rheumatic fever and rheumatic heart disease : i. incidence and sex distribution

Acta Medica Scandinavica. Vol. CLX, fasc. IV, 1958.

From The Bade Institute, Department of Pathology, University of Bergen, Bergen, Norway.

Rheumatic Fever and Rheumatic Heart Disease. I. Incidence and Sex Distribution.

BY

ERIK WAALER, M. D.

(Submitted for publication October 30, 1957.)

Introduction.

Rheumatic heart disease still offers many problems. $In addition to the etiology and pathogenesis which are under discussion there appears to be some disagreement with regard to the incidence of acute and chronic rheumatic valvular disease as a cause of death and their distribution in the two sexes. To some extent these disa- greements may be due to differences in the basic material of the various authors, the diagnostic criteria may have been different and possibly selection may have occurred.

It has also been claimed that the incidence of rheumatic fever has been decreas- ing in Western Europe in recent years. The morbidity and mortality statistics for Denmark 1878-1940 indicate a marked fall, Clemmesen (6). A similar decrease has been noted in Norway by Motzfeldt (16) and later by Hanssen (12).

According t o Wychoff and Lingg (24) rheumatic heart disease lies second among the heart diseases as the cause of death, coming after arteriosclerotic heart disease. The latter causes 40 %, rheumatic failure 25 % of deaths from heart disease. I n the Norwegian Mortality Statistics rheumatic valvular disease is not listed so high but the so called ochronic endocarditis not stated as rheumatic)) (no. 421 in the international list) appears to be quite common. Many of these cases may be of rheumatic origin.

In the autopsy statistics from U.S.A. the incidence of rheumatic disease varies from 9.1 % to 1 .6 % of all autopsies (Claiborne and Wolff (4)). In Mexico, Robles Gil and Lim6n Lason found 16.8 per cent (19). These divergences may to some extent be due to selection and differences in basic hospital material.

Many authors state that the incidence of rheumatic heart disease and rheumatic fever is different in the two sexes. A marked prevalence in women is claimed by some authors (M/F=3/4), (Anderson (1)) Perman (18), Stroud and Twaddle (22), Stone and Feil (2l) , Wedum and Wedum (23), Aubert (3) and Miiller (17). Some authors state that the sex difference is less marked (Glover (l l) , Kaiser (15)), but many authors find the sex difference insignificant or no difference a t all (Hedley

282 ERIK WAALER.

(14), Clawsson (5), Edstriim (lo), Harving (13), Davis and Rosin (a), Arnsrae, Br~ckner-Mortensen and Hastrup (a), Cohn and Lingg (7)). De Graff and Lingg (9) state that there is higher ratio of females among children and of males among adults. The divergences in the literature may therefore be due to variation in the age in the different series.

A large amount of autopsy material may give valuable information here. Close evaluation of the death mechanism is possible and we can also state how often rheumatic heart disease occurs as an incidental finding without being of importance to the cause of death. A study of autopsy material will be particularly valuable if it is derived from a general hospital without special selection of the patients and the frequency of autopsies is high.

Material and Methods. The autopsy material used was derived from The Gade Institute 1941-1955.

During this period the author has been in charge of the autopsy department and the interest in valvular disease and the evaluation of the criteria has been unchanged. I n all there were 5,470 autopsies, still-born not included. 219 cases were classified as rheumatic heart disease, hhronic or acute. The diagnosis was based on the gross and partly on the microscopic pathology of the valves and endocardium. The typical acute lesions with nodules a t the line of closure and the characteristic histology do not leave any room for doubt. The distinction of the chronic valvular disease of rheumatic origin from the degenerative valvular lesions of old age may be more difficult. We have used similar criteria to those stated by Sprague and Garmichael in 1950 (20). Pibrotic thickening of the mitral and aortic valves are the main gross finding. The thickening should be most marked a t the line of closure, a varying degree of calcification may be present. Thickening and shrinkage of the chordae tendineae has been stressed as the best macroscopic criterion. Calcification of the mitral ring has not been recognized as rheumatic unless other stigmata should be present. Microscopic examination have not been carried out in all cases as a routine. The shortage of chemicals for histological work during and immediately after the war, 1940-45, made it necessary to take sections from the doubtful cases only, to prove or disprove the diagnosis. Otherwise sections were as a rule taken from mitral and aortic valves, left ventricle, left atrium and in many cases left auricular appendage. These were stained with hematoxylin and eosin, and also van Gieson. A microscopic diagnosis of chronic rheumatic disease with sclerosis and hyaliniza- tion of the valve leaflets, lymphocytes and some few vessels is, as a rule, easy. The scarred thickening of the endocardium of the left atrium is likewise easy to detect. The small nodular scars left by Aschoff bodies, especially in the immediate vicinity of the vessels, are not so easily revealed.

The autopsy material is derived from the University Hospital which is a general hospital for the city of Bergen and surrounding communities. To a minor degree it is a specialized hospital receiving selected patients from Western Norway. A partic- ular selection or segregation of the basic hospital material should therefore not take place.

RHEUMATIC FEVER AND RHEUMATIC HEART DISEASE. 283

Table 1. Age Distribution. in the Norwegian Mortality Statistics 1946--47, 1951-52 a d T h e Gade Institute Autopsies

I941 -55.

0- 4 . . . . . . 5- g . . . . . .

10-19 . . . . . . 20-29 . . . . . . 30-39.. . . . . 40-49.. . . . . 50-59.. . . . . 60-69.. . . . . 70-79.. . . . .

>80.. . . . .

~ ~~ ~

Per cent Males - Gade Institute

18.01 2.15 3.36 5 .11

11.42 15.52 17.71 15 .53

4.74

6 .45

The Country

9.66

1 .54 3.65 4.30 6.00 9.92

15.59 23.62 24.66

1,02

Per cent Females

Gade Institute

15.92 1 .66 2.95 5 .48 7.03 9.30

13.47 17.96 17 .71

8.48

The Country

7.05 0.59 0.94 2.24 2.83 4.63 7 .71

14.16 25.82 34.00

Post mortem examination is carried out in almost all cases dying in the hospital. On an average the frequency of autopsies has been 90 per cent. The mean age of the autopsied individuals was 4 4 . 2 years for males and 4 7 . 6 years for females. As the mean age at death for the whole country in 1949 was 61.8 years for males and 67.8 years for females. The younger age groups dominate in our material. The age distribution is indicated in table 1 and compared with the age distribution of the mortality statistics for the whole country. It can be seen that the under-representation in our material occurs above the age of 70 years. Below the age of 60 years the autopsy material has relatively twice as many in each age group as the mortality statistics. As the great bulk of rheumatic cases, according to the literature, should be found under the age of 50 years our material should give a good background for an evaluation of the incidence of rheumatic disease.

The sex distribution in our autopsy material was 5 4 . 7 per cent males and 45.3 per cent females. This is a definite over-representation of males. Chart 1 illustrates that the preponderance of males is most marked in two periods: childhood-youth and the 40-59 year groups. Only above 80 years was there preponderance of females.

I n conclusion therefore i t is evident that the older age groups are under- represented in our material and that males dominate to some extent.

For comparison we have examined the deaths from heart disease in 1951-1952 in Norway as they are presented in the official mortality statistics.

A comparison of the autopsy-statistics from the cities Oslo and Bergen has also been carried out and is of special interest as rheumatic fever is said to have been more common in Bergen than in Oslo in the beginning of this century up to the later part of 1930 ( 1 6 ) . Dr. Einar Hval and Dr. Magne Svendsen have kindly supplied me with the necessary information about deaths from rheumatic valvular disease from Ullevaal Hospital, Department of Pathology. Ullevaal Hospital is a general hospital for the city of Oslo, and the percentage of autopsies is the same as

22473599. Acta med. Scandinav. VoI .CLX.

284

-07

10-

20-

30-

40-

50-

60-

70 - 80 - SO-

100-

ERIK WAALER.

C H A R T 1 .

Sex Distribution in Autopsies. THE GADE INSTITUTE 1941 -1955.

AGE GROUPS - in Bergen. The average age of the autopsied individuals is higher than in Bergen, approximately 64 years for males and 69 years for females, because the hospital includes a large geriatric unit. The material used is derived from 1954-1955 and comprises 3,568 autopsies, 212 with rheumatic heart disase.

The autopsies report the occurrence of heart lesions among those dying from and with rheumatic heart disease. As the age and the sex distribution may be different in a group of patients, we have in addition examined the clinical records of 720 con- secutive cases of rheumatic heart failure and (or) rheumatic fever treated in the Department of medicine, and in the Children’s Hospital. These cases cover some 22,081 hospital admissions.

Personal Investigation.

A. Incidence of Rheumatic Heart Disease. >

Table 2 shows that the major cause of death among the heart disease, both in the statistics for the whole country and in the autopsies, is arteriosclerotic heart disease (8.46 per cent and 6.82 per cent of the deaths respectively). Hypertensive heart disease comes second in the official statistics and third in the autopsies. Rheumatic heart disease ranks lower in the official statistics. A direct comparison of the rheumatic group in the two series is however impossible. Altogether we had 219 cases of rheumatic heart disease in the period, but in 99 individuals only was the cause of death related to the heart condition. Of these 99 cases death was due directly to the heart condition in 61 instances, in 38 the immediate or ultimate cause was an embolic complication. Undoubtedly many of these 38 cases in official statistics based on clinical data only would have been listed as rheumatic heart disease, a few only as embolic. On the other hand so called *Chronic endocarditis not specified as rheumat-


I Rheumatic Heart Disease (401-416) . . 530

matic (421) ......................... 761 4,757

41-43) ............................ 1,133

I1 Chron. Endocard. Not Specified as Rheu-

I11 Arterioscl. Heart Disease (420) . . . . . . . . \'I Hypertension with Heart Disease (440-

Table 2. Comparison. of Mortality Statistics for Norway and The Gade Institute Autopsy Statistics.

0.94

1.35 23 0.42 8.46 374 6.82

2.01 85 1.55

1941-45. . . . 1946-50 . . . . 1951-55. . . .

Total

topsies 1941-1955.

60 1,735 77 1,632 82 2,103

299 5,470

Years Heart Dis. Autopsies 1 ; ~ e s 1 Per cent

Rheumatic Cases

3,45 4,71 3,90 4,Ol

ico (no. 421 in the international list) ranks high in the official statistics, but low among the autopsies. We have included here some cases of calcified mitral ring with distortion of the valves and a few individuals with calcified aortic and mitral cusps where we have been unable to find rheumatic stigmata. If the two groups in table 2 , the rheumatic and non-rheumatic (421) are taken together the percentage in hoth statistics will be almost the same (2 .24 per cent - 2 . 2 3 per cent respectively).

The number of rheumatic cases varies considerably from year to year and there is no definite decrease to be noted in our autopsy material. Table 3 shows that when all cases of rheumatic heart disease are included they total, over the whole period, 4.01 per cent. The variation in the different 5 year periods is not large. I n table 4 we have classified our material according to the cause of death. Altogether we had 7 cases of acute rheumatic pancarditis, the lw t case in 1947. Bacterial endocarditis shows but little change in the period. Among the 20 cases 13 occurred before 1947. Chronic valvular disease does not seem to have changed in frequency over the 15 year period.

A comparison between autopsy material in Oslo and Bergen is of special interest in view of the fact that rheumatic fever from the beginning of this century to the later part of 1930 is said to have been more common in Bergen than in Oslo. In the two years 1954 and 1955 rheumatic heart disease accounted for 5 . 9 3 per cent of the autopsies whereas Bergen had 4 .01 per cent (table 5). It is also evident from the

286

2.7

3.1

ERIK WAALER.

I 5.50 4.01

8.95 5.94

Table 4. Chronological Distribution of Rheumatic Heart Disease in Au-

topsies. Classification According to Cause of Death.

Years

1941.. . . 1942.. . . 1943.. . . 1944.. . . 1945.. . . 1946.. . . 1947.. . . 1948.. . . 1949.. . . 1950.. . . 1951 .... 1952.. . . 1953.. . . 1954.. . . 1955.. . .

Total

Cause of Death:

1 Acute

3

3 1

7

2 Chronic

5 7 2 4 8 3 6 3 8 9 G 8 7 5

11 92

3 Bact. Endoc.

2

1 4 3 1 2

1

1 2 2 1

20

4 Non rheumatic

1 9 3 5 G 8 7 5 3

14 9 6 4

14 6

100

- Total Num- ber

6 18 5

13 18 17 15 10 11 24 15 15 13 21 18

219

Number of Autopsies

315 321 354 388 357 322 298 305 342 365 368 384 414 478 459

5,470

1: Acute Pancarditis. 2: Chronic rheumatic heart disease, including rheumatic heart disease

with embolic complications. 3: Rheumatic heart disease with bacterial endocarditis. 4: Rheumatic heart disease either incidental finding or not immediately

related to the cause of death.

Tohle 6. Incidence of Rheumatic Heart Disease in Autopsies. Comparison

between Oslo and Bergen.

Bergen Autopsies All cases with Rh. Heart Disease Oslo Autopsies 1964-55. All cases with Rh. Heart Disease .......................................

Per cent of Deaths

M I F I M + F

table that there is a marked difference between the two sexes, with a definite preponderance of females in both samples. We will return to this question later.

B. Distribution o f Rheumatic Heart Disease in the two Sexes.

In our 219 cases with rheumatic heart disease there were 82 males and 137 females (table 6). We have classified the cases according to the cause of death as follows:


0.16 0.57 0.27

0.13 0.30 0.33 0.97

2.81

0.97

Table 6. Rheumatic Heart Disease in Autopsy Material. Incidence and Classification According to

Cause of Death.

0.08 1.19 0.77

0.28 0.48 0.65 1.78

5.55

'1.35

Cause of Death Number

-- I T I F

1. Acute Pancarditis ......................... 2. Chron. Valv. Disease ...................... 3. Chron. Valv. Dis. + C'erebral Embol. ...... 4. Chron. Valv. Dis. + Non Cerebral Complica-

tions ..................................... 5. Chron. Valv. Dis. + Bact. Endocard. . . . . . . 6. Non Rheumat. Dis. Heart Condition Import. . . 7. Non Rheumat. Dis. Heart Dis. Incid. Finding . .

Total .................................... Total Number Deaths from Chronic Rheu- matic Disease. 2+3+4. . . . . . . . . . . . . . . . . . . .

5 17 8

4 9

10 29 82

29

2 37 19

7 12 16 44

137

63

Per Cent of Rh. Cases

M

6.10 20.7 3

9.76

4.88 10.97 12.20 35.36

100.00

35.36

F

1.46 27.01 13.87

5.11 8.76

11.68 32.12

100.00

45.98

Total Number of Autopsies: M 2,993, P 2,477 (Stillborn not Included).

1. Death during an attack of acute rheumatic fever with acute pancarditis. 2. Death from cardiac insufficiency with chronic valvular disease. 3. Death from cerebral catastrophe with longstanding chronic valvular disease. 4. Death from non-cerebral complications with longstanding chronic valvular

disease. 5. Bacterial endocarditis superimposed on chronic valvular disease, mostly suba-

cute cases. 6. The cause of death not immediately related to rheumatic heart disease, but

t,he heart condition as a rule giving definite symptoms during life and being to some degree a contributory cause of death.

7. The cause of death unrelated to the heart disease and the valvular lesion an incidental finding a t autopsy.

Table 6 shows that the incidence of rheumatic heart disease (all cases) over the whole period was twice as high in females as in males, 2.81 per cent males, 5 . 5 3 per cent females. In all the subgroups, except no, 1, acute pancarditis, we have a similar preponderance of females. I n some diagnostic groups the sex difference is higher as in group 2, cause of death: chronic valvular disease. It is also evident that in approximately 1/3 of the cases the rheumatic heart disease was an incidental finding (35 .36 per cent of the males and 3 2 . 1 2 per cent of the females). I n groups 2, 3 and 4 where chronic valvular disease was responsible directly or indirectly for the death, females predominated ( 4 5 per cent of the females and 35 per cent of the males) whereas the opposite was the case in group 7 (rheumatic heart disease an incidental finding). The difference is not large but noteworthy.

Table 7 indicates the same sex difference. The autopsy material in Bergen comprises 1/3 males and 2/3 females and the clinical material from the Department of

288

Per Cent of Rh. Cases

ERIK WAALER.

Females

Number Per Cent of Rh. Cases

Table 1. Sex Distribution. in Rheumatic Heart Disease.

37 137 154

571

655

Bergen Autopsies 1941-1955. Chron. Rh. H. D. Cause of Death ................................ Bergen Autopsies 1941-1955 All cases . . . . . . . . . . Oslo Autopsies 1954-1955. Rh. H. D. A11 cases. ..... Haulreland Hosp. Med. Dep. Rb. H. D. 1950-1954. Clinical ....................................... Whole Country. Rh. H. D. Mortality Statistice 1951--8.2-53-54 .............................

68.51 &?.SO

72.61

cld.40

57.10

Males

Xumber

17 82 58

345

492

50.0 38.s 30.4 37.4

50.0 61.4 69.0 62.6

31.40 37.40 27.36

37.60

42.90

Table 8. Rheumatic Heart Disease in Autopsies. Sex Distribution in Variuos Age Groups.

Age Groups

0-39.. . . 40-59.. . .

>60 . . . . Total

Total Number

44 83 92

219

Medicine of the University Hospital shows a similar distribution. I n the Oslo autopsy material the sex difference is even more marked. The mortality statistics for the whole country also shows a preponderance of females but the sex difference is defi- nitely smaller.

Table 8 shows that in the younger age groups (below 50 years) there is apparently no sex difference. Of 44 cases below the age of 40, 22 were males and 22 females. The difference in incidence between the two sexes occurs above the age of 40 and the preponderence of females is highest in the oldest age group.

Table 9 shows also that our clinical material on rheumatic heart disease arid rheumatic fever reveals a greater preponderance of females in the older age groups. In childhood and youth, on the other hand, the reverse is true. These findings are contradictory to De Graff’s and Lingg’s statement from 1934.

Discussion. It is impossible to carry out a complete comparison between the mortality statis-

tics for the whole country and the autopsy statistics. The basic material is different and first of all the diagnostic criteria and the evaluation of the cause of death are


Table 9. Sex Distribution in Various Age Groups in 720 Consecutiae Cases T,reated in Department of Medi- cine and Childrens Hospital for Rheumatic Heart

Disease and (or) Rheumatic Fever.

Age Groups I Males I Females

0- g . . . . . . 10-19.. . . . . 20-29.. . . . . 30-39.. .... 40-49.. . . . . 50-59 . . . . . . 6 0 - 6 9 . . . . . .

>70. . .... Total

10 36 14 50 57 48 46 27

288 -

71.4 73.5 29.8 42.0 39.9 34.0 34.9 36.0 40.0

4 13 33 69 86 93 86 48

432

28.6 26.5 S i . 2 58.0 60.1

65.1 64.0 60.0

66.0

not identical. The results stated in table 2 however, show that there can be no doubt about the dominating importance of arteriosclerotic heart disease as a cause of death. The incidence of rheumatic heart disease in the autopsies indicates that the percentage given for the whole country is too low. The diagnostic criteria are cer- tainly more accurate and reliable in a study based on autopsies than in the general mortality statistics. There can be no doubt that the percentage stated for ,chronic endocarditis not specified as rheumatic)) is too high in the mortality statistics. There is reason to believe that the greater part of these cases actually are of rheumatic etiology and that the numbers under the poorly defined diagnosis in the international list (421) should be reduced. It would appear therefore that rheumatic heart disease still is of importance and ranks second with hypertensive heart disease as the cause of death among the heart diseases.

The 15 year period studied has not shown any fall in the total incidence of rheumatic disease in our autopsies. The definite fall in morbidity form rheumatic fever is not reflected in our autopsy material. Our material is probably too small and the period too short to give a correct picture of the situation. The apparent disagreement may be explained as follows. The morbidity of typical rheumatic fever has been declining but still the subclinical and atypical froms of the disease exist in relatively large numbers. The heart is attacked in these atypical cases also and the disease revealed a t autopsy if there have not been definite symptoms or signs of heart disease a t an earlier date. It is possible that the total number of cases of rheumatic heart disease is unchanged, whereas the group with definite and severe disease has been declining. A similar statement has been made by Miiller (17) . Our material cannot elucidate this question.

It is interesting to note that acute pancarditis not has occurred in the last half of the period under study. This may be a result of the modern antibiotic treatment which is so commonly used in these cases. It is also evident, however, that in the same period there has been a spontaneous fall in the incidence of the disease and

290 ERIK WAALER.

the clinical picture is said t o have changed, The malignant and fulminating cases are not so common as in earlier years.

There is only a slight change in the incidence of bacterial endocarditis over the period. It is evident however that our material is too small to give a significant picture of the situation. Besides we have included in our group of bacterial endocarditis cases where the actual lesion a t autopsy was clearly thrombotic without bac- teria but with positive bacteriology in the clinical history. These cases should therefore correctly have been listed as obacterial endocarditis in the stage of healing)).

We had a 4.01 per cent incidence of rheumatic heart when all cases were included (table 5 ) . The apparent lower incidence in the Bergen autopsies compared to that in Oslo does not support the theory that rheumatic fever should be more common in Bergen than in Oslo. The morbidity statistics depend upon the diagnostic work of the practitioners and are of course likely to vary from place to place and froni time t o time. On the other hand the basic autopsy material in Oslo and Bergen is incongruent and cannot be directly compared. The average age of the Oslo autopsies is more than 10 years higher than in Bergen. The higher incidence of rheumatic heart disease in the Oslo autopsies may therefore be apparent and not real. Our results however do not indicate that rheumatic heart disease is more common in Oslo than in Bergen. Neither is there any definite indication that the morbidity statistics in the two cities in former days were fundamentally wrong. The difference in morbidity from rheumatic fever in Oslo and Bergen in previous years may have been due to the fact that the insidious non-characteristic types of the disease which are not diagnosed as rheumatic fever have been more common in Oslo than i Bergen. The mild atypical forms of the disease are followed by valvular lessions as are the more typical otextbook caseso which may have occurred more often in Bergen. This may to some extent explain the apparent disagreement between the morbidity statistics from rheumatic fever in Oslo and Bergen and the incidence of deaths with rheumatic heart disease as revealed a t autopsies 20-30 years later in the two cities.

Our most interesting finding is the difference in incidence in the two sexes. The difference, 82 males and 137 females, is statistically significant. Is this difference real? Is i t possible that we have overlooked minor rheumatic lesions in males in our autopsies? This would mean an increase in the number of males in group 7 , table 6, individuals with rheumatic heart disease as an incidental finding. It is easy to overlook minor aortic lesions particularly if the mitral valves with the chordae are normal. In view of our great interest in these lesions we do not believe that the minor lesions in males have been overlooked, and the different incidence in the two sexes in our material is real. Is the difference valid for general application?

In our basic material there is a preponderance of males and it is therefore a striking fact that our figure for rheumatic heart disease in males is low. The age distribution in our basic material should also give us a valid background and we believe therefore that the higher incidence of females in our material really reflects the general conditions in Norway. This is also supported by the results in table 7 . We must place significance upon the fact that this tendency in sex distribution is the same in Oslo, in the clinical material in Bergen and in the mortality statistics for

RHEUMATIC FEVER AND RHEUMATIC HEART DISEASE. 29 1

the whole country. The sex distribution is also the same in Auberts (3) clinical material from Bergen and Mullers (17) autopsy material from Oslo.

It is not unlikely that the two sexes react differently to rheumatic infection. In- fections caused by haemolytic streptococci have probably the same incidence in the two sexes, but the hyperergic tissue response is naturally not identical. It is likely that hormonal influence makes the soil different. The other collageneous diseases also show a marked sex difference. Rheumatoid athritis and disseminated lupus erythematosus are more common in females.

Table 6 also indicates another difference between the two sexes. The total number of deaths from chronic rheumatic heart disease in males (groups 2 + 3 + 4 in the table) is 0 . 9 7 per cent of the autopsies, and the insignificant heart lesions (group 7) also amount to 0 . 9 7 per cent. The corresponding percentage in females were: severe cases 2.54 per cent, mild cases 1.78 per cent. In our material therefore, the females are not only more often affected but they also have a relatively larger number of severe cases. It would appear that the tendency to severe hyperergic inflam- matory reaction is greater in females than in males.

It is striking that the sex difference is apparently more marked in the Oslo autopsies than those in Bergen (table 7). The explanation is probably that the mean age is higher in Oslo than in Bergen.

Table 8 touches on this problem. Below the age of 40 years there is an equal number of cases of either sex. Above 40 years our autopsies reveal a preponderance of females and the diffference is statistically significant. Our autopsy material is too small to give a more detailed view of the conditions in the various age groups. Among those treated for rheumatic heart disease (639 cases) and/or rheumatic fever (81 cases) there is a definite preponderance of males in childhood (table 9). Even if we exclude the acute cases the same difference is apparent. The greater hospitaliza- tion of males in childhood and youth may mean that boys are more susceptible than girls, or the disease may run a milder course or may be less characteristic in girls. The complete change in incidence which appears with sexual maturity shows that the acutal sensitivity is probably higher in females than in males. This may mean that the course of the disease is often different in the two sexes, that for instance the atypical nilento attacks of rheumatic fever not diagnosed clinically are more common in females than in males. We will return to this question in a following paper.

The results recorded in table 8 and 9 disagree entirely with the statements made by De Graff and Lingg in 1934. They made a study of 644 cases of rheumatic heart disease which had been treated in hospital, in a cardiac clincic and in private prac- tices and which died after a 10-year period. They had more males (55.8 %) than females, and state that the age of onset differs in the sexes as follows: up to about 13 years of age girls predominate over boys. From 13 to 28 years the incidence is about the same for both and afterwards men are more likely to develop rheumatic infection leading to heart disease. How can this disagreement with the findings in a Norwegian hospital and autopsy material be explained? The diagnostic criteria have been the same, and the possibility therefore arises that the diverging results are due to selection. The American series is younger than ours, 33 years a t death as compared

292 ERIK WAALER.

to 5 2 years. This may partly explain the difference in the total sex distribution, but the difference in the various age groups is not explained. Evidently a series made up of patients from private practice, cardiac clinic and hospital department is less ho- mogenous than ours which is derived from a general hospital, but still the diverging results cannot be adequately explained.

Summary.

1. Rheumatic heart disease was found in 4 per cent of all autopsies in the period 1941-1955. In 35 per cent of the males and 45 per cent of the females the heart failure was the cause of death either directly or indirectly after embolic complications. Rheumatic heart failure appears to be the second most frequent cause of death among the heart diseases, as frequent as hypertensive heart disease.

2. There has been no definite decrease in rheumatic heart disease during the period of study. All cases of acute pancarditis occurred in the first part of the period, probably a result of the modern treatment with antibiotics.

3. Rheumatic heart disease occurs quite as commonly in the autopsies in Oslo as in Bergen. Our results do not substantiate the supposition that rheumatic fever in earlier years was more common in Bergen than in Oslo. It is, however, possible that there has been a higher tendence to a non-characteristic course of the disease in Oslo than in Bergen and that the clinical diagnosis, which gives the material for the morbidity statistics, has for this reason been more rare in Oslo.

4. Rheumatic heart disease occurs more often in males than in females, the ratio M/P is approximately 213. The preponderance of females is due to a great number of cases in adults. Below 20 years, on the other hand, there is a higher percentage of males.

Referenoes.

1. Anderson, W. A. D.: Pathohology. The C. V. Mosby Company. St. Louis. 1953. - 2. Arnsq E., Brmhner-Mortensen, K. and Hastrup, B.: Acta med. scandinav. 141: 77, 1951. - 3. Aubert, A. B.: Bidrag ti1 hjertssykdommenes etiologi og patogenese, skrifter utgitt av Klaus Hanssens Fond. - No XV, Bergen 1943. - 4. Claiborne, T. S. and Wolff, 13. P.: gouth. med. J. 34: 684, 1941. - 5. Clawson, B. J.: Am. Heart J. 20: 454, 1940. - 6. Clemmesen, S.: Ugeskr. f. Lzeger. 105: 723, 1943. - 7. Cohn, A. E. and Lingg, C.: J. A. M. A. 121: 1,1943. - 8. Davis, D. B. and Rosin, S.: J. Pediat. 24: 502,1944. - 9. De Graff, A. C. and Lingg, C.: Am. Heart. J. 10: 459, 1934. - 10. Edstrom, 0.: Febris rheumatica. A-I3 Gleerupska, Lund, Schweden. 1935. - 11. Glover, J. A.: Lancet. 2: 51, 1943. - 12. Hanssen, P.: Tidsskr. f. Den Norske LBgef. 77: 143, 1957. - 13. Harving, F.: Nord. med. 31: 2127, 1946. - 14. Hedley, 0. F.: Publ. Health Rep. 52: 1907, 1937. - 15. Kaiser, A. D.: J. A. M. A. 183: 886, 1934. - 16. Motzfeldt, K.: Nord. med. 8: 1197, 1934. - 17. Miiller, C.: Acta med. scandinav 156: 241, 1956. - 18. Perman, E.: Acta Endoorinol. 13: 371, 1953. - 19. Robles Gil, J. and Limbn Lason, R.: Arch. Inst. Cardiol. Mexico 18: 240, 1948. - 20. Sprague, H. B. and Garmichael, D. B.: Geriatrics. 5: 239, 1950. - 21. Stone, C. 8. and E’eil, H. S.: Am. Heart J. 9: 53. 1933. - 22. Stroud, W. D. and Twaddle, P. H.: J. A. M. A. 114: 629, 1940. - 23. Wedum, A. G. and Wedum, B. S.: Am. J. Dis. Child. 67: 182, 1944. - 24. Wyckoff, J. and Lingg, C.: Quoted by Cohn, A.E. and Lingg, C. J. A. M. A. 121: I, 1943.

rheumatic fever and rheumatic heart disease : i. incidence and sex distribution

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