P2-16-10: Practice Variations in Post-Mastectomy Breast Reconstruction: What Are the Roles of Clinical Factors, Access Barriers, and Delayed Reconstruction?

Background: Breast reconstruction rates vary widely by race, income, and location. Proposed explanations have included clinical contraindications to reconstruction, access barriers, and patient or surgeon preference for delayed reconstruction. We sought to determine whether clinical contraindications (planned radiation, comorbidities) or access barriers (distance to care, surgeon) were associated with reconstruction and to estimate the frequency of delayed reconstruction over time.

Methods: A retrospective cohort study was conducted among women treated with mastectomy for Stage 0-IIIa breast cancer between 2002 and 2007 at one institution. Demographics, stage, comorbidities, adjuvant therapy plans, and treatments were obtained from the medical record. Multivariable modified Poisson regression analyses were performed, with immediate and any reconstruction (immediate or delayed) as outcomes. Interaction terms were added to examine surgeon effects. Kaplan-Meier survival analysis was performed. Results: Among 539 women, 18.9% had a plan for chemotherapy; 13.7% had a plan for radiation. Comorbidities were: obesity 17.1%, diabetes 11.9%, smoking 16.3%, heart disease 5.6%, immunodeficiency 2.2%. Most patients (59.8%) lived within 50 miles of the hospital. 33.8% had immediate reconstruction; 5.6% had delayed. Patients who had a plan for adjuvant therapy or comorbidity were less likely to have reconstruction. Patients who lived farther from the hospital were slightly more likely to have reconstruction, but this was not statistically significant (p<0.08). None of the associations varied significantly by surgeon. Few patients had reconstruction more than 2 years after mastectomy.

Experiences and challenges in data monitoring for clinical trials within an international tropical disease research network

BACKGROUND

Models for the structure and procedures of data and safety monitoring boards (DSMBs) continue to evolve in response to issues of new and of old concern. Some authors have called for an open dialogue on these questions through publication of the experiences of DSMBs in addressing them.

PURPOSE

The goal of this paper is to add to the current discussion about acceptable models for establishing, serving on, and reporting to monitoring committees, particularly those that oversee multiple studies in less developed countries. The paper seeks to do so by describing the establishment and subsequent operation of one such multi-trial DSMB over a five-year period. This DSMB was formed to monitor trials conducted by members of the International Centers for Tropical Disease Research (ICTDR) network of the National Institute of Allergy and Infectious Diseases (NIAID).

METHODS

The operational model and experiences are summarized by the authors, who had immediate responsibilities for directing the DSMB's activities.

RESULTS

The board played an active, traditional role in assuring that patient safety was maintained and that current standards for clinical research were met. In addition, both NIAID and the board members viewed education of investigators to be an important role for the board to play in this particular setting. This affected the threshold for identifying which trials would be monitored, and it impacted several procedures adopted by the board.

LIMITATIONS

This report reflects the observations of those involved in managing the DSMB, including comments offered by the DSMB and by investigators, but not data gathered in a systematic way.

CONCLUSIONS

The operational model described here has allowed the DSMB to fulfill its role in the oversight of the trials. We hope that the ideas we present may help others facing similar situations and may stimulate further critical thinking about DSMB structure and function.

A statistical model for the evaluation of barrier contraceptive efficacy

This paper describes an approach for the analysis of barrier contraceptive efficacy trials that accounts for timing frequency of intercourse and compliance. We allow exposure variables to vary for each act of intercourse and we control for timing of each act through a specific parametric function of the day of the act relative to the last day of the follicular phase of the cycle. The model can be used to examine the level of protection provided by a barrier versus no contraceptive method even when no control group of non-users is studied, as long as there are acts with no barrier use during the fertile window. We present results of a simulation study which examines performance of estimators and power under a variety of scenarios, including situations where an accurate benchmark for ovulation day is not available. As compared to the survival analysis approach commonly used in this setting, simulation results show that the new approach yields considerable gains in power to detect differences between the efficacy of contraceptive methods. An application to data from the FemCap versus diaphragm trial show results consistent with previous findings suggesting superiority of the diaphragm but also provides new evidence of the per act protection provided by both methods.

Two randomized controlled trials comparing the Hulka and Filshie Clips for tubal sterilization

To compare the effectiveness and safety of the Filshie Clip System and Hulka Clip System when applied via minilaparotomy and laparoscopy, we conducted 2 multicenter randomized controlled trials of 2126 women (878 in the minilaparotomy study and 1248 in the laparoscopy study) who received either the Filshie or Hulka Clip. A physician other than the operator evaluated patients postoperatively and again at 1, 6, and 12 months after surgery. We compared the cumulative incidence of pregnancy and the frequency of safety related events for the device groups. Twenty-four month follow-up was planned for a subset of 599 women in the laparoscopy study. One woman who received the Filshie Clip and 6 women who received the Hulka Clip became pregnant within one year. The 12-month life-table pregnancy probability was 1.1 per 1000 women in the Filshie Clip group and 6.9 per 1000 women in the Hulka Clip group. The difference in the risk of pregnancy through 12 months between device groups neared statistical significance (p = 0.06). Among the extended follow-up subset, the 12- and 24-month cumulative pregnancy probabilities were 3.9 and 9.7 per 1000 women for the Filshie Clip group and 11.7 and 28.1 per 1000 women for the Hulka Clip group (p = 0.16 for comparison through 24 months). Both the Filshie and Hulka Clips are effective and safe for use in tubal occlusion.

Two randomized controlled trials comparing the tubal ring and filshie clip for tubal sterilization

OBJECTIVE

To compare the effectiveness and safety of the Filshie Clip and Tubal Ring systems when applied via minilaparotomy and laparoscopy.

DESIGN

Prospective, multicenter randomized controlled clinical trial, with postoperative evaluation by a physician who was masked to the operative technique.

SETTING

Healthy volunteers in a variety of hospital settings.

PATIENT(S)

2746 women (915 in the minilaparotomy study and 1831 in the laparoscopy study) who had requested permanent surgical sterilization.

INTERVENTION(S)

Surgical tubal ligation, using either Filshie Clips or Tubal Rings. A physician other than the surgeon evaluated the patients after the operation and again at 1, 6, and 12 months after surgery.

MAIN OUTCOME MEASURE(S)

Pregnancy rates and safety-related events.

RESULT(S)

During the 12 months after surgery, two women who received the Filshie Clip and two women who received the Tubal Ring became pregnant, giving a 12-month life-table pregnancy probability of 1.7 per 1000 women in both groups. The Tubal Ring was more difficult to apply and had higher rates of tubal or mesosalpingeal injuries at surgery. The Filshie Clip group had three cases of spontaneous clip expulsion during the follow-up period.

CONCLUSION(S)

Both the Filshie Clip and Tubal Ring are effective and safe for use in tubal occlusion.

A transitional model of barrier methods compliance with unbalanced loss to follow-up

Differential loss to follow-up can substantially influence the evaluation of treatment effects on a dichotomous outcome of interest in longitudinal trials. The use of transitional models incorporating loss to follow-up as an additional category of response and the nature of the correlated responses can provide a comprehensive view of a trial with unbalanced loss to follow-up. Under the Markov assumption, transitional models estimate the probability of changing from one outcome to another outcome between follow-up visits. Patterns of the response variable can be described by the estimated transition probabilities. The effects of intervention and covariates on the outcome of interest can also be estimated using a conditional likelihood function or a multinomial logit regression. Data from a randomized barrier method study designed to compare the proportion of participants using barrier methods consistently in two counselling groups are used to illustrate the proposed model.

Failure rates among perfect users and during perfect use: a distinction that matters

To make an informed decision when choosing a contraceptive, women and couples need to know how effective different methods are when used perfectly, where perfect use is defined as following the directions for use. In this article, we show that unbiased estimates of pregnancy rates during perfect use can be guaranteed only if information on consistency and correctness of use is available for each menstrual cycle. The estimated probability of pregnancy during a year of perfect use among the subset of women who always used a method perfectly will be biased upward.

A comparative study of the no scalpel and standard incision approaches to vasectomy in 5 countries. The Male Sterilization Investigator Team

PURPOSE

We compare the safety, ease of use and effectiveness of the no scalpel and standard incision approaches to vasectomy.

MATERIALS AND METHODS

A multicenter, randomized, partially masked controlled trial was conducted at 8 sites in Brazil, Guatemala, Indonesia, Sri Lanka and Thailand. Semen samples were collected 10 weeks postoperatively and tested to ascertain sterility using verification of no living spermatozoa.

RESULTS

The study included 1,429 men seeking vasectomy. The efficacy of the 2 approaches was virtually identical. In the no scalpel group operating time was significantly shorter, and complications and pain were less frequent than in the standard incision group. The no scalpel group resumed intercourse sooner, probably as a result of less pain following the procedure.

CONCLUSIONS

The no scalpel approach is an important advance in the surgical approach to vasectomy, and offers fewer side effects and greater comfort compared to the standard incision technique, without compromising efficacy.

A comparative study of the safety and efficacy of FemCap, a new vaginal barrier contraceptive, and the Ortho All-Flex diaphragm. The FemCap Investigators' Group

The FemCap is a new silicone rubber barrier contraceptive shaped like a sailor's hat, with a dome that covers the cervix, a rim that fits into the fornices, and a brim that conforms to the vaginal walls around the cervix. It was designed to result in fewer dislodgments and less pressure on the urethra than the cervical cap and diaphragm, respectively, and to require less clinician time for fitting. This was a phase II/III, multicenter, randomized, open-label, parallel group study of 841 women at risk for pregnancy. A subset of 42 women at one site underwent colposcopy. Women were randomized to use the FemCap or Ortho All-Flex contraceptive diaphragm, both with 2% nonoxynol-9 spermicide, for 28 weeks. The objectives were to compare the two devices with regard to their safety and acceptability and to determine whether the probability of pregnancy among FemCap users was no worse than that of the diaphragm (meaning not more than 6 percentage points higher). The 6-month Kaplan-Meier cumulative unadjusted typical use pregnancy probabilities were 13.5% among FemCap users and 7.9% among diaphragm users. The adjusted risk of pregnancy among FemCap users was 1.96 times that among diaphragm users, with an upper 95% confidence limit of 3.01. Clinical equivalence (noninferiority) of the FemCap compared with the diaphragm, as defined in this study, would mean that the true risk of pregnancy among FemCap users was no more than 1.73 times the pregnancy risk of diaphragm users. Because the observed upper 95% confidence limit (and even the point estimate) exceeded 1.73, the probability of pregnancy among FemCap users, compared with that among diaphragm users, did not meet the definition of clinical equivalence used in this study. The FemCap was believed to be safe and was associated with significantly fewer urinary tract infections. More women reported problems with the FemCap with regard to insertion, dislodgement, and especially removal, although their general assessments were positive. The two devices were comparable with regard to safety and acceptability, but a 6-point difference in the true 6-month pregnancy probabilities of the two devices could not be ruled out. Further studies are needed to determine whether design modifications can simplify insertion and removal.

Contraceptive effectiveness of two spermicides: a randomized trial

OBJECTIVE

We conducted a multinational randomized trial to determine whether a spermicidal film containing 72 mg of nonoxynol-9 per film was at least as effective in preventing pregnancy as a foaming tablet containing 100 mg of nonoxynol-9 per tablet.

METHODS

Between September 1995 and July 1997, 765 women aged 18-35 years who had no evidence of subfecundity were randomly assigned to use one of the two spermicides as their only contraceptive method at every coital act for 28 weeks. Participants were asked to keep coital diaries throughout the study period. Pregnancy tests were performed on a scheduled basis. Each participant was followed for 28 weeks or until she stopped considering the spermicide as her primary method of contraception.

RESULTS

The Kaplan-Meier estimate of the 6-month probability of pregnancy during typical use of the spermicide was 28.0% in the tablet group and 24.9% in the film group (P = .78, one-tailed test). The study had nearly 75% power to have detected a difference of seven percentage points between groups. Results were almost identical when the analysis included only months when the participants reported use of the spermicide during every coital act. Reported levels of sexual activity and compliance with use of the spermicide were high in both groups.

CONCLUSION

The contraceptive effectiveness of these two spermicidal products appeared similar. Both products were associated with a fairly high risk of pregnancy in this young, highly sexually active population.

Emergency contraception use and the evaluation of barrier contraceptives. New challenges for study design, implementation, and analysis

The availability of emergency contraception (EC) introduces new complexities to barrier contraceptive evaluation. Researchers must determine whether the primary objective of interest is to measure the effectiveness of the barrier plus EC back-up or the effectiveness of the barrier alone. Barrier contraceptive effectiveness study protocols must specify what study volunteers will be told about EC, under what conditions EC will be dispensed, what information about EC use will be collected, and how EC use will be addressed during data analysis.

Measuring contraceptive effectiveness: a conceptual framework

We present a conceptual model that outlines the four measures of how well a contraceptive method works: 1) efficacy, 2) effectiveness, 3) perfect-use pregnancy rate, and 4) typical-use pregnancy rate. Moreover, we illustrate how four variables influence these measures: 1) capacity to conceive, 2) frequency and timing of intercourse, 3) degree of compliance, and 4) inherent protection of the method. Because of inter-individual as well as intra-individual variability of the first three variables, generalizing results from a contraceptive clinical trial to other populations is problematic. There is a hierarchy of generalizability of the four outcome measures, with the typical-use pregnancy rate the least generalizable but the easiest to measure, and efficacy the most generalizable but the most difficult to measure. These four variables should be considered in the design and analysis of future contraceptive clinical trials. Finally, this article illustrates why the terms "pregnancy rate" and "failure rate" are not synonymous and why we recommend that the latter term not be used.

Lea's Shield: a study of the safety and efficacy of a new vaginal barrier contraceptive used with and without spermicide

The purpose of this study was to evaluate the safety, efficacy and acceptability of Lea's Shield, a new vaginal contraceptive barrier device, when used with either spermicidal or non-spermicidal lubricant. One-hundred-eighty-five (185) women enrolled at six centers. Half were randomized to use the device with spermicide and half with a non-spermicidal lubricant. To be eligible, volunteers had to be 18-40 years old (inclusive), in good health with regular menses, sexually active in an ongoing relationship and at risk for pregnancy, and willing to use Lea's Shield as their sole means of contraception for six months. Participants were seen at admission, one week, one month, three months and six months. Gross cumulative life table rates were calculated for pregnancy and others reasons for discontinuation. Adverse experiences and responses to an acceptability questionnaire were evaluated. One-hundred-eighty-two (182) volunteers contributed data to the analysis of safety and 146 to that of contraceptive efficacy. The unadjusted six-month life table pregnancy rate was 8.7 per 100 women for spermicide users and 12.9 for non-spermicide users (p = 0.287). After controlling for age, center, and frequent prior use of barrier methods, the adjusted six-month life table pregnancy rate was 5.6 for spermicide users and 9.3 for non-spermicide users (p = 0.086), indicating that use of spermicide lowered pregnancy rates, although not significantly, during typical use. For purposes of comparison, it is important to note that this study differed from the cap/diaphragm and sponge/ diaphragm studies in that a high percentage (84%) of volunteers were parous. For reasons that are unclear, pregnancy rates among parous women using barrier contraceptives tend to be higher than among nulliparous women. Indeed, in this study there were no pregnancies among nulliparous users of Lea's Shield. Standardization of parity of this study population on those of the cap/diaphragm and sponge/diaphragm studies suggests that unadjusted pregnancy rates for this device would have been considerably lower (2.2 and 2.9 per 100 users of spermicide and non-spermicide, respectively) had the study been done using the populations of earlier studies. Since no directly comparative study has been done, these figures provide a tentative estimate of the relative efficacy of Lea's Shield compared with the sponge, cap, and diaphragm. There were no serious adverse experiences attributed to the use of Lea's Shield. Acceptability was very good. Seventy-five percent (75%) of women responded to an end-of-study questionnaire; 87% of these reported that they would recommend Lea's Shield to a friend. Lea's Shield is a new vaginal contraceptive that does not require clinician fitting. Pregnancy rates in this study compare favorably with other studies of barrier contraceptive methods including the cervical cap, diaphragm, and sponge, even though this study was done with greater rigor and with a greater percentage of parous women than previous barrier studies. Lea's Shield appears to be safe and very acceptable to study volunteers.

The diaphragm with and without spermicide. A randomized, comparative efficacy trial

OBJECTIVE

To determine the relative contraceptive efficacy of a diaphragm used with spermicide as compared to one used without.

STUDY DESIGN

Two hundred sixteen women entered the study between September 1985 and December 1990. Of these, 84 were randomly assigned to the diaphragm-only group and 80 to the diaphragm-with-spermicide group as their primary method of contraception. In addition, a spermicide-only group was planned originally to serve as a control group to assess the contribution to efficacy made by a spermicide alone. Thirty-nine women were randomly assigned to this group, and 13 selected themselves for it. All were followed for a maximum of 12 months. The primary outcome variable was accidental pregnancy. The statistical difference between the two diaphragm groups was analyzed.

RESULTS

The 12-month "typical use" failure rates for the diaphragm-only group were 28.6 per 100 women and for the diaphragm-with-spermicide group, 21.2. The 12-month cumulative consistent-use failure rates were 19.3 per 100 women for the diaphragm-only group as compared to 12.3 per 100 women for users of a diaphragm with spermicide.

CONCLUSION

Although the consistent use rates were not significantly different, this study had low statistical power and hence gives no support to the hypothesis that adjunctive spermicide use fails to improve the effectiveness of the diaphragm method, especially in view of the magnitude and direction of the difference observed. Unless a study with sufficient power proves that the use of a diaphragm alone is statistically as effective as use of a diaphragm with spermicide, use of a spermicide in conjunction with the diaphragm continues to be the appropriate clinical recommendation.

Comparative contraceptive efficacy of the female condom and other barrier methods

Because the research design for the clinical trial establishing the contraceptive efficacy of the female condom--a six-month life-table probability of failure of 15% (12% in the United States vs. 22% in Latin America)--did not include randomization with another method of contraception, no definite conclusion about its comparative efficacy is possible. Comparisons using other female barrier methods as historical controls, however, provide evidence that, among women in the United States, the contraceptive efficacy of the female condom during typical use is not significantly different from that of the diaphragm, the sponge or the cervical cap. The six-month probability of failure during perfect use of the female condom is 2.6% among U.S. women, similar to rates for the diaphragm and the cervical cap but significantly lower than that for the sponge. Meaningful comparisons with the male condom are not possible because of the lack of data from carefully controlled prospective clinical trials. Extrapolations from the results on contraceptive efficacy suggest that perfect use of the female condom may reduce the annual risk of acquiring the human immunodeficiency virus by more than 90% among women who have intercourse twice weekly with an infected male.

Management and treatment of diarrhea in Honduran children: factors associated with mothers' health care behaviors

Data from the 1984 National Maternal-Child Health and Family Planning Survey in Honduras showed that one fifth (n = 711) of the children under five had experienced diarrhea on the day of the interview or the two days preceding the interview. The health care behaviors of the mothers of these children and the factors associated with these behaviors were the focus of this study. Only 22% of the mothers consulted medical personnel concerning the diarrhea episode; 74% treated their children with some type of medication while only 17% of the children received the recommended treatment, oral rehydration therapy. Most children were treated inappropriately, often receiving a combination of antibiotics, antidiarrheals and other drugs. Bivariate and multivariate analyses showed that the variables that most consistently predicted any and all three of the behaviors were the child's age and the severity of symptoms. Mothers of children two years and older were less likely to consult or use ORT than mothers of children 6-23 months of age. Mothers whose children's diarrhea had lasted three or more days or who were vomiting were usually twice as likely to consult, give any type of treatment, or give ORT than mothers whose children had diarrhea for fewer days or who were not vomiting.

Do retroverted uteri adversely affect insertions and performance of IUDs?

A large international multi-center IUD data set (N = 5520) coordinated by Family Health International was analysed to determine if the uterine position of a woman (anteverted, mid-positioned or retroverted) affects the ease of IUD insertion and if knowledge of uterine position would diminish insertion-related problems and improve IUD performance. Findings showed that insertion-related events were rare irrespective of uterine position. Women with retroverted uteri were not associated with higher termination rates for accidental pregnancy, expulsion or removal for bleeding and/or pain after 12 months of IUD use, as compared to the other two uterine position groups. All insertions in this data set were performed by experienced obstetricians/gynecologists, and our findings suggest that women with retroverted uteri should be equally good candidates for IUD contraception.

Cervical laceration at IUD insertion--incidence and risk factors

Incidence and risk factors of cervical laceration at IUD insertion are studied as the one remaining IUD insertion-related rare event using the multi-center IUD database developed by Family Health International. Two-hundred-ten lacerations were reported from 11,646 insertions (1.8 per 100 insertions) performed between 1977 and 1987. The incidence was twice as high in insertions with the copper devices and the multiload devices as in those with the Loop devices. Nulliparous women were found to be at an increased risk compared to multiparous women. Use of a tenaculum at insertion may also be a risk factor for laceration, but this finding needs to be confirmed by future studies. Data were not adequate to examine the effect of insertor's experience on the incidence of cervical lacerations at insertion.