Cost-effectiveness of 'immediate IVF' versus 'delayed IVF': a prospective study.

STUDY QUESTION: How does the cost-effectiveness (CE) of immediate IVF compared with postponing IVF for 1 year, depend on prognostic characteristics of the couple? SUMMARY ANSWER: The CE ratio, i.e. the incremental costs of immediate versus delayed IVF per extra live birth, is the highest (range of €15 000 to >€60 000) for couples with unexplained infertility and for them depends strongly on female age and the duration of infertility, whilst being lowest for endometriosis (range 8000-23 000) and, for such patients, only slightly dependent on female age and duration of infertility. WHAT IS KNOWN ALREADY: A few countries have guidelines for indications of IVF, using the diagnostic category, female age and duration of infertility. The CE of these guidelines is unknown and the evidence base exists only for bilateral tubal occlusion, not for the other diagnostic categories. STUDY DESIGN, SIZE, DURATION: A modelling approach was applied, based on the literature and data from a prospective cohort study among couples eligible for IVF or ICSI treatment, registered in a national waiting list in The Netherlands between January 2002 and December 2003. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 5962 couples was included. Chances of natural ongoing pregnancy were estimated from the waiting list observations and chances of ongoing pregnancy after IVF from follow-up data of couples with primary infertility that began treatment. Prognostic characteristics considered were female age, duration of infertility and diagnostic category. Costs of IVF were assessed from a societal perspective and determined on a representative sample of patients. A cost-effectiveness comparison was made between two scenarios: (I) wait one more year and then undergo IVF for 1 year and (II) immediate IVF during 1 year, and try to conceive naturally in the following year. Comparisons were made for strata determined by the prognostic factors. The final outcome was a live birth. MAIN RESULTS AND THE ROLE OF CHANCE: The gain in live birth rate of the immediate IVF scenario versus postponed IVF increased with female age, and was independent from diagnostic category or duration of infertility. By contrast, the corresponding increase in costs primarily depended on diagnostic category and duration of infertility. The lowest CE ratio was just below €10 000 per live birth for endometriosis from age 34 onwards at 1 year duration. The highest CE ratio reached €56 000 per live birth for unexplained infertility at age 30 and 3 years duration, dropping to values below € 30 000 per live birth from age 32 onwards. It reached values below €20 000 per live birth with 3 years duration at age 34 and older. The CE ratio was in between for the three other diagnostic categories (i.e. Male infertility, Hormonal and Immunological/Cervical). LIMITATIONS, REASONS FOR CAUTION: We applied estimates of chances with IVF, excluding frozen embryos, for which we had no data. Therefore, we do not know the effect of frozen embryo transfers on the CE. WIDER IMPLICATIONS OF THE FINDINGS: The duration of infertility at which IVF becomes cost-effective depends, firstly, on the level of society's willingness to pay for one extra live birth, and secondly, given a certain level of willingness to pay, on the woman's age and the diagnostic category. In current guidelines, the chances of a natural conception should always be taken into account before deciding whether to start IVF treatment and at which time. STUDY FUNDING/COMPETING INTEREST(S): Supported by Netherlands Organisation for Health Research and Development (ZonMW, grant 945-12-013). ZonMW had no role in designing the study, data collection, analysis and interpretation of data or writing of the report. Competing interests: none.

Comparison of two models predicting IVF success; the effect of time trends on model performance.

STUDY QUESTION: How well does the recently developed UK model predicting the success rate of IVF treatment (the 2011 Nelson model) perform in comparison with a UK model developed in the early 1990s (the Templeton model)? SUMMARY ANSWER: Both models showed similar performance, after correction for the increasing success rate over time of IVF. WHAT IS KNOWN ALREADY: For counselling couples undergoing IVF treatment it is of paramount importance to be able to predict success. Several prediction models for the chance of success after IVF treatment have been developed. So far, the Templeton model has been recommended as the best approach after having been validated in several independent patient data sets. The Nelson model, developed in 2011 and characterized by the largest development sample containing the most recently treated couples, may well perform better. STUDY DESIGN, SIZE, DURATION: We tested both models in couples that were included in a national cohort study carried out in the Netherlands between the beginning of January 2002 and the end of December 2004. PARTICIPANTS/MATERIALS, SETTING, METHODS: We analysed the IVF cycles of Dutch couples with primary infertility (n = 5176). The chance of success was calculated using the two UK models that had been developed using the information collected in the Human Fertilisation and Embryology Authority database. Women were treated in 1991-1994 (Templeton) or 2003-2007 (Nelson). The outcome of success for both UK models is the occurrence of a live birth after IVF but the outcome in the Dutch data is an ongoing pregnancy. In order to make the outcomes compatible, we used a factor to convert the chance of live birth to ongoing pregnancy and use the overall terms 'success or no success after IVF'. The discriminative ability and the calibration of both models were assessed, the latter before and after adjustment for time trends in IVF success rates. MAIN RESULTS AND THE ROLE OF CHANCE: The two models showed a similarly limited degree of discriminative ability on the tested data (area under the receiver operating characteristic curve 0.597 for the Templeton model and 0.590 for the Nelson model). The Templeton model underestimated the success rate (observed 21% versus predicted 14%); the Nelson model overestimated the success rate (observed 21% versus predicted 29%). When the models were adjusted for the changing success rates over time, the calibration of both models considerably improved (Templeton observed 21% versus predicted 20%; Nelson observed 21% versus predicted 24%). LIMITATIONS, REASONS FOR CAUTION: We could only test the models in couples with primary infertility because detailed information on secondary infertile couples was lacking in the Dutch data. This shortcoming may have negatively influenced the performance of the Nelson model. WIDER IMPLICATIONS OF THE FINDINGS: The changes in success rates over time should be taken into account when assessing prediction models for estimating the success rate of IVF treatment. In patients with primary infertility, the choice to use the Templeton or Nelson model is arbitrary.

Risk of cardiovascular disease after pre-eclampsia and the effect of lifestyle interventions: a literature-based study.

OBJECTIVE: This study addresses the following questions. Do cardiovascular risk factors fully explain the odds ratio of cardiovascular risk after pre-eclampsia? What is the effect of lifestyle interventions (exercise, diet, and smoking cessation) after pre-eclampsia on the risk of cardiovascular disease? DESIGN: Literature-based study. SETTING: N/A. POPULATION OR SAMPLE: N/A. METHODS: Data for the calculations were taken from studies identified by PubMed searches. First, the differences in cardiovascular risk factors after pre-eclampsia compared with an uncomplicated pregnancy were estimated. Second, the effects of lifestyle interventions on cardiovascular risk were estimated. Validated risk prediction models were used to translate these results into cardiovascular risk. RESULTS: After correction for known cardiovascular risk factors, the odds ratios of pre-eclampsia for ischaemic heart disease and for stroke are 1.89 (IQR 1.76-1.98) and 1.55 (IQR 1.40-1.71), respectively. After pre-eclampsia, lifestyle interventions on exercise, dietary habits, and smoking cessation decrease cardiovascular risk, with an odds ratio of 0.91 (IQR 0.87-0.96). CONCLUSIONS: Cardiovascular risk factors do not fully explain the risk of cardiovascular disease after pre-eclampsia. The gap between estimated and observed odds ratios may be explained by an additive risk of cardiovascular disease by pre-eclampsia. Furthermore, lifestyle interventions after pre-eclampsia seem to be effective in decreasing cardiovascular risk. Future research is needed to overcome the numerous assumptions we had to make in our calculations.

Having a Pap smear, quality of life before and after cervical screening: a questionnaire study.

OBJECTIVE: To assess the health-related quality of life (HRQoL) impact of cervical cancer screening in women with normal test results. DESIGN: Questionnaire study. SETTING: Maastricht, the Netherlands. POPULATION: A cohort of 789 women were followed from screening invitation until after the receipt of screening results. A female age-matched reference group (n=567) was included. METHODS: Questionnaires were sent to the home address of the women before screening, after screening, and again with the screening results. MAIN OUTCOME MEASURES: Generic HRQoL (SF-12, EQ-5D), generic anxiety (STAI-6), screen-specific anxiety (PCQ), and potential symptoms and feelings related to the smear-taking procedure. RESULTS: A total of 60% of screening participants completed questionnaire 1(n=924): 803 of these women granted permission to access their files; 789 of these 803 women had normal test results (Pap 1), and were included in the analyses. Generic HRQoL (SF-12, EQ-5D) and anxiety (STAI-6) scores were similar in the study and reference groups. Before screening, after screening, and also after the receipt of test results, screening participants reported less screen-specific anxiety (PCQ, P<0.001) than the reference group (n=567), with differences indicating clinical relevance. 19% of screening participants were bothered by feelings of shame, pain, inconvenience, or nervousness during smear taking, and 8 and 5% of women experienced lower abdominal pain, vaginal bleeding, discharge, or urinary problems for 2-3 and 4-7 days, respectively, following the Pap smear. CONCLUSION: The reduced levels of screen-specific anxiety in screening participants, possibly indicating reassurance, are worthwhile addressing in more depth. We conclude that although considerable numbers of women reported unpleasant effects, there were no adverse HRQoL consequences of cervical screening in women with normal test results.

Concurrence of dermatological and ophthalmological morbidity in onchocerciasis.

Prevalence of skin and eye disorders in African onchocerciasis (river blindness) is well documented. However, less is known about their joint occurrence. Information on concurrence may improve our understanding of disease pathogenesis and is required to estimate the disease burden of onchocerciasis. We analysed data from 765 individuals from forest villages in the Kumba and Ngambe Health districts, Cameroon. These data were collected in 1998, as baseline data for the evaluation of the African Programme for Onchocerciasis Control. Concurrence of symptoms was assessed using logistic regression. Onchocerciasis was highly endemic in the study population (63% nodule prevalence among males aged ≥20). Considerable overall prevalences of onchocercal visual impairment (low vision or blindness: 4%), troublesome itch (15%), reactive skin disease (19%), and skin depigmentation (25%) were observed. The association between onchocercal visual impairment and skin depigmentation (OR 9.0, 95% CI 3.9-20.8) was partly explained by age and exposure to infection (OR 3.0, 95% CI 1.2-7.7). The association between troublesome itch and reactive skin disease was hardly affected by adjustment (adjusted OR 6.9, 95% CI 4.2-11.1). Concluding, there is significant concurrence of morbidities within onchocerciasis. Our results suggest a possible role of host characteristics in the pathogenesis of depigmentation and visual impairment. Further, we propose a method to deal with concurrence when estimating the burden of disease.

Advance notification letters increase adherence in colorectal cancer screening: a population-based randomized trial.

OBJECTIVE: The population benefit of screening depends not only on the effectiveness of the test, but also on adherence, which, for colorectal cancer (CRC) screening remains low. An advance notification letter may increase adherence, however, no population-based randomized trials have been conducted to provide evidence of this. METHOD: In 2008, a representative sample of the Dutch population (aged 50-74 years) was randomized. All 2493 invitees in group A were sent an advance notification letter, followed two weeks later by a standard invitation. The 2507 invitees in group B only received the standard invitation. Non-respondents in both groups were sent a reminder 6 weeks after the invitation. RESULTS: The advance notification letters resulted in a significantly higher adherence (64.4% versus 61.1%, p-value 0.019). Multivariate logistic regression analysis showed no significant interactions between group and age, sex, or socio-economic status. Cost analysis showed that the incremental cost per additional detected advanced neoplasia due to sending an advance notification letter was € 957. CONCLUSION: This population-based randomized trial demonstrates that sending an advance notification letter significantly increases adherence by 3.3%. The incremental cost per additional detected advanced neoplasia is acceptable. We therefore recommend that such letters are incorporated within the standard CRC-screening invitation process.

The impact of mobility on HIV control: a modelling study.

Mobility is associated with HIV due to more risky sexual behaviour of mobile groups such as travellers and migrants. Limited participation of such groups may reduce the effectiveness of HIV interventions disproportionally. The established STDSIM model, which simulates transmission and control of HIV and STD, was extended to simulate mobility patterns based on data from Tanzania. We explored the impact of non-participation of mobile groups (travellers and recent migrants) on the effectiveness of two interventions: condom promotion and health education aiming at partner reduction. If mobile groups do not participate, the effectiveness of both interventions could be reduced by 40%. The impact of targeting travellers with a combined HIV campaign is close to that of a general population intervention. In conclusion, it is important to account for possible non-participation of migrants and travellers. If non-participation is substantial, impact of interventions can be greatly improved by actively approaching these people.

Screening for colorectal cancer: comparison of perceived test burden of guaiac-based faecal occult blood test, faecal immunochemical test and flexible sigmoidoscopy.

BACKGROUND: Perceived burden of colorectal cancer (CRC) screening is an important determinant of participation in subsequent screening rounds and therefore crucial for the effectiveness of a screening programme. This study determined differences in perceived burden and willingness to return for a second screening round among participants of a randomised population-based trial comparing a guaiac-based faecal occult blood test (gFOBT), a faecal immunochemical test (FIT) and flexible sigmoidoscopy (FS) screening. METHODS: A representative sample of the Dutch population (aged 50-74years) was randomised to be invited for gFOBT, FIT and FS screening. A random sample of participants of each group was asked to complete a questionnaire about test burden and willingness to return for CRC screening. RESULTS: In total 402/481 (84%) gFOBT, 530/659 (80%) FIT and 852/1124 (76%) FS screenees returned the questionnaire. The test was reported as burdensome by 2.5% of gFOBT, 1.4% of FIT and 12.9% of FS screenees (comparing gFOBT versus FIT p=0.05; versus FS p<0.001). In total 94.1% of gFOBT, 94.0% of FIT and 83.8% of FS screenees were willing to attend successive screening rounds (comparing gFOBT versus FIT p=0.84; versus FS p<0.001). Women reported more burden during FS screening than men (18.2% versus 7.7%; p<0.001). CONCLUSIONS: FIT slightly outperforms gFOBT with a lower level of reported discomfort and overall burden. Both FOBTs are better accepted than FS screening. All three tests have a high level of acceptance, which may affect uptake of subsequent screening rounds and should be taken into consideration before implementing a CRC screening programme.

Preferences for colorectal cancer screening strategies: a discrete choice experiment.

BACKGROUND: Guidelines underline the role of individual preferences in the selection of a screening test, as insufficient evidence is available to recommend one screening test over another. We conducted a study to determine the preferences of individuals and to predict uptake for colorectal cancer (CRC) screening programmes using various screening tests. METHODS: A discrete choice experiment (DCE) questionnaire was distributed among naive subjects, yet to be screened, and previously screened subjects, aged 50-75 years. Subjects were asked to choose between scenarios on the basis of faecal occult blood test (FOBT), flexible sigmoidoscopy (FS), total colonoscopy (TC) with various test-specific screening intervals and mortality reductions, and no screening (opt-out). RESULTS: In total, 489 out of 1498 (33%) screening-naïve subjects (52% male; mean age+/-s.d. 61+/-7 years) and 545 out of 769 (71%) previously screened subjects (52% male; mean age+/-s.d. 61+/-6 years) returned the questionnaire. The type of screening test, screening interval, and risk reduction of CRC-related mortality influenced subjects' preferences (all P<0.05). Screening-naive and previously screened subjects equally preferred 5-yearly FS and 10-yearly TC (P=0.24; P=0.11), but favoured both strategies to annual FOBT screening (all P-values <0.001) if, based on the literature, realistic risk reduction of CRC-related mortality was applied. Screening-naive and previously screened subjects were willing to undergo a 10-yearly TC instead of a 5-yearly FS to obtain an additional risk reduction of CRC-related mortality of 45% (P<0.001). CONCLUSION: These data provide insight into the extent by which interval and risk reduction of CRC-related mortality affect preferences for CRC screening tests. Assuming realistic test characteristics, subjects in the target population preferred endoscopic screening over FOBT screening, partly, due to the more favourable risk reduction of CRC-related mortality by endoscopy screening. Increasing the knowledge of potential screenees regarding risk reduction by different screening strategies is, therefore, warranted to prevent unrealistic expectations and to optimise informed choice.

Screening for colorectal cancer: randomised trial comparing guaiac-based and immunochemical faecal occult blood testing and flexible sigmoidoscopy.

BACKGROUND: Screening for colorectal cancer (CRC) is widely accepted, but there is no consensus on the preferred strategy. We conducted a randomised trial comparing participation and detection rates (DR) per screenee of guaiac-based faecal occult blood test (gFOBT), immunochemical FOBT (FIT), and flexible sigmoidoscopy (FS) for CRC screening. METHODS: A representative sample of the Dutch population (n = 15 011), aged 50-74 years, was 1:1:1 randomised prior to invitation to one of the three screening strategies. Colonoscopy was indicated for screenees with a positive gFOBT or FIT, and for those in whom FS revealed a polyp with a diameter > or = 10 mm; adenoma with > or = 25% villous component or high grade dysplasia; serrated adenoma; > or = 3 adenomas; > or = 20 hyperplastic polyps; or CRC. RESULTS: The participation rate was 49.5% (95% confidence interval (CI) 48.1 to 50.9%) for gFOBT, 61.5% (CI, 60.1 to 62.9%) for FIT and 32.4% (CI, 31.1 to 33.7%) for FS screening. gFOBT was positive in 2.8%, FIT in 4.8% and FS in 10.2%. The DR of advanced neoplasia was significantly higher in the FIT (2.4%; OR, 2.0; CI, 1.3 to 3.1) and the FS arm (8.0%; OR, 7.0; CI, 4.6 to 10.7) than the gFOBT arm (1.1%). FS demonstrated a higher diagnostic yield of advanced neoplasia per 100 invitees (2.4; CI, 2.0 to 2.8) than gFOBT (0.6; CI, 0.4 to 0.8) or FIT (1.5; CI, 1.2 to 1.9) screening. CONCLUSION: This randomised population-based CRC-screening trial demonstrated superior participation and detection rates for FIT compared to gFOBT screening. FIT screening should therefore be strongly preferred over gFOBT screening. FS screening demonstrated a higher diagnostic yield per 100 invitees than both FOBTs.

Can differences in IVF success rates between centres be explained by patient characteristics and sample size?

BACKGROUND: Pregnancy rates cannot be used reliably for comparison of IVF clinic performance because of differences in patients between clinics. We investigate if differences in pregnancy chance between IVF centres remain after adjustment for patient mix. METHODS: We prospectively collected IVF and ICSI treatment data from 11 out of 13 IVF centres in the Netherlands, between 2002 and 2004. Adjustment for sampling variation was made using a random effects model. A prognostic index for subfertility-related factors was used to adjust for differences in patient mix. The remaining variability between centres was split into random variation and true differences. RESULTS: The crude 1-year ongoing pregnancy chance per centre differed by nearly a factor 3 between centres, with hazard ratios (HRs) of 0.48 (95% CI: 0.34-0.69) to 1.34 (95% CI: 1.18-1.51) compared with the mean 1-year ongoing pregnancy chance of all centres. After accounting for sampling variation, the difference shrank since HRs became 0.66 (95% CI: 0.51-0.85) to 1.28 (95% CI: 1.13-1.44). After adjustment for patient mix, the difference narrowed somewhat further to HRs of 0.74 (95% CI: 0.57-0.94) to 1.33 (95% CI: 1.20-1.48) and 17% of the variation between centres could be explained by patient mix. The 1-year cumulative ongoing pregnancy rate in the two most extreme centres was 36% and 55%. CONCLUSIONS: Only a minor part of the differences in pregnancy chance between IVF centres is explained by patient mix. Further research is needed to elucidate the causes of the remaining differences.

What determines individuals' preferences for colorectal cancer screening programmes? A discrete choice experiment.

INTRODUCTION: In many countries uptake of colorectal cancer (CRC) screening remains low. AIM: To assess how procedural characteristics of CRC screening programmes determine preferences for participation and how individuals weigh these against the perceived benefits from participation in CRC screening. METHODS: A discrete choice experiment was conducted among subjects in the age group of 50-75 years, including both screening-naïve subjects and participants of a CRC screening programme. Subjects were asked on their preferences for aspects of CRC screening programmes using scenarios based on pain, risk of complications, screening location, preparation, duration of procedure, screening interval and risk reduction of CRC-related death. RESULTS: The response was 31% (156/500) for screening-naïve and 57% (124/210) for CRC screening participants. All aspects proved to significantly influence the respondents' preferences. For both groups combined, respondents required an additional relative risk reduction of CRC-related death by a screening programme of 1% for every additional 10 min of duration, 5% in order to expose themselves to a small risk of complications, 10% to accept mild pain, 10% to undergo preparation with an enema, 12% to use 0.75l of oral preparation combined with 12h fasting and 32% to use an extensive bowel preparation. Screening intervals shorter than 10 years were significantly preferred to a 10-year screening interval. CONCLUSION: This study shows that especially type of bowel preparation, risk reduction of CRC related death and length of screening interval influence CRC screening preferences. Furthermore, improving awareness on CRC mortality reduction by CRC screening may increase uptake.

Screening for colorectal cancer: random comparison of guaiac and immunochemical faecal occult blood testing at different cut-off levels.

Immunochemical faecal occult blood testing (FIT) provides quantitative test results, which allows optimisation of the cut-off value for follow-up colonoscopy. We conducted a randomised population-based trial to determine test characteristics of FIT (OC-Sensor micro, Eiken, Japan) screening at different cut-off levels and compare these with guaiac-based faecal occult blood test (gFOBT) screening in an average risk population. A representative sample of the Dutch population (n=10 011), aged 50-74 years, was 1 : 1 randomised before invitation to gFOBT and FIT screening. Colonoscopy was offered to screenees with a positive gFOBT or FIT (cut-off 50 ng haemoglobin/ml). When varying the cut-off level between 50 and 200 ng ml(-1), the positivity rate of FIT ranged between 8.1% (95% CI: 7.2-9.1%) and 3.5% (95% CI: 2.9-4.2%), the detection rate of advanced neoplasia ranged between 3.2% (95% CI: 2.6-3.9%) and 2.1% (95% CI: 1.6-2.6%), and the specificity ranged between 95.5% (95% CI: 94.5-96.3%) and 98.8% (95% CI: 98.4-99.0%). At a cut-off value of 75 ng ml(-1), the detection rate was two times higher than with gFOBT screening (gFOBT: 1.2%; FIT: 2.5%; P<0.001), whereas the number needed to scope (NNscope) to find one screenee with advanced neoplasia was similar (2.2 vs 1.9; P=0.69). Immunochemical faecal occult blood testing is considerably more effective than gFOBT screening within the range of tested cut-off values. From our experience, a cut-off value of 75 ng ml(-1) provided an adequate positivity rate and an acceptable trade-off between detection rate and NNscope.

The impact of healthcare costs in the last year of life and in all life years gained on the cost-effectiveness of cancer screening.

It is under debate whether healthcare costs related to death and in life years gained (LysG) due to life saving interventions should be included in economic evaluations. We estimated the impact of including these costs on cost-effectiveness of cancer screening. We obtained health insurance, home care, nursing homes, and mortality data for 2.1 million inhabitants in the Netherlands in 1998-1999. Costs related to death were approximated by the healthcare costs in the last year of life (LastYL), by cause and age of death. Costs in LYsG were estimated by calculating the healthcare costs in any life year. We calculated the change in cost-effectiveness ratios (CERs) if unrelated healthcare costs in the LastYL or in LYsG would be included. Costs in the LastYL were on average 33% higher for persons dying from cancer than from any cause. Including costs in LysG increased the CER by 4040 euro in women, and by 4100 euro in men. Of these, 660 euro in women, and 890 euro in men, were costs in the LastYL. Including unrelated healthcare costs in the LastYL or in LYsG will change the comparative cost-effectiveness of healthcare programmes. The CERs of cancer screening programmes will clearly increase, with approximately 4000 euro. However, because of the favourable CER's, including unrelated healthcare costs will in general have limited policy implications.

A prognostic model for amputation in critical lower limb ischemia.

In a (negative) multicenter randomized trial on management for inoperable critical lower limb ischemia, comparing spinal cord stimulation and best medical treatment, a number of pre-defined factors were analyzed for prognostic value. We included a radiological arterial disease score, modified from the SVS/ISCVS runoff score. The purpose of this analysis was to evaluate clinical factors and commonly used circulatory measurements for prognostic modeling in patients with critical lower limb ischemia. We determined the incidence of amputation and its relation to various pre-defined risk factors. A total of 120 patients with critical limb ischemia were included in the study. The integrity of circulation in the affected limb was evaluated on five levels: suprainguinal, infrainguinal, popliteal, infrapopliteal and pedal. A total radiological arterial disease score was calculated from 1 (full integrity of circulation) to 20 (maximally compromised state). We used Cox regression analysis to quantify prognostic effects and differential treatment (predictive) effects. Major amputation occurred in 33% of the patients at 6 months and in 51% at 2 years. The presence of ischemic skin lesions and the radiological arterial disease score were independent prognostic factors for amputation. Patients with ulcerations or gangrene had a higher amputation risk (hazard ratio 2.38, p = 0.018 and 2.30, p = 0.036 respectively) as well as patients with a higher radiological arterial disease score (hazard ratio 1.17 per increment, p = 0.003). We did not observe significant interactions between prognostic factors and the effect of spinal cord stimulation. In conclusion, in patients with critical lower limb ischemia, the presence of ischemic skin lesions and the described radiological arterial disease score can be used to estimate amputation risk.

What is the evidence on efficacy of spinal cord stimulation in (subgroups of) patients with critical limb ischemia?

The use of spinal cord stimulation (SCS) has been advocated for the management of ischemic pain and the prevention of amputations in patients with inoperable critical limb ischemia (CLI), although data on benefit are conflicting. Several reports described apparently differential treatment effects in subgroups. The purpose of this study was to analyze the data on the efficacy of SCS and to clarify preselection issues. Five randomized trials have been performed with a total number of 332 patients. Primary outcome measures were mortality and limb survival. In the largest multicenter randomized trial (n = 120), which compared SCS treatment and best medical treatment alone in patients with inoperable CLI, we determined the incidence of amputation and its relation to various predefined risk factors. We used Kaplan-Meier and Cox regression analyses to quantify prognostic effects and differential treatment effects. Meta-analysis yielded a relative risk for amputation of 0.79 and a risk difference of -0.07 (p = 0.15). The risk factor analysis clearly showed that patients with ischemic skin lesions (ulcerations or gangrene) had a worse prognosis (i.e., higher risk of amputation) (relative risk 2.30, p = 0.01). We did not observe significant interactions between this prognostic factor (or any other) and the effect of SCS. The analysis did not indicate a subgroup of patients who might specifically be helped by SCS. Meta-analysis including all randomized data shows insufficient evidence for higher efficacy of SCS treatment compared with best medical treatment alone. Although some factors provide prognostic information as to the risk of amputation in patients with CLI, there are no data supporting a more favorable treatment effect in any group.

[Insufficient basis for the inclusion of Human papillomavirus vaccination in the National Immunisation Programme in The Netherlands]. / Onvoldoende gronden voor opname van vaccinatie tegen Humaan papillomavirus in het Rijksvaccinatieprogramma.

The Dutch Minister of Health, Welfare and Sportintends to implement Human papillomavirus (HPV) vaccination for 12-year-old girls and catch-up vaccination for 13- 16-year-old girls, as part of the National Immunisation Programme from September 2009 onwards. However, due to a well-organised screening programme, cervical cancer is not an important public health problem in the Netherlands any more, which limits the possible impact of HPV vaccination. Vaccine trials thus far have involved a relatively small number ofparticipants with limited follow-up, so the efficacy of the vaccine in preventing cervical cancer is not yet known. There are no data on frequency and severity of possible adverse events and the vaccine has not yet been tested in the intention-to-vaccinate group of 12-year-old girls. Even when we assume that HPV16/18-related cervical cancer is prevented on a lifelong basis, the cost-effectiveness ratio of HPV vaccination is estimated not to be favourable. In conclusion, HPV vaccination does not seem to be urgent in the Netherlands. Therefore we advise studying the safety in 12-year-old girls first while at the same time waiting for the longer follow-up results of ongoing trials.

[Intra-uterine insemination with controlled ovarian hyperstimulation compared to an expectant management in couples with unexplained subfertility and an intermediate prognosis: a randomised study]. / Intra-uteriene inseminatie met gecontroleerde ovariële hyperstimulatie vergeleken met een afwachtend beleid bij paren met onverklaarde subfertiliteit en een gemiddelde prognose: een gerandomiseerd onderzoek.

OBJECTIVE: Intrauterine insemination (IUI) with controlled ovarian hyperstimulation (COH) is commonly used as treatment of first choice in couples with unexplained subfertility. This treatment should only be applied when there is a realistic increase in chance of pregnancy, particularly because it carries the increased risk of multiple pregnancies. We evaluated the effectiveness of IUI with COH relative to expectant management in couples with unexplained subfertility and an intermediate prognosis of a spontaneous ongoing pregnancy. DESIGN: Multicentre randomised clinical study. METHOD: 253 couples with unexplained subfertility and a probability of a spontaneous ongoing pregnancy of 30% to 40% within 12 months, were randomly assigned to IUI with COH for 6 months or expectant management for 6 months. The primary endpoint of our study was ongoing pregnancy within 6 months. Analysis was carried out according to the intention to treat principle. This study was registered with the Dutch Trial Register and has the International Standard Randomised Clinical Trial number ISRCTN72675518. RESULTS: Of the 253 couples included, 127 couples were allocated to IUI with COH and 126 to expectant management. In the intervention group, 42 women (33%) conceived, of which 29 pregnancies were ongoing (23%). In the expectant management group, 40 women (32%) conceived, of which 34 pregnancies were ongoing (27%) (relative risk: 0.85; 95% CI: 0.63-1.1). In the expectant management group one twin pregnancy occurred and in the intervention group one woman conceived twins and one a triplet. CONCLUSION: A substantial beneficial effect of IUI with COH in couples with unexplained subfertility and an intermediate prognosis can be excluded. Expectant management for a period of 6 months therefore appears justified in these couples.

MUSIDH, multiple use of simulated demographic histories, a novel method to reduce computation time in microsimulation models of infectious diseases.

Microsimulation of infectious diseases requires simulation of many life histories of interacting individuals. In particular, relatively rare infections such as leprosy need to be studied in very large populations. Computation time increases disproportionally with the size of the simulated population. We present a novel method, MUSIDH, an acronym for multiple use of simulated demographic histories, to reduce computation time. Demographic history refers to the processes of birth, death and all other demographic events that should be unrelated to the natural course of an infection, thus non-fatal infections. MUSIDH attaches a fixed number of infection histories to each demographic history, and these infection histories interact as if being the infection history of separate individuals. With two examples, mumps and leprosy, we show that the method can give a factor 50 reduction in computation time at the cost of a small loss in precision. The largest reductions are obtained for rare infections with complex demographic histories.