Quantitative assessment of the microstructure of the mesorectum with different prognostic statuses by intravoxel incoherent motion diffusion-weighed magnetic resonance imaging.

BACKGROUND: The mesorectum surrounding the rectum provides an ideal substrate for tumour spread. However, preoperative risk assessment is still an issue. This study aimed to investigate the microstructural features of mesorectum with different prognostic statuses by intravoxel incoherent motion diffusion-weighted imaging (IVIM DWI). METHODS: Patients with pathologically proven rectal adenocarcinoma underwent routine high-resolution rectal magnetic resonance imaging (MRI) and IVIM DWI sequences were acquired. The MRI-detected circumferential resection margin (mrCRM) and extramural vascular invasion (mrEMVI) were evaluated. IVIM parameters of the mesorectum adjacent to (MAT) and distant from (MDT) the tumour were measured and compared between and within the prognostic factor groups. RESULTS: The positive mrCRM (pMAT < 0.001; pMDT = 0.013) and mrEMVI (pMAT = 0.001; pMDT < 0.001) groups demonstrated higher D values in the MAT and MDT than the corresponding negative groups. Conversely, the positive mrCRM (p = 0.001) and mrEMVI (p < 0.001) groups both demonstrated lower f values in the MAT. Similarly, in the self-comparison between the MAT and MDT in the above subgroups, D showed a significant difference in all subgroups (p < 0.001 for all), and f showed a significant difference in the positive mrCRM (p = 0.001) and mrEMVI (p = 0.002) groups. Moreover, the MAT displayed a higher D* in the positive mrCRM (p = 0.014), negative mrCRM (p = 0.009) and negative mrEMVI groups (p < 0.001). CONCLUSION: The microstructure of the mesorectum in patients with rectal cancer with poor prognostic status shows changes based on IVIM parameters. IVIM parameters might be promising imaging biomarkers for risk assessment of tumour spread in mesorectum preoperatively.

Temporal trends of device-related infection in de novo transvenous implantable cardioverter-defibrillator Medicare patients with underlying kidney disease.

BACKGROUND: Kidney disease is a risk factor for device infection in transvenous implantable cardioverter-defibrillator (TV-ICD) implants, with mechanisms that include immunodeficiency and a portal of entry for bacteria that can seed indwelling devices. OBJECTIVE: The purpose of this study was to examine the impact of both kidney disease and dialysis-dependence on the incidence of device-related infection after de novo TV-ICD implantation and how the incidence changes over time in. METHODS: Medicare 100% administrative and claims data were used to identify patients who underwent de novo TV-ICD implantation between July 1, 2016, and December 31, 2018. Baseline characteristics included underlying kidney disease (none, nondialysis, dialysis) plus device infection during follow-up. Patients were followed for TV-ICD infection up to 78 weeks after implantation. Piecewise Poisson regression was used to predict the incidence of and hazard ratios for infection over time. RESULTS: Overall, 809 of 42,200 patients (1.9%) had at least 1 device infection during mean follow-up of 66 weeks: 484 of 31,217 (1.6%) none; 202 of 9151 (2.2%) nondialysis; and 123 of 1832 (6.7%) dialysis (P <.001 via log-rank test). The incidence of infection increased during the first 8-12 weeks and declined thereafter. Hazard ratios increased over time (dialysis week 12 = 4.9/1000 patient-years; week 52 = 9.8; nondialysis week 12 = 1.4; week 52 = 2.5; all P <.05), as did the difference in cumulative incidence compared with none (dialysis week 12 = Δ11.8 and week 78 = Δ53.5; nondialysis week 12 = Δ1.4 and week 78 = Δ7.0). CONCLUSION: The incidence of infection after de novo TV-ICD implantation is higher when patients have kidney disease and is substantially higher when patients are dialysis-dependent.

Device-related infection associated with increased mortality risk in de novo transvenous implantable cardioverter-defibrillator medicare patients.

INTRODUCTION: Transvenous implantable cardioverter-defibrillators (TV-ICD) infection is a serious complication that frequently requires complete device removal for attempted cure, which can be associated with patient morbidity and mortality. The objective of this study is to assess mortality risk associated with TV-ICD infection in a large Medicare population with de novo TV-ICD implants. METHODS: A survival analysis was conducted using 100% fee-for-service Medicare facility-level claims data to identify patients who underwent de novo TV-ICD implantation between 7/2016 and 1/2018. TV-ICD infection within 2 years of implantation was identified using International Classification of Disease, 10th Edition and current procedural terminology codes. Baseline patient risk factors associated with mortality were identified using the Charlson Comorbidity Index categories. Infection was treated as a time-dependent variable in a multivariate Cox proportional hazards model to account for immortal time bias. RESULTS: Among 26,742 Medicare patients with de novo TV-ICD, 518 (1.9%) had a device-related infection. The overall number of decedents was 4721 (17.7%) over 2 years, with 4555 (17%) in the noninfection group and 166 (32%) in the infection group. After adjusting for baseline patient demographic characteristics and various comorbidities, the presence of TV-ICD infection was associated with an increase of 2.4 (95% CI: 2.08-2.85) times in the mortality hazard ratio. CONCLUSION: The rate of TV-ICD infection and associated mortality in a large, real-world Medicare population is noteworthy. The positive association between device-related infection and risk of mortality further highlights the need to reduce infections.

Non-invasive MR assessment of the microstructure and microcirculation in regional lymph nodes for rectal cancer: a study of intravoxel incoherent motion imaging.

BACKGROUND: The aim of this study is to evaluate the microstructure and microcirculation of regional lymph nodes (LNs) in rectal cancer by using non-invasive intravoxel incoherent motion MRI (IVIM-MRI), and to distinguish metastatic from non-metastatic LNs by quantitative parameters. METHODS: All recruited patients underwent IVIM-MRI (b = 0, 5, 10, 20, 30, 40, 60, 80, 100, 150, 200, 400, 600, 1000, 1500 and 2000 s/mm2) on a 3.0 T MRI system. One hundred sixty-eight regional LNs with a short-axis diameter equal to or greater than 5 mm from 116 patients were evaluated by two radiologists independently, including 78 malignant LNs and 90 benign LNs. The following parameters were assessed: the short-axis diameter (S), long-axis diameter (L), short- to long-axis diameter ratio (S/L), pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion factor (f). Intraclass correlation coefficients (ICCs) were calculated to assess the interobserver agreement between two readers. Receiver operating characteristic curves were applied for analyzing statistically significant parameters. RESULTS: Interobserver agreement of IVIM-MRI parameters between two readers was excellent (ICCs> 0.75). The metastatic group exhibited higher S, L and D (P < 0.001), but lower f (P < 0.001) than the non-metastatic group. The area under the curve (95% CI, sensitivity, specificity) of the multi-parameter combined equation for D, f and S was 0.811 (0.744~0.868, 62.82%, 87.78%). The diagnostic performance of the multi-parameter model was better than that of an individual parameter (P < 0.05). CONCLUSION: IVIM-MRI parameters provided information about the microstructure and microcirculation of regional LNs in rectal cancer, also improved diagnostic performance in identifying metastatic LNs.

Comparison group selection in the presence of rolling entry for health services research: Rolling entry matching.

OBJECTIVE: To demonstrate rolling entry matching (REM), a new statistical method, for comparison group selection in the context of staggered nonuniform participant entry in nonrandomized interventions. STUDY SETTING: Four Health Care Innovation Award (HCIA) interventions between 2012 and 2016. STUDY DESIGN: Center for Medicare and Medicaid Innovation HCIA participants entering these interventions over time were matched with nonparticipants who exhibited a similar pattern of health care use and expenditures during each participant's baseline period. DATA EXTRACTION METHODS: Medicare fee-for-service claims data were used to identify nonparticipating, fee-for-service beneficiaries as a potential comparison group and conduct REM. PRINCIPAL FINDINGS: Rolling entry matching achieved conventionally-accepted levels of balance on observed characteristics between participants and nonparticipants. The method overcame difficulties associated with a small number of intervention entrants. CONCLUSIONS: In nonrandomized interventions, valid inference regarding intervention effects relies on the suitability of the comparison group to act as the counterfactual case for the intervention group. When participants enter over time, comparison group selection is complicated. Rolling entry matching is a possible solution for comparison group selection in rolling entry interventions that is particularly useful with small sample sizes and merits further investigation in a variety of contexts.

Transition Home Plus Program Reduces Medicaid Spending and Health Care Use for High-Risk Infants Admitted to the Neonatal Intensive Care Unit for 5 or More Days.

OBJECTIVE: To evaluate the effects of a transition home intervention on total Medicaid spending, emergency department visits, and unplanned readmissions for preterm infants born at ≤366/7 weeks gestation and high-risk full-term infants. STUDY DESIGN: The Transition Home Plus (THP) program incorporated enhanced support services before and after discharge from the neonatal intensive care unit (NICU) provided by social workers and family resource specialists (trained peers) working with the medical team from October 2012 to October 2014. Rhode Island Medicaid claims data were used to study the 321 infants cared for in the NICU for ≥5 days, who were enrolled in the THP program. THP infants were compared with a historical comparison group of 365 high-risk infants born and admitted to the same NICU in 2011 before the full launch of the THP program. Intervention and comparison group outcomes were compared in the eight 3-month quarters after the infant's birth. Propensity score weights were applied in regression models to balance demographic characteristics between groups. RESULTS: Infants in the intervention group had significantly lower total Medicaid spending, fewer emergency department visits, and fewer readmissions than the comparison group. Medicaid spending savings for the intervention group were $4591 per infant per quarter in our study period. CONCLUSIONS: Transition home support services for high-risk infants provided both in the NICU and for 90 days after discharge by social workers and family resource specialists working with the medical team can reduce Medicaid spending and health care use.

Employer contribution and premium growth in health insurance.

We study whether employer premium contribution schemes could impact the pricing behavior of health plans and contribute to rising premiums. Using 1991-2011 data before and after a 1999 premium subsidy policy change in the Federal Employees Health Benefits Program (FEHBP), we find that the employer premium contribution scheme has a differential impact on health plan pricing based on two market incentives: 1) consumers are less price sensitive when they only need to pay part of the premium increase, and 2) each health plan has an incentive to increase the employer's premium contribution to that plan. Both incentives are found to contribute to premium growth. Counterfactual simulation shows that average premium would have been 10% less than observed and the federal government would have saved 15% per year on its premium contribution had the subsidy policy change not occurred in the FEHBP. We discuss the potential of similar incentives in other government-subsidized insurance systems such as the Medicare Part D and the Health Insurance Marketplace under the Affordable Care Act.