Abstract of Comparative Mortality - Children with Exstrophy of the Bladder

of Comparative Mortality CHILDREN WITH EXSTROPHY OF THE BLADDER Reference: M.T. Macfarlane, J.K. Lattimer and T.W. Hensle, "Improved Life Expectancy for Children with Exstrophy of the Bladder". JA~MA, 242:442-444 (1979). Subjects Studied: The series consists of 163 patients with classical exstrophy of the bladder treated on the Pediatric Urological Service of the Babies Hospital, Columbia-Presbyterian Medical Center, New York. Infants with bladder exstrophy complicated by multiple serious congenital defects were excluded; death in such cases ordinarily occurred early in life. More cases were referred than diagnosed initially at Babies Hospital, and some had been treated medically for a period of months or years prior to referral. No age or sex distribution is given. No calendar period of operation is given. Earlier operations were uterosigmoidostomy, but for the past 20 years primary closure was the major type of surgery, with only 12 patients treated by primary conduit diversion. Follow-Up: Methods used are not given. Survival was calculated from birth "regardless of the age a~ which the patient entered into follow-up study at our institution". Out of 150 patients born at least i0 years prior to the end of follow-up 73% were traced; 63% of 88 patients with 20 or more years of potential follow-up were traced, and 53% of 32 patients with 30 years or more. Results: In the derivation of expected survival and mortality for this abstract it has been assumed that follow-up begins at age 4 weeks instead of birth. This does not eliminate all retrospective "exposure", which should be eliminated completely because of the bias introduced by its use. However, it does eliminate that part of the first year of life which contributes most heavily to expected mortality. Observed data and derivation of expected deaths are shown in Table A, and comparative mortality and survival in Table B. Over half of the total exposure and three of six. observed deaths were concentrated within the first ten years of life. The mortality ratio was only 146% because of the high expected mortality in the first year, even with the first four weeks excluded (compare qJ values for the different attained age intervals). The mortality ratio was 410% in the second decade and 235% thereafter. The highest EDR was only 2.0 per i000 per year in the second decade. With only 6 total deaths the overall excess mortality above the 2.98 expected deaths was significant at the 91% level but not the 95% level (single-tailed test p~0.09 by the Poisson distribution). Comment: The authors cite two early reports from the Mayo Clinic on survival in patients with operation for bladder exstrophy and comment: "In 1925 the majority died. In 1978 practically all lived". These references and the quoted 20-year survival rates are shown in Table C, together with the 20-year survival rate from Table B. In an effort to provide comparative mortality data over a wide range of time, about 1910-to 1978, I have used two sets of U.S. Life tables for each of the Mayo C~inic reports and calculated geometric mean annual survival rates and ~ and ~. 2Ls above, deaths in the first 4 weeks of life have been excluded and equal numbers of male and female patients have been assumed. Because of the marked decrease in ~ from the 1909-11 tables to the 1959-61, mortality ratios have not been calculated. The low survival rate in the earliest (1926) report is associated with an EDR of 42-43 per 1000 per year, and the somewhat better survival in the 1951 report with an EDR of 27-30 per i000. On this geometric mean method the corresponding EDR of the Columbla-Presbyterlan series is only 1.0 per 1000 per year. Although bladder exstrophy is very rarely encountered in underwriting I felt this limited experience was worth abstracting, because it contradicts the opinion I held until recently that mortality was still high enough to make declination necessary in all such applicants. On the basis of this 1979 report properly treated and managed cases of bladder exstrophy certainly appear to be acceptable on a rated basis. January 24, 1980 Richard B. Singer, M.D.