Multiple imputation for estimation of an occurrence rate in cohorts with attrition and discrete follow-up time points: a simulation study

<p>Abstract</p> <p>Background</p> <p>In longitudinal cohort studies, subjects may be lost to follow-up at any time during the study. This leads to attrition and thus to a risk of inaccurate and biased estimations. The purpose of this paper is to show how multiple imputation can take advantage of all the information collected during follow-up in order to estimate the cumulative probability <it>P(E) </it>of an event <it>E</it>, when the first occurrence of this event is observed at <it>t </it>successive time points of a longitudinal study with attrition.</p> <p>Methods</p> <p>We compared the performance of multiple imputation with that of Kaplan-Meier estimation in several simulated attrition scenarios.</p> <p>Results</p> <p>In missing-completely-at-random scenarios, the multiple imputation and Kaplan-Meier methods performed well in terms of bias (less than 1%) and coverage rate (range = [94.4%; 95.8%]). In missing-at-random scenarios, the Kaplan-Meier method was associated with a bias ranging from -5.1% to 7.0% and with a very poor coverage rate (as low as 0.2%). Multiple imputation performed much better in this situation (bias <2%, coverage rate >83.4%).</p> <p>Conclusions</p> <p>Multiple imputation shows promise for estimation of an occurrence rate in cohorts with attrition. This study is a first step towards defining appropriate use of multiple imputation in longitudinal studies.</p

Australian women's use of complementary and alternative medicines to enhance fertility: exploring the experiences of women and practitioners

<p>Abstract</p> <p>Background</p> <p>Studies exploring the use of complementary and alternative medicine (CAM) to enhance fertility are limited. While Australian trends indicate that women are using CAM during pregnancy, little is known about women's use of CAM for fertility enhancement. With the rising age of women at first birth, couples are increasingly seeking assisted reproductive technologies (ART) to achieve parenthood. It is likely that CAM use for fertility enhancement will also increase, however this is not known. This paper reports on an exploratory study of women's use of CAM for fertility enhancement.</p> <p>Methods</p> <p>Three focus groups were conducted in Melbourne, Australia in 2007; two with women who used CAM to enhance their fertility and one with CAM practitioners. Participants were recruited from five metropolitan Melbourne CAM practices that specialise in women's health. Women were asked to discuss their views and experiences of both CAM and ART, and practitioners were asked about their perceptions of why women consult them for fertility enhancement. Groups were digitally recorded (audio) and transcribed verbatim. The data were analysed thematically.</p> <p>Results</p> <p>Focus groups included eight CAM practitioners and seven women. Practitioners reported increasing numbers of women consulting them for fertility enhancement whilst also using ART. Women combined CAM with ART to maintain wellbeing and assist with fertility enhancement. Global themes emerging from the women's focus groups were: women being willing to 'try anything' to achieve a pregnancy; women's negative experiences of ART and a reluctance to inform their medical specialist of their CAM use; and conversely, women's experiences with CAM being affirming and empowering.</p> <p>Conclusions</p> <p>The women in our study used CAM to optimise their chances of achieving a pregnancy. Emerging themes suggest the positive relationships achieved with CAM practitioners are not always attained with orthodox medical providers. Women's views and experiences need to be considered in the provision of fertility services, and strategies developed to enhance communication between women, medical practitioners and CAM practitioners. Further research is needed to investigate the extent of CAM use for fertility enhancement in Australia, and to explore the efficacy and safety of CAM use to enhance fertility, in isolation or with ART.</p

Early life factors and being overweight at 4 years of age among children in Malmö, Sweden

<p>Abstract</p> <p>Background</p> <p>Rising rates of obesity and overweight is an increasing public health problem all over the world. Recent research has shown the importance of early life factors in the development of child overweight. However, to the best of our knowledge there are no studies investigating the potential synergistic effect of early life factors and presence of parental overweight on the development of child overweight.</p> <p>Methods</p> <p>The study was population-based and cross-sectional. The study population consisted of children who visited the Child Health Care (CHC) centers in Malmö for their 4-year health check during 2003-2008 and whose parents answered a self-administered questionnaire (n = 9009 children).</p> <p>Results</p> <p>The results showed that having overweight/obese parents was strongly associated with the child being overweight or obese. Furthermore, there was an association between unfavorable early life factors (i.e., mother smoking during pregnancy, presence of secondhand tobacco smoke early in life, high birth weight) and the development of child overweight/obesity at four years of age, while breastfeeding seemed to have a protective role. For example, maternal smoking during pregnancy was associated with an odds ratio (OR) of 1.47 (95% CI: 1.22, 1.76) for overweight and 2.31 (95% CI: 1.68, 3.17) for obesity. The results further showed synergistic effects between parental overweight and exposure to unfavourable early life factors in the development of child overweight.</p> <p>Conclusions</p> <p>The present study shows the importance of early life factors in the development of child overweight and obesity, and thus puts focus on the importance of early targeted interventions.</p

Unexplained infertility: overall ongoing pregnancy rate and mode of conception

Item does not contain fulltextBACKGROUND: Unexplained infertility is one of the most common diagnoses in fertility care. The aim of this study was to evaluate the outcome of current fertility management in unexplained infertility. METHODS: In an observational, longitudinal, multicentre cohort study, 437 couples were diagnosed with unexplained infertility and were available for analysis. They were treated according to their prognosis using standing national treatment protocols: (i) expectant management-IUI-IVF (main treatment route), (ii) IUI-IVF and (iii) directly IVF. Primary outcome measures were: ongoing pregnancy rate, patient flow over the strategies, numbers of protocol violation and drop out rates. A secondary outcome measure was the prediction of ongoing pregnancy and mode of conception. RESULTS: Of all couples 81.5% (356/437) achieved an ongoing pregnancy and 73.9% (263/356) of the pregnancies were conceived spontaneously. There were 408 couples (93.4%) in strategy-1, 21 (5.0%) in strategy-2 and 8 (1.8%) in strategy-3. In total, 33 (7.6%) couples entered the wrong strategy. There were 104 couples (23.8%) who discontinued fertility treatment prematurely: 26 on doctor's advice (with 4 still becoming pregnant) and 78 on their own initiative (with 33 still achieving a pregnancy). Predictors for overall pregnancy chance and mode of conception were duration of infertility, female age and obstetrical history. CONCLUSIONS: Overall success rate in couples with unexplained infertility is high. Most pregnancies are conceived spontaneously. We recommend that if the pregnancy prognosis is good, expectant management should be suggested. The prognosis criteria for treatment with IUI or IVF needs to be investigated in randomized controlled trials

Feasibility of screening patients for emotional risk factors before in vitro fertilization in daily clinical practice: a process evaluation

Item does not contain fulltextSTUDY QUESTION: Is patient screening for emotional risk factors before starting IVF treatment feasible? SUMMARY ANSWER: Introduction of screening for emotional risk factors by a validated instrument (SCREENIVF) in couples treated by IVF or ICSI is feasible, indicated by a moderate to high and stable uptake rate, a high acceptance of the process of SCREENIVF, and a high acceptability of the presented risk profile by the patients. WHAT IS KNOWN ALREADY: SCREENIVF is a validated screening tool to identify women at risk for emotional maladjustment preceding the start of their IVF/ICSI treatment. STUDY DESIGN, SIZE AND DURATION: This was a prospective cohort study, including data of two cohorts of patients (304 and 342 patients), with a duration of 3 months per cohort. For the first cohort, we sent a process evaluation to 210 patients and it was completed by 91 patients. PARTICIPANTS/MATERIALS, SETTINGAND METHODS: All 304 patients (male and female) who started IVF/ICSI between 1 December 2009 and 28 February 2010 in our tertiary IVF clinic were eligible. The uptake rate of SCREENIVF was assessed as the response rate to the screening questionnaire. One year later, we re-assessed the uptake rate in 342 new patients to assess the stability of the uptake rate. A non-responder assessment in patients who did not complete SCREENIVF was carried out. Finally, patients' characteristics and their experiences with SCREENIVF as well as their consequent actions were assessed by an additional process evaluation questionnaire sent some months later to 210 patients. MAIN RESULTS AND THE ROLE OF CHANCE: The uptake rate of SCREENIVF was 78-80%. One-third of the responders were found to be at risk for emotional maladjustment, which was comparable with previous studies using SCREENIVF. Of 27 non-responders to SCREENIVF, 41% explained non-response by 'no actual need for psychological help' and 19% forgot to complete the screening. The response rate to the process evaluation was 43% (n = 91). Of these, 90% found the screening was useful, and almost all patients were positive about the SCREENIVF questionnaire. Furthermore, 93% recognized themselves in the risk profile based on SCREENIVF. Of the patients at risk, 21% reported planning to seek professional help, but 46% of the at-risk patients experienced travelling distance as an obstacle to seek psychological help. We concluded that screening patients for emotional risk factors is feasible. In future, psychosocial care offered by the Internet may be promising in meeting the barrier of travelling distance. LIMITATIONS, REASONS FOR CAUTION: People were asked to fill in SCREENIVF for clinical purposes pretreatment. There might be a selection bias in the people who did not fill in SCREENIVF, which may be due to already existing psychological problems or language problems. The low response rate of the process evaluation questionnaire and the mono-centre evaluation may be confounders and may have influenced our analysis opportunities. WIDER IMPLICATIONS OF THE FINDINGS: The generalizability of this data is unknown with respect to other ethnic groups. Furthermore, more research is needed to evaluate psychosocial factors in male partners. Future research should also focus on the barriers and facilitators for help-seeking behaviour. STUDY FUNDING/COMPETING INTEREST(S): There was no funding for this study and no conflict of interest