Nederlands tijdschrift voor geneeskunde
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Not all questions concerning therapeutic effects in medical research can be answered satisfactorily by standard trials. The stepped wedge cluster design is a special form of randomised study in which an intervention at group level is implemented in stages. ⋯ The statistical analysis of cluster trials should account for the fact that individuals within clusters may show many similarities. Ethical aspects of stepped wedge design should be considered carefully, especially when obtaining individual informed consent is not possible.
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Ned Tijdschr Geneeskd · Jan 2012
Review[Down with odds ratios: risk ratios in cohort studies and randomised clinical trials].
Various effect measures are available for quantifying the relationship between an intervention or a risk factor and an outcome, such as the risk ratio and the odds ratio. Odds ratios are intended for use in case-control studies in which they are an appropriate measure for estimating the relative risk; however, this measure is also often presented in cohort studies and in randomized clinical trials. ⋯ For cohort studies and randomized clinical trials, however, there are methods to estimate adjusted risk ratios; these include the Mantel-Haenszel method, log-binomial regression, Poisson regression with robust standard error, and 'doubling of cases' method with robust standard error. To avoid misinterpretation of odds ratios, risk ratios should be calculated in cohort studies and randomized clinical trials.
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Frostbite injuries rarely occur in healthy Dutch persons. However, as the number of people engaging in winter and outdoor activities and travelling to high altitudes increases, the risk of frostbite also increases. ⋯ Iloprost infusion and possibly (r)tPA are indicated if a patient presents within 24 hours after the tissue has thawed and the injury is such that severe morbidity can be expected. If the patient presents after this time period, hyperbaric oxygen therapy may be considered; however, the evidence available on this type of treatment is limited.
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Vaccination against the human papilloma virus (HPV) has been included in the national Vaccination Programme of the Netherlands for 12-year-old girls since 2010. Vaccination coverage for the birth cohort of 1997 was 56.; there is a gradual increase in uptake. Continuous safety monitoring brought no new unknown serious side effects to light; many girls suffered from transient symptoms such as painful arm, fatigue and headache. ⋯ HPV vaccination of 12-year-old girls is cost-effective, even for relatively low vaccination coverage. The potential protection of HPV vaccination extends beyond prevention of cervical cancer by preventing other oncological manifestations of HPV infection in women as well as men and genital warts. The preventive HPV vaccines do not appear to be effective in treating existing abnormalities.
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A good performance indicator reflects the quality of care and uses clinical outcomes. When outcomes are difficult to obtain, process and structure variables can provide a good picture of quality of care. ⋯ There are limitations to the use of performance indicators to compare hospitals; these include correction for case mix, the statistical reliability of the measurements and the validation of performance indicators. Well-considered performance indicators can be used to monitor trends and identify providers that perform below a certain benchmark, but not to rank them.