A Trade-off Analysis of Routine Newborn Circumcision Dimitri A. Christakis, MD, MPH*‡; Eric Harvey, PharmD, MBA‡; Danielle M. Zerr, MD, MPH*; Chris Feudtner, MD, PhD*§; Jeffrey A. Wright, MD*; and Frederick A. Connell, MD, MPH‡i Abstract. Background. The risks associated with outine circumcision of newborn infants re- newborn circumcision have not been as extensively mains controversial.1–3 Although a recent evaluated as the benefits. Rpolicy statement by the American Academy Objectives. The goals of this study were threefold: 1) of Pediatrics recommended that parents be given to derive a population-based complication rate for new- accurate and unbiased information regarding the born circumcision; 2) to calculate the number needed to risks and benefits of the procedure,3 accomplishing harm for newborn circumcision based on this rate; and this task of well informed consent is hindered both 3) to establish trade-offs based on our complication rates and published estimates of the benefits of circumcision by the lack of precise information about potential including the prevention of urinary tract infections and harm and by the lack of clear ways to present this penile cancer. information. Methods. Using the Comprehensive Hospital Ab- The benefits of circumcision have been described stract Reporting System for Washington State, we retro- in numerous previous studies using a variety of spectively examined routine newborn circumcisions methodologies.4–8 Reported benefits include reduc- performed over 9 years (1987–1996). We used Interna- tion in the risk of penile cancer,9 urinary tract in- tional Classification of Diseases, Ninth Revision codes fections (UTIs),4,5 and sexually transmitted diseas- to identify both circumcisions and complications and es.10,11 Although the extent to which circumcision limited our analyses to children without other surgical decreases the risk of each of these outcomes has procedures performed during their initial birth hospi- been debated,6,12–15 a consensus appears to be talization. emerging that there are some small protective ef- Results. Of 354 297 male infants born during the fects.3 study period, 130 475 (37%) were circumcised during their newborn stay. Overall 287 (.2%) of circumcised These protective effects of circumcision (or any children and 33 (.01%) of uncircumcised children had other therapy) can be meaningfully conveyed in complications potentially associated with circumcision terms of a number needed to treat (NNT). The NNT coded as a discharge diagnosis. Based on our findings, a is calculated from the reciprocal of the absolute risk complication can be expected in 1 out every 476 circum- reduction associated with a given treatment.16 In cisions. Six urinary tract infections can be prevented for the case of circumcision, this number represents every complication endured and almost 2 complications the number of children who would need to be can be expected for every case of penile cancer pre- circumcised to prevent 1 undesired outcome such vented. as UTI. Conclusions. Circumcision remains a relatively safe Although NNTs inform both providers and pa- procedure. However, for some parents, the risks we tients of the benefits of a given therapy or proce- report may outweigh the potential benefits. This infor- dure, by themselves the NNTs present only half of mation may help parents seeking guidance to make an the pertinent equation. What is also needed to informed decision. Pediatrics 2000;105:246–249; new- born circumcision, complications, urinary tract infec- make an informed decision is the number needed tions. to harm (NNH). By analogy to NNTs, NNHs are based on the absolute difference in complication rates between treatment and control groups and tell ABBREVIATIONS. UTI, urinary tract infection; NNT, number one in effect how many patients would need to be needed to treat; NNH, number needed to harm; CHARS, Com- circumcised before an adverse event can be ex- prehensive Hospital Abstract Reporting System. pected to occur. Taken together, NNTs and NNHs can be used to construct a framework of “trade- offs”; in essence, one can compute how many un- From the *Department of Pediatrics, University of Washington; ‡Child desirable outcomes will be prevented per compli- Health Institute, University of Washington; §Robert Wood Johnson Clin- cation incurred. Trade-offs can be useful to patients ical Scholars Program, University of Washington; iDepartment of Health and providers seeking to weigh the pros and cons of Services, University of Washington, Seattle, Washington. Dr Christakis is a Robert Wood Johnson Generalist Physician Faculty a given procedure. Scholar. Although existing data are sufficient to enable us Received for publication Jun 9, 1999; accepted Sep 1, 1999. to estimate the NNT with circumcision for given Address correspondence to Dimitri A. Christakis, MD, MPH, Child outcomes, the risks of the procedure have received Health Institute 146 N Canal St, Suite 300, Seattle, WA 98103. E-mail: [email protected] considerably less attention, hindering our ability to PEDIATRICS (ISSN 0031 4005). Copyright © 2000 by the American Acad- calculate NNHs. Previous studies of newborn cir- emy of Pediatrics. cumcision complications have reported rates be- 246 PEDIATRICS Vol.Downloaded 105 No. 1 from January www.aappublications.org/news 2000 by guest on September 28, 2021 tween .19 and .60%, but because these data were (based on life table analyses and assuming circumcision to be either derived from single institutions or from the 100% effective at preventing penile cancer), suggest a NNT of 909.24,25 Data for the reduction of the risk of human immunode- children of army recruits they are not population- ficiency virus exist, but have been derived from very different 6,17,18 based. Therefore we undertook a large, retro- populations than US adults and have led to conflicting conclu- spective, population-based cohort study of circum- sions.11,26,27 Data from a sexually transmitted disease clinic sug- cision of newborn infants. Our goals were gest that circumcision reduces the risk of contracting syphilis,10 threefold: 1) to obtain population-based estimates although results from a population-based study appear to refute this association.28 Moreover, sexual behavioral practices remain of complications associated with circumcision; 2) the most important modifiable risk factor for sexually transmit- to convert these complication rates into NNHs; and ted diseases.3 Therefore, we focused on the potential role of 3) to use these NNHs in conjunction with pub- circumcision in the prevention of UTIs and penile cancer. These lished data of the benefits of the procedure to de- 2 outcomes also usefully frame all others: UTI is the most prevalent serious outcome deemed modifiable through circum- velop a framework for presenting NNT versus NNH cision and penile cancer is the least prevalent one. trade-offs to better inform both practitioners and parents about routine newborn circumcision. NNH Based on Adverse Events Related to Circumcision Procedure METHODS We limited our analysis to complications coded only during Data Source the postpartum hospital stay, because the overwhelming major- We used the Comprehensive Hospital Abstract Reporting Sys- ity of complications related to circumcision occur shortly after tem (CHARS) to conduct a retrospective analysis of 9 years the procedure,10,11,17,18 and because we could not ascertain (1987–1996) of routine newborn circumcisions performed in whether children who were not circumcised during their initial hospitals throughout Washington State. The CHARS contains newborn stay were not subsequently circumcised as outpatients. International Classification of Diseases, Ninth Revision diagno- However, we did include children who were transferred from sis and procedure codes for all discharges from short-stay hos- one hospital to another and thus were continuously hospitalized pitals in Washington State including birth hospitalizations. from birth. Based on previous reports of complications attrib- Each patient is assigned a unique yet anonymous identifier, utable to circumcision,6,18,29–31 we searched for specific Inter- enabling the analysis of patient level data without compromis- national Classification of Diseases, Ninth Revision codes dur- ing confidentiality. ing postpartum hospitalizations. These codes are presented in Table 1. Patients A retrospective cohort was assembled by using the CHARS to Analysis identify all newborn male infants who had circumcision coded x2 was used to compare proportions of circumcised and un- as a procedure during their birth hospitalization. We excluded circumcised children with complications. Exact tests were used children who had any other surgical procedure documented in where indicated based on expected cell frequencies. Indepen- the database to ensure that all surgical complications we discov- dent sample t tests were used to compare mean lengths of stay. ered were appropriately attributable to the circumcision proce- NNH were calculated based on the reciprocal of the absolute risk dure. Using the unique patient identifiers, we ensured that our difference between complications in the circumcised versus the analysis counted individual patients who had 1 or more com- uncircumcised cohorts. Trade-offs were calculated based on the plications, and not simply complications themselves. number of complications that could be expected conditioned on circumcising 100 children to prevent 1 UTI and 909 children to NNTs to Prevent Undesired