scholarly journals Semi‐parametric analysis of overdispersed count and metric data with varying follow‐up times: Asymptotic theory and small sample approximations

2018 ◽  
Vol 61 (3) ◽  
pp. 616-629 ◽  
Author(s):  
Frank Konietschke ◽  
Tim Friede ◽  
Markus Pauly
Keyword(s):  
Parametric Analysis ◽  
Asymptotic Theory ◽  
Small Sample

447 Cost-Effectiveness of a 3-Year Tele-OSA Intervention

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A177-A177
Author(s):  
Jaejin An ◽  
Dennis Hwang ◽  
Jiaxiao Shi ◽  
Amy Sawyer ◽  
Aiyu Chen ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Willingness To Pay ◽  
Incremental Cost ◽  
Economic Benefits ◽  
Small Sample ◽  
Apnea Hypopnea Index ◽  
Obstructive Sleep ◽  
Group 2 ◽  
The Cost

Abstract Introduction Trial-based tele-obstructive sleep apnea (OSA) cost-effectiveness analyses have often been inconclusive due to small sample sizes and short follow-up. In this study, we report the cost-effectiveness of Tele-OSA using a larger sample from a 3-month trial that was augmented with 2.75 additional years of epidemiologic follow-up. Methods The Tele-OSA study was a 3-month randomized trial conducted in Kaiser Permanente Southern California that demonstrated improved adherence in patients receiving automated feedback messaging regarding their positive airway pressure (PAP) use when compared to usual care. At the end of the 3 months, participants in the intervention group pseudo-randomly either stopped or continued receiving messaging. This analysis included those participants who had moderate-severe OSA (Apnea Hypopnea Index >=15) and compared the cost-effectiveness of 3 groups: 1) no messaging, 2) messaging for 3 months only, and 3) messaging for 3 years. Costs were derived by multiplying medical service use from electronic medical records times costs from Federal fee schedules. Effects were average nightly hours of PAP use. We report the incremental cost per incremental hour of PAP use as well as the fraction acceptable. Results We included 256 patients with moderate-severe OSA (Group 1, n=132; Group 2, n=79; Group 3, n=45). Group 2, which received the intervention for 3 months only, had the highest costs and fewest hours of use and was dominated by the other two groups. Average 1-year costs for groups 1 and 3 were $6035 (SE, $477) and $6154 (SE, $575), respectively; average nightly hours of PAP use were 3.07 (SE, 0.23) and 4.09 (SE, 0.42). Compared to no messaging, messaging for 3 years had an incremental cost ($119, p=0.86) per incremental hour of use (1.02, p=0.03) of $117. For a willingness-to-pay (WTP) of $500 per year ($1.37/night), 3-year messaging has a 70% chance of being acceptable. Conclusion Long-term Tele-OSA messaging was more effective than no messaging for PAP use outcomes but also highly likely cost-effective with an acceptable willingness-to-pay threshold. Epidemiologic evidence suggests that this greater use will yield both clinical and additional economic benefits. Support (if any) Tele-OSA study was supported by the AASM Foundation SRA Grant #: 104-SR-13

scholarly journals The Long-Term Follow-Up of Patients with Cystine Stones: A Single-Center Experience for 13 Years

2021 ◽  
Vol 10 (7) ◽  
pp. 1336
Author(s):  
Toshifumi Takahashi ◽  
Shinya Somiya ◽  
Katsuhiro Ito ◽  
Toru Kanno ◽  
Yoshihito Higashi ◽  
...  
Keyword(s):  
Surgical Intervention ◽  
Median Number ◽  
Small Sample ◽  
Age At Diagnosis ◽  
Surgical Interventions ◽  
Significant Difference ◽  
Long Term Follow Up ◽  
Cystine Stones

Introduction: Cystine stone development is relatively uncommon among patients with urolithiasis, and most studies have reported only on small sample sizes and short follow-up periods. We evaluated clinical courses and treatment outcomes of patients with cystine stones with long-term follow-up at our center. Methods: We retrospectively analyzed 22 patients diagnosed with cystine stones between January 1989 and May 2019. Results: The median follow-up was 160 (range 6–340) months, and the median patient age at diagnosis was 46 (range 12–82) years. All patients underwent surgical interventions at the first visit (4 extracorporeal shockwave lithotripsy, 5 ureteroscopy, and 13 percutaneous nephrolithotripsy). The median number of stone events and surgical interventions per year was 0.45 (range 0–2.6) and 0.19 (range 0–1.3) after initial surgical intervention. The median time to stone events and surgical intervention was 2 years and 3.25 years, respectively. There was a significant difference in time to stone events and second surgical intervention when patients were divided at 50 years of age at diagnosis (p = 0.02, 0.04, respectively). Conclusions: Only age at a diagnosis under 50 was significantly associated with recurrent stone events and intervention. Adequate follow-up and treatment are needed to manage patients with cystine stones safely.

scholarly journals AB0571 IS RITUXIMAB AN ADEQUATE GLUCOCORTICOID SPARING AGENT IN IDIOPATHIC INFLAMMATORY MYOPATHIES?

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1582.1-1582
Author(s):  
B. H. Egeli ◽  
S. Ergun ◽  
Y. K. Gursoy ◽  
A. Cetin ◽  
S. Ugurlu
Keyword(s):  
Disease Activity ◽  
Alternative Treatment ◽  
Statistical Power ◽  
Signs And Symptoms ◽  
Small Sample ◽  
Idiopathic Inflammatory Myopathies ◽  
Inflammatory Myopathies ◽  
Treatment Methods ◽  
Before And After

Background:Idiopathic inflammatory myopathies (IIM) are essentially treated aiming improvement of muscle function and extra muscular disease manifestations. The backbone of the treatment is corticosteroids enhancing the survival and patient quality of life. The lack of consensus on target-specific immunosuppressive treatment highlights the need for further studies evaluating alternative treatment methods. Rituximab is potentially a glucocorticoid-sparing agent which was reviewed in multiple studies with small sample sizes due to the rarity of the disease.Objectives:Higher statistical power can enhance the trustworthiness of alternative treatment methods yielding the main objective of this study.Methods:This retrospective study was conducted at a tertiary rheumatology center. Patients were diagnosed with an idiopathic inflammatory myopathy (dermatomyositis [DM], polymyositis [PM]) and were treated with rituximab in order to be included in this study. Clinical signs and symptoms of the presentation were noted during the first patient encounter as well as the follow-up. Parameters of disease activity including acute phase reactants, muscle enzyme levels, and disease-specific autoantibodies were analyzed.Results:The study includes 28 patients (20 DM, 8 PM). The age of diagnosis was 43.44 ± 15.77 years, follow-up duration was 60.7 ± 70.7 months. The presenting signs and symptoms of the patients are shown in Figure 1. The parameters of disease activity before and after treatment are summarized in Table 1. The mean corticosteroid dose decreased from 31.429 ±23.934 mg to 10.278 ±12.001 (p=0.001). Other treatment methods were methotrexate (n=18), Intravenous Immunoglobulin (IVIG) (n=7), and cyclophosphamide (n=2). There were not any deaths during the follow-up. Two patients were lost to follow-up.Table 1.The Parameters of Disease Activity Before and After TreatmentBefore TreatmentAfter TreatmentP ValueCPK, mean ± std (U/L)1426 ± 2049.92263.44 ± 265.630.004LDH, mean ± std (U/L)557.5 ± 365379.78 ± 192.10.03AST, mean ± std (U/L)62.52 ± 5930.16 ± 27.590.01ALT, mean ± std (U/L)56.48 ± 49.2127.64 ± 24.520.008ESR, mean ± std (mm/hour)26.38 ± 28.9820.39 ± 18.760.36CRP, mean ± std (mg/L)19.23 ± 46.1512.53 ± 26.670.5RF, mean ± std (U/mL)0 (0)N/AN/AANA, n (%)3 (10.71)N/AN/AFigure 1.The Presenting Signs and Symptoms of the PatientsConclusion:Rituximab is shown to be effective in treating myositis along with corticosteroids as well as a corticosteroid-sparing agent in retrospective studies and open-label clinical trials; however, lack of statistical power should be underlined. Long term decrease in steroid use and decrease in disease activity markers hints the effective use of rituximab as a glucocorticoid sparing agent as well as its safety with minimal side effects.Disclosure of Interests:None declared

scholarly journals Design and analysis of a 2-year parallel follow-up of repeated ivermectin mass drug administrations for control of malaria: Small sample considerations for cluster-randomized trials with count data

2021 ◽  
pp. 174077452110285
Author(s):  
Conner L Jackson ◽  
Kathryn Colborn ◽  
Dexiang Gao ◽  
Sangeeta Rao ◽  
Hannah C Slater ◽  
...  
Keyword(s):  
Randomized Trial ◽  
Cluster Randomized Trial ◽  
Mixed Effects ◽  
Small Sample ◽  
Mixed Effects Models ◽  
Type I ◽  
Cluster Randomized ◽  
Cluster Level ◽  
Generalized Estimating

Background: Cluster-randomized trials allow for the evaluation of a community-level or group-/cluster-level intervention. For studies that require a cluster-randomized trial design to evaluate cluster-level interventions aimed at controlling vector-borne diseases, it may be difficult to assess a large number of clusters while performing the additional work needed to monitor participants, vectors, and environmental factors associated with the disease. One such example of a cluster-randomized trial with few clusters was the “efficacy and risk of harms of repeated ivermectin mass drug administrations for control of malaria” trial. Although previous work has provided recommendations for analyzing trials like repeated ivermectin mass drug administrations for control of malaria, additional evaluation of the multiple approaches for analysis is needed for study designs with count outcomes. Methods: Using a simulation study, we applied three analysis frameworks to three cluster-randomized trial designs (single-year, 2-year parallel, and 2-year crossover) in the context of a 2-year parallel follow-up of repeated ivermectin mass drug administrations for control of malaria. Mixed-effects models, generalized estimating equations, and cluster-level analyses were evaluated. Additional 2-year parallel designs with different numbers of clusters and different cluster correlations were also explored. Results: Mixed-effects models with a small sample correction and unweighted cluster-level summaries yielded both high power and control of the Type I error rate. Generalized estimating equation approaches that utilized small sample corrections controlled the Type I error rate but did not confer greater power when compared to a mixed model approach with small sample correction. The crossover design generally yielded higher power relative to the parallel equivalent. Differences in power between analysis methods became less pronounced as the number of clusters increased. The strength of within-cluster correlation impacted the relative differences in power. Conclusion: Regardless of study design, cluster-level analyses as well as individual-level analyses like mixed-effects models or generalized estimating equations with small sample size corrections can both provide reliable results in small cluster settings. For 2-year parallel follow-up of repeated ivermectin mass drug administrations for control of malaria, we recommend a mixed-effects model with a pseudo-likelihood approximation method and Kenward–Roger correction. Similarly designed studies with small sample sizes and count outcomes should consider adjustments for small sample sizes when using a mixed-effects model or generalized estimating equation for analysis. Although the 2-year parallel follow-up of repeated ivermectin mass drug administrations for control of malaria is already underway as a parallel trial, applying the simulation parameters to a crossover design yielded improved power, suggesting that crossover designs may be valuable in settings where the number of available clusters is limited. Finally, the sensitivity of the analysis approach to the strength of within-cluster correlation should be carefully considered when selecting the primary analysis for a cluster-randomized trial.

scholarly journals Assessing Biomarkers of Breast Cancer Risk in Underserved Women in a Midwestern County

2021 ◽  
Vol 12 ◽  
pp. 215013272110177
Author(s):  
Marla A. DeWitt ◽  
Ivana T. Croghan ◽  
Celine M. Vachon ◽  
Thomas D. Thacher ◽  
Marcia R. Venegas Pont ◽  
...  
Keyword(s):  
Vitamin D ◽  
Mammographic Density ◽  
Small Sample Size ◽  
Vitamin D Insufficiency ◽  
Screening Mammography ◽  
Small Sample ◽  
Vitamin D Status ◽  
Small Pilot Study ◽  
Unexpected Findings

Objective: The primary aim of this study was to evaluate the feasibility of collecting risk factor information and accessing digitized mammographic data in a medically marginalized population. A secondary aim was to examine the association between vitamin D status and mammographic density. Methods: Breast-screening examinations were provided for age-appropriate patients, and a referral for no-cost screening mammography was offered. Study participants were asked to undergo 25-hydroxyvitamin D testing at mammography and 1-year follow-up. Results: Of 62 women approached, 35 (56%) consented to participate. Of 32 participants who had baseline mammography, the median mammographic density measured by VolparaDensity (Volpara Solutions Limited) was 5.7%. After 1 year, 9 women obtained follow-up mammograms, with a median density of 5.7%. Vitamin D status was measured for 31 participants at baseline and 13 participants in the following year. Insufficient vitamin D status (<30 ng/mL) was noted in 77% at each time point. Mammographic density was not significantly correlated with vitamin D status ( P = .06). Conclusions: On the basis of this small pilot study, vitamin D insufficiency is common in this study population. Owing to the small sample size, an association between vitamin D insufficiency and breast density was not clear. Additional unexpected findings included substantial barriers in initial access to care and longitudinal follow-up in this population. Further study of these issues is needed.

Metastatic Basal Cell Carcinoma: Four Case Reports, Review of Literature, and Immunohistochemical Evaluation

2006 ◽  
Vol 130 (1) ◽  
pp. 45-51
Author(s):  
Diana N. Ionescu ◽  
Muammar Arida ◽  
Drazen M. Jukic
Keyword(s):  
Basal Cell Carcinoma ◽  
Cell Carcinoma ◽  
Basal Cell ◽  
Case Reports ◽  
Small Sample ◽  
Ki 67 ◽  
Immunohistochemical Markers ◽  
Metastatic Basal Cell Carcinoma ◽  
Metastatic Sites

Abstract Context.—Metastatic basal cell carcinoma (BCC) is relatively rare and is seldom considered a complication in the routine treatment and follow-up of patients with BCC. Although multiple studies have tried to distinguish aggressive from nonaggressive BCCs, to our knowledge, no consistent clinical, histopathologic, or immunohistochemical features have yet been reported. Objective.—To report 4 cases of metastatic BCCs and to evaluate these in addition to known nonmetastatic BCCs with specific immunostains in an attempt to find distinct morphologic or immunohistochemical patterns that could be helpful in identifying aggressive BCCs. Design.—We reviewed 4 cases of metastatic BCCs and recorded the clinical and morphologic findings. We then searched our archives for 14 cases of BCC that followed the usual nonaggressive course. We evaluated these 18 cases with immunohistochemical stains for Ki-67, p53, and bcl-2. Results.—In metastasizing BCC, Ki-67 staining was slightly higher in metastatic sites than in primary sites (average 63% and 51%, respectively). p53 was expressed in 3 of 4 primary sites and 2 of 4 metastatic sites. Bcl-2 was positive in both primary and metastatic sites in 3 of 4 cases. In the 14 cases of nonaggressive BCC, staining for Ki-67 averaged 38%, p53 was positive in 11 cases, and Bcl-2 staining was noted in 13 cases. Conclusions.—Overall, in the small sample that we evaluated, the immunohistochemical markers for Ki-67, p53, and Bcl-2 did not distinguish between metastatic and nonaggressive BCCs.

Photoablative atherectomy followed by a paclitaxel-coated balloon to inhibit restenosis in instent femoro-popliteal obstructions (PHOTOPAC)

VASA ◽  
2021 ◽  
pp. 1-7
Author(s):  
Tanja Böhme ◽  
Elias Noory ◽  
Ulrich Beschorner ◽  
Frederik Lerke ◽  
Andrej Schmidt ◽  
...  
Keyword(s):  
Primary Endpoint ◽  
Ankle Brachial Index ◽  
Target Lesion ◽  
Primary Patency ◽  
Small Sample ◽  
Adverse Event Rate ◽  
Control Cohort ◽  
Procedural Success ◽  
Laser Atherectomy

Summary: Background: To evaluate the safety and effectiveness of preparing instent femoropopliteal lesion with photoablative laser atherectomy or plain balloon angioplasty (POBA) prior to drug-coated balloon (DCB) angioplasty. Patients and methods: The prospective, multicenter, randomized study enrolled patients with Rutherford-Becker-class (RBC) 1 to 5 and instent lesions located in superficial femoral artery and/or popliteal artery above the knee joint. Primary endpoint was target lesion percent stenosis at 1 year as determined by the angiographic core-laboratory. Secondary endpoints included procedural success, major adverse event rate, clinical improvement and improvement in ankle-brachial index (ABI), clinically-driven target lesion revascularization (CD-TLR), and primary patency rate at until 2-year follow-up. Results: The study was terminated prior to the enrollment goal due to slow enrollment. Thirty patients were included in the laser plus DCB cohort and 31 patients in the control cohort. Primary endpoint was not significantly different (p=0.331). Procedural success was 83.3% and 87.1% for the laser plus DCB and the control cohort, respectively. Serious adverse events at 30 days and 1-year were not statistically different between the two cohorts. For the ABI, significant improvements were present at discharge as well as at the follow-up visits. This was also evident for the RBC at the follow-up visits. One- and two-year freedom from CD-TLR was 86.7% vs. 87.1%, and 63.6% vs. 72%, respectively. Duplex derived primary patency was 90% at 6-months, 65.5% at one year and 56.5% at two year for the laser cohort and 90.3%, 75.9% and 53.8% for the control cohort. Conclusions: Safety of instent photoablative laser atherectomy followed by DCB angioplasty is confirmed by this study. Due to the small sample size, no benefit over POBA as vessel preparation could be shown.

Role of multiparametric MRI in long-term surveillance following focal laser ablation of prostate cancer

2021 ◽  
pp. 20210414
Author(s):  
Mark Paxton ◽  
Eitan Barbalat ◽  
Nathan Perlis ◽  
Ravi J Menezes ◽  
Mark Gertner ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Recurrent Disease ◽  
Small Sample Size ◽  
Focal Therapy ◽  
Outcome Data ◽  
Small Sample ◽  
Restricted Diffusion ◽  
Treatment Site ◽  
Imaging Characteristics

Objective: Determine the multiparametric magnetic resonance imaging (mpMRI) appearance of the prostate following focal laser ablation (FLA) for PCa and to identify imaging characteristics associated with recurrent disease. Methods: Retrospective analysis of patients who underwent FLA for low-intermediate risk PCa between 2010 and 2014 was performed. Early (median 4 months) and late mpMRI (median 49 months) follow-up were qualitatively assessed for T2-weighted, dynamic contrast enhanced (DCE) and diffusion weighted imaging (DWI) appearances and also compared to corresponding PSA values and biopsy results. Results: 55 cancers were treated in 54 men (mean age 61.0 years). Early mpMRI was performed in 30 (54.5%) patients while late follow-up mpMRI in 42 (84%). Ill-defined scarring with and without atrophy at the treatment site were the most common appearances. In patients with paired MRI and biopsy, one of four patients with clinically significant PCa on biopsy (≥GG2 or≥6 mm GG1) showed hyperenhancement or restricted diffusion at early follow-up. At late follow-up, positive biopsies were seen in 5/8 (63%) cases with hyperenhancement and 5/6 (83%) cases with restricted diffusion at the treatment site. PSA change was not associated with biopsy results at either time point. Conclusion: mpMRI is able to document the morphological and temporal changes following focal therapy. It has limited ability to detect recurrent disease in early months following treatment. Late-term mpMRI is sensitive at identifying patients with recurrent disease. Small sample size is, however, a limitation of the study. Advances in knowledge: Implementing MRI in follow-up after FT may be useful in predicting residual or recurrent PCa and therefore provide reliable outcome data.

scholarly journals Cannabis and breastfeeding

2020 ◽  
Vol 25 (Supplement_1) ◽  
pp. S26-S28 ◽  
Author(s):  
Lisa Graves
Keyword(s):  
Health Care Providers ◽  
Small Sample ◽  
Adverse Outcomes ◽  
Care Providers ◽  
High Quality ◽  
High Quality Evidence ◽  
Small Sample Sizes ◽  
The Impact ◽  
Quality Evidence

Abstract Cannabis is one of the most commonly used substances in Canada with 15% of Canadians reporting use in 2019. There is emerging evidence that cannabis is linked to an impact on the developing brain in utero and adverse outcomes in infants, children, and adolescents. The impact of cannabis during breastfeeding has been limited by studies with small sample sizes, follow-up limited to 1 year and the challenge of separating prenatal exposure from that during breastfeeding. In the absence of high-quality evidence, health care providers need to continue to engage women in conversation about the potential concerns related to breastfeeding and cannabis use.

scholarly journals A Prospective Study on Treatment of Distal Radial Fractures Using Volar Locking Plate

2020 ◽  
Vol 3 (1) ◽  
Keyword(s):  
Internal Fixation ◽  
Distal Radius ◽  
Open Reduction ◽  
Locking Plate ◽  
Small Sample ◽  
Care Hospital ◽  
Volar Locking Plate ◽  
Distal Radial Fractures ◽  
Compression Plating

Introduction: Distal radius fractures are one of the most common injuries which come to the orthopaedic surgeons. Displaced extra-or intra-articular fractures require anatomical reduction for a good outcome. Historically, these fractures were treated with manipulation and casting, with or without Kirschner (K) wire fixation. Modern plating techniques have been advocated to restore anatomical alignment and allow early mobilisation. Despite the wide variety of treatment options available there is still debate about the best way to treat these fractures. The aim of this study was to evaluate fifty cases of fracture distal end radius treated by open reduction and internal fixation using locking compression plating (LCP). Methods: The present study was carried out on 50 cases of acute fracture distal radius admitted at a tertiary care hospital treated by open reduction and internal fixation using locking compression plating (LCP) between January 2018 and December 2018. Functional results were rated at the end of the study as excellent, good or poor as criteria laid down by Gartland and Werley’s combined subjective and objective criteria. Results: 50 cases of fracture distal radius were selected for study that fulfill the inclusion criteria, were operated and studied. 10 fractures were fixed using Extra-articular Locking Compression T-Plates, 40 fractures were fixed using Juxtaarticular Locking Compression T-Plates. According to the Gartland and Werley’s rating scale, 20 had excellent results, 23 good results, and 07 fair results during latest follow up. Conclusion: Notwithstanding a very small sample size and a short follow up, Volar locking plate osteosynthesis at the distal radius signifies a significant improvement in the treatment of distal radial fractures in terms of restoration of the shape and function of the wrist.

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