Inter-clinic variation in the chances of natural conception of subfertile couples

Tjon-Kon-Fat, R.I.; Lar, D.N.; Steyerberg, E.W.; Broekmans, F.J.; Hompes, P.; Mol, B.W.J.; Steures, P.; Bossuyt, P.M.M.; van der Veen, F.; van der Steeg, J.W.; Eijkemans, M.J.C.
May 2013
Human Reproduction;May2013, Vol. 28 Issue 5, p1391
Academic Journal
STUDY QUESTION Are there differences between clinics in the chances of natural conception of couples? SUMMARY ANSWER We found significant differences between clinics in the couples' natural conception chances, which could not be explained by differences in characteristics of the patients or the clinics. WHAT IS KNOWN ALREADY In pooled data from multiple centers the synthesis prediction model for natural conception was found to be valid, yet the outcome of interest (i.e. natural conception) might differ between centers. Possible differences between clinics in natural conception rates, as well as the validity of the prediction model in each individual clinic are addressed in this paper. STUDY DESIGN, SIZE AND DURATION A secondary data-analysis of a prospective cohort study among 3020 subfertile couples recruited in 38 clinics in the Netherlands between January 2002 and December 2004. Clinics with less than 20 couples were excluded from the analyses, resulting in 21 clinics with 2916 couples. PARTICIPANTS/MATERIALS, SETTING, METHODS Inclusion of 2916 subfertile couples who underwent a basic fertility work-up. Couples were excluded who had a fertility disorder (one or two-sided tubal pathology, ovulation disorder, total motile sperm count <3 × 106). Included couples were counseled for expectant management for at least six months or followed until the first day of treatment. Follow-up began at the completion of the fertility work-up. Couples lost to follow-up were censored at the last day of contact. Kaplan–Meier survival curves and a log-rank statistic were estimated. Crude and adjusted hazard ratios were determined, adjusted for patient characteristics and the type of clinic (university hospitals with an assisted conception unit (ACU), non-university hospitals with an ACU and non-university hospitals without an ACU). Hazard ratios were also ascertained with empirical Bayes (EB) estimates. Validation of the prediction model per clinic was performed through calibration. MAIN RESULTS AND THE ROLE OF CHANCE We found significant differences between clinics in the chance of ongoing pregnancy (P < 0.001); even after adjustment for female age, duration of subfertility, percentage of progressive motile sperm, primary/secondary subfertility and post-coital test (P < 0.001). Adjusted hazard ratios and EB estimates ranged from 0.50 to 2.21 and 0.58 to 1.53, respectively. Among the 21 clinics, there were 4 university hospitals, 10 non-university hospitals with an ACU and 7 non-university hospitals without an ACU. In the multivariable analysis, the type of clinic was not significant (P = 0.11). Calibration gave an average intercept of −0.25 (95% range: −1.04–0.53) and average slope of 0.81 (95% range: 0.03–1.60). Six clinics had a negative intercept that differed significantly from zero and three clinics had a negative or positive slope that differed significantly from one. LIMITATIONS, REASONS FOR CAUTION A more extensive model including more predictors could give less variation in the differences between the clinics. Variation in work-up protocol between clinics could also have played a role. In fertility prediction research the Cox proportional hazards regression is the most widely used statistical model, but as the underlying assumptions have rarely been evaluated, this model could lead to biased outcomes. WIDER IMPLICATIONS OF THE FINDINGS Our findings suggest that the synthesis model to predict natural conception is useful overall in clinical practice but in a minority of clinics the model is not well calibrated. Updating the synthesis model to include a center-specific baseline chance might improve the synthesis model for certain clinics. STUDY FUNDING/COMPETING INTEREST(S) The study (on which this secondary data-analysis was based) was ...


Related Articles

  • Variable Importance and Prediction Methods for Longitudinal Problems with Missing Variables. Díaz, Iván; Hubbard, Alan; Decker, Anna; Cohen, Mitchell // PLoS ONE;Mar2015, Vol. 10 Issue 3, p1 

    We present prediction and variable importance (VIM) methods for longitudinal data sets containing continuous and binary exposures subject to missingness. We demonstrate the use of these methods for prognosis of medical outcomes of severe trauma patients, a field in which current medical practice...

  • Thrombelastography Maximal Clot Strength Could Predict One-Year Functional Outcome in Patients with Ischemic Stroke. Yao, Xiaoying; Dong, Quan; Song, Yeping; Wang, Yanqing; Deng, Ye; Li, Yansheng // Cerebrovascular Diseases;Nov2014, Vol. 38 Issue 3, p182 

    Background: Elevated maximal clot strength, measured by thrombelastography (TEG) maximum amplitude (MA) has been associated with a higher risk for ischemic events in patients with coronary artery diseases. However, it has not been investigated in patients with cerebrovascular diseases. In the...

  • Tailored expectant management: risk factors for non-adherence. van den Boogaard, N.M.; Oude Rengerink, K.; Steures, P.; Bossuyt, P.M.; Hompes, P.G.A.; van der Veen, F.; Mol, B.W.J.; van der Steeg, J.W. // Human Reproduction;Jul2011, Vol. 26 Issue 7, p1784 

    INTRODUCTION Prediction models for spontaneous pregnancy are useful tools to prevent overtreatment, complications and costs in subfertile couples with a good prognosis. The use of such models and subsequent expectant management in couples with a good prognosis are recommended in the Dutch...

  • The Predictive Influence of Family and Neighborhood Assets on Fighting and Weapon Carrying from Mid- to Late Adolescence. Haegerich, Tamara; Oman, Roy; Vesely, Sara; Aspy, Cheryl; Tolma, Eleni // Prevention Science;Aug2014, Vol. 15 Issue 4, p473 

    Using a developmental, social-ecological approach to understand the etiology of health-risk behavior and inform primary prevention efforts, we assess the predictive effects of family and neighborhood social processes on youth physical fighting and weapon carrying. Specifically, we focus on...

  • Automated Semen Analyzers Provide Rapid Results with High Precision.  // Fertility Weekly;7/28/2014, p9 

    The article discusses the study conducted in France suggesting the use of automated semen analyzers for routine semen analysis providing rapid and precise results. The study involves a total of 250 men who were measured with sperm concentration, total sperm number and total motility as well as...

  • Use of Tunneled-Cuffed Central Catheters in Patients with Cancer: A Single-Center Experience. Madabhavi, Irappa; Patel, Apurva; Anand, Asha; Kataria, Pritam; Kadakol, Nagaveni; Sarkar, Malay // Journal of the Association for Vascular Access;Mar2018, Vol. 23 Issue 1, p23 

    Background Effective and reliable venous access is among the cornerstones of modern medical therapy in oncology. Materials and Methods This was a prospective observational study of collected data of patients with a diagnosis of any cancer, at a tertiary care oncology hospital in Ahmadabad,...

  • Leukotriene Receptor Blockade as a Life-Saving Treatment in Severe Bronchopulmonary Dysplasia. Rupprecht, Thomas; Rupprecht, Christian; Harms, Dieter; Sterlacci, William; Vieth, Michael; Seybold, Kathrin // Respiration;Oct2014, Vol. 88 Issue 4, p285 

    Background: Bronchopulmonary dysplasia (BPD) is a major cause of mortality and morbidity in infants with an extremely low birth weight. Because there is no effective therapy, the mortality of this condition in severely affected patients is high. Therapeutic blocking of the leukotriene system...

  • Prediction models for infertility treatment. Zarinara, A.; Zeraati, H.; Kamali, K.; Akhondi, M. // Iranian Journal of Reproductive Medicine;Jun2014 Supplement, Vol. 12, p34 

    Introduction: About 10% of couples are infertile. They are faced with several problems that affect their marital life. Infertility treatment is expensive and time consuming and occasionally isn't simply possible. Because, prediction of treatment success is important this paper has reviewed...

  • Visualising disease progression on multiple variables with vector plots and path plots. Lazic, Stanley E.; Mason, Sarah L.; Michell, Andrew W.; Barker, Roger A. // BMC Medical Research Methodology;2009, Vol. 9, Special section p1 

    Background: It is often desirable to observe how a disease progresses over time in individual patients, rather than graphing group averages; and since multiple outcomes are typically recorded on each patient, it would be advantageous to visualise disease progression on multiple variables...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics