Plasma IL-6 and IL-10 Concentrations Predict AKI and Long-Term Mortality in Adults after Cardiac Surgery

Inflammation has an integral role in the pathophysiology of AKI. We investigated the associations of two biomarkers of inflammation, plasma IL-6 and IL-10, with AKI and mortality in adults undergoing cardiac surgery. Patients were enrolled at six academic centers (n=960). AKI was defined as a ≥50% or ≥0.3-mg/dl increase in serum creatinine from baseline. Pre- and postoperative IL-6 and IL-10 concentrations were categorized into tertiles and evaluated for associations with outcomes of in-hospital AKI or postdischarge all-cause mortality at a median of 3 years after surgery. Preoperative concentrations of IL-6 and IL-10 were not significantly associated with AKI or mortality. Elevated first postoperative IL-6 concentration was significantly associated with higher risk of AKI, and the risk increased in a dose-dependent manner (second tertile adjusted odds ratio [OR], 1.61 [95% confidence interval (95% CI), 1.10 to 2.36]; third tertile adjusted OR, 2.13 [95% CI, 1.45 to 3.13]). First postoperative IL-6 concentration was not associated with risk of mortality; however, the second tertile of peak IL-6 concentration was significantly associated with lower risk of mortality (adjusted hazard ratio, 0.75 [95% CI, 0.57 to 0.99]). Elevated first postoperative IL-10 concentration was significantly associated with higher risk of AKI (adjusted OR, 1.57 [95% CI, 1.04 to 2.38]) and lower risk of mortality (adjusted HR, 0.72 [95% CI, 0.56 to 0.93]). There was a significant interaction between the concentration of neutrophil gelatinase-associated lipocalin, an established AKI biomarker, and the association of IL-10 concentration with mortality (P=0.01). These findings suggest plasma IL-6 and IL-10 may serve as biomarkers for perioperative outcomes.     

Kidney Transplant Outcomes for Prior Living Organ Donors

The Organ Procurement and Transplantation Network gives priority in kidney allocation to prior live organ donors who require a kidney transplant. In this study, we analyzed the effect of this policy on facilitating access to transplantation for prior donors who were wait-listed for kidney transplantation in the United States. Using 1:1 propensity score–matching methods, we assembled two matched cohorts. The first cohort consisted of prior organ donors and matched nondonors who were wait-listed during the years 1996–2010. The second cohort consisted of prior organ donors and matched nondonors who underwent deceased donor kidney transplantation. During the study period, there were 385,498 listings for kidney transplantation, 252 of which were prior donors. Most prior donors required dialysis by the time of listing (64% versus 69% among matched candidates; P=0.24). Compared with matched nondonors, prior donors had a higher rate of deceased donor transplant (85% versus 33%; P<0.001) and a lower median time to transplantation (145 versus 1607 days; P<0.001). Prior donors received higher-quality allografts (median kidney donor risk index 0.67 versus 0.90 for nondonors; P<0.001) and experienced lower post-transplant mortality (hazard ratio, 0.19; 95% confidence interval, 0.08 to 0.46; P<0.001) than matched nondonors. In conclusion, these data suggest that prior organ donors experience brief waiting time for kidney transplant and receive excellent-quality kidneys, but most need pretransplant dialysis. Individuals who are considering live organ donation should be provided with this information because this allocation priority will remain in place under the new US kidney allocation system.     

A National Study of Outcomes among HIV-Infected Kidney Transplant Recipients

Kidney transplantation is a viable treatment for select patients with HIV and ESRD, but data are lacking regarding long-term outcomes and comparisons with appropriately matched HIV-negative patients. We analyzed data from the Scientific Registry of Transplant Recipients (SRTR; 2002–2011): 510 adult kidney transplant recipients with HIV (median follow-up, 3.8 years) matched 1:10 to HIV-negative controls. Compared with HIV-negative controls, HIV-infected recipients had significantly lower 5-year (75.3% versus 69.2%) and 10-year (54.4% versus 49.8%) post-transplant graft survival (GS) (hazard ratio [HR], 1.37; 95% confidence interval [95% CI], 1.15 to 1.64; P<0.001) that persisted when censoring for death (HR, 1.43; 95% CI, 1.12 to 1.84; P=0.005). However, compared with HIV-negative/hepatitis C virus (HCV)–negative controls, HIV monoinfected recipients had similar 5-year and 10-year GS, whereas HIV/HCV coinfected recipients had worse GS (5-year: 64.0% versus 52.0%, P=0.02; 10-year: 36.2% versus 27.0%, P=0.004 [HR, 1.38; 95% CI, 1.08 to 1.77; P=0.01]). Patient survival (PS) among HIV-infected recipients was 83.5% at 5 years and 51.6% at 10 years and was significantly lower than PS among HIV-negative controls (HR, 1.34; 95% CI, 1.08 to 1.68; P<0.01). However, PS was similar for HIV monoinfected recipients and HIV-negative/HCV-negative controls at both times. HIV/HCV coinfected recipients had worse PS compared with HIV-negative/HCV-infected controls (5-year: 67.0% versus 78.6%, P=0.007; 10-year: 29.3% versus 56.23%, P=0.002 [HR, 1.57; 95% CI, 1.11 to 2.22; P=0.01]). In conclusion, HIV-negative and HIV monoinfected kidney transplant recipients had similar GS and PS, whereas HIV/HCV coinfected recipients had worse outcomes. Although encouraging, these results suggest caution in transplanting coinfected patients.     

Risk Adjustment and the Assessment of Disparities in Dialysis Mortality Outcomes

Standardized mortality ratios (SMRs) reported by Medicare compare mortality at individual dialysis facilities with the national average, and are currently adjusted for race. However, whether the adjustment for race obscures or clarifies disparities in quality of care for minority groups is unknown. Cox model-based SMRs were computed with and without adjustment for patient race for 5920 facilities in the United States during 2010. The study population included virtually all patients treated with dialysis during this period. Without race adjustment, facilities with higher proportions of black patients had better survival outcomes; facilities with the highest percentage of black patients (top 10%) had overall mortality rates approximately 7% lower than expected. After adjusting for within-facility racial differences, facilities with higher proportions of black patients had poorer survival outcomes among black and non-black patients; facilities with the highest percentage of black patients (top 10%) had mortality rates approximately 6% worse than expected. In conclusion, accounting for within-facility racial differences in the computation of SMR helps to clarify disparities in quality of health care among patients with ESRD. The adjustment that accommodates within-facility comparisons is key, because it could also clarify relationships between patient characteristics and health care provider outcomes in other settings.     

Provider Visits and Early Vascular Access Placement in Maintenance Hemodialysis

Medicare reimbursement policy encourages frequent provider visits for patients with ESRD undergoing hemodialysis. We hypothesize that patients seen more frequently by their nephrologist or advanced practitioner within the first 90 days of hemodialysis are more likely to undergo surgery to create an arteriovenous (AV) fistula or place an AV graft. We selected 35,959 patients aged ≥67 years starting hemodialysis in the United States from a national registry. We used multivariable regression to evaluate the associations between mean visit frequency and AV fistula creation or graft placement in the first 90 days of hemodialysis. We conducted an instrumental variable analysis to test the sensitivity of our findings to potential bias from unobserved characteristics. One additional visit per month in the first 90 days of hemodialysis was associated with a 21% increase in the odds of AV fistula creation or graft placement during that period (95% confidence interval, 19% to 24%), corresponding to an average 4.5% increase in absolute probability. An instrumental variable analysis demonstrated similar findings. Excluding visits in months when patients were hospitalized, one additional visit per month was associated with a 10% increase in odds of vascular access surgery (95% confidence interval, 8% to 13%). In conclusion, patients seen more frequently by care providers in the first 90 days of hemodialysis undergo earlier AV fistula creation or graft placement. Payment policies that encourage more frequent visits to patients at key clinical time points may yield more favorable health outcomes than policies that operate irrespective of patients’ health status.     

Persistent BK Viremia Does Not Increase Intermediate-Term Graft Loss but Is Associated with De Novo Donor-Specific Antibodies

There are limited data regarding intermediate-term outcomes in patients with persistent BK viremia. Other viral infections have been implicated in the development of allosensitization through heterologous immunity, but the relationship between BK viremia and donor-specific antibodies (DSAs) is unexplored. In 2008, we initiated routine post-transplant BK viremia and DSA screening at our center; 785 kidney or kidney–pancreas transplant recipients were included in our study. Of these recipients, 132 (17%) recipients developed BK viremia during the study period. The median duration of BK viremia was 140 days (interquartile range=40–393 days), and persistent BK viremia was defined as lasting ≥140 days. Kaplan–Meier curves were generated to assess differences in patient and allograft survival on the basis of BK viremia status; survival was modeled using Cox proportional hazard regression. After a median follow-up of 3 years, there was no significant difference in terms of patient (hazard ratio [HR], 0.83; 95% confidence interval [95% CI], 0.28 to 2.49) or allograft survival (HR, 0.80; 95% CI, 0.37 to 1.73) between patients with and without BK viremia, which was confirmed in a time-varying analysis. In our logistic regression model, persistent BK viremia was strongly associated with the development of class II (HR, 2.55; 95% CI, 1.30 to 4.98) but not class I (HR, 1.13; 95% CI, 0.46 to 2.77) DSAs. These data suggest that persistent BK viremia does not negatively affect intermediate-term patient or allograft survival but is associated with increased risk for de novo DSA, although the exact mechanism is unclear.     

Development and psychometric characteristics of the SCI-QOL Bladder Management Difficulties and Bowel Management Difficulties item banks and short forms and the SCI-QOL Bladder Complications scale

ObjectiveTo describe the development and psychometric properties of the Spinal Cord Injury – Quality of Life (SCI-QOL) Bladder Management Difficulties and Bowel Management Difficulties item banks and Bladder Complications scale.DesignUsing a mixed-methods design, a pool of items assessing bladder and bowel-related concerns were developed using focus groups with individuals with spinal cord injury (SCI) and SCI clinicians, cognitive interviews, and item response theory (IRT) analytic approaches, including tests of model fit and differential item functioning.SettingThirty-eight bladder items and 52 bowel items were tested at the University of Michigan, Kessler Foundation Research Center, the Rehabilitation Institute of Chicago, the University of Washington, Craig Hospital, and the James J. Peters VA Medical Center, Bronx, NY.ParticipantsSeven hundred fifty-seven adults with traumatic SCI.ResultsThe final item banks demonstrated unidimensionality (Bladder Management Difficulties CFI = 0.965; RMSEA = 0.093; Bowel Management Difficulties CFI = 0.955; RMSEA = 0.078) and acceptable fit to a graded response IRT model. The final calibrated Bladder Management Difficulties bank includes 15 items, and the final Bowel Management Difficulties item bank consists of 26 items. Additionally, 5 items related to urinary tract infections (UTI) did not fit with the larger Bladder Management Difficulties item bank but performed relatively well independently (CFI = 0.992, RMSEA = 0.050) and were thus retained as a separate scale.ConclusionThe SCI-QOL Bladder Management Difficulties and Bowel Management Difficulties item banks are psychometrically robust and are available as computer adaptive tests or short forms. The SCI-QOL Bladder Complications scale is a brief, fixed-length outcomes instrument for individuals with a UTI.     

Development and psychometric characteristics of the SCI-QOL Pressure Ulcers scale and short form

ObjectiveTo develop a self-reported measure of the subjective impact of pressure ulcers on health-related quality of life (HRQOL) in individuals with spinal cord injury (SCI) as part of the SCI quality of life (SCI-QOL) measurement system.DesignGrounded-theory based qualitative item development methods, large-scale item calibration testing, confirmatory factor analysis (CFA), and item response theory-based psychometric analysis.SettingFive SCI Model System centers and one Department of Veterans Affairs medical center in the United States.ParticipantsAdults with traumatic SCI.Results189 individuals with traumatic SCI who experienced a pressure ulcer within the past 7 days completed 30 items related to pressure ulcers. CFA confirmed a unidimensional pool of items. IRT analyses were conducted. A constrained Graded Response Model with a constant slope parameter was used to estimate item thresholds for the 12 retained items.ConclusionsThe 12-item SCI-QOL Pressure Ulcers scale is unique in that it is specifically targeted to individuals with spinal cord injury and at every stage of development has included input from individuals with SCI. Furthermore, use of CFA and IRT methods provide flexibility and precision of measurement. The scale may be administered in its entirety or as a 7-item “short form” and is available for both research and clinical practice.