate at 1 year after the surgery was 82% on average . to calculate medication - free rate
, we excluded holep , because holep had only been used in this cohort after 2010 .
medication - free rate was highest for open prostatectomy ( 90.0% ) and lowest for thermal therapy ( 78.1% ) .
after 1 year , medication - free rate plateaued ( average 82.9% ) , and at 36-month postsurgery , 83.9% of patients were not taking any medication . among the patients who were taking medications at 36 months after the surgery ,
alpha - blockers were the most common type of medication used ( alpha - blockers , a ; 5-alpha reductase inhibitors , b ; anticholinergics , c ; a 5.2% , ab 3.9% , abc 0.7% , ac 1.1% ) , and anticholinergic - containing regimens were maintained in 4.0% of patients , including anticholinergic monotherapy in 2.1% of patients .
for those who were taking anticholinergics preoperatively , medication - free rate after 1 year was 73.3% , which was lower than the average , and 11.8% of them had maintained anticholinergics - containing regimens .
a total of 386,873 men were identified and included in the bph cohort of 2008 .
the incidence of bph was 2,105 per 100,000 men , and increased with age ( fig .
mean age was 59.7 years . for index patients who were diagnosed with bph in 2008 ,
during the 3 years of follow - up , 27.1% of patients received medication for more than 9 months , 17.6% of patients took medication for more than a year .
for the surgical treatment , 7,955 patients ( 2.1% ) underwent surgery , including 252 patients who underwent surgery twice or more . the treatment rate increased with age until the age of 70 years ( fig .
turp was the most commonly performed surgical procedure , followed by pvp and thermal therapy ( fig .
as our cohort comprised patients diagnosed with bph in 2008 and followed up until 2011 , holep constituted only 2% of bph surgeries , as it has only been performed after 2010 .
although the symptom severity was not assessed , older patients were more likely to receive treatment , with an or of 1.56 for each additional decade ( 95% confidence interval , 1.551.58 ; p<0.001 ) . to assess medication free - rate ,
patients taking medication at 1 month preoperatively were assessed and traced until 3 years after the surgery ( fig .
were the most common type of medication used , followed by 5-alpha reductase inhibitors . medication - free rate at 1 year after the surgery was 82% on average . to calculate medication - free rate
, we excluded holep , because holep had only been used in this cohort after 2010 .
medication - free rate was highest for open prostatectomy ( 90.0% ) and lowest for thermal therapy ( 78.1% ) .
after 1 year , medication - free rate plateaued ( average 82.9% ) , and at 36-month postsurgery , 83.9% of patients were not taking any medication . among the patients who were taking medications at 36 months after the surgery , alpha - blockers were the most common type of medication used ( alpha - blockers , a ; 5-alpha reductase inhibitors , b ; anticholinergics , c ; a 5.2% , ab 3.9% , abc 0.7% , ac 1.1% ) , and anticholinergic - containing regimens were maintained in 4.0% of patients , including anticholinergic monotherapy in 2.1% of patients . for those who were taking anticholinergics preoperatively ,
medication - free rate after 1 year was 73.3% , which was lower than the average , and 11.8% of them had maintained anticholinergics - containing regimens .
this study demonstrates the incidence of luts / bph , their treatment patterns , and medication - free rates after the surgery in a 3-year follow - up in a population - based bph cohort .
the overall incidence of luts / bph was found to be 15 cases per 1,000 man - years in the triumph project from the netherlands from 1995 to 2000 .
our study showed similar or slightly higher incidence rates compared to those in these studies .
differences in time period , population size , and age distribution could have affected the result .
a few reports have focused on the longitudinal changes of luts in population - based studies . in our study , less than one in 5 ( 17.6% ) initially diagnosed patients continued medication for > 1 year , which could be partially explained by the dynamic nature of luts .
many previous studies have shown that patients with more profound or bothersome symptoms are more likely to visit clinics and seek medical care .
men who reported worse symptoms at baseline were four times more likely to be treated compared with those who reported less severe symptoms . in our study , about half of the surgeries were performed during the initial 6 months , which is in line with previous studies .
parsons et al .   reported that when community - dwelling older men having american urological association symptom index 8 or greater were followed up for 2 years , 4% underwent bph surgery and 13% started new prescription medication . in the proscar long - term efficacy and safety study , 5% of finasteride - treated patients and 10% of placebotreated patients with moderate - to - severe symptoms with an enlarged prostate underwent bph surgery during the 4-year follow - up period .
our study included 3-year followup data , and the reported surgery rate was lower compared to that in studies of symptomatic patients . in the urologic diseases in america project , 87,400 prostatectomies for bph were performed among 8 million visitors who visited urology clinics with a primary or secondary diagnosis of bph .
as our study was longitudinal , it demonstrated the timing of surgeries during the 3 years of follow - up in a population - based cohort .
alpha - blockers were the most common single category of medication prescribed , and this was concordant with previous studies in korea .
as han et al .   showed that older age , the presence of comorbidities , and preoperative anticholinergic usage could be associated with the continuation of medication after turp .
although detailed clinical information regarding the voiding status and the size of prostates could not be identified from this data , it is still meaningful considering the scarcity of nationwide data containing information on both prescriptions and surgical treatment .
detrusor underactivity or detrusor overactivity is contributable for this , and is considered to be one of important factors affecting the prognosis after transurethral prostatectomy in patients with bph .
detrusor underactivity was not changed by the surgery whereas detrusor overactivity was significantly decreased after the surgery . in our study ,
because medication free rate was calculated only for those who were taking medications preoperatively during one month before the surgery , the actual postoperative medication rate can be different from our result .
the database did not include clinical variables ; and the diagnosis of bph was based only on the physician 's opinion .
the incidence of luts may have been underestimated because only patients who had visited the clinic were included in the analysis .
in addition , medical management can be underestimated because we assigned the patient 's status as surgery if he underwent surgery during that period .
third , the incidence of surgery might be underestimated because we have excluded those diagnosed with acute urinary retention .
lastly , we could not analyze the clinical predictors for surgery and medication as this data lack clinical variables .
the incidence of luts / bph increases with age until the 7th decade of life .
about 1/5 of patients were taking medications for more than a year and 2.1% of patients were treated surgically .
more than 80% of patients discontinued medications after the surgery , while patients having anticholinergics preoperatively are less likely to .
 purposeto investigate the incidence of benign prostatic hyperplasia ( bph ) in korea and treatment patterns for 3 years after the diagnosis in a nationwide database.materials and methodswe created a cohort of patients diagnosed of bph between 2007 and 2011 from the health insurance review & assessment database , a nationwide database of reimbursement . 
 the diagnosis of bph was defined as having the diagnosis of bph ( n40.0 in international classification of diseases , 10th revision ) as a primary or secondary diagnosis 2 times in 2008 . 
 the incidence of bph in 2008 was calculated . 
 treatment patterns were determined in 3 months interval and traced for 3 years . the incidence and timing of surgery were also determined . for patients taking medications preoperatively , 
 medication - free rate was calculated.resultsthe incidence of bph was 2,105 per 100,000 men ( mean age , 59.711.4 years ) , and increased with age . 
 surgery was performed for 7,955 patients ( 2.1% ) , half of the surgery being performed within the first 6 months . 
 transurethral resection of the prostate was the most commonly performed surgery . 
 the proportion of treatment increased with age until the 7th decade of life . 
 the patients taking medication for > 1 year after the initial diagnosis was 21.4% . on average , 82% of patients became medication - free at postoperative 1 year . 
 for patients taking preoperative anticholinergics , 1 year medication - free rate was 73.3%.conclusionsthe incidence of bph increased with age . 
 surgery was performed in 2.1% of patients . 
 more than 4/5 patients discontinued medication after surgery , while patients taking preoperative anticholinergics were less likely to . 