Abstract
Background/Aims
Little is known about the national colonoscopy volume in Asian countries. This study aimed to assess the national colonoscopy volume in Korea over a 12-year period on the basis of a nationwide population-based database.
Methods
We conducted a population-based study for colonoscopy claims (14,511,158 colonoscopies performed on 13,219,781 patients) on the basis of the Korean National Health Insurance Service database from 2002 to 2013. The 12-year national colonoscopy burden was analyzed according to patient age, patient sex, and healthcare facility type.
Results
The overall volume of colonoscopy increased 8-fold over the 12-year period. The annual colonoscopic polypectomy rate significantly increased in all patient sex and age groups over the 12-years period (all p<0.001). The yearly colonoscopic polypectomy rate for men was significantly increased compared with that for women (2.3% vs 1.7%, p<0.001) and for the screening-age group compared with that for the young-age group (2.0% vs 1.6%, p<0.001). The yearly colonoscopic polypectomy rate relative to the total colonoscopy volume significantly increased in primary, secondary, and tertiary facilities by 2.4%, 1.9%, and 1.4% during the 12-year period (all p<0.001). In addition, the annual colonoscopy volume covered by high-volume facilities significantly increased by 1.8% in primary healthcare facilities over the 12-year period (p<0.001).
Conclusions
Healthcare resources should be prioritized to allow adequate colonoscopic capacity, especially for men, individuals in the screening-age group, and at primary healthcare facilities. Cost-effective strategies to improve the quality of colonoscopy may focus on primary healthcare facilities and high-volume facilities in Korea.
Keywords: Big data, Colonoscopy, Polypectomy, Population
INTRODUCTION
Colorectal cancer (CRC) is a significant public health problem, as its incidence has been increasing worldwide.1,2 Colonoscopy is very effective to reduce the risk of CRC, as most CRCs develop from colorectal adenoma through the adenoma-carcinoma sequence.3-5 CRC screening rate has been steadily increasing over the years, which significantly prevents the development of CRC.6 As a national CRC screening program, most countries, including Korea, use fecal occult blood tests, whereas several Western countries use colonoscopy.6,7 The national CRC screening program in Korea coexists alongside opportunistic colonoscopy screening of persons with an average risk of CRC.8
In Western countries, limited resources for colonoscopy have been an obstacle in expanding CRC screening program, because only certain specialists are trained to perform colonoscopy and colonoscopic polypectomy.9-12 The estimated colonoscopy capacity was sufficient to screen 80% of the eligible U.S. population with fecal test, colonoscopy, or a mix of tests in 2014.9 Survey study conducted in the United Kingdom reported that 50% of the endoscopy units provided an adequate colonoscopy service.12 In some Asian countries such as Korea, Japan, and China, however, colonoscopy burden may be different from that of Western countries because of the excellent accessibility of colonoscopy, low cost of colonoscopy, and many available experienced colonoscopists.13 Currently, however, no population-based studies have reported the national burden of colonoscopy in Asian countries. A better understanding of national colonoscopy burden may be the first step toward successful implementation of CRC screening program as well as identification of deficits in the current colonoscopy resources in Asian countries.
In this context, we aimed to assess the national burden of colonoscopy according to age, sex, and healthcare facility type, based on a nationwide population-based database in Korea.
MATERIALS AND METHODS
1. Data source and study population
This study is a retrospective nationwide population-based study using the Korean National Health Insurance Service (NHIS) database, which contains all inpatient and outpatient data nationwide since 1989 in Korea. The NHIS database provides a comprehensive healthcare coverage for all Koreans and contains information on claims billed by physicians for services, admissions, diagnoses, procedures, discharge status, and patient demographics.14,15 Procedure codes in physician claims databases had a very high level of agreement with data in medical charts.15
We identified all persons who had at least one colonoscopy in the NHIS physician billing claims database between January 2002, and December 2013. Longitudinal time change in the national burden of colonoscopy was assessed according to age, sex, and healthcare facility type in 12 years. We determined whether patients had undergone colonoscopy without polypectomy (E7660) or with polypectomy (Q7701, single polypectomy; Q7702, two or more polypectomies; Q7703, endoscopic mucosal resection) using NHIS codes. In this study, colonoscopic polypectomy included endoscopic mucosal resection (Q7703), but endoscopic submucosal dissection was excluded because this procedure is rarely performed and not reimbursed by NHIS. Colonoscopic procedures were analyzed per procedure, as some patients had multiple colonoscopic procedures, whereas an early repeat colonoscopy within 12 months was analyzed per patient.
Study variables were time (2002 to 2013), colonoscopy with or without polypectomy, age groups (young age, <50 years; screening age, 50 to 74 years; and elderly age, ≥75 years), sex, healthcare facility type (primary, secondary, tertiary, and others) and annual volume of facility (high-volume or not). Age group classification was based on the current guidelines that recommend CRC screening for 50- to 75-year-old adults at an average risk for CRC.4,5 Primary facility includes a primary outpatient clinic, secondary facility includes a hospital and a general hospital, and tertiary facility includes a specialized general hospital on referral from primary and secondary healthcare facility. Other facility includes dental hospital, nursing hospital, public hospital, and oriental hospital/clinic (traditional medicine hospital/clinics prescribing herbal drug or practicing acupuncture). A high-volume facility was defined as a facility with an annual colonoscopy volume more than 200 cases, because the minimum volume of annual colonoscopy to maintain competency for colonoscopy was 200 cases per year and other universal definition is not available.16,17 As a unique situation in Korea, primary healthcare facility includes profit health promotion centers which account for most of high-volume center. As the information used in this study was related only to pseudonyms, the requirement of informed consent was waived. This study was approved by the Institutional Review Board of Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea (IRB number: KHNMC 2018-08-021).
2. Statistical analysis
Descriptive analysis was performed on the entire population during the study period. A generalized linear regression model was applied for sex, age group, and healthcare facility type using the annual proportion of colonoscopy/polypectomy among the total volume of colonoscopy at each year, compared with those in 2002 as a reference. The trends in the annual colonoscopic polypectomy burden in each age group were assessed by subtraction using the chi-square distribution. All statistical tests were two-sided, and a p-value <0.05 was considered statistically significant. All statistical analyses were conducted using SAS 9.4 statistical software (SAS institute Inc., Cary, NC, USA) and R software packages R version 3.5.1 (R Foundation for Statistical Computing, Vienna, Austria; https://www.R-project.org).
RESULTS
1. National burden of colonoscopy
Table 1 shows the longitudinal time change in the national colonoscopy burden for 12 years, based on 14,511,158 colonoscopies on 13,219,781 patients. Compared with the total volume of colonoscopy in 2002, the total volume of colonoscopy doubled within 2 years in 2004, quadrupled within 5 years in 2007, hextupled within 8 years in 2010, and octupled within 10 years in 2012. The annual proportion of polypectomy performed at each year among the total volume of colonoscopy significantly increased by +2.0% from 2002 to 2013 (p<0.001). However, in-patient polypectomy rate per year significantly decreased by –2.4% (p<0.001).
Table 1.
National Colonoscopy Burden over the 12-Year Period in Korea
| Year | Total volume | Colonoscopy without polypectomy* | Colonoscopic polypectomy* | In-patient polypectomy |
|---|---|---|---|---|
| 2002 | 264,345 | 240,167 (90.8) | 24,178 (9.1) | 9,523 (39.4) |
| 2003 | 448,051 | 408,397 (91.1) | 39,654 (8.9) | 16,016 (40.4) |
| 2004 | 546,190 | 487,466 (89.2) | 58,724 (10.8) | 23,367 (39.8) |
| 2005 | 751,535 | 657,790 (87.5) | 93,745 (12.5) | 35,033 (37.4) |
| 2006 | 957,534 | 812,859 (84.9) | 144,675 (15.1) | 45,369 (31.4) |
| 2007 | 1,080,359 | 892,151 (82.6) | 188,208 (17.4) | 54,583 (29.0) |
| 2008 | 1,207,613 | 968,661 (80.2) | 238,952 (19.8) | 61,273 (25.6) |
| 2009 | 1,441,564 | 1,136,222 (78.8) | 305,342 (21.2) | 75,095 (24.6) |
| 2010 | 1,601,688 | 1,226,376 (76.6) | 375,312 (23.4) | 84,706 (22.6) |
| 2011 | 1,975,279 | 1,467,324 (74.3) | 507,955 (25.7) | 96,464 (19.0) |
| 2012 | 2,138,150 | 1,542,315 (72.1) | 595,835 (27.9) | 103,647 (17.4) |
| 2013 | 2,098,850 | 1,474,064 (70.2) | 624,786 (29.8) | 105,374 (16.9) |
| Percent change | –2.0 | +2.0 | –2.4 | |
Data are presented as number or number (%).
The percent is the proportion of procedures performed each year relative to the total colonoscopy volume.
2. National burden of colonoscopy according to sex and age group
The overall colonoscopy burden was higher in men than women with ratio of 1.2 to 1 (Table 2). Compared with the volume of polypectomy in 2002, the proportion of polypectomy among the total volume of colonoscopy per year was significantly increased for both sexes in 12 years (both p<0.001). For sex difference, the proportion of polypectomy performed at each year among the total volume of colonoscopy was significantly increased in men than in women (2.3% vs 1.7%, p<0.001).
Table 2.
National Colonoscopy Burden According to Sex over the 12-Year Period in Korea
| Year | Men | Women | ||||
|---|---|---|---|---|---|---|
| Total volume | Colonoscopy without polypectomy* | Polypectomy* | Total volume | Colonoscopy without polypectomy* | Polypectomy* | |
| 2002 | 144,252 | 127,678 (88.5) | 16,574 (11.5) | 120,093 | 112,489 (93.7) | 7,604 (6.3) |
| 2003 | 241,827 | 214,526 (88.7) | 27,301 (11.3) | 206,224 | 193,871 (94.0) | 12,353 (6.0) |
| 2004 | 293,264 | 252,753 (86.2) | 40,511 (13.8) | 252,926 | 234,713 (92.8) | 18,213 (7.2) |
| 2005 | 408,158 | 344,383 (84.4) | 63,775 (15.6) | 343,377 | 313,407 (91.3) | 29,970 (8.7) |
| 2006 | 523,894 | 426,143 (81.3) | 97,751 (18.7) | 433,640 | 386,716 (89.2) | 46,924 (10.8) |
| 2007 | 600,398 | 472,939 (78.8) | 127,459 (21.2) | 479,961 | 419,212 (87.3) | 60,749 (12.7) |
| 2008 | 666,918 | 507,257 (76.1) | 159,661 (23.9) | 540,695 | 461,404 (85.3) | 79,291 (14.7) |
| 2009 | 792,350 | 590,410 (74.5) | 201,940 (25.5) | 649,214 | 545,812 (84.1) | 103,402 (15.9) |
| 2010 | 882,390 | 634,393 (71.9) | 247,997 (28.1) | 719,298 | 591,983 (82.3) | 127,315 (17.7) |
| 2011 | 1,115,603 | 776,992 (69.6) | 338,611 (30.4) | 859,676 | 690,332 (80.3) | 169,344 (19.7) |
| 2012 | 1,198,330 | 804,831 (67.2) | 393,499 (32.8) | 939,820 | 737,484 (78.5) | 202,336 (21.5) |
| 2013 | 1,166,880 | 761,413 (65.3) | 405,467 (34.7) | 931,970 | 712,651 (76.5) | 219,319 (23.5) |
| Percent change | –2.3 | +2.3 | –1.7 | +1.7 | ||
Data are presented as number or number (%).
The percent is the proportion of procedures performed each year relative to the total colonoscopy volume.
The burden of total colonoscopy in young age, screening age, and elderly age groups was 38.8%, 57.2%, and 4.0%, respectively (Table 3). Compared with the volume of polypectomy in 2002, the proportion of polypectomy among the total volume of colonoscopy per year was significantly increased for all age groups in 12 years (all p<0.001). For age group difference, the proportion of polypectomy among the total volume of colonoscopy per year significantly increased in the screening and elderly age groups compared with the young age group (2.0% and 2.1% vs 1.6%, both p<0.001).
Table 3.
National Colonoscopy Burden According to Age Group over the 12-Year Period in Korea
| Year | Young age (<50 yr) | Screening age (50–74 yr) | Elderly age (≥75 yr) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Total volume | CS without polypectomy | Polypectomy | Total volume | CS without polypectomy* | Polypectomy* | Total volume | CS without polypectomy* | Polypectomy* | |
| 2002 | 131,431 | 124,226 (94.5) | 7,205 (5.5) | 125,060 | 109,097 (87.2) | 15,963 (12.8) | 7,854 | 6,844 (87.1) | 1,010 (12.9) |
| 2003 | 229,271 | 217,796 (95.0) | 11,475 (5.0) | 206,768 | 180,233 (87.2) | 26,535 (12.8) | 12,012 | 10,368 (86.3) | 1,644 (13.7) |
| 2004 | 267,815 | 251,194 (93.8) | 16,621 (6.2) | 262,325 | 222,634 (84.9) | 39,691 (15.1) | 16,050 | 13,638 (85.0) | 2,412 (15.0) |
| 2005 | 361,729 | 335,013 (92.6) | 26,716 (7.4) | 367,829 | 304,638 (82.8) | 63,191 (17.2) | 21,977 | 18,139 (82.5) | 3,838 (17.5) |
| 2006 | 442,551 | 401,190 (90.7) | 41,361 (9.3) | 483,284 | 386,253 (79.9) | 97,031 (20.1) | 31,699 | 25,416 (80.2) | 6,283 (19.8) |
| 2007 | 479,373 | 425,120 (88.7) | 54,253 (11.3) | 563,229 | 437,513 (77.7) | 125,716 (22.3) | 37,757 | 29,518 (78.2) | 8,239 (21.8) |
| 2008 | 508,168 | 439,933 (86.6) | 68,235 (13.4) | 654,693 | 494,628 (75.6) | 160,065 (24.4) | 44,752 | 34,100 (76.2) | 10,652 (23.8) |
| 2009 | 578,202 | 494,490 (85.5) | 83,712 (14.5) | 807,666 | 600,228 (74.3) | 207,438 (25.7) | 55,696 | 41,504 (74.5) | 14,192 (25.5) |
| 2010 | 588,331 | 493,360 (83.9) | 94,971 (16.1) | 946,442 | 684,963 (72.4) | 261,479 (27.6) | 66,915 | 48,053 (71.8) | 18,862 (28.2) |
| 2011 | 709,141 | 577,893 (81.5) | 131,248 (18.5) | 1,186,855 | 834,456 (70.3) | 352,399 (29.7) | 79,283 | 54,975 (69.3) | 24,308 (30.7) |
| 2012 | 691,351 | 552,549 (79.9) | 138,802 (20.1) | 1,351,311 | 926,350 (68.6) | 424,961 (31.4) | 95,488 | 63,416 (66.4) | 32,072 (33.6) |
| 2013 | 649,927 | 507,664 (78.1) | 142,263 (21.9) | 1,340,951 | 896,796 (66.9) | 444,155 (33.1) | 107,972 | 69,604 (64.5) | 38,368 (35.5) |
| Percent change | –1.6 | +1.6 | –2.0 | +2.0 | –2.1 | +2.1 | |||
Data are presented as number or number (%).
The percent is the proportion of procedures performed each year relative to the total colonoscopy (CS) volume.
3. National burden of colonoscopy according to healthcare facility type
Our analysis was focused on primary, secondary, and tertiary facilities, as the colonoscopy volume in other facility type was only 0.2% (Table 4). The number of facilities claimed that colonoscopy procedures increased by 3.2-fold and 4.8-fold in primary and secondary facilities in 12 years. In total, 41.3%, 43.3%, and 15.2% of polypectomies were performed in primary, secondary, and tertiary facilities for 12 years. Compared with the colonoscopy database in 2002, the proportion of polypectomy among the total volume of colonoscopy per year significantly increased in primary, secondary, and tertiary facilities by 2.4%, 1.9%, and 1.4%, respectively (all p<0.001). The annual polypectomy rate of each facility type among total polypectomies was significantly increased only in the primary facilities (p<0.001), but, significantly decreased in the tertiary facilities (p<0.001) and not changed in the secondary facilities (p=0.274) (Fig. 1).
Table 4.
National Colonoscopy Burden According to Healthcare Facility Type over the 12-Year Period in Korea
| Year | Primary healthcare facility | Secondary healthcare facility | ||||||
|---|---|---|---|---|---|---|---|---|
| Total facility | Total CS volume | CS without polypectomy* | Polypectomy | Total facility | Total CS volume | CS without polypectomy* | Polypectomy | |
| 2002 | 741 | 97,302 | 89,447 (91.9) | 7,855 (8.1) | 213 | 89,074 | 80,322 (90.2) | 8,752 (9.8) |
| 2003 | 941 | 173,580 | 161,535 (93.1) | 12,045 (6.9) | 307 | 172,338 | 155,935 (90.5) | 16,403 (9.5) |
| 2004 | 1,118 | 208,541 | 188,736 (90.5) | 19,805 (9.5) | 454 | 225,861 | 200,916 (89.0) | 24,945 (11.0) |
| 2005 | 1,281 | 286,832 | 252,915 (88.2) | 33,917 (11.8) | 571 | 328,030 | 286,629 (87.4) | 41,401 (12.6) |
| 2006 | 1,508 | 367,715 | 312,673 (85.0) | 55,042 (15.0) | 660 | 425,631 | 361,774 (85.0) | 63,857 (15.0) |
| 2007 | 1,635 | 420,900 | 346,348 (82.3) | 74,552 (17.7) | 717 | 481,575 | 397,277 (82.5) | 84,298 (17.5) |
| 2008 | 1,791 | 479,126 | 380,046 (79.3) | 99,080 (20.7) | 809 | 538,892 | 433,290 (80.4) | 105,602 (19.6) |
| 2009 | 1,894 | 584,781 | 452,727 (77.4) | 132,054 (22.6) | 856 | 627,587 | 499,776 (79.6) | 127,811 (20.4) |
| 2010 | 2,040 | 664,000 | 497,557 (74.9) | 166,443 (25.1) | 908 | 696,670 | 539,123 (77.4) | 157,547 (22.6) |
| 2011 | 2,221 | 862,130 | 627,247 (72.8) | 234,883 (27.2) | 950 | 857,009 | 642,009 (74.9) | 215,000 (25.1) |
| 2012 | 2,316 | 938,075 | 661,358 (70.5) | 276,717 (29.5) | 992 | 923,782 | 671,683 (72.7) | 252,099 (27.3) |
| 2013 | 2,408 | 918,035 | 626,622 (68.3) | 291,413 (31.7) | 1,020 | 916,029 | 648,732 (70.8) | 267,297 (29.2) |
| Percent change | –2.4 | +2.4 | –1.9 | +1.9 | ||||
| Year | Tertiary healthcare facility | Other healthcare facility | ||||||
| Total facility | Total CS volume | CS without polypectomy* | Polypectomy | Total facility | Total CS volume | CS without polypectomy* | Polypectomy | |
| 2002 | 41 | 77,969 | 70,398 (90.3) | 7,571 (9.7) | 0 | 0 | 0 (0.0) | 0 (0.0) |
| 2003 | 42 | 102,126 | 90,921 (89.0) | 11,205 (11.0) | 1 | 7 | 6 (85.7) | 1 (14.3) |
| 2004 | 43 | 111,648 | 97,691 (87.5) | 13,957 (12.5) | 5 | 140 | 123 (87.9) | 17 (12.1) |
| 2005 | 41 | 136,467 | 118,046 (86.5) | 18,421 (13.5) | 14 | 206 | 200 (97.1) | 6 (2.9) |
| 2006 | 43 | 163,608 | 137,889 (84.3) | 25,719 (15.7) | 18 | 580 | 523 (90.2) | 57 (9.8) |
| 2007 | 45 | 176,816 | 147,695 (83.5) | 29,121 (16.5) | 28 | 1,068 | 831 (77.8) | 237 (22.2) |
| 2008 | 48 | 188,401 | 154,408 (82.0) | 33,993 (18.0) | 53 | 1,194 | 917 (76.8) | 277 (23.2) |
| 2009 | 44 | 227,388 | 182,176 (80.1) | 45,212 (19.9) | 69 | 1,808 | 1,543 (85.3) | 265 (14.7) |
| 2010 | 44 | 238,498 | 187,558 (78.6) | 50,940 (21.4) | 84 | 2,520 | 2,138 (84.8) | 382 (15.2) |
| 2011 | 45 | 252,192 | 194,992 (77.3) | 57,200 (22.7) | 97 | 3,948 | 3,076 (77.9) | 872 (22.1) |
| 2012 | 47 | 269,869 | 204,870 (75.9) | 64,999 (24.1) | 127 | 6,424 | 4,404 (68.6) | 2,020 (31.4) |
| 2013 | 45 | 259,116 | 194,901 (75.2) | 64,215 (24.8) | 136 | 5,670 | 3,809 (67.2) | 1,861 (32.8) |
| Percent change | –1.4 | +1.4 | ||||||
Data are presented as number or number (%).
The percent is the proportion of procedures performed each year relative to the total colonoscopy (CS) volume.
Fig. 1.
Annual colonoscopic polypectomy volume in each type of healthcare facility. The proportion of colonoscopic polypectomies performed relative to the total polypectomy volume significantly increased by 1.6% in primary facilities and decreased by 1.8% in tertiary facilities (both p<0.001) compared with the rates in the 2002 database.
4. Colonoscopy burden by high-volume facility
Compared to that in the 2002 database, the number of high-volume facility significantly increased by 2.8% and by 2.0% in primary and secondary facilities (both p<0.001), but was not changed in the tertiary facilities (p>0.1) (Table 5). The annual colonoscopy volume covered by a high-volume facility among the total volume of colonoscopy significantly increased in primary and secondary facilities by 1.8% and by 0.4% per year (both p<0.001), but it was not changed in the tertiary facilities in 12 years (p=0.196).
Table 5.
Colonoscopy Burden of HVFs over the 12-Year Period in Korea
| Year | Primary facility | Secondary facility | Tertiary facility | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total facility | HVF | Total CS volume | CS by HVF | Total facility | HVF | Total CS volume | CS by HVF | Total facility | HVF | Total CS volume | CS by HVF | |
| 2002 | 741 | 138 (18.6) | 97,302 | 65,532 (67.3) | 213 | 78 (36.6) | 89,074 | 81,441 (91.4) | 41 | 38 (92.7) | 77,969 | 77,607 (99.5) |
| 2003 | 941 | 241 (25.6) | 173,580 | 128,733 (74.2) | 307 | 146 (47.6) | 172,338 | 162,967 (94.6) | 42 | 42 (100.0) | 102,126 | 102,126 (100.0) |
| 2004 | 1,118 | 310 (27.7) | 208,541 | 159,744 (76.6) | 454 | 195 (43.0) | 225,861 | 209,954 (93.0) | 43 | 42 (97.7) | 111,648 | 111,646 (100.0) |
| 2005 | 1,281 | 405 (31.6) | 286,832 | 230,342 (80.3) | 571 | 273 (47.8) | 328,030 | 309,221 (94.3) | 41 | 41 (100.0) | 136,467 | 136,467 (100.0) |
| 2006 | 1,508 | 497 (33.0) | 367,715 | 302,222 (82.2) | 660 | 363 (55.0) | 425,631 | 407,472 (95.7) | 43 | 42 (97.7) | 163,608 | 163,599 (100.0) |
| 2007 | 1,635 | 555 (33.9) | 420,900 | 349,481 (83.0) | 717 | 371 (51.7) | 481,575 | 457,269 (95.0) | 45 | 42 (93.3) | 176,816 | 176,812 (100.0) |
| 2008 | 1,791 | 623 (34.8) | 479,126 | 400,216 (83.5) | 809 | 418 (51.7) | 538,892 | 511,956 (95.0) | 48 | 43 (89.6) | 188,401 | 188,372 (100.0) |
| 2009 | 1,894 | 737 (38.9) | 584,781 | 505,555 (86.5) | 856 | 489 (57.1) | 627,587 | 602,607 (96.0) | 44 | 43 (97.7) | 227,388 | 227,319 (100.0) |
| 2010 | 2,040 | 824 (40.4) | 664,000 | 578,234 (87.1) | 908 | 518 (57.0) | 696,670 | 668,812 (96.0) | 44 | 43 (97.7) | 238,498 | 238,482 (100.0) |
| 2011 | 2,221 | 1,030 (46.4) | 862,130 | 771,774 (89.5) | 950 | 588 (61.9) | 857,009 | 830,944 (97.0) | 45 | 43 (95.6) | 252,192 | 252,177 (100.0) |
| 2012 | 2,316 | 1,113 (48.1) | 938,075 | 847,351 (90.3) | 992 | 613 (61.8) | 923,782 | 896,816 (97.1) | 47 | 46 (97.9) | 269,869 | 269,704 (99.9) |
| 2013 | 2,408 | 1,113 (46.2) | 918,035 | 820,108 (89.3) | 1,020 | 613 (60.1) | 916,029 | 887,043 (96.8) | 45 | 44 (97.8) | 259,116 | 259,115 (100.0) |
| Percent change | +2.8 | +1.7 | +2.0 | +0.3 | +0.0 | +0.0 | ||||||
Data are presented as number or number (%). A high volume facility (HVF) was defined as a facility with an annual colonoscopy (CS) volume of more than 200 colonoscopies.
5. Early repeat colonoscopy within 12 months
Overall, 8.4% of 13,219,781 persons had an early repeat colonoscopy, and 3.3% of 10,922,565 persons had an early repeat colonoscopy without polypectomy by per-patient analysis (Supplementary Table 1). The proportion of an early repeat colonoscopy without polypectomy among the total volume of colonoscopy significantly decreased in 12 years (by 0.3% for two colonoscopies and by 0.1% for ≥3 colonoscopies) (both p<0.001).
DISCUSSION
This population-based study is the first Asian study that investigated the national colonoscopy volume according to age, sex, and healthcare facility type. The national colonoscopy volume has progressively increased in all sex, age groups, and healthcare facility types in the 12 years. The volume of colonoscopic polypectomy significantly increased in men than in women and in the screening age group than in the young age group. These findings are predictable because old age and male sex are well-known risk factors for colorectal neoplasia.18,19 The colonoscopic polypectomy volume significantly increased in the primary facility than the secondary and tertiary facility. A steep rise in the volume of colonoscopy by the primary healthcare facilities may be explained by the introduction of the “National CRC Screening Program” in 2004 in Korea.8 In Canada, similarly, the proportion of colonoscopies performed in the nonhospital setting increased with the introduction of the “ColonCancerCheck” program: 18.9% increase from 2000 to 200720 and 35.1% increase from 2013 to 2014.21 Higher rates of the polypectomy in the primary healthcare facilities may be explained by that diminutive polyps may be removed by polypectomy, not by biopsy forceps, as well as that non-adenomatous polyps on the distal colon may be removed by polypectomy in primary healthcare facilities. Our findings may indicate that healthcare resources should be prioritized such that there is adequate colonoscopic capacity, especially for men, screening age group, and primary healthcare facilities.
We could estimate the capacity of screening colonoscopy at the population level on the basis of our data. In 2012, 15,537,702 Koreans were invited to undergo CRC screening and 3,884,839 (25.0%) of them underwent CRC screening with the “National CRC Screening Program.”8 One-third of the colonoscopic capacity may be used for CRC screening, because screening indication was about one-third of the total colonoscopy.22 Theoretically, if the 3,884,839 persons are eligible for CRC screening and one-third (i.e., 699,617) of the total volume of colonoscopy of 2012 are provided, 5.6 years may be required to screen the potential population of CRC screening in 2012. Therefore, 5- to 10-year interval of screening colonoscopy may cover all eligible CRC screening population in Korea. However, the potential capacity of screening colonoscopy at the population level may consider the growing rate of the target population, participation rate of screening program, screening interval, cost-effectiveness, and safety and quality of colonoscopy screening.
In previous studies, the quality of colonoscopy was suboptimal in primary healthcare facilities.20,21,23-25 In a population-based study from Ontario,20 the odds ratio of early repeat colonoscopy ≤5 years after a negative complete colonoscopy was 1.26 when the index colonoscopy had been performed in a nonhospital setting. Similarly, the adjusted odds ratio for an early repeat colonoscopy ≤6 months was 1.41 when baseline colonoscopy was performed at a nonhospital facility compared with a teaching or community hospital.21 The early repeat colonoscopy at a nonhospital facility may be explained by their suboptimal baseline colonoscopy. In addition, direct access colonoscopy of primary facility had lower detection rate of large (≥10 mm) polyp and lower completion rate of colonoscopy than conventional colonoscopy group.23 An important variation in colonoscopy quality among outpatient facilities was suggested by significant variation in the unplanned hospital visits within 7 days of colonoscopy.24 In a retrospective study from Florida,25 a higher risk of adverse events was associated with colonoscopies performed in ambulatory surgery centers (odds ratio, 1.27; 95% confidence interval, 1.16 to 1.40). Considering the predominantly increasing colonoscopy volume in primary healthcare facilities, the colonoscopy quality improvement program may be reinforced in primary healthcare facilities.
We also investigated the volume of an early repeat colonoscopy within 12 months. The volume of an early repeat colonoscopy without polypectomy among the total volume of colonoscopy decreased by 0.3% for two colonoscopies and by 0.1% for ≥3 colonoscopies from 2002 to 2013. In Canada, 2.4% of 334,663 persons had an early repeat colonoscopy within 6 months.21 In the Veterans Health Administration data,26 colonoscopy was used more frequently than the recommended intervals on guidelines by 16% of patients without adenoma. In addition, 46.2% of the Medicare population underwent a repeated examination within 7 years and 23.5% of patients had no clear indication for the early repeat examination.27 In our study, the number of high-volume facility significantly increased in primary and secondary facilities, and the annual colonoscopy volume covered by the high-volume facilities also increased regardless of facility types. For example, only 11.7% of colonoscopy volume in primary facilities and 3.2% of colonoscopy volume in secondary facilities was performed in low-volume facilities in 2013. Therefore, the cost-effective strategy to increase colonoscopy quality may be focused on high-volume facilities in Korea.
The use of a NHIS enabled us to perform the largest study to date that assessed the national volume of colonoscopy, and the results are virtually free from referral bias and readily generalizable owing to the population-based design. However, some limitations should be considered. We concede that one of the limitations of our study is secondary data with the uncertainty regarding the accuracy of the diagnosis. However, previous studies with NHIS as data sources have generally shown that procedures and diagnoses are coded accurately.14,15 As no specific details of the colonoscopy were recorded in the NHIS, safety, quality, and the cost of colonoscopy were not addressed in this study. In addition, we cannot assess detailed clinical information for the cause of an early repeat colonoscopy within 12 months. We defined high-volume facility (i.e., annual colonoscopy volume ≥200) based on some evidence,16,17 but it may still be arbitrary as it was a criterion for an endoscopist, not a healthcare facility. In a German screening colonoscopy registry, the detection rate of any neoplasm was better for annual colonoscopy volume ≥200 than annual colonoscopy volume <50 (27.5% vs 21.9%, p<0.001).16 Spanish Society of Gastrointestinal Endoscopy also recommended at least 200 annual screening colonoscopies to maintain colonoscopy quality in CRC screening.17
In conclusion, the national volume of colonoscopy has been progressively increasing regardless of sex, age group, and healthcare facility types for the past 12 years in Korea. Healthcare resources should be prioritized such that there is adequate colonoscopic capacity, especially for men, subjects of screening age, and primary healthcare facilities. Considering difference in colonoscopy quality among facilities and majority of colonoscopy volume covered by high-volume facility, cost-effective strategy to improve colonoscopy quality may be focused on primary healthcare facilities and high-volume facilities in Korea.
SUPPLEMENTAL MATERIALS
ACKNOWLEDGEMENTS
This study was supported by grants from the Korean Society of Gastroenterology, the National R&D Program for Cancer Control (HA17C0046 and 1720230) and the Korean National Health Clinical Research (NHCR) project (HC16C2320), Ministry of Health and Welfare, Republic of Korea. Data source: National Health Information Database (NHIS-2018-4-062) made by the National Health Insurance Service (NHIS) was used.
Footnotes
CONFLICTS OF INTEREST
No potential conflict of interest relevant to this article was reported.
AUTHOR CONTRIBUTIONS
Study concept and design, analysis, and interpretation of data, drafting of the manuscript, critical revision of the manuscript for important intellectual content: J.M.C., H.S.K. Data management, statistical analysis: M.S.K., G.U.P., S.P., J.K.L., S.Y.K., S.J.K., H.H.L. Acquisition of data, administrative, and technical support of this study: J.S.K., W.H.K. Study supervision: J.M.C., H.S.K., J.S.K., W.H.K.
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