COLUMBIA LIBRARIES OFFSITE HEALTH SCIENCES STANDARD HX64117855 RC1 87 .D85 Typhoid fever and it RECAP ' Columbia Sanitiersfftp College of ^ijpsiciaits! anb ^urfleons Hitirarp Typhoid Fever and Its Sequelae Read before the Section on Vital Statistics, American Public Health Association, Jacksonville, Fla., December, 1914 BY LOUIS I. DUBLIN, Ph.D., Statistician Metropolitan Life Insurance Company, New York 1914 Digitized by tine Internet Arciiive in 2010 witii funding from Open Knowledge Commons http://www.archive.org/details/typhoidfeveritssOOdubl TYPHOID FEVER AND ITS SEQUELAE. Our problem in this study was to measure the effect of typhoid fever upon vitality during the first three years following recovery, and also to note the causes of death which predominate during this period. Records Used. For this purpose, we turned to the reports of the Visiting Nurse Service of the Metropolitan Life Insurance Company for the year 1911. In that year, 1,936 cases of typhoid fever were recorded. A fairly complete record of the illness in these cases was available. A further advantage in this series was the fact that the subsequent whereabouts and condition of those who were treated could be obtained from the insurance records. In this way, we could at once be informed with regard to the present status of these persons; whether they were living or dead, the date of death, as well as a complete record of the conditions at death in these later cases. It was, in other words, possible for us to trace this series fairly completely and to determine the consequences and effects of typhoid fever on these persons. An examination of our 1,936 cases led to the elimination of 362 in which the record did not appear satisfactory from the point of view of accu- racy of diagnosis. As a result, we had, after careful analysis, a residue of 1,574 cases. All of these presented satisfactory evidence, so far as such records alone could, that the patient had suffered from an attack of "ty- phoid fever" at the time of 1911 nursing. The cases were in the hands of physicians and nurses. The treatment of the disease in every case indi- cated typhoid fever. The duration of the service as well as the large num- ber of visits made, all pointed conclusively that our series was well selected and sound. The average number of visits made per case by our Visiting Nurse Service to these patients was close to seventeen (16.85) and the dura- tion of nm-sing was close to twenty-four (23.87) days. Distribution by Age axd Sex. Table 1 shows the distribution of the 1,574 cases by age and sex. It will be noted at once that 70.3 per cent, of the total cases were under twenty years of age and that 34. 1 per cent, were under ten years. This proportion is somewhat higher than that usually observed in other typhoid fever series. The explanation Hes in the fact that our Visiting Nurse Service is more readily availed of by women and children. It is important also to remem- ber this large incidence at the earlier ages in view of its bearing on our find- ings later with reference to the sequelee. TABLE 1. DISTRIBUTION BY AGE AND SEX OF 1,574 CASES OF TYPHOID FEVER. Visiting Nitrse Service, 1911, Metropolitan Life Insurance Company. Age period. Males and females. Number. Per cent. 536 34.1 570 36.2 230 14.6 114 7.2 81 5.2 43 2.7 Males. Females. Under 10 10-19 20-29 30-39 . 40-49 50 and over . Total — all ages , 1,574 I Per cent, of total — by sex I 251 254 85 35 23 17 285 316 145 79 58 100.0 665 909 100.0 42.3 57.7 Lethal Rates. Table 2 presents the lethal rate per 100 treated for each period. The least rate is that for the children under ten; the highest trustworthy rate is for the group 20-29 which was 13.91 per 100. At the higher ages there are too few exposed to make the rate dependable. For the entire series of 1,574 cases treated, the lethal rate was 9.28 per 100 treated. This figure is consistent with that of other series which vary slightly above and below a mean of 10 deaths per 100 cases treated. TABLE 2. LETHAL RATES PER 100 CASES TREATED FOR TYPHOID FEVER- CLASSIFIED BY AGE PERIOD. Visiting Nurse Service, 1911, Metropolit.an Life Insurance Company. Age period. Number treated. Number died under treatment. Lethal rate per 100 treated. Under 10 536 570 230 114 81 43 36 45 32 12 13 8 6 72 10-19 7 89 20-29 13 91 30-39 10 53 40-49 16 05 50 and over 18 60 Total — ^all ages 1,574 146 9 28 COMPLICATIOXS. Table 3 shows the complications in these 146 cases. These are important in view of our interest in the sequelae to be referred to later. Interest should be centered in the fact that over 15 per cent, involve intestinal per- foration, hemorrhage, peritonitis and other similar conditions. Meningitis and pneumonia were present in 10.3 per cent, of the fatal cases, heart con- ditions in 8.2 per cent, of the cases. Other complications, such as tuber- culosis and acute nephritis indicated that the lungs and kidneys were im- paired in a considerable number of cases in coimection with the typhoid infection. TABLE 3. COMPLICATIONS IN 146 FATAL CASES OF TYPHOID FEVER. Visiting Ntikse Service, 1911, Metropolitan Life Insurance "CoWany. Complications -nitli typlioid fever. Number of Per cent, of deaths. total deaths. 60 41.1 22 15.1 15 10.3 15 10.3 12 8.2 8 5.5 4 2.7 10 6.8 146 100.0 No complications stated Intestinal perforation, hemorrhage Meningitis Pnemnonia Heart involvements Tuberculosis (all forms) Acute nephritis Other compHcations Total fatal cases DlSTRIBUTIOX OF RECOVERED CaSES. Table 4 shows the distribution by age and sex of the 1,4£8 persons who recovered from the typhoid fever. This distribution is very slightly dif- ferent from that of Table 1 which showed the distribution of the initial cases. Relation Actual to Expected Mortality. From this point onward, our effort was directed to a comparison of the actual and expected mortality among the 1,428 survivors. Our method was as follows: The 1,428 cases were distributed by sex and color and by ten-year age periods. A separate schedule was prepared for each sex and color. The mortality rates of the Company for each individual age. sex and color class was employed as a standard. We assumed that the mor- 3 TABLE 4. DISTRIBUTION BY AGE AND SEX OF 1,428 PERSONS WHO RECOVERED FROM TYPHOID FEVER. Visiting Nurse Service, 1911, Metropolitan Life Insurance Company. Males and females. Males. Age period. Number. Per cent. Females. Under 10 j 500 35.0 239 232 68 30 14 9 261 10-19 525 198 102 36.8 13.9 7.1 293 20-29 30-39 130 72 40-49 68 ' 4.8 35 2.5 54 26 Total — all ages 1,428 100.0 592 836 Per cent, of total — -by sex 100.0 41.5 58.5 tality actually experienced in 1911 by the Company in the Industrial De- partment should serve as the measure of the expected deaths for the cor- responding group of these persons who had recovered from typhoid fever in 191 1 for the first year after recovery. For the second year after recovery, we employed similar mortality figures for the year 1912 as a standard and for the third year we employed the figures for 1913. In other words, the mortality table used was not an arbitrary measure but exhibited the death- rates which persons of the same sex, color and age among our Industrial policyholders actually experienced. By throwing these rates into the num- ber of years of life of each group in successive years since recovery we obtained the number of expected deaths for each age period. In this way we found, as shown in Table 5, that in the series of 1,428 persons the expected number of deaths was equal to 26.45. As a matter of fact, our record showed 54 actual deaths. The ratio of actual to ex- pected deaths was, therefore, for our entire series, 204 per cent. In other words, more than twice the mortality expected was realized. You will note that the total number of years of life was nearly 3,850 years. A number of persons dropped out, either by death or lapsing their policies during the first, second or third year after recovery. Each such exit from our series involved an adjustment in the number of years of life exposed to risk, by taking the proportionate part of a year from the date of recovery to the date of exit. In this way, every day of experience was used. For- tunately, the fullness of the Company's record made this much desired 4 TABLE 5. COMPARISON OF ACTUAL AND EXPECTED MORTALITY IN THREE YEARS FOLLOWIxXG RECOVERY FROM TYPHOID FEVER— CLASSIFIED BY AGE PERIOD. Cases The.\ted by Visitixg Nurse Service, 1911, Metropolitax Life Insurance Company. Age period. Number of years of life. Number of expected deaths. Number of actual deaths. Per cent. actual of expected deaths. Under 10 1,354.15 1,434.66 521 . 27 274.16 173.05 92.62 8.07 5.61 3.92 2.94 2.46 3.45 13 12 13 5 8 3 161 10-19 214 20-29 30-39 40-49 50 and over 332 170 325 87 Total — all ages .... 3,849.91 26.45 54 204 step possible. It would be difficult in many other sendees to keep such complete control of the whereabouts of the indi\aduals composing a large series. Our conclusion from our own series is, therefore, that during the first three years after recovery from typhoid fever, the mortality is twice the normal. It is interesting to note, however, that this increased rate is not uni- formly evident in all the three years of the series. Thus, in the first year following recovery from typhoid fever the ratio of actual to expected deaths was 284, in other words nearly three times as great as it should be. In the second year, the percentage actual of expected deaths was 217, and in the third year it fell below the expected, namely to 80 actual deaths per 100 expected deaths. This last fact is puzzKng. A careful reexamination was made of our series. No effort was spared in finding a possible source of error and yet at the very end, we find no evidence of an additional death which would in any way change our figure. It would appear from our figures that typhoid fever has its impairing effect in the first two years after recovery. It would seem, although we would not press this explanation, that the weakhngs had been eliminated by the immediate deaths and those that followed in the first two years after recovery. Table 7 shows the causes of death in the 54 cases that occurred in the three years subsequent to recovery. Tuberculosis heads the list with twenty-one deaths (39 per cent.), of which aU but three cases were of the pulmonary type. The second important group are the diseases of the heart with a total of eight cases. Pneumonia, and kidney disease follow with four cases each. ^ tf H > O U H W O 1— 1 < o 1^ ^ o ^ m f^ « Q O w m § f=H Q Q ^ 1— 1 O Iz; U W C3 H P^ 2; s >^ H >< Eh 2 o Q )^ H -+ tf <3 Ck g O u 1:^ °3 >. ^ Pk rt • i-H i-H S5 -^ 1— 1 O Q? C ^ ■* i> 05 O CO -# i> I-H ©» -# 00 oo »o i> ©J oi « CO »o CO 00 Tji s< t- 00 ■* o GO S< ©« EO 1— t '"* ""* '"' o T-( O T' 05 Oi Oi OS c2 ^ rH Gf< CO -# S il II. H^ o o o o hJ 1-1 e< so -* Our conclusion, then, from this table is that the incidences of tuberculosis and the diseases of the heart are increased subsequent to typhoid fever. This -is borne out by the previous statement of complications which oc- curred in the immediate deaths, Table 3, where a considerable number of cases showed heart and pulmonary complications. This condition has been noted consistently by other observers of typhoid fever and its sequelae. Effect of Sequels upon General Death Rate. We will close this paper with an estimate of the effect of typhoid fever upon mortality in the three years subsequent to an attack. On the basis of the estimated population of Continental United States in 1914, we have calculated that each year a minimum of close to 8,000 deaths occur which can be attributed annually to the impairments which follow typhoid fever. In this estimate, we have assumed a minimal death-rate from typhoid fever of 20 per 100,000. We have also assumed the number of cases to be ten times as great as the number of deaths in accordance with the usual practice. The number of recoveries, therefore, is 90 per cent, of the, cases. For each of the three years following, we have assumed an expected death-rate for the entire country to be at least 15 per 1,000 from aU causes. A calcula- tion of the additional deaths due to sequelse of typhoid fever gives us a TABLE 7. CAUSES OF 5i DEATHS IN THREE YEARS FOLLOWING RECOVERY AMONG 1.428 CASES OF TYPHOID FE^^ER. Treated By Visiting Ntjese Service, 1911, Metropolitan"^ Life IssuRAisrcE Company. Cause of death. Number of deaths. Per cent, of total deaths. Tuberculosis: Pulmonary Other forms Diseases of the heart: Endocarditis Myocarditis Valvular disease of the heart . Pneumonia Nephritis : Acute Bright's disease Acute articular rheumatism. . . Violent causes Other causes Total — all causes 18 33.3 3 5.6 4 7.4 2 3.7 2 3.7 4 7.4 1 ■ 1.9 3 5.6 2 3.7 7 13.0 8 14.8 54 100.0 total of 7,781. This is the price that is paid annually over and above the registered direct loss from typhoid fever according to the results of our study. It is not only the £0,000 immediate deaths that we have to con- sider, but the additional 8,000 who, although recovered, cannot sur\nve the strain which modern industrial life makes necessary and who either because of tubercular or cardiac lesions die untimely deaths within the first or the second year after recovery. TABLE 8. ESTIMATED NUMBER OF DEATHS TO BE ATTRIBUTED ANNUALLY TO SEQUELS OF TYPHOID FEVER IN THE LuS^ITED STATES. Population, Continental United States, 1914 98,781,324 Typhoid Fever: " * Death rate per 100,000, Continental United States, 1914 (minimal estimate) ... 20 Deaths in United States in 1914 19,800 Cases in United States in 1914 198,000 Recoveries, each year, in United States 178,200 Extra deaths to be attributed annually to sequelae of typhoid fever. (On basis of double mortality in three years following recovery) 7,781 COLUMBIA UNIVERSITY LIBRARIES This book is due on the date indicated below, or at the expiration of a definite period after the date of borrowing, as provided by the rules of the Library or by special arrange- ment with the Librarian in charge. DATE BORROWED DATE DUE DATE BORROWED DATE DUE 1 j ! C28(i14|)m100 RC137 D85 Dublin