Could congressionally mandated incentives lead to deployment of large-scale CO2 capture, facilities for enhanced oil recovery CO2 markets and geologic CO2 storage?

In passing the Bipartisan Budget Act of 2018, Congress reformed and strengthened a section of the tax code, 45Q, which provides tax credits of up to $35/ton CO₂ for the capture and utilization of CO₂ in qualifying applications such as enhanced oil recovery (EOR) and up to $50/ton CO₂ for CO₂ that is captured and permanently stored in a geologic repository. Earlier versions of the tax credit with lower credit values generated limited interest. This change to the tax code could potentially alter U.S. energy systems. This paper examines the effect of the increased 45Q credits on CO₂ capture, utilization and storage (CCUS) deployment in the United States and on petroleum and power production. A range of potential outcomes is explored using five modeling tools. The paper goes on to explore the potential impact of possible modifications of the current tax credit including extension of its availability in time, the period over which 45Q tax credits can be utilized for any given asset and increases in the value of the credit as well as interactions with technology availability and carbon taxation. The paper concludes that 45Q tax credits could stimulate additional CCUS beyond that which is already underway.

Alternativen zum klassischen Histogramm

Als Alternativen — insbesondere innerhalb von Computerprogrammen — zum klassischen Histogramm werden verschiedene Methoden der nichtparametrischen Dichteschätzungen vorgeschlagen; besonders geeignet erscheint eine Modifikation der Kern-Methoden: die Verwendung variabler Kerne. Für jede der Methoden wird auf die Einflüsse einer Diskretisierung der Daten eingegangen.

The Role of Biometry in the Training of Medical Informaticians

Medical informatics and medical biometry, as well as the medical biometrician´s and medical informatician´s fields of activity, overlap significantly. The affinity between the two disciplines can be illustrated by a comparison of the definitions of both disciplines, by examples of research projects for which the application of methods from both fields is necessary in order to complete the project successfully, and by an analysis of the professional fields of medical informatics graduates working in their occupation. Therefore, a stronger integration of both disciplines is advocated.

On Clinically Relevant Differences and Shifted Nullhypotheses

The currently usual one value for the judgement of the clinical relevance of therapeutic effects frequently does not suffice to adequately formulate the problems of clinical studies, and the statistical standard procedure (the testing of the classical nullhypothesis) fails to take this value duly into account.

Therefore, it is proposed to judge the clinical relevance and importance by means of four values, fixed in discussions with the clinician before commencement of the study, and to proceed by testing non-zero nullhypotheses (shifted nullhypotheses) where the “clinically relevant difference” is the shift parameter.

Methodical problems resulting from the shifting of the nullhypothesis are discussed, and other possibilities to take into account the clinically relevant difference (introduction of criteria of success) are considered.

Some Problems Arising in the Statistical Treatment of Diagnosis

For the most frequently used model of a one-step diagnostic process, where a patient can be allocated to exactly one disease, a mathematical formulation is presented. Possible criticism of the model is discussed. Statistical problems arising from the determination of the allocation rules are outlined with special emphasis on plug-in-rules. Finally, mention is made of some problems occurring in the practical application of diagnostic algorithms.

Diagnostic Rules for Qualitative Variables with Interactions

An allocation rule for qualitative variables is derived which permits taking into account s-th order interactions (Lancaster’s definition is used). A formula is given using only the relative frequencies of the (s+1)-dimensional marginals for the estimation of the cell probabilities. In contrast to other procedures (e.g. the log-linear-model), the method is practicable for a large number of symptoms, too, and the estimates of the parameters of the allocation rule are stable even if samples of relatively small size are used. For the examination of the practicability of the method, two modular programs were written which permit the estimation of the parameters of the model and the expectations of the error rates. The modules are designed in a way which permits the implementation in a sequential diagnostic process.

Einsatz von Diskriminanzanalysen in der medizinischen Diagnostik beim Vorliegen qualitativer Daten

Es wird der Versuch beschrieben, die (nichtlineare) Diskriminanzanalyse in der Vergiftungsdiagnostik einzusetzen. Da es sich bei den zur Trennung benutzten Variablen fast ausschließlich um qualitative Größen handelt, wird ausführlich auf geeignete Zusammenfassungen und Transformationen von Variablen zur Anpassung derselben an die Voraussetzungen der Diskriminanzanalyse eingegangen. Die Ergebnisse zeigen, daß sich die am stärksten besetzten Gruppen »Barbiturate« und »Nichtbarbiturate« zufriedenstellend trennen lassen.

Die Trennung der übrigen Gruppen war bei Verwendung der sogenannten »Reklassifikation« zur Schätzung der Zuteilungsraten ebenfalls gut; jedoch konnten diese Ergebnisse wegen der kleinen Fallzahlen nicht validiert werden.

Probabilistische Zuordnungsverfahren

Ausgehend von der optimalen Zuordnungsregel für beliebige Verteilungsfunktionen (stetig oder diskret) werden die üblichen Anwendungsformen dieser Regel abgeleitet. Einige häufig verwendete Diagnoseverfahren werden als Spezialfälle der optimalen Regel unter bestimmten Voraussetzungen dargestellt. Anschließend wird auf Probleme beim praktischen Einsatz dieser Verfahren in der algorithmischen Diagnostik eingegangen.

Deficits and Remedy of the Standard Random Effects Methods in Meta-analysis

The random effects model is often used in meta-analyses. A corresponding significance test based on a normal approximation has been established. Its type I error is derived in this article by theoretical considerations and computer simulations. The test can be conservative as well as unacceptably anti-conservative. The anti-conservatism increases with the increasing number of patients and the decreasing number of studies. A modification is proposed, which keeps the nominal level asymptotically as the number of patients approaches infinity. Simulations show that the modified test is often conservative, but its conservatism is small in those situations where the standard test is highly anti-conservative.

Surgical management of subfoveal choroidal neovascular membranes in age-related macular degeneration by macular relocation: experiences of an early-stopped randomised clinical trial (MARAN Study)

RATIONALE

The MARAN (Macular Relocation in Age-related Neovascular disease) trial was planned to assess the effectiveness of full macular relocation (MR) in patients with neovascular age-related macular degeneration (AMD).

DESIGN

Randomised, prospective, controlled clinical trial.

METHODS

Patients suffering from visual loss because of AMD were randomised to either surgery or a control group receiving standard treatment (observation or photodynamic therapy (PDT)). The primary end point was the change of visual acuity (VA) (ETDRS) 52 weeks after randomisation compared with initial VA, and secondary end points included reading performance, contrast sensitivity, stability of fixation, eye-specific quality of life, and the absolute number of letters read correctly at 52 weeks compared with initial examination.

RESULTS

Owing to early determination, only 28 patients were included in the study. The study did not show a difference between the two groups with respect to the final visual result or any of the secondary outcomes measured. The study was limited by the low recruitment that was, at least in part, attributed to the inherent risks for those patients randomised to the surgical arm of the study as well as to the emerging new treatments for AMD.

CONCLUSION

The results of the MARAN trial failed to recruit a sufficient number of patients and a superiority of surgery over observation or PDT in patients with exudative AMD was not shown. There was a trend that the reading function was superior after surgery. In the light of the new pharmacological treatments, surgical options such as MR will be an option for only selected cases.

Prevention of major venous thromboembolism following total hip or knee replacement: a randomized comparison of low-molecular-weight heparin with unfractionated heparin (ECHOS Trial)

AIM

Venous thromboembolism remains a frequent complication after total hip or knee replacement surgery despite routine prophylaxis. However, the ability of pharmacologic thromboprophylaxis to prevent major venous thromboembolism, defined as proximal deep vein thrombosis, and/or pulmonary embolism, and/or death, has not been previously validated.

METHODS

In a double-blind randomized study, 2018 patients, undergoing either total hip or knee replacement surgery, were allocated to receive subcutaneous preoperative reviparin (4,200 anti Xa IU) once daily or 7,500 IU unfractionated heparin twice daily, for a minimum of 11 days. The primary efficacy outcome was major venous thromboembolism, defined as the composite of venographically confirmed proximal deep vein thrombosis, and/or symptomatic pulmonary embolism and death, recorded up to day 14.

RESULTS

The primary efficacy outcome was assessed in 1,628 patients and demonstrated a significant reduction in the reviparin group (3.4% [28 of 813 patients] compared with unfractionated heparin (5.5% [45 of 815]) (odds ratio, 0.61; 95% confidence interval, 0.38 to 0.99, P=0.04) by day 11 to 14. A significant reduction in venous thromboembolism was maintained up to 6-8 weeks (3.4% [28 of 813 reviparin patients] versus 5.6% [46 of 815 unfractionated heparin patients]) (odds ratio, 0.6; 95% confidence interval, 0.37 to 0.97, P=0.03). Major bleeding events occurred in 9 reviparin-treated patients (0.9%) and in 12 unfractionated heparin-treated patients (1.2%).

CONCLUSIONS

Prophylaxis with reviparin significantly reduces the risk of major venous thromboembolism compared with unfractionated heparin in patients undergoing elective hip or knee replacement without increasing the risk of bleeding.

Protocol design and current status of CLIVIT: a randomized controlled multicenter relevance trial comparing clips versus ligatures in thyroid surgery

BACKGROUND

Annually, more than 90000 surgical procedures of the thyroid gland are performed in Germany. Strategies aimed at reducing the duration of the surgical procedure are relevant to patients and the health care system especially in the context of reducing costs. However, new techniques for quick and safe hemostasis have to be tested in clinically relevance randomized controlled trials before a general recommendation can be given. The current standard for occlusion of blood vessels in thyroid surgery is ligatures. Vascular clips may be a safe alternative but have not been investigated in a large RCT.

METHODS/DESIGN

CLIVIT (Clips versus Ligatures in Thyroid Surgery) is an investigator initiated, multicenter, patient-blinded, two-group parallel relevance randomized controlled trial designed by the Study Center of the German Surgical Society. Patients scheduled for elective resection of at least two third of the gland for benign thyroid disease are eligible for participation. After surgical exploration patients are randomized intraoperatively into either the conventional ligature group, or into the clip group. The primary objective is to test for a relevant reduction in operating time (at least 15 min) when using the clip technique. Since April 2004, 121 of the totally required 420 patients were randomized in five centers.

DISCUSSION

As in all trials the different forms of bias have to be considered, and as in this case, a surgical trial, the role of surgical expertise plays a key role, and will be documented and analyzed separately. This is the first randomized controlled multicenter relevance trial to compare different vessel occlusion techniques in thyroid surgery with adequate power and other detailed information about the design as well as framework. If significant, the results might be generalized and may change the current surgical practice.

Some problems with the investigation of noninferiority in meta-analysis

OBJECTIVES

Noninferiority trials have become commonplace in recent years. Like individual clinical trials, meta-analyses can also investigate noninferiority. However, certain important topics have to be considered.

METHODS

The proposed methods in this paper have their origin in the framework of noninferiority trials and meta-analyses. This paper can therefore be seen as a combination of both fields. Two issues are highlighted in the paper; difficulties in the choice of delta for a noninferiority meta-analysis leading to different deltas and methods for meta-analyses with different analysis sets, based on the full-analysis set with the intention-to-treat principle or the per-protocol population. Analytical methods, sensitivity analyses, meta-regression, and a bivariate method are introduced. The proposed graphical presentations support the analytical results.

CONCLUSION

The confidence interval approach using meta-regression or bivariate methods is appropriate using both analysis sets for meta-analyses investigating noninferiority.

Efficacy and Safety of the Platelet-Activating Factor Receptor Antagonist BN???52021 (Ginkgolide??B) in Patients with Severe Sepsis

OBJECTIVE

To evaluate the efficacy and safety of the natural platelet-activating factor receptor antagonist, BN 52021 (ginkgolide B) in the treatment of patients with severe sepsis related to Gram-negative and mixed bacterial infection.

DESIGN AND SETTING

Prospective, randomised, double-blind, placebo-controlled, multicentre study carried out in 13 academic medical intensive care centres in Germany with up to 14 patients per centre.

PATIENTS

88 patients with severe sepsis under standard medical and surgical care: nine patients with pure Gram-positive infection, 79 patients with Gram-negative or mixed bacterial infections (subgroup for which efficacy was to be established).

INTERVENTIONS

Patients were randomised to receive either placebo or BN 52021 1.25 mg/kg bodyweight intravenously every 12h over a 4-day period in addition to their standard medical and surgical care.

MAIN OUTCOME MEASURES AND RESULTS

The primary efficacy variable was the 28-day all-cause mortality rate. The treatment groups were similar with respect to demographic data and prognostic factors influencing the outcome except for bodyweight and adequacy of antibiotic therapy. Analysis of patients with Gram-negative or mixed bacterial infection, for which efficacy was to be established, resulted in a 28-day all-cause mortality of 42.5% in the placebo group (n = 40; 17 deaths) versus 38.5% in the BN 52021 group (n = 39; 15 deaths). Among all randomised patients, the 28-day all-cause mortality rate was 40.9% in the placebo group (n = 44; 18 deaths) and 38.6% in the BN 52021 group (n = 44; 17 deaths). There were no differences in frequency and severity of adverse events between the two treatment groups.

CONCLUSIONS

Four-day administration of BN 52021 failed to demonstrate a statistically significant reduction in mortality in patients with severe sepsis suspected or confirmed to be related to infections other than Gram-positive bacterial infection.

[Meta-analysis of the efficacy of adenosylmethionine and oxaceprol in the treatment of osteoarthritis]

The aim of this meta-analysis based on the literature was to gather all evidence of randomized clinical trials to assess the efficacy of adenosylmethionine (SAM) and oxaceprol in the treatment of osteoarthritis. Findings in MEDLINE and EMBASE were added to publications catalogued by the AkdA and a reference search. The meta-analysis was based mostly on pain scores but also on pain and function scores. We used the fixed effects and the random effects model.A superiority of SAM vs placebo ( n=468) could not be shown; the 95% CI of standardized difference of pain scores was (-0.89, 0.12). The comparison of SAM vs NSAIDs with seven studies ( n=850) did not show a difference: (-0.59, 0.19). This cannot be seen as proof for equivalence. A post-hoc analysis of SAM vs ibuprofen gave nearly a positive result for SAM: (-0.43, 0.02). No adequate placebo-controlled RCT was found. There was no significance for a difference between oxaceprol and NSAIDs using the four trials found (two diclofenac and two ibuprofen); the 95% CI of standardized difference of pain and function scores was (-0.19, 0.27). Since only a few trials with heterogeneous results were found which mostly have a low quality of the studies and/or publications, the results must be interpreted very carefully. The meta-analysis does not give enough evidence for the efficacy of SAM and oxaceprol for treating the symptoms of osteoarthritis, but it might be that there is a comparable effect to other NSAIDs.

Deficits and remedy of the standard random effects methods in meta-analysis

The random effects model is often used in meta-analyses. A corresponding significance test based on a normal approximation has been established. Its type I error is derived in this article by theoretical considerations and computer simulations. The test can be conservative as well as unacceptably anti-conservative. The anti-conservatism increases with the increasing number of patients and the decreasing number of studies. A modification is proposed, which keeps the nominal level asymptotically as the number of patients approaches infinity. Simulations show that the modified test is often conservative, but its conservatism is small in those situations where the standard test is highly anti-conservative.

Low Molecular Weight Heparin and Unfractionated Heparin in Thrombosis Prophylaxis: Meta-Analysis Based on Original Patient Data

A meta-analysis (MA) based on original patient data has been performed comparing low molecular weight heparins (LMWH) with unfractionated heparin (UFH) in thrombosis prophylaxis after major surgical interventions. The analyses have been done for the following prespecified groups of studies: all studies, studies in orthopaedic surgery (OS) and studies in general surgery (GS, with further separation into low-dose studies [GS-LD] and high-dose studies [GS-HD]). Deep vein thrombosis (DVT, all locations) and wound haematoma were used as primary endpoints for efficacy and safety, respectively. The analysis confirms the results of previous publication-based meta-analyses. In GS there is no relevant difference between LMWH and UFH regarding efficacy; the safety results strongly depend on the dosage: under low-dose LMWH the risk of wound haematoma is significantly lower, under high-dose LMWH it is significantly higher than under UFH. However, most of the studies in the last group used regimens of LMWH that are not considered appropriate any more. In OS there is a trend towards a better efficacy and safety of LMWH. In addition, LMWHs are superior to UFH, in OS, with respect to the secondary endpoints proximal DVT and pulmonary embolism. The rates of proximal DVT and pulmonary embolism, respectively, are consistently lower under LMWH than under UFH, whereas slightly smaller rates of distal DVT are observed under UFH.

Low molecular weight heparin and unfractionated heparin in thrombosis prophylaxis after major surgical intervention: update of previous meta-analyses

BACKGROUND

Previous meta-analyses comparing low molecular weight heparin (LMWH) and unfractionated heparin for thrombosis prophylaxis after surgical interventions need updating.

METHODS

This is a publication-based meta-analysis of 36 double-blind studies including 16583 patients. Main outcome measures are incidence of deep vein thrombosis (efficacy) and wound haematoma (safety).

RESULTS

In general surgery there is no increased efficacy in favour of LMWH (odds ratio (OR) 0.88, 95 per cent confidence interval (c.i.) 0.60-1.30) but there exists a higher incidence of bleeding complications (OR 1.47, 95 per cent c.i. 1.07-2.01). Low-dose LMWH is equally efficacious (OR 1.03, 95 per cent c.i. 0.85-1.26) but safer than unfractionated heparin (OR 0.68, 95 per cent c.i. 0.56-0.82). In orthopaedic surgery there is a trend towards an increased efficacy for LMWH (OR 0.83, 95 per cent c.i. 0.68-1.02) with equivalent safety (OR 0.96, 95 per cent c.i. 0.68-1.36).

CONCLUSION

A superiority of LMWH is suggested but heterogeneity might make generalizability to future patients questionable. A meta-analysis on individual patient data should be the next step before randomizing additional patients in future trials.

Toxic epidermal necrolysis and Stevens-Johnson syndrome. An epidemiologic study from West Germany

Little work has been carried out on the epidemiology of the two serious skin reactions--toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS). We collected details of all the hospitalized cases of TEN and SJS in the Federal Republic of Germany for the years 1981 through 1985 inclusive. Inquiries by telephone, letter, and personal visits produced an overall response of 91%; 259 cases of TEN and 315 cases of SJS were identified. From these data, we were able to calculate an overall annual risk of 0.93 and 1.1 per million for TEN and SJS, respectively. The average age group was higher for TEN (63 years) than for SJS (25 years). Women are markedly more at risk for TEN in the ratio of 2:1, these figures being reversed for SJS. The mortality was 34% (87/259) for TEN and only 1% (2/315) for SJS. An association with previous medication defined as "definite, probable, possible" could be established for 89% of cases of TEN and 54% of cases of SJS. The drugs most commonly involved were antibiotics (TEN, 40%; SJS, 34%), followed by the analgesics (TEN, 23%; SJS, 33%). As with the drug groups, the incidences being based on the defined daily doses, were high for sulfonamides, beta-lactam antibiotics, and some nonsteroidal anti-inflammatory drugs.

The role of biometry in the training of medical informaticians

Medical informatics and medical biometry, as well as the medical biometrician's and medical informatician's fields of activity, overlap significantly. The affinity between the two disciplines can be illustrated by a comparison of the definitions of both disciplines, by examples of research projects for which the application of methods from both fields is necessary in order to complete the project successfully, and by an analysis of the professional fields of medical informatics graduates working in their occupation. Therefore, a stronger integration of both disciplines is advocated.

[Suspected acute coronary events in emergency room patients]

Identification of patients in whom chest pain is due to an acute coronary event is among the most challenging problems in emergency medicine. Because of the dangers of missing the diagnosis in patients with a possibly fatal condition, emergency room (ER) physicians often admit patients for 'observation' or 'to rule out MI.' As a result of such a policy, only 30-50% of such patients admitted to the CCU may finally be diagnosed as having an acute myocardial infarction (AMI), resulting in deleterious medical, psychological and economic consequences for the others. A series of 2280 patients who were referred to the ER was followed for 2 weeks. 1362 (59.7%) of those admitted were discharged; 16.1% were hospitalized in the CCU and 83.9% in medical wards. 95 (64.6%) of those hospitalized in the CCU and 97 (12.7%) of those admitted to medical wards had an AMI. The proportion of cases in which hospitalization was unnecessary was 10.2% in the CCU and 29.8% in the medical wards. Unjustified discharges from the ER were 4.3% of referrals. These data are similar to those reported from the USA and from our first study in 1969. It is hoped that by using a triage algorithm in the ER, differentiation between chest pain due to coronary heart disease and that due to other causes will be more accurate and therefore the demand on scarce resources due to unnecessary admissions will be substantially reduced.

Risk-benefit analyses of drugs: fundamental considerations and requirements from the point of view of the biometrician. Problems in the assessment of the combination of trimethoprim with sulfamethoxazole

Risk-benefit analyses are a prerequisite for a rational decision about therapies, e.g. drugs. Ingredients of a risk-benefit analysis are: 1. quality and quantity of the benefit; 2. quality and quantity of the harm; 3. benefit and harm of the natural history of the disease; 4. benefit and harm of therapeutic alternatives; 5. commensurability of harm and benefit; 6. consideration of all types of adverse drug reactions together. The available evidence was not suitable for a sound risk-benefit analysis of the use of trimethoprim-sulfamethoxazole. However, there seems to be enough evidence to restrict the use of trimethoprim-sulfamethoxazole in diseases with a benign prognosis and/or when there are therapeutic alternatives with a smaller risk/benefit ratio. Reliable rules for risk-benefit analyses have to be developed and the necessary information has to be gained also in methodologically sound phase IV research.

The prognostic value of response to the first cycle of chemotherapy in small cell lung cancer. Results of a multicenter German trial

The prognostic significance of evaluation of response according to chest X-ray after only one cycle of treatment was investigated in patients with small cell lung cancer (SCLC). Three hundred and six patients entered a multicenter randomized German trial testing alternating vs. sequential chemotherapy. Decrease of tumor size after the first cycle was seen to be 78% in the alternating group and 70% in the sequential group. Stable disease occurred in 25% of the sequentially treated and 19% of the alternatingly treated patients. No substantial differences in pretreatment characteristics were noticed between patients with stable disease in sequential and alternating treatment. In sequential therapy, median survival was 323 days for patients with decrease of tumor size after the first cycle and 219 days for patients with no change. Only five out of 21 patients with no change after one cycle responded to continuous administration of this regimen including one complete remission. In alternating therapy, median survival was 347 days for patients with decrease in tumor size after the first cycle and 378 days for patients with no change indicating no difference in prognosis. Twelve out of 18 patients with no change responded to continuous administration of alternating treatment including six complete remissions. We concluded that response to the first cycle according to chest X-ray is a reliable and prognostically valid response criterion if sequential therapy is used. In this treatment modality no change in tumor size after the first cycle indicates poor prognosis, and improvement of the patients' outcome may be achieved by a switch to a second non-cross resistant drug combination.

Alternating versus sequential chemotherapy in small cell lung cancer. A randomized German multicenter trial

A total of 306 patients with small cell lung cancer (SCLC) were randomized to receive chemotherapy in a sequential or alternating mode. Sequential chemotherapy consisted of eight cycles of cyclophosphamide, Adriamycin (doxorubicin), and vincristine (CAV) and alternating chemotherapy consisted of three cycles (1, 3, 5) of etoposide, vindesine, and ifosfamide (EVI); three cycles (2, 4, 6) of cisplatin, Adriamycin, and vincristine (PAV); and two cycles (7, 8) of cyclophosphamide, methotrexate, and CCNU (CMC). Responsive patients received prophylactic cranial irradiation after three cycles and chest irradiation after eight cycles of chemotherapy. No maintenance therapy was applied to patients achieving complete remission. Minimum follow-up was 2 years. Of the 302 patients evaluable, overall response rate was 59% in the sequential arm and 70% in the alternating arm. Patients treated with CAV had a complete response rate of 21% in contrast to 36% for those receiving alternating therapy. The median survival for all patients was 9.8 versus 11.3 months, for limited disease 11.1 versus 13.4 months, and for extensive disease 8.9 versus 9.9 months, all in favor of the alternating treatment. Two-year survival rate for all patients was 6% versus 9%, for limited disease 11% versus 14%, and for extensive disease 3% versus 6%, all preferring the alternating treatment mode. Progression-free survival demonstrated a strong correlation to the extent of response irrespective of the treatment regimen applied. Toxicity included 11 lethal and 8 life-threatening complications with a higher frequency in the alternating treatment arm. These results suggest that alternating treatment of SCLC with different drug combinations is more effective than sequential application of CAV.