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Trends in hospital admission, perforation, and mortality of peptic ulcer in Hong Kong from 1970 to 1980
GASTROENTEROLOGY
1983;84:1558-62
Trends in Hospital Admission, Perforation, and Mortality of Peptic Ulcer in Hong Kong From 1970 to 1980 JARLEY
KOO, Y. K. NGAN, and S. K. LAM
Combined Gastrointestinal Unit, Departments Kong, Queen Mary Hospital, Hong Kong
During 1970-1980, admissions for peptic ulcers per 100,000 population to all government and government-assisted hospitals in Hong Kong increased by 21% from 152 to 185. At the same time, peptic ulcer perforations per 100,000 population increased by 71% from 9.3 to 15.9. The percentage of men >60 yr of age with ulcer perforation rose from 18.1 to 24.4, while that in the genera1 population rose from 2.9 to 3.9. However, the male/female ratio has remained stable at -6: 1. During the same period, mortality rate per 100,000 population due to peptic ulcer declined by 26% from 4.2 to 3.1. Thus, while the hospitalization and perforation rates for peptic ulcer appeared to be falling in the United States and the United Kingdom over the past decade, the opposite has occurred in Hong Kong. Recently accumulated data from the United States (1) and the United Kingdom (2) indicate that peptic ulcer disease is declining in both countries. It is not known whether or not this downward trend is observed in other parts of the world. So far, little or no data have been published from non-Western sources. This paper examines the data on hospital admission, perforation, and mortality of peptic ulcer in Hong Kong for the period 1970-1980.
Received December 15. 1981. Accepted January 18, 1983. Address requests for reprints to: Dr. Jarley Koo, Department of Surgery, University of Alberta, Edmonton, Alberta, Canada. The authors thank Mrs. Carol A. Koo for her patient tabulation of the data, the Medical and Health Department of Hong Kong for supplying some of the data, and particularly Mrs. Josephine Tam and Mr. K. C. Tam for their cooperation. They also thank the Medical Superintendents, the Consultant Surgeons, and the Operating Room Staff of the Queen Mary, Queen Elizabeth, Princess Margaret, and Kwong Wah hospitals for their permission and cooperation to use the OR logbooks. This work was stimulated by the late Morton Grossman during his visit to the University of Hong Kong in October 1980. 8 1983 by the American Gastroenterological Association 0016-5065183/061558-05$03.00
of Medicine
and Surgery, University
of Hong
Methods Data Sources Hospital admissions. In Hong Kong, the population are served by three different types of hospitals: government (51), government-assisted (ZO), and private institutions (23). They respectively provided 46%, 42%, and 12% of the total hospital beds available and were responsible for -SO%, 30%, and 20% of the total hospitalization, respectively, per annum during the period 1970-1980. Each hospital sends its statistics yearly to the Medical and Health Department of Hong Kong, from whom the data on hospital admissions for peptic ulcer disease used in this study were obtained (3). For hospital admissions, the annual figures from the private hospitals were not available until 1977. The admission figures listed in this study, therefore, included only those from the government and government-assisted hospitals. From the available figures from 1977 to 1980, it was estimated that the private hospitals accounted for 20%-25% of the total yearly hospitalizations for peptic ulcer disease. Because the proportions of hospital beds and the proportions of total annual hospital admissions into the three categories of hospitals were quite stable over the last decade, it is likely that hospital admission data in this study were underestimated by a proportionate amount. The admission figures included all uncomplicated and complicated peptic ulcer disease patients. However, categorization according to sex, age of patients, and the nature of complications was not uniformly recorded by individual hospitals. Perforations. The data on ulcer perforation were obtained from a detailed search of the operating room logbooks from all four regional general hospitals in Hong Kong (Queen Mary, Queen Elizabeth, Princess Margaret, and Kwong Wah hospitals). Each of these regional hospi-1200-2000 hospital beds; together they tals provides admit the majority (285%) of all acute medical and surgical emergencies in Hong Kong. Surveys made for the years 1970-1972 and 1978-1980 indicated that, of the total number of perforated ulcers operated on in all the acutecare hospitals in Hong Kong, the four regional hospitals accounted for 87% and 83%, respectively, of the total during these two periods. The total number of perforations
PEPTIC:
June 1983
ULCER
HOSPITALIZATION
IN HONG
KONG
1559
Perforations
100
1
*
70
,
,
72
,
,
,
74
76
78
,
60
Year Figure
1.
Peptic ulcer admission: annual number (open trianand number per 100,000 (closed triangles) from 1970 to 1980. In this and subsequent figures, * indicates that both the r, and x2 are significant.
gles)
obtained from these regional hospitals was used to calcuThe resultant data, late the rates per 100,000population. therefore, represented an underestimation but were representative for the time-trend analysis. For the purpose of this study, all perforations in the duodenal or juxtapyloric region were grouped as duodenal ulcers, and all other ulcers of the stomach were classified as gastric ulcers.
Deuths. The mortality figures due to peptic ulcer disease were complete for the whole population and were based on a complete tabulation of death certificates supplied by the Medical and Health Department (3).
Statistical
Analysis
The time trends of the data were assessed by computing the Spearman’s rank correlation coefficients (r,). The amount of change was estimated by comparing the mean value (number per 100,000population] of the last 3 yr with that of the first 3 yr and by computing the corresponding x2 values. (See Appendix.) The observed changes were marked as significant only when both the rank correlation coefficients and the x2 values were significant at the 5% level.
Table 1 shows the numbers and rates of ulcer perforations according to sex and ulcer site. The mean rate of perforation for all peptic ulcer increased by 71%. The increase was 71% for men and 48% for women. The time-trend increases for duodenal ulcer perforations were significant for both sexes. For perforated gastric ulcers, as the number of cases was small (6% of total), stratification according to sex was not meaningful. Even though the annual number of perforated gastric ulcers increased significantly over the years, time-trend analysis of the rate of perforation was not significant. The increase in the frequency of perforated peptic ulcers was related to age and sex (Figure 2). For male patients, time-trend increases were significant from age 40 yr onwards: for the 40-59yr age group, the mean rate of perforation for 197861980 was 54.0 per 100,000 compared with 36.3 for l970-‘1972 (x” = 47.4, p < 0.01; r, = 0.8, p = 0.01); the corresponding figures for the ?60-yr age group were 83.8 vs. 49.5 (x’ = 35.0, p < 0.01; r, = 0.9, p c 0.01). For female patients, only those ~70 yr had significant time-trend increase (r, = 0.9, p < 0.01) and significantly increased mean rate of perforation (37.6 vs. 21.0: x2 = 12.5, p < 0.01). Over the period studied, the percentage of patients with ulcer perforation and aged 260 yr increased by 35% for tnen (x” = 38.2, p < 0.01; rs = 0.8, p i 0.01) and 19% for women (x’ = 10.1, p < 0.01: r.+ = 0.5, p = NS). The male/female ratio had remained stable at 6:l. Over the same period, the percentage of the general population aged 260 yr increased by 34% for men and 20% for women (both xZ :> 100 and rs = 1.0, p < 0.01).
Deaths
Results Hospital
Admissions
During the period studied, 1970-1980, the number of admissions per annum to governand government-assisted hospitals in Hong for all peptic ulcers increased by 46%, from a of 6147 for 1970-1972 to 8952 for 1978-1980 the admission rate (x” > 100, p < 0.01). Likewise, increased by 21% from a mean of 152 per 100,000 per annum to 185 over the same periods (Figure 1). Time trends for the increase of admissions (r, = 0.9, p < 0.01) and admission rate for all peptic ulcers (r, = 0.6, p < 0.05) were significant. As the ulcer site was not specified in a major proportion of hospitalizations, time-trend analysis according to the type of ulcer was not performed. mean ment Kong mean
The average mortality rate due to all peptic ulcers for the whole population decreased from 4.2 per 100,000 for 1970-1972 to 3.1 for 1978-1980; the reduction was, however, significant for men onlyfrom 5.7 to 3.8 per 100,000 (x’ =: 27.3, p < 0.01) (Figure 3). The effect of age on the mortality rate is shown in Figure 4. For male patients aged 40-59 yr, the mortality rate dropped from 7.6 per 100,000 during 1970-1972 to 4.2 per 100,000 during 19781980 (x" = 13.5, p < 0.01; rs = -1.0, p < 0.01). The corresponding figures for male patients 260 yr old were 61.3 and 36.0 (x” = 31.0, p < 0.01; rs = -0.9, p < 0.01). In female patients only those aged between 40 and 59 yr had significant time trend (r, = -0.9, p < 0.01) and significant reduction in mortality rate-from 2.3 per 100,000 to 1.2 (x’ = 4.5, p < 0.05)
1560
Table
KOO ET AL.
1.
GASTROENTEROLOGY
Vol. 84. No. 6
Perforated Peptic Ulcer: Total Number (n) and Rate per 100,000 Population According to Sex and Site of Perforation DU Women
Men Year
n
1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
323 285 278 331 381 426 442 466 704 577 575
rs
All
Rate 16.1 14.0 13.3 15.4 17.3 19.0 19.4 21.0 29.8 22.7 21.7
n
n
9.3 8.2 8.5 9.6 10.7 11.5 12.1 13.1 17.1 13.7 13.2
31 26 24 25 24 29 31 37 66 49 35
Men Rate
Rate
n
Rate
M/F ratio
347 305 297 350 399 449 465 515 756 614 603
17.3 14.8 14.2 16.3 18.1 20.0 20.1 22.3 32.0 24.2 22.8
52 53 77 78 89 84 102 115 126 105 101
2.7 2.7 3.8 3.8 4.2 3.9 4.7 5.2 5.2 4.4 4.2
6.7 5.8 3.9 4.5 4.5 5.3 4.6 4.5 6.0 5.8 6.0
10.0 8.8 9.1 10.2 11.3 12.1 12.8 14.0 19.1 14.6 13.9
0.2 NS
+0.9 CO.001
2.3 2.4 3.6 3.5 3.9 3.6 4.3 4.9 5.0 3.9 3.9 iO.8 CO.01
+0.9
+0.7 <0.05
+0.6 NS
f0.9
+0.9
+0.9
+0.8
+54 20.4
+69 >lOO
+85
+54 9.3
f108
f71 >lOO
+a2
+48 22.7
+0.9
+0.9
+0.9
CO.001
CO.01
Percent change of mean 1978-1980 1970-1972
+110
+70 >lOO
+82
0.8 0.6 0.6 0.6 0.6 0.7 0.7 0.8 1.4 1.0 0.7
Women
n
45 47 72 72 83 78 94 107 112 93 94
P
X2
GU
M+F rate
+7
M+F rate
+71 >lOO
NS = not significant.
Discussion Previous studies on hospital admissions for peptic ulcer were based on sampling a small proportion (1%10%) of the total admission figures (1,2]. Because of the much smaller population involved, our study made use of the actual raw data available; and as the population at risk was known, the rate per 100,000 population could be calculated. During the decade 1970-1980, the total number of hospital admissions and the admission rate for all peptic ulcers in Hong Kong increased. This is in sharp contrast to the experiences reported for the United States (l), where an overall decline of 26% was observed from 1970 to 1978 (43% for duodenal ulcer and 9% for gastric ulcer) and from England and
Wales (4), where a decline of 21% was recorded from 1958 to 1972 (12% for duodenal ulcer and 34% for gastric ulcer). Continuing decline in hospital admissions for peptic ulcer in England and Wales was reported from 1973 to 1977 (2). Similar magnitude of decline in peptic ulcer hospitalization (30%) was registered by the Scottish Health Services Agency from 1968-1975 (5). Parallel to the increase in hospital admissions, the number of ulcer perforations and the perforation rate in Hong Kong increased substantially over the same period. For comparison, a decrease in duodenal ulcer perforation in England and Wales (25%) and in the Seattle area (36%) had been observed in the last 2 decades (4,6). In Hong Kong, although the increase in ulcer perforation occurred in all age groups and in both sexes, the increase in
lo90g 7$j 6r, 5P 4p 32l70
72
74 76 Year
70
80
Figure 2. Peptic ulcer perforation: number per 100,000 of male patients according to age groups 20-39 yr, 40-59 yr, and 260 yr from 1970 to 1980.
TO
72
74 76 Year
78
,
60
Figure 3. Peptic ulcer death: number per 100,000 of male (closed circles) and female [open circles] patients from 1970 to 1960.
PEPTIC
Tune 1983
70
72
74 76 Year
78
80
Figure 4 Peptic
ulcer death: number per 100,000 of male patients according to age groups 20-39 yr, 40-59 yr, and 260 yr from 1970 to 1980.
men was age related, being greater in the older age groups. This increase of ulcer perforation in the older age groups may be partly explained by an increase of elderly persons in the general population; but it is interesting to contrast the situation in Hong Kong to West Scotland where the perforation rate fell in all age groups during the periods 19541963 and 1965-1973, except for the extremely elderly (270 yr) (7,8). The changing patterns of hospital admission and perforation of peptic ulcer in different parts of the world are compared in Table 2. An appreciable decline in mortality due to peptic ulcer was observed in male patients during the period studied. The mortality trend was related to age. For comparison, the U.S. data showed a decline of 28% in total deaths and 36% in the mortality rate, the decline being evident for duodenal ulcer and gastric ulcer, men and women, for complications Table 2. Percentage of Change
of the Total Number
(n]
in Hospital
and Rate
per
Admissions
and Perforations of Peptic Ulcer From Various Parts of the World
Reported
Place
100,000
Reference
Hong Kong (1970-1980) United States (1970-1978) England and Wales (1958-19721 Scotland (1968-1975) Seattle (1966-1975) Glasgow (1954-1963)
Population
Hospital admission
Perforation
n
Rate
11
f46
+21
(11
-26
(41
-21
(51
-30
+70
-24 -26
(6) (71
" Applies only to perforated duodenal 1954-1964. ’ From 1950-1960.
+1of3
Rate
ulcer.
-20
-20"
-36 -16"
-41'
lJ From 1944-1953
to
ULCER
HOSPITALIZATION
IN HONG
KONG
1561
such as hemorrhage (25%) and perforation (21%), and occurred in all age groups (1). Thus in Hong Kong, mortality due to peptic ulcer declined in the face of increasing hospital admission and perforation rate. For a disease such as peptic ulcer, which is associated with a low overall mortality and from which deaths occur almost exclusively in hospitals, improvement in hospital care could be expected to make a significant impact on the mortality rate. The significant increase in ulcer patients >60 yr old in Hong Kong during the last decade likewise most probably reflects a general improvement in health care. Do the present data in Hong Kong indicate that peptic ulcer was on the rise during the decade 19701980? The increase in hospital admissions can be explained by (a) increased diagnostic rate, (b) increased frequency of multiple admissions of the same patient, (c) increased ulcer complication rate, and (d) increased incidence of peptic ulcer in the population. If we assume that the incidence of perforation in persons with peptic ulcer disease has remained constant, then the rate of ulcer perforation would be a better index of the overall incidence of peptic ulcer disease than either admissions or deaths. Throughout the period studied, >80% of all ulcer perforation patients were admitted to the regional hospitals where surgical intervention was the rule; therefore, few perforations would have escaped diagnosis. Thus the increase in the rate of ulcer perforation in Hong Kong during the decade 19701980 strongly suggests an increased incidence of peptic ulcer disease in the population. Although, in terms of percentage, the increase in perforation rate was more than three times that of hospitalization rate, in terms of absolute numbers, the increase in the number of perforation patients during 1978-1980 over 1970-1972 (mean 324) accounted for only 12% of the increase in the number of hospital admissions over the same period (mean 2805). Therefore, 88% of the increased number of admissions was due to reasons other than perforation. Unfortunately, we do not have figures similar to those of perforation to say whether or not other ulcer complications such as hemorrhage or obstruction had increased. Is the rise in incidence of peptic ulcer related in some ways to the growth of population in Hong Kong? The population increased by 29% from 1970 to 1980. This increase was accounted for by an annual birth rate, which fell from 20 per 1000 in 1970 to 17 per 1000 in 1980, and by fluctuating influxes of immigrants from the surrounding countries. Inclusive of both the natural increase and immigration, the annual population growth rate was 1.9% from 1970 to 1977, 3.4% in 1978, 6.3% in 1979,
1562 KOO ET AL.
GASTROENTEROLOGY
and 2.6% in 1980 (9). Immigration
was particularly heavy in the last 3 yr: the number was estimated to be between 200,000 and 300,000.However there is no reason to believe that these individuals are more susceptible to ulcer disease. Even if they were, it is unlikely that they would influence our results significantly because they represent <.s% of the total population. Certainly the unexpected population increase caused serious social strains, and the addition of large numbers of unskilled laborers lowered the workers’ standard of living. Whether or not these environmental factors contributed to the observed increased incidence of peptic ulcer hospitalization and perforation is entirely speculative.
RI = nIbI + xd(n, + n2). R2= n&,
+ x2Hnl + nd,
x2 = (Xl - X,)“/X, + (x* - X,)“&.
References 1. Elashoff 2.
3. 4. 5.
Appendix 6.
The x2 values are computed as follows: Let the observed number of cases for 1970-1972 be x1 and for 1978-1980 be x2. Let the total populations for 1970-1972 be nl and for 1978-1980 be n2. Then the expected number of cases x1 for 1970-1972 and gz for 1978-1980 are
Vol.84, No. 6
7. 8. 9.
JD, Grossman MI. Trends in hospital admissions and death rates for peptic ulcer in the United States from I970 to 1978. Gastroenterology 1980:78:280-5. Coggon D, Lambert PM, Langman MFS. Twenty years of hospital admissions for peptic ulcer in England and Wales. Lancet 1981:i:1302-4. Annual Department Reports: Medical and Health Services, Hong Kong. 1970-1980. Brown KC, Langman MFS, Lambert PM. Hospital admissions for peptic ulcer during 1858-1972. Br Med J 1976;1:35-7. “What has been happening to peptic ulcer in Scotland?” ISD occasional papers No. 2. Scottish Health Service, Common Services Agency, Edinburgh EH5 3SQ. Smith MP. Decline in duodenal ulcer surgery. JAMA 1977; 237:987-a. Mackay C. Perforated peptic ulcer in the West of Scotland: a survey of 5343 cases during 1954-63. Br Med J 1966;1:701-5. Mackay C, MacKay HP. Perforated peptic ulcer in the West of Scotland 1964-1973. Br J Surg 1976;13(2):158. Wood D. Hong Kong 1981. Hong Kong: Rick DR, Government Printer, 1981.
1983;84:1558-62
Trends in Hospital Admission, Perforation, and Mortality of Peptic Ulcer in Hong Kong From 1970 to 1980 JARLEY
KOO, Y. K. NGAN, and S. K. LAM
Combined Gastrointestinal Unit, Departments Kong, Queen Mary Hospital, Hong Kong
During 1970-1980, admissions for peptic ulcers per 100,000 population to all government and government-assisted hospitals in Hong Kong increased by 21% from 152 to 185. At the same time, peptic ulcer perforations per 100,000 population increased by 71% from 9.3 to 15.9. The percentage of men >60 yr of age with ulcer perforation rose from 18.1 to 24.4, while that in the genera1 population rose from 2.9 to 3.9. However, the male/female ratio has remained stable at -6: 1. During the same period, mortality rate per 100,000 population due to peptic ulcer declined by 26% from 4.2 to 3.1. Thus, while the hospitalization and perforation rates for peptic ulcer appeared to be falling in the United States and the United Kingdom over the past decade, the opposite has occurred in Hong Kong. Recently accumulated data from the United States (1) and the United Kingdom (2) indicate that peptic ulcer disease is declining in both countries. It is not known whether or not this downward trend is observed in other parts of the world. So far, little or no data have been published from non-Western sources. This paper examines the data on hospital admission, perforation, and mortality of peptic ulcer in Hong Kong for the period 1970-1980.
Received December 15. 1981. Accepted January 18, 1983. Address requests for reprints to: Dr. Jarley Koo, Department of Surgery, University of Alberta, Edmonton, Alberta, Canada. The authors thank Mrs. Carol A. Koo for her patient tabulation of the data, the Medical and Health Department of Hong Kong for supplying some of the data, and particularly Mrs. Josephine Tam and Mr. K. C. Tam for their cooperation. They also thank the Medical Superintendents, the Consultant Surgeons, and the Operating Room Staff of the Queen Mary, Queen Elizabeth, Princess Margaret, and Kwong Wah hospitals for their permission and cooperation to use the OR logbooks. This work was stimulated by the late Morton Grossman during his visit to the University of Hong Kong in October 1980. 8 1983 by the American Gastroenterological Association 0016-5065183/061558-05$03.00
of Medicine
and Surgery, University
of Hong
Methods Data Sources Hospital admissions. In Hong Kong, the population are served by three different types of hospitals: government (51), government-assisted (ZO), and private institutions (23). They respectively provided 46%, 42%, and 12% of the total hospital beds available and were responsible for -SO%, 30%, and 20% of the total hospitalization, respectively, per annum during the period 1970-1980. Each hospital sends its statistics yearly to the Medical and Health Department of Hong Kong, from whom the data on hospital admissions for peptic ulcer disease used in this study were obtained (3). For hospital admissions, the annual figures from the private hospitals were not available until 1977. The admission figures listed in this study, therefore, included only those from the government and government-assisted hospitals. From the available figures from 1977 to 1980, it was estimated that the private hospitals accounted for 20%-25% of the total yearly hospitalizations for peptic ulcer disease. Because the proportions of hospital beds and the proportions of total annual hospital admissions into the three categories of hospitals were quite stable over the last decade, it is likely that hospital admission data in this study were underestimated by a proportionate amount. The admission figures included all uncomplicated and complicated peptic ulcer disease patients. However, categorization according to sex, age of patients, and the nature of complications was not uniformly recorded by individual hospitals. Perforations. The data on ulcer perforation were obtained from a detailed search of the operating room logbooks from all four regional general hospitals in Hong Kong (Queen Mary, Queen Elizabeth, Princess Margaret, and Kwong Wah hospitals). Each of these regional hospi-1200-2000 hospital beds; together they tals provides admit the majority (285%) of all acute medical and surgical emergencies in Hong Kong. Surveys made for the years 1970-1972 and 1978-1980 indicated that, of the total number of perforated ulcers operated on in all the acutecare hospitals in Hong Kong, the four regional hospitals accounted for 87% and 83%, respectively, of the total during these two periods. The total number of perforations
PEPTIC:
June 1983
ULCER
HOSPITALIZATION
IN HONG
KONG
1559
Perforations
100
1
*
70
,
,
72
,
,
,
74
76
78
,
60
Year Figure
1.
Peptic ulcer admission: annual number (open trianand number per 100,000 (closed triangles) from 1970 to 1980. In this and subsequent figures, * indicates that both the r, and x2 are significant.
gles)
obtained from these regional hospitals was used to calcuThe resultant data, late the rates per 100,000population. therefore, represented an underestimation but were representative for the time-trend analysis. For the purpose of this study, all perforations in the duodenal or juxtapyloric region were grouped as duodenal ulcers, and all other ulcers of the stomach were classified as gastric ulcers.
Deuths. The mortality figures due to peptic ulcer disease were complete for the whole population and were based on a complete tabulation of death certificates supplied by the Medical and Health Department (3).
Statistical
Analysis
The time trends of the data were assessed by computing the Spearman’s rank correlation coefficients (r,). The amount of change was estimated by comparing the mean value (number per 100,000population] of the last 3 yr with that of the first 3 yr and by computing the corresponding x2 values. (See Appendix.) The observed changes were marked as significant only when both the rank correlation coefficients and the x2 values were significant at the 5% level.
Table 1 shows the numbers and rates of ulcer perforations according to sex and ulcer site. The mean rate of perforation for all peptic ulcer increased by 71%. The increase was 71% for men and 48% for women. The time-trend increases for duodenal ulcer perforations were significant for both sexes. For perforated gastric ulcers, as the number of cases was small (6% of total), stratification according to sex was not meaningful. Even though the annual number of perforated gastric ulcers increased significantly over the years, time-trend analysis of the rate of perforation was not significant. The increase in the frequency of perforated peptic ulcers was related to age and sex (Figure 2). For male patients, time-trend increases were significant from age 40 yr onwards: for the 40-59yr age group, the mean rate of perforation for 197861980 was 54.0 per 100,000 compared with 36.3 for l970-‘1972 (x” = 47.4, p < 0.01; r, = 0.8, p = 0.01); the corresponding figures for the ?60-yr age group were 83.8 vs. 49.5 (x’ = 35.0, p < 0.01; r, = 0.9, p c 0.01). For female patients, only those ~70 yr had significant time-trend increase (r, = 0.9, p < 0.01) and significantly increased mean rate of perforation (37.6 vs. 21.0: x2 = 12.5, p < 0.01). Over the period studied, the percentage of patients with ulcer perforation and aged 260 yr increased by 35% for tnen (x” = 38.2, p < 0.01; rs = 0.8, p i 0.01) and 19% for women (x’ = 10.1, p < 0.01: r.+ = 0.5, p = NS). The male/female ratio had remained stable at 6:l. Over the same period, the percentage of the general population aged 260 yr increased by 34% for men and 20% for women (both xZ :> 100 and rs = 1.0, p < 0.01).
Deaths
Results Hospital
Admissions
During the period studied, 1970-1980, the number of admissions per annum to governand government-assisted hospitals in Hong for all peptic ulcers increased by 46%, from a of 6147 for 1970-1972 to 8952 for 1978-1980 the admission rate (x” > 100, p < 0.01). Likewise, increased by 21% from a mean of 152 per 100,000 per annum to 185 over the same periods (Figure 1). Time trends for the increase of admissions (r, = 0.9, p < 0.01) and admission rate for all peptic ulcers (r, = 0.6, p < 0.05) were significant. As the ulcer site was not specified in a major proportion of hospitalizations, time-trend analysis according to the type of ulcer was not performed. mean ment Kong mean
The average mortality rate due to all peptic ulcers for the whole population decreased from 4.2 per 100,000 for 1970-1972 to 3.1 for 1978-1980; the reduction was, however, significant for men onlyfrom 5.7 to 3.8 per 100,000 (x’ =: 27.3, p < 0.01) (Figure 3). The effect of age on the mortality rate is shown in Figure 4. For male patients aged 40-59 yr, the mortality rate dropped from 7.6 per 100,000 during 1970-1972 to 4.2 per 100,000 during 19781980 (x" = 13.5, p < 0.01; rs = -1.0, p < 0.01). The corresponding figures for male patients 260 yr old were 61.3 and 36.0 (x” = 31.0, p < 0.01; rs = -0.9, p < 0.01). In female patients only those aged between 40 and 59 yr had significant time trend (r, = -0.9, p < 0.01) and significant reduction in mortality rate-from 2.3 per 100,000 to 1.2 (x’ = 4.5, p < 0.05)
1560
Table
KOO ET AL.
1.
GASTROENTEROLOGY
Vol. 84. No. 6
Perforated Peptic Ulcer: Total Number (n) and Rate per 100,000 Population According to Sex and Site of Perforation DU Women
Men Year
n
1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
323 285 278 331 381 426 442 466 704 577 575
rs
All
Rate 16.1 14.0 13.3 15.4 17.3 19.0 19.4 21.0 29.8 22.7 21.7
n
n
9.3 8.2 8.5 9.6 10.7 11.5 12.1 13.1 17.1 13.7 13.2
31 26 24 25 24 29 31 37 66 49 35
Men Rate
Rate
n
Rate
M/F ratio
347 305 297 350 399 449 465 515 756 614 603
17.3 14.8 14.2 16.3 18.1 20.0 20.1 22.3 32.0 24.2 22.8
52 53 77 78 89 84 102 115 126 105 101
2.7 2.7 3.8 3.8 4.2 3.9 4.7 5.2 5.2 4.4 4.2
6.7 5.8 3.9 4.5 4.5 5.3 4.6 4.5 6.0 5.8 6.0
10.0 8.8 9.1 10.2 11.3 12.1 12.8 14.0 19.1 14.6 13.9
0.2 NS
+0.9 CO.001
2.3 2.4 3.6 3.5 3.9 3.6 4.3 4.9 5.0 3.9 3.9 iO.8 CO.01
+0.9
+0.7 <0.05
+0.6 NS
f0.9
+0.9
+0.9
+0.8
+54 20.4
+69 >lOO
+85
+54 9.3
f108
f71 >lOO
+a2
+48 22.7
+0.9
+0.9
+0.9
CO.001
CO.01
Percent change of mean 1978-1980 1970-1972
+110
+70 >lOO
+82
0.8 0.6 0.6 0.6 0.6 0.7 0.7 0.8 1.4 1.0 0.7
Women
n
45 47 72 72 83 78 94 107 112 93 94
P
X2
GU
M+F rate
+7
M+F rate
+71 >lOO
NS = not significant.
Discussion Previous studies on hospital admissions for peptic ulcer were based on sampling a small proportion (1%10%) of the total admission figures (1,2]. Because of the much smaller population involved, our study made use of the actual raw data available; and as the population at risk was known, the rate per 100,000 population could be calculated. During the decade 1970-1980, the total number of hospital admissions and the admission rate for all peptic ulcers in Hong Kong increased. This is in sharp contrast to the experiences reported for the United States (l), where an overall decline of 26% was observed from 1970 to 1978 (43% for duodenal ulcer and 9% for gastric ulcer) and from England and
Wales (4), where a decline of 21% was recorded from 1958 to 1972 (12% for duodenal ulcer and 34% for gastric ulcer). Continuing decline in hospital admissions for peptic ulcer in England and Wales was reported from 1973 to 1977 (2). Similar magnitude of decline in peptic ulcer hospitalization (30%) was registered by the Scottish Health Services Agency from 1968-1975 (5). Parallel to the increase in hospital admissions, the number of ulcer perforations and the perforation rate in Hong Kong increased substantially over the same period. For comparison, a decrease in duodenal ulcer perforation in England and Wales (25%) and in the Seattle area (36%) had been observed in the last 2 decades (4,6). In Hong Kong, although the increase in ulcer perforation occurred in all age groups and in both sexes, the increase in
lo90g 7$j 6r, 5P 4p 32l70
72
74 76 Year
70
80
Figure 2. Peptic ulcer perforation: number per 100,000 of male patients according to age groups 20-39 yr, 40-59 yr, and 260 yr from 1970 to 1980.
TO
72
74 76 Year
78
,
60
Figure 3. Peptic ulcer death: number per 100,000 of male (closed circles) and female [open circles] patients from 1970 to 1960.
PEPTIC
Tune 1983
70
72
74 76 Year
78
80
Figure 4 Peptic
ulcer death: number per 100,000 of male patients according to age groups 20-39 yr, 40-59 yr, and 260 yr from 1970 to 1980.
men was age related, being greater in the older age groups. This increase of ulcer perforation in the older age groups may be partly explained by an increase of elderly persons in the general population; but it is interesting to contrast the situation in Hong Kong to West Scotland where the perforation rate fell in all age groups during the periods 19541963 and 1965-1973, except for the extremely elderly (270 yr) (7,8). The changing patterns of hospital admission and perforation of peptic ulcer in different parts of the world are compared in Table 2. An appreciable decline in mortality due to peptic ulcer was observed in male patients during the period studied. The mortality trend was related to age. For comparison, the U.S. data showed a decline of 28% in total deaths and 36% in the mortality rate, the decline being evident for duodenal ulcer and gastric ulcer, men and women, for complications Table 2. Percentage of Change
of the Total Number
(n]
in Hospital
and Rate
per
Admissions
and Perforations of Peptic Ulcer From Various Parts of the World
Reported
Place
100,000
Reference
Hong Kong (1970-1980) United States (1970-1978) England and Wales (1958-19721 Scotland (1968-1975) Seattle (1966-1975) Glasgow (1954-1963)
Population
Hospital admission
Perforation
n
Rate
11
f46
+21
(11
-26
(41
-21
(51
-30
+70
-24 -26
(6) (71
" Applies only to perforated duodenal 1954-1964. ’ From 1950-1960.
+1of3
Rate
ulcer.
-20
-20"
-36 -16"
-41'
lJ From 1944-1953
to
ULCER
HOSPITALIZATION
IN HONG
KONG
1561
such as hemorrhage (25%) and perforation (21%), and occurred in all age groups (1). Thus in Hong Kong, mortality due to peptic ulcer declined in the face of increasing hospital admission and perforation rate. For a disease such as peptic ulcer, which is associated with a low overall mortality and from which deaths occur almost exclusively in hospitals, improvement in hospital care could be expected to make a significant impact on the mortality rate. The significant increase in ulcer patients >60 yr old in Hong Kong during the last decade likewise most probably reflects a general improvement in health care. Do the present data in Hong Kong indicate that peptic ulcer was on the rise during the decade 19701980? The increase in hospital admissions can be explained by (a) increased diagnostic rate, (b) increased frequency of multiple admissions of the same patient, (c) increased ulcer complication rate, and (d) increased incidence of peptic ulcer in the population. If we assume that the incidence of perforation in persons with peptic ulcer disease has remained constant, then the rate of ulcer perforation would be a better index of the overall incidence of peptic ulcer disease than either admissions or deaths. Throughout the period studied, >80% of all ulcer perforation patients were admitted to the regional hospitals where surgical intervention was the rule; therefore, few perforations would have escaped diagnosis. Thus the increase in the rate of ulcer perforation in Hong Kong during the decade 19701980 strongly suggests an increased incidence of peptic ulcer disease in the population. Although, in terms of percentage, the increase in perforation rate was more than three times that of hospitalization rate, in terms of absolute numbers, the increase in the number of perforation patients during 1978-1980 over 1970-1972 (mean 324) accounted for only 12% of the increase in the number of hospital admissions over the same period (mean 2805). Therefore, 88% of the increased number of admissions was due to reasons other than perforation. Unfortunately, we do not have figures similar to those of perforation to say whether or not other ulcer complications such as hemorrhage or obstruction had increased. Is the rise in incidence of peptic ulcer related in some ways to the growth of population in Hong Kong? The population increased by 29% from 1970 to 1980. This increase was accounted for by an annual birth rate, which fell from 20 per 1000 in 1970 to 17 per 1000 in 1980, and by fluctuating influxes of immigrants from the surrounding countries. Inclusive of both the natural increase and immigration, the annual population growth rate was 1.9% from 1970 to 1977, 3.4% in 1978, 6.3% in 1979,
1562 KOO ET AL.
GASTROENTEROLOGY
and 2.6% in 1980 (9). Immigration
was particularly heavy in the last 3 yr: the number was estimated to be between 200,000 and 300,000.However there is no reason to believe that these individuals are more susceptible to ulcer disease. Even if they were, it is unlikely that they would influence our results significantly because they represent <.s% of the total population. Certainly the unexpected population increase caused serious social strains, and the addition of large numbers of unskilled laborers lowered the workers’ standard of living. Whether or not these environmental factors contributed to the observed increased incidence of peptic ulcer hospitalization and perforation is entirely speculative.
RI = nIbI + xd(n, + n2). R2= n&,
+ x2Hnl + nd,
x2 = (Xl - X,)“/X, + (x* - X,)“&.
References 1. Elashoff 2.
3. 4. 5.
Appendix 6.
The x2 values are computed as follows: Let the observed number of cases for 1970-1972 be x1 and for 1978-1980 be x2. Let the total populations for 1970-1972 be nl and for 1978-1980 be n2. Then the expected number of cases x1 for 1970-1972 and gz for 1978-1980 are
Vol.84, No. 6
7. 8. 9.
JD, Grossman MI. Trends in hospital admissions and death rates for peptic ulcer in the United States from I970 to 1978. Gastroenterology 1980:78:280-5. Coggon D, Lambert PM, Langman MFS. Twenty years of hospital admissions for peptic ulcer in England and Wales. Lancet 1981:i:1302-4. Annual Department Reports: Medical and Health Services, Hong Kong. 1970-1980. Brown KC, Langman MFS, Lambert PM. Hospital admissions for peptic ulcer during 1858-1972. Br Med J 1976;1:35-7. “What has been happening to peptic ulcer in Scotland?” ISD occasional papers No. 2. Scottish Health Service, Common Services Agency, Edinburgh EH5 3SQ. Smith MP. Decline in duodenal ulcer surgery. JAMA 1977; 237:987-a. Mackay C. Perforated peptic ulcer in the West of Scotland: a survey of 5343 cases during 1954-63. Br Med J 1966;1:701-5. Mackay C, MacKay HP. Perforated peptic ulcer in the West of Scotland 1964-1973. Br J Surg 1976;13(2):158. Wood D. Hong Kong 1981. Hong Kong: Rick DR, Government Printer, 1981.