Sample size re-estimation for clinical trials with longitudinal negative binomial counts including time trends

In some diseases, such as multiple sclerosis, lesion counts obtained from magnetic resonance imaging (MRI) are used as markers of disease progression. This leads to longitudinal, and typically overdispersed, count data outcomes in clinical trials. Models for such data invariably include a number of nuisance parameters, which can be difficult to specify at the planning stage, leading to considerable uncertainty in sample size specification. Consequently, blinded sample size re-estimation procedures are used, allowing for an adjustment of the sample size within an ongoing trial by estimating relevant nuisance parameters at an interim point, without compromising trial integrity. To date, the methods available for re-estimation have required an assumption that the mean count is time-constant within patients. We propose a new modeling approach that maintains the advantages of established procedures but allows for general underlying and treatment-specific time trends in the mean response. A simulation study is conducted to assess the effectiveness of blinded sample size re-estimation methods over fixed designs. Sample sizes attained through blinded sample size re-estimation procedures are shown to maintain the desired study power without inflating the Type I error rate and the procedure is demonstrated on MRI data from a recent study in multiple sclerosis.     

Editorial Commentary: “Dancing the Hip Away”—Does Joint Laxity Correlate With Worse Outcome in Dancers Undergoing Hip Arthroscopy for Femoral Acetabular Impingement?

Dancers have a disproportionately high prevalence of hip issues compared with other types of athletes. Many of these hip issues are complex: a cam and/or pincer impingement combined with a seemingly paradoxical borderline dysplasia, capsular laxity, and subsequent instability. Our experience as nonarthritic hip surgeons tells us that careful patient selection is critical for a successful outcome after the arthroscopic treatment of a dancer. But, there is little guidance in the literature on the management of this specific group of patients. We have studies that advise us to repair the labrum when possible versus performing labral debridement in female patients with predominantly pincer-type impingement and studies that support capsular plication and careful capsule closure in patients, predominantly female patients, with combined hip impingement and dysplasia or borderline dysplasia. However, few studies have examined predictors of outcomes after hip arthroscopy in dancers.     

Personal trauma among healthcare providers: implications for screening practices

ABSTRACT

Screening rates for trauma are low in health care settings. We examined the association between health care providers’ (HCPs) experience of physical or sexual trauma and their screening of female patients for trauma. HCPs at an urban academic medical institution were surveyed from September through November 2016. The Brief Trauma (BTQ) and Sexual and Physical Abuse History Questionnaires (SPAHQ) assessed their own experiences of trauma. The Screening Practices Questionnaire (SPQ) assessed HCPs trauma screening. Multiple regression analyses were performed. Among 212 respondents aged 22–67 years, most were female (78.3%) and white (76.1%). Nurses (41.0%) were the largest occupational group. Overall, 85.8% reported having experienced trauma. No significant difference was observed in median SPQ scores between HCPs who had experienced trauma (3.88 [Interquartile Range (IQR) 3.44–4.31]) and those who had not (4.00 [IQR 3.47–4.33], p = .645). In an adjusted model, screening policy awareness and having an obstetrics & gynecology or psychiatry specialty were associated with higher SPQ scores (p < .001). The prevalence of trauma experience in this sample was high, but not associated with screening. Screening policy awareness and practice specialty were associated with screening. HCP factors associated with greater trauma screening should be explored.     

Robotic surgery does not affect upstaging of T1 renal masses

Partial nephrectomy is the mainstay of treatment for localized kidney cancer. A proportion of patients are upstaged post-operatively to locally advanced di