Model Performance Evaluation (Validation and Calibration) in Model-based Studies of Therapeutic Interventions for Cardiovascular Diseases

Decision analytic models play an increasingly important role in the economic evaluation of health technologies. Given uncertainties around the assumptions used to develop such models, several guidelines have been published to identify and assess ‘best practice’ in the model development process, including general modelling approach (e.g., time horizon), model structure, input data and model performance evaluation. This paper focuses on model performance evaluation. In the absence of a sufficient level of detail around model performance evaluation, concerns regarding the accuracy of model outputs, and hence the credibility of such models, are frequently raised. Following presentation of its components, a review of the application and reporting of model performance evaluation is presented. Taking cardiovascular disease as an illustrative example, the review investigates the use of face validity, internal validity, external validity, and cross model validity. As a part of the performance evaluation process, model calibration is also discussed and its use in applied studies investigated. The review found that the application and reporting of model performance evaluation across 81 studies of treatment for cardiovascular disease was variable. Cross-model validation was reported in 55 % of the reviewed studies, though the level of detail provided varied considerably. We found that very few studies documented other types of validity, and only 6 % of the reviewed articles reported a calibration process. Considering the above findings, we propose a comprehensive model performance evaluation framework (checklist), informed by a review of best-practice guidelines. This framework provides a basis for more accurate and consistent documentation of model performance evaluation. This will improve the peer review process and the comparability of modelling studies. Recognising the fundamental role of decision analytic models in informing public funding decisions, the proposed framework should usefully inform guidelines for preparing submissions to reimbursement bodies.     

A randomized,triple‐blind,placebo‐controlled clinical trial,evaluating the sesamin supplement effects on proteolytic enzymes,inflammatory markers,and clinical indices in women with rheumatoid arthritis

Inflammation is one of the main characteristics of rheumatoid arthritis. Based on the antiinflammatory properties of sesame, this study was conducted to evaluate the sesamin supplement effects on serum levels of some proteolytic enzymes, inflammatory biomarkers, and clinical indices in women with rheumatoid arthritis. In this randomized, triple‐blind, placebo‐controlled clinical trial, 44 patients were randomly divided in intervention and control groups. Patients received 200‐mg/day sesamin supplement or placebo in the intervention and control group for 6 weeks. Serum levels of proteolytic enzymes (hyaluronidase, aggrecanase, and matrix metalloproteinases‐3) and inflammatory biomarkers (hs‐CRP, IL‐1β, IL‐6, TNF‐α, and cyclooxygenase‐2) were measured with enzyme‐linked immunosorbent assay method at the beginning and end of the study. After intervention, serum levels of hyaluronidase and matrix metalloproteinases‐3 decreased significantly in sesamin group. Also, serum levels of hs‐CRP, TNF‐α, and cyclooxygenase‐2 in intervention group were significantly decreased in intervention group compared with placebo group. Sesamin supplementation also caused a significant reduction in the number of tender joints and severity of pain in these patients. According to the results, it seems that the sesamin by reducing inflammatory mediators can relieve clinical symptoms and pathological changes that caused by inflammatory impairment in patients with rheumatoid arthritis.     

Effect of single‐dose injection of vitamin D on immune cytokines in ulcerative colitis patients: a randomized placebo‐controlled trial

Ulcerative colitis (UC) is a chronic recurrent inflammation of the colon. It has been proposed that the UC pathogenesis may be related to vitamin D deficiency and/or vitamin D administration in UC patients may have an ameliorating effect on the intestinal inflammation. The aim of this study was to assess the effect of vitamin D on the serum levels of immune cytokines in UC patients. In this double‐blind randomized controlled trial, 90 mild‐to‐moderate UC patients were assigned to get either a single muscular injection of 7.5 mg vitamin D3 or 1 mL normal saline as placebo. Three months later serum levels of IL‐4, IL‐10, IL‐12p70, IFN‐γ, and TNF‐α were measured. Two group variables were compared using independent t‐test and analysis of covariance (ANCOVA). There was a significant increase in vitamin D only in the vitamin D group. Compared to placebo, vitamin D had significant decreasing effects on serum TNF‐α, IFN‐γ, and IL12p70 levels, but it had no significant effect on serum levels of IL4 and IL10. Vitamin D seems to inhibit Th1 immune responses and have no effect on Th2 responses. The findings of this study support several in vitro studies, which suggest a therapeutic immunomodulatory potential of vitamin D.     

Effects of upper-body resistance exercise training on serum nesfatin-1 level,insulin resistance,and body composition in obese paraplegic men

Background

As a recently discovered adipokine, nesfatin-1 is conducive to insulin sensitivity, lipid profile, energy balance, and probably obesity.

Hematological and biochemical indices of kutum Rutilus frisii kutum,associated with capture methods

The aim of current research was to determine hematological and biochemical parameters of captured kutum with gill net and beach seine. A total of 16 matured kutums were used for blood sampling from each device. The result showed significant differences in white blood cells, red blood cell, mean corpuscle volume, Ca²⁺, Cl^?, and cholesterol between gill net and beach seine methods, but there were no significant differences in other parameters. Based on obtained results during our experiment, we concluded that the stress due to capture can influence the blood parameters, and different capture methods lead to different reactions in blood parameters.     

Comparison of the effect of endoscopic sinus surgery versus medical therapy on olfaction in nasal polyposis

Chronic rhinosinusitis is a common inflammatory condition in western countries. Nasal polyposis has different symptoms such as nasal obstruction, anterior or posterior nasal drip, reduced sense of smell, and facial pain. Medical and endoscopic treatments are the two main treatments for nasal polyposis. Our aim was to compare the efficacy of different methods on olfactory function. This is a non-randomized clinical trial study that was done on 60 patients who were divided into two groups (medical and surgical). Patients were matched based on age, history of smoking, and the severity of obstruction. The radiologist score of Lund-Mackay staging system was used to match patients in two arms of the trial based on the severity of nasal obstruction. Patients in surgery groups underwent functional endoscopic sinus surgery under general anesthesia and then received Fluticasone propionate nasal spray for 8 weeks (400 mcg bd). Patients in the medical group were only prescribed with Fluticasone propionate with the same duration and same dose as mentioned. As a result of treatment protocol, both medical and surgical group experienced improvement in olfactory function but statistical analyses revealed that surgery resulted in better resolution of symptoms. Our observation revealed that combined treatment had a better effect than medical treatment in restoring olfaction in patients with nasal polyposis.