Renal and Pulmonary Aspects of Birt-Hogg-Dubé syndrome

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Ascertainment correction in frailty models for recurrent events data

In retrospective studies involving recurrent events, it is common to select individuals based on their event history up to the time of selection. In this case, the ascertained subjects might not be representative for the target population, and the analysis should take the selection mechanism into account. The purpose of this paper is two-fold. First, to study what happens when the data analysis is not adjusted for the selection and second, to propose a corrected analysis. Under the Andersen–Gill and shared frailty regression models, we show that the estimators of covariate effects, incidence, and frailty variance can be biased if the ascertainment is ignored, and we show that with a simple adjustment of the likelihood, unbiased and consistent estimators are obtained. The proposed method is assessed by a simulation study and is illustrated on a data set comprising recurrent pneumothoraces.Development and application of statistical models for medical scientific researc

Health related quality of life assessment instruments: a prospective study on preference and acceptability among cancer patients referred for radiotherapy

The aim of this study was to determine the preferences for and acceptability of existing Quality of Life (QoL) questionnaires among cancer patients. Sixty-two patients completed a set of questionnaires. Criteria were the percentage of missing values, difficult items and the preferences for the answer options. Results indicated small proportions of missing values and difficult items for the EORTC QLQ-C30, the MFI, RSCL, and the MQ (0.0-1.0%). Considerably higher proportions of missing values and difficult items were found for the VAS and the PFS (2.5-3.4%). The answer option of the RSCL subscale 'activity level' was most preferred (29% of subjects), whereas the VAS and PFS were least preferred (19% and 21%, respectively). Our results indicate that patients prefer answer categories that have descriptors in words or a narrow range of answer options, rather than non-described answer options or a broad range of answer options per question

Patient safety in elderly hip fracture patients: design of a randomised controlled trial.

BACKGROUND: The clinical environment in which health care providers have to work everyday is highly complex; this increases the risk for the occurrence of unintended events. The aim of this randomised controlled trial is to improve patient safety for a vulnerable group of patients that have to go through a complex care chain, namely elderly hip fracture patients. METHODS/DESIGN: A randomised controlled trial that consists of three interventions; these will be implemented in three surgical wards in Dutch hospitals. One surgical ward in another hospital will be the control group. The first intervention is aimed at improving communication between care providers using the SBAR communication tool. The second intervention is directed at stimulating the role of the patient within the care process with a patient safety card. The third intervention consists of a leaflet for patients with information on the most common complications for the period after discharge. The primary outcome measures in this study are the incidence of complications and adverse events, mortality rate within six months after discharge and functional mobility six months after discharge. Secondary outcome measures are length of hospital stay, quality and completeness of information transfer and patient satisfaction with the instruments. DISCUSSION: The results will give insight into the nature and scale of complications and adverse events that occur in elderly hip fracture patients. Also, the implementation of three interventions aimed at improving the communication and information transfer provides valuable possibilities for improving patient safety in this increasing patient group. This study combines the use of three interventions, which is an innovative aspect of the study. TRIAL REGISTRATION: The Netherlands National Trial Register NTR1562. (aut. ref.

Psychometric properties of the revised Piper Fatigue Scale in Dutch cancer patients were satisfactory

OBJECTIVE: To examine the psychometric properties of the revised Piper Fatigue Scale (PFS) in Dutch cancer patients. STUDY DESIGN AND SETTING: Participants were 64 patients with lung (any stage, nonsurgery) and breast (any stage) cancer, selected for curative high-dose radiotherapy (>/=50 Gy). Prior to radiotherapy, patients completed the revised PFS (translated into Dutch), the Multidimensional Fatigue Inventory (MFI), and the Rotterdam Symptom Checklist (RSCL). Reliability and construct and criterion validity of the PFS were investigated. RESULTS: Overall, the structure of the Dutch revised PFS appeared appropriate, with corrected item-subscale correlations being higher than the correlations of the same item with the three other subscales; furthermore, internal consistency was excellent (Cronbach's alpha >/=0.90). Lung cancer patients were significantly more tired then breast cancer patients, supporting construct validity. Criterion validity was also satisfactory, with highest correlations of PFS total fatigue with the MFI subscale general fatigue (0.84) and RSCL overall quality of life score (0.74). Internal consistency was similar in Dutch and U.S. breast cancer patients; fatigue scores were lower on several PFS subscales in the Dutch study population. CONCLUSION: Psychometric properties of the Dutch version of the revised PFS, as tested in cancer patients prior to radiotherapy, were satisfactory. AD - Department of Epidemiology, NUTRIM, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands