Energy cost and mechanical efficiency of riding a four-wheeled, human-powered, recumbent vehicle

Oxygen consumption at steady state (V˙O ₂, l · min⁻¹) and mechanical power (W˙, W) were measured in five subjects riding a human-powered vehicle (HPV, the Karbyk, a four-wheeled recumbent cycle) on a flat concrete road at constant sub-maximal speeds. The external mechanical work spent per unit of distance (W, J · m⁻¹), as calculated from the ratio of W˙ to the speed (v, m · s⁻¹), was found to increase with the square of v: W˙=8.12+(0.262 ·v ²) (r=0.986, n=31), where the first term represents the mechanical energy wasted, over a unit of distance, against frictional forces (rolling resistance, R_r), and the second term (k · v ²) is the work performed, per unit distance, to overcome the air drag. The rolling coefficient (C_r, obtained dividing R_r by m · g, where m is the overall mass and g is the acceleration of gravity) amounted to [mean (SD)] 0.0084 (0.0008), that is about 60% higher than that of a racing bicycle. The drag coefficient was calculated from the measured values of k, air density (ρ) and frontal area (A) [C_x=k · (0.5 · A · ρ)⁻¹], and amounted to 1.067 (0.029), that is about 20% higher than that of a racing bicycle. The energy cost of riding the HPV (C_k, J · m⁻¹) was measured from the ratio of metabolic power above rest (net V˙O ₂, expressed in J · s⁻¹) to the speed (v, m · s⁻¹); the value of this parameter increased with the square of v, as described by: C_k=61.45 + (0.675 · v ²) (r=0.711, n=23). The net mechanical efficiency (η) was calculated from the ratio of W to C_k: over the investigated speed range this turned out to be 0.22 (0.021). Best performance times (BPTs) of a “typical”élite athlete riding the Karbyk were calculated over the distances of 1, 5 and 10 km: these were about 8% longer than the BPTs calculated, on the same subjects, when riding a conventional racing bicycle. Accepted: 7 August 2000     

费用成本转换法的优化及实证研究

目的优化费用成本转换法,进一步完善成本单元划分原则,提高费用成本转换法的核算准确性,推广方法学的应用价值。方法在已有研究的基础上,进一步细分成本单元,采用费用成本转换法测算病种成本,分析病种盈亏情况。结果甲状腺恶性肿瘤治疗成本为37444.48元,平均支付价格为22474.90元,亏损14945.50元,亏损率为39.94%。结论优化后的费用成本转换法更加契合当前医改政策,核算精度更高,有效提升部分专科医院的核算精度。费用成本转换法能够为政府的病种定价与医院运营管理提供科学的方法学支撑。     

Suprachoroidal Injection of Triamcinolone Acetonide Injectable Suspension for the Treatment of Macular Edema Associated With Uveitis in the United States: A Cost-Effectiveness Analysis

ObjectivesSuprachoroidal injection of triamcinolone acetonide is the first Food and Drug Administration–approved treatment for macular edema associated with uveitis. A cost-effectiveness analysis was performed comparing this treatment with best supportive care (BSC) for the management of this indication from US Medicare and commercial payer perspectives.MethodsA patient-level simulation was developed per the patient characteristics and changes in best-corrected visual acuity letter scores observed in a phase III study of triamcinolone acetonide (PEACHTREE). The wholesale acquisition cost of triamcinolone acetonide was $1650/injection; suprachoroidal injection cost was assumed at $200/injection. Healthcare costs were informed by a US claims–based analysis. Mortality risk associated with severe vision loss and blindness was modeled by applying a hazard ratio to all-cause mortality rates of the US general population. Health-related quality of life weights, obtained from a regression model fitted to the Visual Function Questionnaire-25 data from PEACHTREE, were applied based on the best-corrected visual acuity scores of both eyes. Costs (2020 US dollar) and benefits were discounted at 3% annually. Incremental cost-effectiveness ratios were estimated over a 10-year horizon.ResultsIn the base-case, the incremental cost-effectiveness ratio comparing triamcinolone acetonide with BSC was $28 479 per quality-adjusted life-year gained. The wholesale acquisition cost for triamcinolone acetonide for suprachoroidal use was ～68%, ～56%, and ～27% below the willingness-to-pay thresholds of $150 000, $100 000, and $50 000 per quality-adjusted life-year gained, respectively. Results were robust in sensitivity and scenario analyses.ConclusionsTriamcinolone acetonide for suprachoroidal use is cost-effective compared with BSC for patients with macular edema associated with uveitis.     

Healthcare Cost Savings Associated with Increased Whole Grain Consumption among Australian Adults

Many dietary guidelines emphasise “mostly” whole grain food choices as part of an overall healthy eating pattern based on evidence for enhancing nutritional status and reducing chronic disease. Still, countries including Australia fall short of their consumption targets. Furthermore, healthcare cost savings associated with increasing the consumption of whole grains in alignment with the Daily Target Intake (DTI) recommendation of 48 g are unknown. The aim of this study was to assess the potential savings in costs of healthcare and lost productivity associated with a reduction in the incidence of Type 2 Diabetes Mellitus (T2DM) and cardiovascular disease (CVD) through meeting the 48 g DTI recommendation for whole grains among the Australian adult population (>20 years). A three-step cost-of-illness analysis was conducted using input parameters from: 1) estimates of proportions of consumers (5%, 15%, 50%, and 100%) who would increase their current intake of whole grains to meet the recommended DTI in Australia; 2) relative reductions in risk of T2DM and CVD associated with specific whole grain consumption, as reported in meta-analysis studies; and 3) data on costs of healthcare and productivity loss based on monetary figures by national healthcare authorities. A very pessimistic (5% of the population) through to universal (100% of the population) adoption of the recommended DTI was shown to potentially yield AUD 37.5 (95% CI 22.3–49.3) to AUD 750.7 (95% CI 445.7–985.2) million, and AUD 35.9 (95% CI 8.3–60.7) to AUD 717.4 (95% CI 165.5–1214.1) million in savings on annual healthcare and lost productivity costs for T2DM and CVD, respectively. Given such economic benefits of the recommended consumption of whole grains, in exchange for refined grains, there is a real opportunity to facilitate relevant socioeconomic cost-savings for Australia and reductions in disease. These results are suggestive of a much greater opportunity to communicate the need for dietary change at all levels, but particularly through food-based dietary guidelines and front-of-pack labelling initiatives.     

Estimate of Burden and Direct Healthcare Cost of Infectious Waterborne Disease in the United States

Provision of safe drinking water in the United States is a great public health achievement. However, new waterborne disease challenges have emerged (e.g., aging infrastructure, chlorine-tolerant and biofilm-related pathogens, increased recreational water use). Comprehensive estimates of the health burden for all water exposure routes (ingestion, contact, inhalation) and sources (drinking, recreational, environmental) are needed. We estimated total illnesses, emergency department (ED) visits, hospitalizations, deaths, and direct healthcare costs for 17 waterborne infectious diseases. About 7.15 million waterborne illnesses occur annually (95% credible interval [CrI] 3.88 million–12.0 million), results in 601,000 ED visits (95% CrI 364,000–866,000), 118,000 hospitalizations (95% CrI 86,800–150,000), and 6,630 deaths (95% CrI 4,520–8,870) and incurring US $3.33 billion (95% CrI 1.37 billion–8.77 billion) in direct healthcare costs. Otitis externa and norovirus infection were the most common illnesses. Most hospitalizations and deaths were caused by biofilm-associated pathogens (nontuberculous mycobacteria, Pseudomonas, Legionella), costing US $2.39 billion annually.     

Mortality,Health Care Use,and Costs of Clostridioides difficile Infections in Older Adults

ObjectivesEstimate mortality, cost, and health care resource utilization for Medicare beneficiaries aged ≥65 years who suffered a primary Clostridioides difficile infection (CDI) episode only or any recurrent CDI, and understand how outcomes covary with death.DesignRetrospective observational claims analysis.Setting and ParticipantsPatients aged ≥65 years who had an inpatient or outpatient CDI diagnosis claim to Medicare and continuous enrollment in Medicare parts A, B, and D during the 12-month pre- and post-index periods.MethodsUsing 100% Medicare Fee-for-Service claims data for 2009–2017, primary (pCDI, n = 345,893) and recurrent (rCDI: n = 151,596) CDI episodes were identified. Demographic and clinical characteristics, mortality, health care resource utilization, and costs (per patient per month) were summarized for 12 months before and up to 12 months after episode start. Regression models were estimated for hospitalization risk, hospital length of stay (LOS), and cost to adjust for comorbidities.ResultsCDI-associated deaths were almost 10 times higher after recurrent CDI (25.4%) than primary CDI (2.7%). Compared with survivors, decedents were older, had higher Charlson Comorbidity Index scores, and were more likely Black. Adjusting for comorbidities, during follow-up, decedents had higher hospitalization rates [pCDI: odds ratio (OR) = 1.83, P < .001; rCDI: OR = 2.58, P < .001], and recurrent CDI decedents had more intensive care unit use (OR = 2.34, P < .001) compared with survivors. Decedents also had a longer length of stay (pCDI: +3.2 days, P < .001; rCDI: +2.6 days, P < .001), and higher total cost (pCDI: +303%, P < .001; rCDI: +297%, P < .001).Conclusions and ImplicationsCDI is an important contributing diagnosis to all-cause mortality, particularly for recurrences. Prior to death, older Medicare beneficiaries who experienced CDI received longer, more intensive, and more costly care compared with survivors. Clinicians should be particularly attentive to prevention, identification, and appropriate treatment of CDI in older adults. Better treatments to reduce primary C difficile infection and recurrences in this vulnerable population can lower both mortality and economic burden.     

市场均衡就业区间及其对社会就业的影响

现代市场经济运行中 ,厂商将其供给量调整到合理水平所需的费用可称为微观调节成本。由于存在微观调节成本这种特殊的经济运行费用 ,因而传统分析中宏观层面上市场就业均衡点的两侧便分别存在着“低位临界点”与“高位临界点” ,这两点界定了一个“市场均衡就业区间” ,社会就业一旦进入该区间 ,市场机制便不可能再对其作出调节。市场均衡就业区间的主要特点在于 ,其均衡是就区间外部而言的 ,在区间内部仍可以存在一定程度的就业失衡 ;市场均衡就业区间内部的就业失衡是一种特殊的就业失衡 ,市场机制对之无能为力 ,一般的宏观经济政策亦无法对其发生作用。市场均衡就业区间的存在对社会就业有着多方面的重要影响 ,它使社会就业对供求总量波动的反应呈现出一定“粘性” ;使市场机制对社会就业的调节空间减小 ;使政府调控社会就业的重点二元化 ;使个体经济在缓解就业失衡压力、扩大社会就业方面占有了特殊重要的地位。     

Projected Economic Burden of Periprosthetic Joint Infection of the Hip and Knee in the United States

BackgroundIn addition to the significant morbidity and mortality associated with periprosthetic joint infection (PJI), the cost of treating PJI is substantial. Prior high-quality national estimates of the economic burden of PJI utilize data up to 2009 to project PJI growth in the United States through 2020. Now in the year 2020, it is appropriate to evaluate these past projections and incorporate the latest available data to better understand the current scale and burden of PJI in the United States.MethodsThe Nationwide Inpatient Sample (2002-2017) was used to identify rates and associated inpatient costs for primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) and PJI-related revision TKA and THA. Poisson regression was utilized to model past growth and project future rates and cost of PJI of the hip and knee.ResultsUsing the most recent data, the combined annual hospital costs related to PJI of the hip and knee were estimated to be $1.85 billion by 2030. This includes $753.4 million for THA PJI and $1.1 billion for TKA PJI, in that year. Increases in PJI costs are mainly attributable to increases in volume. Although the growth in incidence of primary THA and TKA has slowed in recent years, the incidence of PJI and the cost per case of PJI remained relatively constant from 2002 to 2017.DiscussionUnderstanding the current and potential future financial burden of PJI for surgeons, patients, and healthcare systems is essential. There is an urgent need for efficacious preventive strategies in reducing rates of PJI after THA and TKA.     

Early and Direct Rehab Transfer Leads to Significant Cost Savings and Decreased Hospital Length of Stay for Total Joint Arthroplasty in a Veteran Population

BackgroundTotal joint arthroplasty is the most common elective orthopedic procedure in the Veterans Affairs hospital system. In 2019, physical medicine and rehabilitation began screening patients before surgery to select candidates for direct transfer to acute rehab after surgery. The primary outcome of this study was to demonstrate that the accelerated program was successful in decreasing inpatient costs and length of stay (LOS). The secondary outcome was to show that there was no increase in complication, reoperation, and readmission rates.MethodsA retrospective review of total joint arthroplasty patients was conducted with three cohorts: 1) control (n = 193), 2) transfer to rehab orders on postop day #1 (n = 178), and 3) direct transfers to rehab (n = 173). To assess for demographic disparities between cohorts, multiple analysis of variance tests followed by a Bonferroni P-value correction were used. Differences between test groups regarding primary outcomes were assessed with analysis of variance tests followed by pairwise t-tests with Bonferroni P-value corrections.ResultsThere were no significant differences between the cohort demographics or comorbidities. The mean total LOS decreased from 7.0 days in the first cohort, to 6.9 in the second, and 6.0 in the third (P = .00034). The mean decrease in cost per patient was $14,006 between cohorts 1 and 3, equating to over $5.6 million in savings annually. There was no significant change in preintervention and postintervention short-term complications (P = .295).ConclusionsSignificant cost savings and decrease in total LOS was observed. In the current health care climate focused on value-based care, a similar intervention could be applied nationwide to improve Veterans Affair services.     

Cost of Aseptic Revision Total Knee Arthroplasty at a Tertiary Medical Center

BackgroundRevision total knee arthroplasty (TKA) involves varying levels of case complexity and costs depending on the following: (1) number of components revised, (2) duration of operating room time, and (3) length of hospital stay. However, the cost associated with different types of aseptic TKA revisions, based on number and type of components revised, is not well described. We sought to determine differences in cost associated with different revision types, and to correlate this with average national hospital and surgeon reimbursement based on current Centers for Medicare and Medicaid Services data.MethodsThis is a retrospective review of aseptic revision TKAs performed at a single tertiary referral center from 2015 to 2018. Patient demographic data, operating room time, and direct surgery and total hospital costs obtained from an internal accounting database (Enterprise Performance Systems, Inc) were collected. Patients were stratified by the components revised (polyethylene liner only, tibia only, femur only, or both femur and tibia). We hypothesized that direct surgery and total hospital costs would increase as case complexity increased from poly exchange to single-component revisions and both-component revisions.ResultsIn total, 106 patients were included (19 poly exchanges, 10 tibia-only revisions, 13 femur-only revisions, and 64 both-component revisions). Operating room time was significantly lower for poly exchange than all other groups (P < .001). Direct surgery and total hospital costs were significantly lower for poly exchange than all other groups (P < .001), and were significantly lower for tibia-only and femur-only revisions compared to both-component revisions (P < .001). Average national surgeon reimbursement by Medicare decreased as a percentage of direct surgery cost as case complexity increased from poly exchange to tibia-only, femur-only, and both-component revisions. Total hospital cost per average Diagnosis Related Group weight was lowest for single-component revisions and highest for both-component revision.ConclusionThere are significant differences in cost associated with aseptic TKA revisions based on number and type of components revised. These differences may not be accurately reflected in reimbursement, and often represent a burden to those who treat complex revisions.