Investigation Of Foam Stability On Injection Rate

The project is basically about simulation study to identify the effect of injection rate on the foam stability based on a foam model. Gas has properties of higher mobility ratio and very low density. Due to this properties, the gas tends moves upwards and override the oil zones causing less oil production. Foam flooding was introduced to avoid this gas overriding problem. The foam model was built based on reservoir rock properties and foam half-life parameter. The analysis were done focusing on injection rate, bottom-hole pressure and decaying rate of the foam over injection time. The model was run for 19 years with injector and producer wel

Comparison of iron-sucrose with ferric carboxymaltose for treatment of postpartum iron deficiency anaemia

Background: Anaemia is a major public health problem worldwide. Haemoglobin (Hb) cut-off in anaemia should be taken as 11 gm/dl in the first and third trimester and 10.5 gm/dl in the second trimester, and a post-partum Hb of 10.0 gm/dl. The aim of the study is to compare the efficacy of iron-sucrose versus ferric carboxymaltose (FCM) in the treatment of postpartum anaemia.Methods: A prospective randomized interventional study of 132 post-partum females was conducted at a tertiary care hospital, over a 6-month period. Post-partum females delivered via normal vaginal delivery or caesarean section with Hb levels of above 7 gm/dl and below 9.9 gm/dl were randomized into 2 groups. Iron deficit calculated, in mg, according to Ganzoni’s formula. One group received intravenous FCM – 500 mg in 250 ml normal saline (NS) over 30 minutes and the other received intravenous iron sucrose - each ampoule containing 200 mg in 100 ml NS over 30 minutes up to a maximum dose of 1000 mg. Follow up done after 15 days, 4 weeks and 6 weeks. The data was tabulated and compared using statistical analysis.Results: At a 4 and 6 weeks follow up, the mean rise in hemoglobin (Hb) of group A (1.4 g/dl) was significantly greater than that of group B (0.89 g/dl).Conclusions: The study concludes that thought efficacy of drugs is similar, injection FCM shows a prompt rise in Hb, allows a higher dose to be dispensed in a single seating and is more significant in improving quality of life over a period of time even though it has a marginally higher cost

Cost-Effectiveness of Radiofrequency Catheter Ablation for Atrial Fibrillation

ObjectivesWe sought to compare the cost-effectiveness of left atrial catheter ablation (LACA), amiodarone, and rate control therapy in the management of atrial fibrillation (AF).BackgroundLeft atrial catheter ablation has been performed to eliminate AF, but its cost-effectiveness is unknown.MethodsWe developed a decision-analytic model to evaluate the cost-effectiveness of LACA in 55- and 65-year-old cohorts with AF at moderate and low stroke risk. Costs, health utilities, and transition probabilities were derived from published literature and Medicare data. We performed primary threshold analyses to determine the minimum level of LACA efficacy and stroke risk reduction needed to make LACA cost-effective at $50,000 and$100,000 per quality-adjusted life-year (QALY) thresholds.ResultsIn 65-year-old subjects with AF at moderate stroke risk, relative reduction in stroke risk with an 80% LACA efficacy rate for sinus rhythm restoration would need to be ≥42% and ≥11% to yield incremental cost-effectiveness ratios (ICERs) <$50,000 and$100,000 per QALY, respectively. Higher and lower LACA efficacy rates would require correspondingly lower and higher stroke risk reduction for equivalent ICER thresholds. In the 55-year-old moderate stroke risk cohort, lower LACA efficacy rates or stroke risk reduction would be needed for the same ICER thresholds. In patients at low stroke risk, LACA was unlikely to be cost-effective.ConclusionsThe use of LACA may be cost-effective in patients with AF at moderate risk for stroke, but it is not cost-effective in low-risk patients. Our threshold analyses may provide a framework for the design of future clinical trials by providing effect size estimates for LACA efficacy needed

Informal Caregiving for Diabetes and Diabetic Complications Among Elderly Americans

Objectives: Little is known regarding the amount of time spent by unpaid caregivers providing help to elderly individuals for disabilities associated with diabetes mellitus (DM). We sought to obtain nationally representative estimates of the time, and associated cost, of informal caregiving provided to the elderly with diabetes, and to determine the complications of DM that contribute most significantly to the subsequent need for informal care. Methods: We estimated multivariable regression models using data from the 1993 Asset and Health Dynamics (AHEAD) Study, a nationally representative survey of people aged 70 or older (N=7,443), to determine the weekly hours of informal caregiving and imputed cost of caregiver time for community-dwelling elderly with and without a diagnosis of DM. Results: Those without DM received an average of 6.1 hours per week of informal care, those with DM taking no medications received 10.5 hours, those with DM taking oral medications received 10.1 hours, and those with DM taking insulin received 14.4 hours of care (P

Adherence to Competing Strategies for Colorectal Cancer Screening Over 3 Years

We have shown that, in a randomized trial comparing adherence to different colorectal cancer (CRC) screening strategies, participants assigned to either fecal occult blood testing (FOBT) or given a choice between FOBT and colonoscopy had significantly higher adherence than those assigned to colonoscopy during the first year. However, how adherence to screening changes over time is unknown

Letter: biological drugs for inducing remission in ulcerative colitis – authors' reply

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106897/1/apt12724.pd

Letter: comparative efficacy of biological therapy in patients with ulcerative colitis – authors’ reply

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107370/1/apt12773.pd

Multivariable risk prediction can greatly enhance the statistical power of clinical trial subgroup analysis

BACKGROUND: When subgroup analyses of a positive clinical trial are unrevealing, such findings are commonly used to argue that the treatment's benefits apply to the entire study population; however, such analyses are often limited by poor statistical power. Multivariable risk-stratified analysis has been proposed as an important advance in investigating heterogeneity in treatment benefits, yet no one has conducted a systematic statistical examination of circumstances influencing the relative merits of this approach vs. conventional subgroup analysis. METHODS: Using simulated clinical trials in which the probability of outcomes in individual patients was stochastically determined by the presence of risk factors and the effects of treatment, we examined the relative merits of a conventional vs. a "risk-stratified" subgroup analysis under a variety of circumstances in which there is a small amount of uniformly distributed treatment-related harm. The statistical power to detect treatment-effect heterogeneity was calculated for risk-stratified and conventional subgroup analysis while varying: 1) the number, prevalence and odds ratios of individual risk factors for risk in the absence of treatment, 2) the predictiveness of the multivariable risk model (including the accuracy of its weights), 3) the degree of treatment-related harm, and 5) the average untreated risk of the study population. RESULTS: Conventional subgroup analysis (in which single patient attributes are evaluated "one-at-a-time") had at best moderate statistical power (30% to 45%) to detect variation in a treatment's net relative risk reduction resulting from treatment-related harm, even under optimal circumstances (overall statistical power of the study was good and treatment-effect heterogeneity was evaluated across a major risk factor [OR = 3]). In some instances a multi-variable risk-stratified approach also had low to moderate statistical power (especially when the multivariable risk prediction tool had low discrimination). However, a multivariable risk-stratified approach can have excellent statistical power to detect heterogeneity in net treatment benefit under a wide variety of circumstances, instances under which conventional subgroup analysis has poor statistical power. CONCLUSION: These results suggest that under many likely scenarios, a multivariable risk-stratified approach will have substantially greater statistical power than conventional subgroup analysis for detecting heterogeneity in treatment benefits and safety related to previously unidentified treatment-related harm. Subgroup analyses must always be well-justified and interpreted with care, and conventional subgroup analyses can be useful under some circumstances; however, clinical trial reporting should include a multivariable risk-stratified analysis when an adequate externally-developed risk prediction tool is available

Systematic review with network meta‐analysis: the efficacy of anti‐ TNF agents for the treatment of Crohn's disease

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107372/1/apt12749.pd