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The fate of the tuberculous cavity
June 1948
TUBERCLE
made for want of careful examination in a good light, than for any other cause.' Therefore the details describing the use of the head mirror are welcomed. If every student and nurse were to read this carefully, the difficulties of the' head mirror would be non-existent. The picture on page 7, showing the method of holding a child for examination, should be studied by every House Surgeon. The substance of the book is divided into six sections-The Nose, Nasal Accessory Sinuses, The Pharynx, The Larynx, Endoscopy and the Ear. Each section is subdivided into chapters on the anatomy, and where relevant, physiology, methods of examination, and signs, symptoms and treatment of disease.
131
There is a chapter on Chemotherapy, Sulphonamldes in nose, throat and ear. diseases, and Penicillin. It is difficult to be dogmatic in instruction in the use of these new drugs, but certain principles have emerged, which are put forward as guides and not rules. To quote from the Preface: 'Experience in the use of penicillin has, in some respects, fundamentally ~iltered the outlook on treatment, and these changes have been reflected in the text. Other o6tstanding advances, such as the Fenestration operation, have been placed in their proper perspective.' There is an Appendix, which contains instruction for the preparation of patients for operation, and Formulae. In the Index, the references to illustrations are in heavy type, which is most useful.
The Fate of the Tuberculous Cavity By BERTRAM MANN, Consultant Tuberculosis Officer, West Riding C.C. of Yorks., Consultant Physician llkley Sanatorium There has been a wealth of conflicting literature on the fate of the tuberculous patient with cavitation and with the advent of collapse therapy this problem has become even more confused. Some of the contradictions have been due to a biased selection of material, viz. sanatorium or hospital patients [I, 2], in others there has been an inadequate period of observation and in some the assembled data has not been presented in a statistical and scientific manner. This epidemiological paper is an endeavour to obtain a more accurate picture of the prognosis and fate of the tuberculous subject with a cavity. Some authors have accepted clinical or radiological signs as indicative of cavitation but such evidence will be regarded by most workers as unsatisfactory criteria, and open to many subjective errors of interpretation [3]. For this reason a diagnosis of cavitation was made only in the presence of tubercle bacilli in the sputum. It should be mentioned at this point that there are excellent laboratory facilities available in the West Riding C.C. of Yorkshire, and it is improbable that more than a tiny fraction of patients with cavitation failed to reveal bacilli after the repeated sputa examinations
carried out at both sanatoria and clinics. In this survey, the fate of 1,233 positive sputum cases was investigated. These represent every positive sputum case between the ages of Io and 59 years notified in the No. 5 Area of the West Riding of Yorkshire during the period I928-42. As patients notified during I942 were observed till ~947, this represents a total surveillance period of twenty years. The 1,233 patients w~re completely unselected, of these a small minority received dispensary supervision alone, others had a conservative sanatorium regime and the remainder some form of collapsh therapy in an institution. Of the above number 659 were males and 574 were females and they showed the following age-group distribution.
Age-group
T~nE I IO-I9 20-29 30-39 40-49 50-59
+ sputum
patients.. 189
4Io
282
I87
I65
As no accurate picture of the changing prognosis could be obtained over. suck a prolonged period of time, the cases were subdivided into five triennial groups, viz. I928-3o (a), i931-33 (b), I934-36 (c), 1937-39 (d), 194o-4~- (e). In all these periods
132
June 1948
TUBERCLE
the age and sex group ratio were found to correspond closely. It is clear that a distorted and incorrect picture would be obtained if 'Lost Sight of' (L.S.O.) and 'Transferred' (T.) patients were included in the course of such an investigation. Both these groups as weIl as the 'Deaths' were therefore excluded from the total 'Recovered and Survived' Group of each subsequent year. Tables were constructed on the lines suggested by Bradford Hill [4] and first employed in this connexion by SmithHartley, Wingfield and Burrows [5] for each of the five trienniaI periods. For Table II, see page x33. From the above findings the survival probability was calculated, i.e.-recovered and survived total alive previous year, e.g. during the rst year the survival probability was I ~4 or
0"41 ,
275 and in the ~nd year 84 or o.73 and for the 3rd year 63 or o.75 &c. On this basis a complete 84: survivorship table was now constructed on the basis of I,ooo 'theoreticaF cases at the beginning of the I928-3 o three-year period. T.AmLE IIA.~PERmD X928, 29, 3~ Probability No. alive on each Year of of surviving anniversaryout of I,ooo Diagnosis eaehy~ar patients (x) (P) (0 O
O'41
I 2 3 4 5 6 7
o.73 0'75 0"79 o.86 o.8~ o.9I 0"94 0.84 o'89
8
9 lo
--
I ~O00
4Io 299 ~24" 177 x52" I26 115 io8" 9I 81"
*Thus during I928, 29 and 30 :-22'4% of positive sputum cases survived 3 years I5"a% of positive sputum cases survived 5 years io.8% of positive sputum cases survived 8 years 8. 1% of positive sputum cases survived I o yem's
Tables III and IIIA show similar findings for the period i931-33. For Table III, see page z33. TABLE IIIA.--PeRmD I93I, 3~, 33 ProbabiliLy No. alive on each Tear of of surviving anniversaryout of i ,ooo diagnosis eachyear patients (,:) (p) (l) o I
0'59 0. 7
2
0" 7
3 4 5 6 7 8 9 Io
0'78 o.88 0"85 0'87 o.88 o"97 0"72 --
I,ooo 590 413 289* 225 ~98' i68 r46 I~8" if8 85*
*Thus during I93 I, 32, 33:-28"9 % of positive sputum cases survived 3 years 19"8 % of positive sputum cases survived 5 years 12.8% of positive sputum cases survived 8 years 8.5% of positive sputum cases survived Io years Tables IV and I V a show similar findings For the period I934-36. For Table IV, see page I33. TABLE IVA.--PmuoD i934, 35, 36 Probability No. alive on each Year of of surviving anniversaryout of i,oo 0 diagnosis each year patients % (p) (l) O I
O'6 0" 7
2 3 4 5 6 7 8 9
0.75 0"85 0.82 0.8 o.86 o'97 z .o 0.8
xo
--
I ,OOO
600
426 32~ 272 2~3" 178 ~53 I48" I48 i18"
*Thus during I934, 35, 3 6 : 32'o% of' positive sputum cases survived 3 years 22 "3% of positive sputum cases survived .5 years 14.8 % of positive sputum cases survived 8 years I 1.8 % of positive sputum cases survived Io years Tables V and VA reveal similar findings for the period ~937-39.
June 1948
TUBERCLE
133
TABLE II.--PERmD I9e8, 29, 30 (A). TOTAL PATIENTS =75
No. alive on each anniversary of investigation Year of investigation Dead Recovered and survived L.S.O. and transferred
I st .. I 6 I .. i 14 .. o
~nd 29 84 1
3rd 2I 63
4th 13 5~
O
0
5th 6 43 I
6th 5 36
7th 3 33
8th 2 31
2
0
0
9th 4 26 I
Ioth 3 ~3 0
TABLE III.--PERmD 193I, 32, 33 (B). TOTAL PATIENTS 27 I
No. alive on each anniversary of investigation Year of investigation Ist Dead . . . . . . 1o 3 Recovered and survived .. z6i L.S.O. and transferred .. 7
~nd 45 II 3 3
3rd 30 8o 3
4th I4 63 3
5th 5 56 2
6th 4 48 4
7th 5 42 I
8th 4 37 I
-gth I 36 o
zoth 7 26 2
9th o 36 o
zoth 4 29 3
TABLE IV.--PERIOD I934, 35, 36 (o), TOTAL PATIENTS 243
No. alive on each anniversary of investigation Year of investigation I st Dead . . . . . . 91 Recovered and survived .. I46 L.S.O. and transferred .. 6
2nd 37 Io4 5
3rd 24 78 2
4th Io 66 2
5th 7 54 5
6th 9 43 2
7th 3 37 3
8th o 36 o
TABLE V.--PEI~][OD I937, 38, 39 (n). TOTAL PATIENTS 245 No. alive on each anniversary of investigation Year of investigation I st Dead . . . . . . 74 Recovered and survived .. I63 L.S.O. xnd transferred ., 8
2nd 28 I29 6
3rd 19 Io5 5
T ~ n E VA.--PERIOD I937, 38, 39
:Fear of diagnosis (X)
Probability No. alive on each of surviving anniversaryout of I,ooo eachyear patients (p) (l)
o I
o'67 0'79
3 4 5 6 7 8
o.86 o'83 o.86 o'95 o'85 --
2
o.8i
*Thus during I937, 38, 42.8 % of positive sputum 3o.5 % of positive sputum '21-2 % of positive sputum
I,ooo 670
529
428* 368 3o5" 262 249 212' 39:-cases survived 3 years cases survived 5 years cases survived 8 years
4th 13 91 i
5th II 76 4
6th 9 65
o
7th I 62 2
8th 5 53 4
T a b l e s V I a n d V I A reveal t h e corresp o n d i n g findings for the period I94O-42.
For: Table VI, see page z34. TABLE VIA.--PERIOD I94o , 41, 42 Probability No. alive On each :Fear of of surviving anniversaryout of I,OOO diagnosis eachyear patients (~) (p) (l) o I ~ 3 4 5
o.66 o'79 o.87 o.86 0'76 --
i,ooo 660 52 I 453* 39 ~ 296*
*Thus during I94O, 4 I, 4 2 : - 45"3 % of positive sputum cases survived 3 years 2 9 ' 6 % of positive sputum cases survived 5 years
134
TUBERCLE
June 1948
Tanr,~. VI.--P~Ru)D 1940, 4 ~, 4r (}~). 'l'cn'a[, ['A'rII,;N'I~ I !1,9
No. alive on each annivm'my ~!/" bn,esligathm Year of" investigation Dead Recovered and survived L,S.O. a n d transferred ,,
.. .,
xst 63
..
]3r 4
,,
,.
m~d ~I I~5
3rd 13
4th !l 7}1
.qx x
i, (;
5th 13 .59 (i
4
'l'allI.E V I I .
_ <
5 ~::SJgmflcant
LEGUt0 ~ ~ I T'"~ J'~ .~-'.allla.L-"--
50~, -
V S ~- Very Significant N S ~, Not Significant V,5
2>
VS
540r. v~ %7 s
z= " ' 207, kJ
v
ILl
1928-30
1931-33
1934-36
1937-39
1940.42,
(~)
(b)
('c)
(a)
(e)
T~IEHHIAL
PERIODS
I1"t
CALENDAP-.
YEARS
'I'AI~.S VIIA.
60~,-
a b c
> >
d e
M
/
107,
,, ,, ,, :
1928-30 1931-33 1934-36 1937 - 39
. 1940-42
iii
k.-7 <
,
I-. 7"
I
tu U 207,
q
I
rr ta
' i
1_ O.
bcd
abode
a
b
c
d
ct
b
c
June 1948
TUBERCLE
In order to obtain a simpler picture of the results of the above tables, the number of patients alive out of each z,ooo patients on the third, fifth, eighth and tmlth years (indicated by asterisk markings) were extracted. The latter were then charted as a percentage survival in each of the five triennial periods and are diagrammatically represented in the appended histogram and graph. It is pertilmnt to note that Tattersall [6] in a recent paper tbund the difference in successive quinquennial periods as being within the limits of random sampling. However, the. live'-year expectation noted both by the. ab()vc: author aald Thompson [7, 81 c'.()rrt:sponcl ch)sely with the I94o, 4z, 4.'2, linclings c)l"this Survey,
135
ment was also noted during z937, 38, 39 in the eight-year survival. It is equally clear that there has been a small but non-significant improvement in the ten-year survival period. Conclusions Ill view of the significant increase in the short-term expectation of life of the positive case (three, five, and to a lesser degree, eight years), great care must be exercised in the interpretation of any clinical in;cestigation. Probably a combination of factors is responsible for this improvement in survival probability. Among the most outstanding of the former are: more satisfactory standards of gcueral hygiene, the advent of collapse therapy and the increased care and supervision of the infective patient resulting fi'om a national organized anti-tuberculosis scheme.
Broadly the histogram of Table VII shows an impr()vement in the three, live and eight year survival rates over the past The evidence as u~ the ten-year survivM twenty years. There would also q~l)ear to of the 'open' case as presented in thi.~ Survey have becn some slight improvement in the is cqulwmal, There is a possibility that the ten-year surviwtl period of positive sputum signific.antly improved thre% five and eight patients. '1'o appraise this @arena improve- year li~i: expectatkm as observed during the merit iu tit(,, prognr o[' the: 'tubercuhms past twenty years might even be followed by cavity,' the standard error of" each group of an unaltered mortality rate ten years or proportions was calculated taking the three, more after notification. A plea is therefore five, eight and ten year periods of I9~8 , 29, entered for a minimum ten-year follow-up 3~ as 'norms.' The fi:)rmula employed is that before the beneficial effects of any specific advocated by Bradford Hill:-line of' therapy is committed to print and given the sanctity of publication. Again, S . E . = % / !) • q + px--q w h e r e n l a n d n = a r e phthisiologists and thoracic surgeons are nI n,~ asked to pause and re-examine their findings the numbers in the two samples drawn from before extolling the virtues of a new line of the same universe. A difference greater than therapy which in fact yields evidence NOT twice the S.E. was regarded as 'significant' S I O N I F I ( . I A N T L ' ir above the life-expectation of and unlikely to be due to chance and where patients where more formal and routine the difference was three times the standard procedures are the current practice. error, the result was accepted as being Bibliography 'very significant.' These findings are represented in the histogram by the abbrevia- [z] Pearson, S. V., Lancet, z935, r, 690. tions 's'=significant and 'v.s.'=very signifi- [9.] Edwards, P. W., Public Health, z934, LVH,'255. [3l B.M.J., Leading Az'ticle. cant, and 'n.s.'.=not significant. There has [4J BracVord Hilt Prine. of Med. Star., I94.~. therefore been an improvemerit greater than [51[ Smhh Hartley, P. I-[., WingfleId, R. CI.,Burrows, V. A., Brom. I-Imp. Rep., r935. that likely to attributable to chance in both [6] Tattersal[, W. H., Tuberde, t947, xxvzzt, 85, the three and five year survival periods from [7] 's B. C., Tubercle, t94~ , xxm, r4~, 1934, 35, 36 onwards. A significant improve- [8] Thompson, B. CI.~/i'.M.ff., r943, xxxI b 7~o.
TUBERCLE
made for want of careful examination in a good light, than for any other cause.' Therefore the details describing the use of the head mirror are welcomed. If every student and nurse were to read this carefully, the difficulties of the' head mirror would be non-existent. The picture on page 7, showing the method of holding a child for examination, should be studied by every House Surgeon. The substance of the book is divided into six sections-The Nose, Nasal Accessory Sinuses, The Pharynx, The Larynx, Endoscopy and the Ear. Each section is subdivided into chapters on the anatomy, and where relevant, physiology, methods of examination, and signs, symptoms and treatment of disease.
131
There is a chapter on Chemotherapy, Sulphonamldes in nose, throat and ear. diseases, and Penicillin. It is difficult to be dogmatic in instruction in the use of these new drugs, but certain principles have emerged, which are put forward as guides and not rules. To quote from the Preface: 'Experience in the use of penicillin has, in some respects, fundamentally ~iltered the outlook on treatment, and these changes have been reflected in the text. Other o6tstanding advances, such as the Fenestration operation, have been placed in their proper perspective.' There is an Appendix, which contains instruction for the preparation of patients for operation, and Formulae. In the Index, the references to illustrations are in heavy type, which is most useful.
The Fate of the Tuberculous Cavity By BERTRAM MANN, Consultant Tuberculosis Officer, West Riding C.C. of Yorks., Consultant Physician llkley Sanatorium There has been a wealth of conflicting literature on the fate of the tuberculous patient with cavitation and with the advent of collapse therapy this problem has become even more confused. Some of the contradictions have been due to a biased selection of material, viz. sanatorium or hospital patients [I, 2], in others there has been an inadequate period of observation and in some the assembled data has not been presented in a statistical and scientific manner. This epidemiological paper is an endeavour to obtain a more accurate picture of the prognosis and fate of the tuberculous subject with a cavity. Some authors have accepted clinical or radiological signs as indicative of cavitation but such evidence will be regarded by most workers as unsatisfactory criteria, and open to many subjective errors of interpretation [3]. For this reason a diagnosis of cavitation was made only in the presence of tubercle bacilli in the sputum. It should be mentioned at this point that there are excellent laboratory facilities available in the West Riding C.C. of Yorkshire, and it is improbable that more than a tiny fraction of patients with cavitation failed to reveal bacilli after the repeated sputa examinations
carried out at both sanatoria and clinics. In this survey, the fate of 1,233 positive sputum cases was investigated. These represent every positive sputum case between the ages of Io and 59 years notified in the No. 5 Area of the West Riding of Yorkshire during the period I928-42. As patients notified during I942 were observed till ~947, this represents a total surveillance period of twenty years. The 1,233 patients w~re completely unselected, of these a small minority received dispensary supervision alone, others had a conservative sanatorium regime and the remainder some form of collapsh therapy in an institution. Of the above number 659 were males and 574 were females and they showed the following age-group distribution.
Age-group
T~nE I IO-I9 20-29 30-39 40-49 50-59
+ sputum
patients.. 189
4Io
282
I87
I65
As no accurate picture of the changing prognosis could be obtained over. suck a prolonged period of time, the cases were subdivided into five triennial groups, viz. I928-3o (a), i931-33 (b), I934-36 (c), 1937-39 (d), 194o-4~- (e). In all these periods
132
June 1948
TUBERCLE
the age and sex group ratio were found to correspond closely. It is clear that a distorted and incorrect picture would be obtained if 'Lost Sight of' (L.S.O.) and 'Transferred' (T.) patients were included in the course of such an investigation. Both these groups as weIl as the 'Deaths' were therefore excluded from the total 'Recovered and Survived' Group of each subsequent year. Tables were constructed on the lines suggested by Bradford Hill [4] and first employed in this connexion by SmithHartley, Wingfield and Burrows [5] for each of the five trienniaI periods. For Table II, see page x33. From the above findings the survival probability was calculated, i.e.-recovered and survived total alive previous year, e.g. during the rst year the survival probability was I ~4 or
0"41 ,
275 and in the ~nd year 84 or o.73 and for the 3rd year 63 or o.75 &c. On this basis a complete 84: survivorship table was now constructed on the basis of I,ooo 'theoreticaF cases at the beginning of the I928-3 o three-year period. T.AmLE IIA.~PERmD X928, 29, 3~ Probability No. alive on each Year of of surviving anniversaryout of I,ooo Diagnosis eaehy~ar patients (x) (P) (0 O
O'41
I 2 3 4 5 6 7
o.73 0'75 0"79 o.86 o.8~ o.9I 0"94 0.84 o'89
8
9 lo
--
I ~O00
4Io 299 ~24" 177 x52" I26 115 io8" 9I 81"
*Thus during I928, 29 and 30 :-22'4% of positive sputum cases survived 3 years I5"a% of positive sputum cases survived 5 years io.8% of positive sputum cases survived 8 years 8. 1% of positive sputum cases survived I o yem's
Tables III and IIIA show similar findings for the period i931-33. For Table III, see page z33. TABLE IIIA.--PeRmD I93I, 3~, 33 ProbabiliLy No. alive on each Tear of of surviving anniversaryout of i ,ooo diagnosis eachyear patients (,:) (p) (l) o I
0'59 0. 7
2
0" 7
3 4 5 6 7 8 9 Io
0'78 o.88 0"85 0'87 o.88 o"97 0"72 --
I,ooo 590 413 289* 225 ~98' i68 r46 I~8" if8 85*
*Thus during I93 I, 32, 33:-28"9 % of positive sputum cases survived 3 years 19"8 % of positive sputum cases survived 5 years 12.8% of positive sputum cases survived 8 years 8.5% of positive sputum cases survived Io years Tables IV and I V a show similar findings For the period I934-36. For Table IV, see page I33. TABLE IVA.--PmuoD i934, 35, 36 Probability No. alive on each Year of of surviving anniversaryout of i,oo 0 diagnosis each year patients % (p) (l) O I
O'6 0" 7
2 3 4 5 6 7 8 9
0.75 0"85 0.82 0.8 o.86 o'97 z .o 0.8
xo
--
I ,OOO
600
426 32~ 272 2~3" 178 ~53 I48" I48 i18"
*Thus during I934, 35, 3 6 : 32'o% of' positive sputum cases survived 3 years 22 "3% of positive sputum cases survived .5 years 14.8 % of positive sputum cases survived 8 years I 1.8 % of positive sputum cases survived Io years Tables V and VA reveal similar findings for the period ~937-39.
June 1948
TUBERCLE
133
TABLE II.--PERmD I9e8, 29, 30 (A). TOTAL PATIENTS =75
No. alive on each anniversary of investigation Year of investigation Dead Recovered and survived L.S.O. and transferred
I st .. I 6 I .. i 14 .. o
~nd 29 84 1
3rd 2I 63
4th 13 5~
O
0
5th 6 43 I
6th 5 36
7th 3 33
8th 2 31
2
0
0
9th 4 26 I
Ioth 3 ~3 0
TABLE III.--PERmD 193I, 32, 33 (B). TOTAL PATIENTS 27 I
No. alive on each anniversary of investigation Year of investigation Ist Dead . . . . . . 1o 3 Recovered and survived .. z6i L.S.O. and transferred .. 7
~nd 45 II 3 3
3rd 30 8o 3
4th I4 63 3
5th 5 56 2
6th 4 48 4
7th 5 42 I
8th 4 37 I
-gth I 36 o
zoth 7 26 2
9th o 36 o
zoth 4 29 3
TABLE IV.--PERIOD I934, 35, 36 (o), TOTAL PATIENTS 243
No. alive on each anniversary of investigation Year of investigation I st Dead . . . . . . 91 Recovered and survived .. I46 L.S.O. and transferred .. 6
2nd 37 Io4 5
3rd 24 78 2
4th Io 66 2
5th 7 54 5
6th 9 43 2
7th 3 37 3
8th o 36 o
TABLE V.--PEI~][OD I937, 38, 39 (n). TOTAL PATIENTS 245 No. alive on each anniversary of investigation Year of investigation I st Dead . . . . . . 74 Recovered and survived .. I63 L.S.O. xnd transferred ., 8
2nd 28 I29 6
3rd 19 Io5 5
T ~ n E VA.--PERIOD I937, 38, 39
:Fear of diagnosis (X)
Probability No. alive on each of surviving anniversaryout of I,ooo eachyear patients (p) (l)
o I
o'67 0'79
3 4 5 6 7 8
o.86 o'83 o.86 o'95 o'85 --
2
o.8i
*Thus during I937, 38, 42.8 % of positive sputum 3o.5 % of positive sputum '21-2 % of positive sputum
I,ooo 670
529
428* 368 3o5" 262 249 212' 39:-cases survived 3 years cases survived 5 years cases survived 8 years
4th 13 91 i
5th II 76 4
6th 9 65
o
7th I 62 2
8th 5 53 4
T a b l e s V I a n d V I A reveal t h e corresp o n d i n g findings for the period I94O-42.
For: Table VI, see page z34. TABLE VIA.--PERIOD I94o , 41, 42 Probability No. alive On each :Fear of of surviving anniversaryout of I,OOO diagnosis eachyear patients (~) (p) (l) o I ~ 3 4 5
o.66 o'79 o.87 o.86 0'76 --
i,ooo 660 52 I 453* 39 ~ 296*
*Thus during I94O, 4 I, 4 2 : - 45"3 % of positive sputum cases survived 3 years 2 9 ' 6 % of positive sputum cases survived 5 years
134
TUBERCLE
June 1948
Tanr,~. VI.--P~Ru)D 1940, 4 ~, 4r (}~). 'l'cn'a[, ['A'rII,;N'I~ I !1,9
No. alive on each annivm'my ~!/" bn,esligathm Year of" investigation Dead Recovered and survived L,S.O. a n d transferred ,,
.. .,
xst 63
..
]3r 4
,,
,.
m~d ~I I~5
3rd 13
4th !l 7}1
.qx x
i, (;
5th 13 .59 (i
4
'l'allI.E V I I .
_ <
5 ~::SJgmflcant
LEGUt0 ~ ~ I T'"~ J'~ .~-'.allla.L-"--
50~, -
V S ~- Very Significant N S ~, Not Significant V,5
2>
VS
540r. v~ %7 s
z= " ' 207, kJ
v
ILl
1928-30
1931-33
1934-36
1937-39
1940.42,
(~)
(b)
('c)
(a)
(e)
T~IEHHIAL
PERIODS
I1"t
CALENDAP-.
YEARS
'I'AI~.S VIIA.
60~,-
a b c
> >
d e
M
/
107,
,, ,, ,, :
1928-30 1931-33 1934-36 1937 - 39
. 1940-42
iii
k.-7 <
,
I-. 7"
I
tu U 207,
q
I
rr ta
' i
1_ O.
bcd
abode
a
b
c
d
ct
b
c
June 1948
TUBERCLE
In order to obtain a simpler picture of the results of the above tables, the number of patients alive out of each z,ooo patients on the third, fifth, eighth and tmlth years (indicated by asterisk markings) were extracted. The latter were then charted as a percentage survival in each of the five triennial periods and are diagrammatically represented in the appended histogram and graph. It is pertilmnt to note that Tattersall [6] in a recent paper tbund the difference in successive quinquennial periods as being within the limits of random sampling. However, the. live'-year expectation noted both by the. ab()vc: author aald Thompson [7, 81 c'.()rrt:sponcl ch)sely with the I94o, 4z, 4.'2, linclings c)l"this Survey,
135
ment was also noted during z937, 38, 39 in the eight-year survival. It is equally clear that there has been a small but non-significant improvement in the ten-year survival period. Conclusions Ill view of the significant increase in the short-term expectation of life of the positive case (three, five, and to a lesser degree, eight years), great care must be exercised in the interpretation of any clinical in;cestigation. Probably a combination of factors is responsible for this improvement in survival probability. Among the most outstanding of the former are: more satisfactory standards of gcueral hygiene, the advent of collapse therapy and the increased care and supervision of the infective patient resulting fi'om a national organized anti-tuberculosis scheme.
Broadly the histogram of Table VII shows an impr()vement in the three, live and eight year survival rates over the past The evidence as u~ the ten-year survivM twenty years. There would also q~l)ear to of the 'open' case as presented in thi.~ Survey have becn some slight improvement in the is cqulwmal, There is a possibility that the ten-year surviwtl period of positive sputum signific.antly improved thre% five and eight patients. '1'o appraise this @arena improve- year li~i: expectatkm as observed during the merit iu tit(,, prognr o[' the: 'tubercuhms past twenty years might even be followed by cavity,' the standard error of" each group of an unaltered mortality rate ten years or proportions was calculated taking the three, more after notification. A plea is therefore five, eight and ten year periods of I9~8 , 29, entered for a minimum ten-year follow-up 3~ as 'norms.' The fi:)rmula employed is that before the beneficial effects of any specific advocated by Bradford Hill:-line of' therapy is committed to print and given the sanctity of publication. Again, S . E . = % / !) • q + px--q w h e r e n l a n d n = a r e phthisiologists and thoracic surgeons are nI n,~ asked to pause and re-examine their findings the numbers in the two samples drawn from before extolling the virtues of a new line of the same universe. A difference greater than therapy which in fact yields evidence NOT twice the S.E. was regarded as 'significant' S I O N I F I ( . I A N T L ' ir above the life-expectation of and unlikely to be due to chance and where patients where more formal and routine the difference was three times the standard procedures are the current practice. error, the result was accepted as being Bibliography 'very significant.' These findings are represented in the histogram by the abbrevia- [z] Pearson, S. V., Lancet, z935, r, 690. tions 's'=significant and 'v.s.'=very signifi- [9.] Edwards, P. W., Public Health, z934, LVH,'255. [3l B.M.J., Leading Az'ticle. cant, and 'n.s.'.=not significant. There has [4J BracVord Hilt Prine. of Med. Star., I94.~. therefore been an improvemerit greater than [51[ Smhh Hartley, P. I-[., WingfleId, R. CI.,Burrows, V. A., Brom. I-Imp. Rep., r935. that likely to attributable to chance in both [6] Tattersal[, W. H., Tuberde, t947, xxvzzt, 85, the three and five year survival periods from [7] 's B. C., Tubercle, t94~ , xxm, r4~, 1934, 35, 36 onwards. A significant improve- [8] Thompson, B. CI.~/i'.M.ff., r943, xxxI b 7~o.