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Recent trends in the mortality rate from renal disease in children and young adults in New York City
928
December 1975 The Journal o f P E D I A T R I C S
Recent trends in the mortality rate from renal disease in children and young adults in New York City Analysis has shown that the over-all death rate from renal disease for residents of New York City under 25 years of age has declined from 4.6 per 100,000 in 1950 to 2.3 per 100,000 in 1970. Nephritis and nephrosis was the major disease eategory aeeounting for this decrease in deaths. A similar trend was Jbund for the United States as a whole. Other causes o f renal disease did not manifest consistent changes in death rates. The decline in deaths from nephritis and nephrosis could not be ascribed solely to changing diagnostic habits or terminology. A possible alternative explanation is a change in the natural history o f these diseases. Data of this type might be useful as an index to future trends in the mortality rate from renal diseases and as one basis for projeetions o f potential future needs for dialysis and renal transplantation. Using 1965 data, we estimate the number o f such potential candidates in New York City would have been 9 per 1,O00,O00 for the 5 to 14 year age group and 23 per 1,O00,O00 for the 15 to 24 year age group. There are significant limitations o f projections based on such data. These estimates of potential candidates for ehronie dialysis or renal transplantation are the first available for children in the United States.
Wallace W. McCrory, M.D.,* Madoka Shibuya, M.D., and Katushiko Yano, M.D., New
Y o r k , N . Y.
RECENT EPIDEMIOLOGIC STUDIES of renal failure due to nephritides in adults 1-~ have demonstrated that there has been a decline in the number of reported deaths attributed to acute and chronic nephritis since the early 1950s. Although the reason for these changes is not clear, one possible explanation among many deserving consideration is that the disease itself is changing in severity. There are no data reporting mortality rate trends for renal deaths in infancy and childhood, either based on the analysis of all causes of renal death or, more particularly, those attributable to acute and chronic nephritis. The lack of such data has now become a matter of increased From the Departments of Pediatrics and Public Health, Cornell University Medical Center and New York Hospital. Presented in part at the X I I I International Congress o f Pediatrics, Vienna, August 29, 1971. *Reprint address: Department of Pediatrics, New York Hospital, 525 E. 68th St., New York, N. Y. 10021.
Vol. 87, No. 6, part 1, pp. 928-932
concern since the feasibility of utilizing chronic dialysis and renal transplantation as treatment for end-stage renal failure in children has now been demonstrated? .... Accordingly, we felt that analysis of the data available for annual reported deaths from renal disorders in infants and children would be of value. The meager data for chronic renal failure available in the literature IH~ are too crude to be useful for any epidemiologic or predictive purposes. This report describes the results of a retrospective study analyzing mortality rates for all deaths ascribed to renal disease in subjects under 25 years of age in the New York City area from 1950 through 1970.
METHODS AND MATERIALS The study population comprised all residents of the city of New York who were under 25 years of age during a 20year period, 1950 to 1970. Through the cooperation of the Bureau of Vital Statistics of the New York City Depart-
Volume 87 Number 6, part 1
Trends in renal disease mortality rate
ment of Health we were provided with the sex, age, and cause of death from all death certificates in which renal disease was listed as the underlying cause of death. The data had been collected from 1950 through 1970, and all renal deaths had been coded by Health Department personnel. These data were then classified into five major categories based on the International Classification of Diseases (ICD) as follows: Underlying cause of death
ICD code number 6th (1949-57) and 7th (1958-67) 8th (since revisions 1968) revision
Malignant neoplasmof urinary system and kidneys Nephritis and nephrosis Infections of kidney Other diseases of urinary system Congenital malformations of kidney and urinary system
180-181 590-594 600 601-609
188-189 580-584 590 591-599
757.1,3
753
It is evident that the five major categories studied do not include all renal conditions. The total number of such ignored deaths would presumably not be numerically great assuming causes of death were properly coded. The death rates per 100,000 population were computed for each renal disease and for 0 to 25 years and also for specific age groupings, specifically 0 to 4 years, 5 to 14 years, and 15 to 24 years. The United States Census data for 1950, 1960, and1970 were used for the denominator in computing annual age-specific data rates. For 1955 and 1965, estimates of population were used. We examined each year but will present only data for five-year interval periods. The interval data are representative of the pattern observed in evaluating individual annual death rates. RESULTS The over-all mortality rates from renal disorders for residents of New York City under 25 years of age were found to have declined approximately 50% from 1950 to 1970 (Table I). The continuous trend of the over-all decline (Fig. 1) is largely accounted for by the decrease observed in the death rate l~or the nephritis-nephrosis category which fell threefold. The death rates of three other categories (infections of the kidney, other diseases of urinary system, and congenital m a l f o r m a t i o n s ) w e r e either not consistently different or were essentially unchanged. The death rate for malignant neoplasms of kidneys and urinary system was an exception in that the rate in 1970 was the lowest recorded. The age group 0 to
929
T a b l e I. Death rates (per 100,000 population) from renal disease for 0 to 24-year-old residents of New York City from 1950 to 1970
Cause of death Malignant neoplasm Nephritis and nephrosis Infections of kidney Other diseases of urinary system Congenital malformations All causes
n~,CnnbDer1950 1955 1960 1965 ]970 180-181 590-594 600 601-609 757.1 757.3
1.0
1.4
1. i
0.9
0.4
2.8 0.1 0.2
2.1 0.3 0.1
1.6 0.6 0.1
1.2 0.1 0.1
0.9 0.2 0.4
0.5
0.4
0.6
0.6
0.4
4.6
4.3
4.0
2.9
2.3
25 years covers the period from birth into early adulthood. A separate analysis of data for developmentally different age groups comprising 0 to 25 years was made. The rate of each disease category was calculated for infancy (0 to 4 years), childhood (5 to 14 years), and young adulthood (15 to 24 years). Data for 1965 are shown in Table II. As expected, the over-all rates changed in the three age groups as did the contributions of each category. The highest over-all death rate was in the 0 to 4 year group (6.3 per t00,000) and~the lowest in the 5 to 14 year group (1.4 per 100,000). Congenital malformations were the major cause of renal deaths in the youngest group (57%), neoplasms next (23%), both accounting for 80% of all infant renal deaths. Congenital malformations contributed only a small number of deaths in the 5 to 14 year age group and no deaths in the 15 to 24 year age group. Nephritis-nephrosis deaths were surprisingly higher in the 0 to 4 year group (0.9 per 100,000) than in the 5 to 14 year group (0.7 per 100,000) and in keeping with the pattern in adulthood 1 was the major cause of death in the 15 to 24 year group. Infections of the kidney (presumably unassociated with malformations of the genitourinary system) were not a significant cause of death in any age group. The decfine in deaths attributed to nephritis-nephrosis was not a unique finding for New York City. As can be seen in Fig, 2, the patterns for the United States as a whole were similar to New York City both with respect to the rate for each age group and the significant decline in overall rate in the two periods examined, 1950 and 1965. The decline in renal deaths due to nephritis-nephrosis in New York City appears to be a reflection of a national phenomenon. DISCUSSION The analysis of over-all mortality statistics of renal diseases in the 0 to 24-year-old population in New York City from 1950 to 1970 reveals that a progressive decline
93 0
"S
McCrory, Shibuya, and Yano
The Journal of Pediatrics December 1975
5
Z O
4 IItI x...
~OLr) Wed <:oo
~.~
3
4x z'x
~ XY
3
m a.
O
_
1950)
~Ny
c
O
wo o~ o c~
I
• x~
gX ~X
X )
o
Z'/
vx
O
V'-
o
o
o o o o
o o
o o o o
1950
1955
o
o
XX
o o
o
o
iOo j~
x,< 1 I'm
---I l~
1960
1965
1970
congenitalmalformations of urinary system
I~
nephritis and nephrosis
infections of kidney
[~
malignantneoplasms
of urinary organs I
/u,
O
~.A
ther diseases of kidney
1 9 6 5 ~
W O
I
< 5 YR
I
I
5o14YR 15-24YR AGE
Fig. 1. Mortality rates from renal diseases for residents of New York City under 25 years of age from 1950 to 1970.
Fig. 2. Age-specific mortality rates due to nephritis-nephrosis.
in the death rate is evident. It can be attributed to a decline in deaths ascribed to nephritis-nephrosis, an observation in keeping with recent reports of similar findings for the adult population in the United States 1-3 and in England and Wales? Kessner and Florey' ~ reported that a decline occurred in the mortality rate from acute and chronic nephritis for all age groups and both sexe~ in the United States between 1940 and 1964, a trend they also cited as worldwide. A simultaneous increase in the mortality rate ascribed to infections of the kidney for both sexes was also noted in the United States 1-,~and in England and Wales between 1950 and 19642 The analysis of multiple causes of death revealed that cardiovascular disorders were the most common underlying cause of death associated with chronic nephritis as the secondary cause in 1955 death certificates. Based on these findings, they concluded that although the decline in the mortality rate from chronic nephritis could reflect a true change in the frequency of chronic renal disease, it was more likely that it resulted from changes in diagnostic habits and effects of competing mortality rates. Waters 4 confirmed that the decline in deaths from I949 to 1965 from nephritis and nephrosis was concomitant with increased deaths from infections of the kidney in England and Wales.
Hansen and Susser~ have recently reported statistical observations of historic trends in death from chronic kidney disease in the United States and Britain showing a true decline since 1930 in the mortality rate from chronic nephritis, whether alone or combined with infections of the kidney, at all ages (except over 75 in Britain) for both sexes in the United States and Britain. They concluded that the decline reflected a generation effect changing the mortality experience of successive generations born after 1850, a pattern parallel with the trend of a decreasing mortality rate for scarlet fever. In our data for the population under 25 years of age in New York City, no consistent rise in death from infections of the kidney was observed. Secorid, there was no opportunity for the effect of competing mortality rates from degenerative cardiovascular disease in this younger population. Last, there was no essential change in coding practice with respect to renal deaths before the sixth (1950-57) and seventh (1958-67) revisions. According to the preliminary report '~ on the comparability of mortality statistics between the seventh and eighth (since 1968) revisions, it can be estimated that deaths from nephritisnephrosis for all ages in the United States would decrease by 12% solely on the basis of differences in classification and coding methods between these two revisions: If the same percentage of reduction is applied to the nephritis-
Volume 87 Number 6, part 1
Trends in renal disease mortality rate
93 1
Table II. Number of deaths from renal disease and age-specific mortality rates (per 100,000 population) for residents of New York City in 1965 Age 0 -4 Cause of death
Malignant neoplasm Nephritis and nephrosis Infections of kidney Other diseases of urinary system Congenital malformations Total
ICD number
No.
180-181 590-594 600 601-609 757.1 757.3
10 6 2
I
1
5 - 14
15 - 24
Total
Rate
No.
Rate
No.
Rate
No.
1.4 0.9 0.3
6 8 0
0.5 0.7
3 23 2
0.3 2.1 0.2
19 37 4
Rate
0.9 1.2 0.1
0.1
0
--
0
--
25
3.6
2
0.2
0
--
27
0.6
44
6.3
16
1.4
28
2.6
88
2.9
nephrosis mortality rate for our population, even though it is likely to be much less in children, it would account for only one half of the observed reduction. Based on these findings, we conclude that the decline in the nephritis-nephrosis mortality rate observed over the last two decades is a reflection of a true decrease due to a less frequent occurrence or to a milder course of these diseases. As Hansen and Susser ~ mentioned, this trend might be related to the better control or changes in the natural history of streptococcal infections since similar phenomena have been noted for rheumatic fever and rheumatic heart disease as well as for scarlet fever. ~6 An additional factor would be operating in the 1965 to 1970 data. Some of the decline in the number of deaths from nephritis-nephrosis in 1965 and 1970 could be ascribed to the prolongation of life resulting from enrollment of patients with chronic renal failure in expanding programs of dialysis and transplantation in New York City. These were first initiated in 1963. Data on the actual number of patients with chronic renal failure due to nephritis-nephrosis in the age group (10 to 24 years) on dialysis or successfully transplanted since 1963 were not available to us. A few recent publicationsTM 1~have utilized crude data derived from mortality statistics or clinical surveys to provide estimates for the magnitude of potential candidates for dialysis or for transplantation. Barratt ':~ estimated the death rate from renal failure in children under 15 years of age to be 3 to 5 per million total population per annum. He cited TM a report that estimated the death rate in European children from 6 months to 16 years of age to be 0.8 per million per annum in 1970. Pendreigh and colleagues 1'-' made a comprehensive survey i n Scotland (1968-69) based on death certificates and hospital records and found the requirements, immediate or within one year, for dialysis or transplantation in children under 15
1
I
0.1
years Of age to be 15.8 for males and 10.5 for females per million population. Any attempt to estimate the over-all prevalence of chronic renal failure for all subjects 0 to 24 years of age per unit Of the total population poses several problems. The reliability of using mortality data as an index of chronic renal failure is unproved. The nature of renal disorders causing renal deaths changes markedly with increasing age during childhood. The major causes of renal deaths in infants are congenital malformations and neoplasms. The youngest subjects (0 to 5 years) are not presently considered to be suitable candidates for therapeutic management by dialysis and transplantation because the technology required is lacking. The children over 5 years of age are potential candidates. Using the data from 1965 for 5 to 14 years of age (Table II) after exclusion of all deaths from malignant neoplasms, there would be nine eligible cases per million population of 5 to 14 years of age per year in New York City, and similar calculations in the 15 to 24 year age group provide an estimate of 23 eligible cases per million population of this age range per year. These age-specific figures can be compared with the estimate of Kessner and Florey ' based on 1964 mortality data for chronic nephritis and infection of the kidney that approximately 50 individuals per million inhabitants in the 15 to 55 year age range may be candidates for dialysis or renal transplantation in the United States per year. The many short-comings inherent in the use of mortality data to derive estimates of the incidence of chronic renal failure have precluded its use, but the exercise may be deserving of further exploration at this stage of the problem. A study testing validity of mortality data indicated that death certificates could be used to obtain reasonable estimates of the need for dialysis and transplantation, provided that this information was
932
McCrory, Shibuya, and Yano
s u p p l e m e n t e d by data for live patients on dialysis or after renal transplantation27 A f u r t h e r note of caution is in order. W e h a v e f o u n d that the over-all a n n u a l mortality rate for r e n a l d e a t h s has b e e n continuously declining since 1950. T h e use o f mortality data for purposes o f estimating p o t e n t i a l candidates for dialysis a n d t r a n s p l a n t a t i o n would thus a p p e a r to be applicable only for short-term projections.
The Journal of Pediatrics December 1975
6. 7.
8.
9. Access to mortality data of the New York City Bureau of Vital Statistics was coordinated by and made possible by Dr. Donna O'Hare, Assistanct Commissioner of Health and Director of Maternal and Child Health Services, New York City Health Department.
10.
11. REFERENCES
1. Kessner DM, and Florey C du V: Mortality trends for acute and chronic nephritis and infections of the kidney, Lancet 2:979, 1967. 2. Florey C du V, and Kessner DM: Mortality trends for acute and chronic nephritis and infections of the kidney, Am Heart J 76:848, 1968. 3. Florey C du V, Kessner DM, Kashgarian M, and Senter MG: Mortality trends for chronic nephritis and infections of the kidney-a clinical and statistical comparison between mortalit~r of New Haven, Connecticut and the United States, 1950-1960, J Chron Dis 24:71, 1971. 4. Waters WE: Trends in mortality from nephritis and infections of the kidney in England and Wales, Lancet 1:241, 1968. 5. Hansen H, and Susser M: Historic trends in deaths from
12. 13. 14. 15.
16. 17.
chronic kidney disease in the United States and Britain, Am J Epidemiol 93:413, 1971. Williams GM, Lee HM, and Hume DM: Renal transplants in children, Transplant Proc 1:262, 1969. Fine RN, Korsch BM, Stiles Q, Riddell H, Edelbrock HH, Brennan LP, Grushkin CM, and Lieberman E: Renal homotransplantation in children, J PEDIATR 76:347, 1970. Potter D, Folkert OB, Rames L, Holliday MA, Kountz SL, and Najarian JS: The treatment of chronic uremia in childhood. I. Transplantation, J PEDIATR 45:432, 1970. La Plante MP, Kaufman JJ, Goldman R, Gonick HC, Martin DC, and Goodwin W E : K i d n e y transplantation in children, J PEDIATR 46:665, 1970. Lilly JR, Giles G, Hurwitz R, Schroter G, Takagi H, Gray S, Penn I, Halgrimson CG, and Starzl TE: Renal homotransplantation in pediatric patients, J PEDIATR 47:548, 1971. Hallan JB, and Harris BSH III: Estimation of a potential hemodialysis population, Med Care 8:209, 1970. Pendreigh DM, et al: Survey of chronic renal failure in Scotland, Lancet 1:304, 1972. Barratt TM: Renal failure in the first year of life, Br Med Bull 27:115, 1971. Barratt TM: Renal failure in children, Proc R Soc Med 64:1045, 1971. National Center for Health Statistics: Provisional estimates of selected comparability ratios based on dual coding of 1966 death certificates by the seventh and eighth revisions of the International Classification of Diseases, Monthly Vital Statistics Report, Vol 17, No 8 (Suppl), October, 1968. Acheson RM: The epidemiology of acute rheumatic fever, 1950-1964, J Chron Dis 18:723, 1965. Modan B, et al: Chronic renal disease in Israel. Validity of death certificates, Isr J Med Sci 7:1550, 1971.
December 1975 The Journal o f P E D I A T R I C S
Recent trends in the mortality rate from renal disease in children and young adults in New York City Analysis has shown that the over-all death rate from renal disease for residents of New York City under 25 years of age has declined from 4.6 per 100,000 in 1950 to 2.3 per 100,000 in 1970. Nephritis and nephrosis was the major disease eategory aeeounting for this decrease in deaths. A similar trend was Jbund for the United States as a whole. Other causes o f renal disease did not manifest consistent changes in death rates. The decline in deaths from nephritis and nephrosis could not be ascribed solely to changing diagnostic habits or terminology. A possible alternative explanation is a change in the natural history o f these diseases. Data of this type might be useful as an index to future trends in the mortality rate from renal diseases and as one basis for projeetions o f potential future needs for dialysis and renal transplantation. Using 1965 data, we estimate the number o f such potential candidates in New York City would have been 9 per 1,O00,O00 for the 5 to 14 year age group and 23 per 1,O00,O00 for the 15 to 24 year age group. There are significant limitations o f projections based on such data. These estimates of potential candidates for ehronie dialysis or renal transplantation are the first available for children in the United States.
Wallace W. McCrory, M.D.,* Madoka Shibuya, M.D., and Katushiko Yano, M.D., New
Y o r k , N . Y.
RECENT EPIDEMIOLOGIC STUDIES of renal failure due to nephritides in adults 1-~ have demonstrated that there has been a decline in the number of reported deaths attributed to acute and chronic nephritis since the early 1950s. Although the reason for these changes is not clear, one possible explanation among many deserving consideration is that the disease itself is changing in severity. There are no data reporting mortality rate trends for renal deaths in infancy and childhood, either based on the analysis of all causes of renal death or, more particularly, those attributable to acute and chronic nephritis. The lack of such data has now become a matter of increased From the Departments of Pediatrics and Public Health, Cornell University Medical Center and New York Hospital. Presented in part at the X I I I International Congress o f Pediatrics, Vienna, August 29, 1971. *Reprint address: Department of Pediatrics, New York Hospital, 525 E. 68th St., New York, N. Y. 10021.
Vol. 87, No. 6, part 1, pp. 928-932
concern since the feasibility of utilizing chronic dialysis and renal transplantation as treatment for end-stage renal failure in children has now been demonstrated? .... Accordingly, we felt that analysis of the data available for annual reported deaths from renal disorders in infants and children would be of value. The meager data for chronic renal failure available in the literature IH~ are too crude to be useful for any epidemiologic or predictive purposes. This report describes the results of a retrospective study analyzing mortality rates for all deaths ascribed to renal disease in subjects under 25 years of age in the New York City area from 1950 through 1970.
METHODS AND MATERIALS The study population comprised all residents of the city of New York who were under 25 years of age during a 20year period, 1950 to 1970. Through the cooperation of the Bureau of Vital Statistics of the New York City Depart-
Volume 87 Number 6, part 1
Trends in renal disease mortality rate
ment of Health we were provided with the sex, age, and cause of death from all death certificates in which renal disease was listed as the underlying cause of death. The data had been collected from 1950 through 1970, and all renal deaths had been coded by Health Department personnel. These data were then classified into five major categories based on the International Classification of Diseases (ICD) as follows: Underlying cause of death
ICD code number 6th (1949-57) and 7th (1958-67) 8th (since revisions 1968) revision
Malignant neoplasmof urinary system and kidneys Nephritis and nephrosis Infections of kidney Other diseases of urinary system Congenital malformations of kidney and urinary system
180-181 590-594 600 601-609
188-189 580-584 590 591-599
757.1,3
753
It is evident that the five major categories studied do not include all renal conditions. The total number of such ignored deaths would presumably not be numerically great assuming causes of death were properly coded. The death rates per 100,000 population were computed for each renal disease and for 0 to 25 years and also for specific age groupings, specifically 0 to 4 years, 5 to 14 years, and 15 to 24 years. The United States Census data for 1950, 1960, and1970 were used for the denominator in computing annual age-specific data rates. For 1955 and 1965, estimates of population were used. We examined each year but will present only data for five-year interval periods. The interval data are representative of the pattern observed in evaluating individual annual death rates. RESULTS The over-all mortality rates from renal disorders for residents of New York City under 25 years of age were found to have declined approximately 50% from 1950 to 1970 (Table I). The continuous trend of the over-all decline (Fig. 1) is largely accounted for by the decrease observed in the death rate l~or the nephritis-nephrosis category which fell threefold. The death rates of three other categories (infections of the kidney, other diseases of urinary system, and congenital m a l f o r m a t i o n s ) w e r e either not consistently different or were essentially unchanged. The death rate for malignant neoplasms of kidneys and urinary system was an exception in that the rate in 1970 was the lowest recorded. The age group 0 to
929
T a b l e I. Death rates (per 100,000 population) from renal disease for 0 to 24-year-old residents of New York City from 1950 to 1970
Cause of death Malignant neoplasm Nephritis and nephrosis Infections of kidney Other diseases of urinary system Congenital malformations All causes
n~,CnnbDer1950 1955 1960 1965 ]970 180-181 590-594 600 601-609 757.1 757.3
1.0
1.4
1. i
0.9
0.4
2.8 0.1 0.2
2.1 0.3 0.1
1.6 0.6 0.1
1.2 0.1 0.1
0.9 0.2 0.4
0.5
0.4
0.6
0.6
0.4
4.6
4.3
4.0
2.9
2.3
25 years covers the period from birth into early adulthood. A separate analysis of data for developmentally different age groups comprising 0 to 25 years was made. The rate of each disease category was calculated for infancy (0 to 4 years), childhood (5 to 14 years), and young adulthood (15 to 24 years). Data for 1965 are shown in Table II. As expected, the over-all rates changed in the three age groups as did the contributions of each category. The highest over-all death rate was in the 0 to 4 year group (6.3 per t00,000) and~the lowest in the 5 to 14 year group (1.4 per 100,000). Congenital malformations were the major cause of renal deaths in the youngest group (57%), neoplasms next (23%), both accounting for 80% of all infant renal deaths. Congenital malformations contributed only a small number of deaths in the 5 to 14 year age group and no deaths in the 15 to 24 year age group. Nephritis-nephrosis deaths were surprisingly higher in the 0 to 4 year group (0.9 per 100,000) than in the 5 to 14 year group (0.7 per 100,000) and in keeping with the pattern in adulthood 1 was the major cause of death in the 15 to 24 year group. Infections of the kidney (presumably unassociated with malformations of the genitourinary system) were not a significant cause of death in any age group. The decfine in deaths attributed to nephritis-nephrosis was not a unique finding for New York City. As can be seen in Fig, 2, the patterns for the United States as a whole were similar to New York City both with respect to the rate for each age group and the significant decline in overall rate in the two periods examined, 1950 and 1965. The decline in renal deaths due to nephritis-nephrosis in New York City appears to be a reflection of a national phenomenon. DISCUSSION The analysis of over-all mortality statistics of renal diseases in the 0 to 24-year-old population in New York City from 1950 to 1970 reveals that a progressive decline
93 0
"S
McCrory, Shibuya, and Yano
The Journal of Pediatrics December 1975
5
Z O
4 IItI x...
~OLr) Wed <:oo
~.~
3
4x z'x
~ XY
3
m a.
O
_
1950)
~Ny
c
O
wo o~ o c~
I
• x~
gX ~X
X )
o
Z'/
vx
O
V'-
o
o
o o o o
o o
o o o o
1950
1955
o
o
XX
o o
o
o
iOo j~
x,< 1 I'm
---I l~
1960
1965
1970
congenitalmalformations of urinary system
I~
nephritis and nephrosis
infections of kidney
[~
malignantneoplasms
of urinary organs I
/u,
O
~.A
ther diseases of kidney
1 9 6 5 ~
W O
I
< 5 YR
I
I
5o14YR 15-24YR AGE
Fig. 1. Mortality rates from renal diseases for residents of New York City under 25 years of age from 1950 to 1970.
Fig. 2. Age-specific mortality rates due to nephritis-nephrosis.
in the death rate is evident. It can be attributed to a decline in deaths ascribed to nephritis-nephrosis, an observation in keeping with recent reports of similar findings for the adult population in the United States 1-3 and in England and Wales? Kessner and Florey' ~ reported that a decline occurred in the mortality rate from acute and chronic nephritis for all age groups and both sexe~ in the United States between 1940 and 1964, a trend they also cited as worldwide. A simultaneous increase in the mortality rate ascribed to infections of the kidney for both sexes was also noted in the United States 1-,~and in England and Wales between 1950 and 19642 The analysis of multiple causes of death revealed that cardiovascular disorders were the most common underlying cause of death associated with chronic nephritis as the secondary cause in 1955 death certificates. Based on these findings, they concluded that although the decline in the mortality rate from chronic nephritis could reflect a true change in the frequency of chronic renal disease, it was more likely that it resulted from changes in diagnostic habits and effects of competing mortality rates. Waters 4 confirmed that the decline in deaths from I949 to 1965 from nephritis and nephrosis was concomitant with increased deaths from infections of the kidney in England and Wales.
Hansen and Susser~ have recently reported statistical observations of historic trends in death from chronic kidney disease in the United States and Britain showing a true decline since 1930 in the mortality rate from chronic nephritis, whether alone or combined with infections of the kidney, at all ages (except over 75 in Britain) for both sexes in the United States and Britain. They concluded that the decline reflected a generation effect changing the mortality experience of successive generations born after 1850, a pattern parallel with the trend of a decreasing mortality rate for scarlet fever. In our data for the population under 25 years of age in New York City, no consistent rise in death from infections of the kidney was observed. Secorid, there was no opportunity for the effect of competing mortality rates from degenerative cardiovascular disease in this younger population. Last, there was no essential change in coding practice with respect to renal deaths before the sixth (1950-57) and seventh (1958-67) revisions. According to the preliminary report '~ on the comparability of mortality statistics between the seventh and eighth (since 1968) revisions, it can be estimated that deaths from nephritisnephrosis for all ages in the United States would decrease by 12% solely on the basis of differences in classification and coding methods between these two revisions: If the same percentage of reduction is applied to the nephritis-
Volume 87 Number 6, part 1
Trends in renal disease mortality rate
93 1
Table II. Number of deaths from renal disease and age-specific mortality rates (per 100,000 population) for residents of New York City in 1965 Age 0 -4 Cause of death
Malignant neoplasm Nephritis and nephrosis Infections of kidney Other diseases of urinary system Congenital malformations Total
ICD number
No.
180-181 590-594 600 601-609 757.1 757.3
10 6 2
I
1
5 - 14
15 - 24
Total
Rate
No.
Rate
No.
Rate
No.
1.4 0.9 0.3
6 8 0
0.5 0.7
3 23 2
0.3 2.1 0.2
19 37 4
Rate
0.9 1.2 0.1
0.1
0
--
0
--
25
3.6
2
0.2
0
--
27
0.6
44
6.3
16
1.4
28
2.6
88
2.9
nephrosis mortality rate for our population, even though it is likely to be much less in children, it would account for only one half of the observed reduction. Based on these findings, we conclude that the decline in the nephritis-nephrosis mortality rate observed over the last two decades is a reflection of a true decrease due to a less frequent occurrence or to a milder course of these diseases. As Hansen and Susser ~ mentioned, this trend might be related to the better control or changes in the natural history of streptococcal infections since similar phenomena have been noted for rheumatic fever and rheumatic heart disease as well as for scarlet fever. ~6 An additional factor would be operating in the 1965 to 1970 data. Some of the decline in the number of deaths from nephritis-nephrosis in 1965 and 1970 could be ascribed to the prolongation of life resulting from enrollment of patients with chronic renal failure in expanding programs of dialysis and transplantation in New York City. These were first initiated in 1963. Data on the actual number of patients with chronic renal failure due to nephritis-nephrosis in the age group (10 to 24 years) on dialysis or successfully transplanted since 1963 were not available to us. A few recent publicationsTM 1~have utilized crude data derived from mortality statistics or clinical surveys to provide estimates for the magnitude of potential candidates for dialysis or for transplantation. Barratt ':~ estimated the death rate from renal failure in children under 15 years of age to be 3 to 5 per million total population per annum. He cited TM a report that estimated the death rate in European children from 6 months to 16 years of age to be 0.8 per million per annum in 1970. Pendreigh and colleagues 1'-' made a comprehensive survey i n Scotland (1968-69) based on death certificates and hospital records and found the requirements, immediate or within one year, for dialysis or transplantation in children under 15
1
I
0.1
years Of age to be 15.8 for males and 10.5 for females per million population. Any attempt to estimate the over-all prevalence of chronic renal failure for all subjects 0 to 24 years of age per unit Of the total population poses several problems. The reliability of using mortality data as an index of chronic renal failure is unproved. The nature of renal disorders causing renal deaths changes markedly with increasing age during childhood. The major causes of renal deaths in infants are congenital malformations and neoplasms. The youngest subjects (0 to 5 years) are not presently considered to be suitable candidates for therapeutic management by dialysis and transplantation because the technology required is lacking. The children over 5 years of age are potential candidates. Using the data from 1965 for 5 to 14 years of age (Table II) after exclusion of all deaths from malignant neoplasms, there would be nine eligible cases per million population of 5 to 14 years of age per year in New York City, and similar calculations in the 15 to 24 year age group provide an estimate of 23 eligible cases per million population of this age range per year. These age-specific figures can be compared with the estimate of Kessner and Florey ' based on 1964 mortality data for chronic nephritis and infection of the kidney that approximately 50 individuals per million inhabitants in the 15 to 55 year age range may be candidates for dialysis or renal transplantation in the United States per year. The many short-comings inherent in the use of mortality data to derive estimates of the incidence of chronic renal failure have precluded its use, but the exercise may be deserving of further exploration at this stage of the problem. A study testing validity of mortality data indicated that death certificates could be used to obtain reasonable estimates of the need for dialysis and transplantation, provided that this information was
932
McCrory, Shibuya, and Yano
s u p p l e m e n t e d by data for live patients on dialysis or after renal transplantation27 A f u r t h e r note of caution is in order. W e h a v e f o u n d that the over-all a n n u a l mortality rate for r e n a l d e a t h s has b e e n continuously declining since 1950. T h e use o f mortality data for purposes o f estimating p o t e n t i a l candidates for dialysis a n d t r a n s p l a n t a t i o n would thus a p p e a r to be applicable only for short-term projections.
The Journal of Pediatrics December 1975
6. 7.
8.
9. Access to mortality data of the New York City Bureau of Vital Statistics was coordinated by and made possible by Dr. Donna O'Hare, Assistanct Commissioner of Health and Director of Maternal and Child Health Services, New York City Health Department.
10.
11. REFERENCES
1. Kessner DM, and Florey C du V: Mortality trends for acute and chronic nephritis and infections of the kidney, Lancet 2:979, 1967. 2. Florey C du V, and Kessner DM: Mortality trends for acute and chronic nephritis and infections of the kidney, Am Heart J 76:848, 1968. 3. Florey C du V, Kessner DM, Kashgarian M, and Senter MG: Mortality trends for chronic nephritis and infections of the kidney-a clinical and statistical comparison between mortalit~r of New Haven, Connecticut and the United States, 1950-1960, J Chron Dis 24:71, 1971. 4. Waters WE: Trends in mortality from nephritis and infections of the kidney in England and Wales, Lancet 1:241, 1968. 5. Hansen H, and Susser M: Historic trends in deaths from
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chronic kidney disease in the United States and Britain, Am J Epidemiol 93:413, 1971. Williams GM, Lee HM, and Hume DM: Renal transplants in children, Transplant Proc 1:262, 1969. Fine RN, Korsch BM, Stiles Q, Riddell H, Edelbrock HH, Brennan LP, Grushkin CM, and Lieberman E: Renal homotransplantation in children, J PEDIATR 76:347, 1970. Potter D, Folkert OB, Rames L, Holliday MA, Kountz SL, and Najarian JS: The treatment of chronic uremia in childhood. I. Transplantation, J PEDIATR 45:432, 1970. La Plante MP, Kaufman JJ, Goldman R, Gonick HC, Martin DC, and Goodwin W E : K i d n e y transplantation in children, J PEDIATR 46:665, 1970. Lilly JR, Giles G, Hurwitz R, Schroter G, Takagi H, Gray S, Penn I, Halgrimson CG, and Starzl TE: Renal homotransplantation in pediatric patients, J PEDIATR 47:548, 1971. Hallan JB, and Harris BSH III: Estimation of a potential hemodialysis population, Med Care 8:209, 1970. Pendreigh DM, et al: Survey of chronic renal failure in Scotland, Lancet 1:304, 1972. Barratt TM: Renal failure in the first year of life, Br Med Bull 27:115, 1971. Barratt TM: Renal failure in children, Proc R Soc Med 64:1045, 1971. National Center for Health Statistics: Provisional estimates of selected comparability ratios based on dual coding of 1966 death certificates by the seventh and eighth revisions of the International Classification of Diseases, Monthly Vital Statistics Report, Vol 17, No 8 (Suppl), October, 1968. Acheson RM: The epidemiology of acute rheumatic fever, 1950-1964, J Chron Dis 18:723, 1965. Modan B, et al: Chronic renal disease in Israel. Validity of death certificates, Isr J Med Sci 7:1550, 1971.