Evaluating the implementation of a multi-level mHealth study to improve hydroxyurea utilization in sickle cell disease

Background

Sickle Cell Disease (SCD) is a progressive genetic disease that causes organ damage and reduces longevity. Hydroxyurea is an underutilized evidence-based medication that reduces complications and improves survival in SCD. In a multi-site clinical trial, part of the NIH-funded Sickle Cell Disease Implementation Consortium (SCDIC), we evaluate the implementation of a multi-level and multi-component mobile health (mHealth) patient and provider intervention to target the determinants and context of low hydroxyurea use. Given the complexity of the intervention and contextual variability in its implementation, we combined different behavioral and implementation theories, models, and frameworks to facilitate the evaluation of the intervention implementation. In this report, we describe engagement with stakeholders, planning of the implementation process, and final analytical plan to evaluate the implementation outcomes.

Methods

During 19 meetings, a 16-member multidisciplinary SCDIC implementation team created, conceived, and implemented a project that utilized Intervention Mapping to guide designing an intervention and its evaluation plan. The process included five steps: (1) needs assessment of low hydroxyurea utilization, (2) conceptual framework development, (3) intervention design process, (4) selection of models and frameworks, and (5) designing evaluation of the intervention implementation.

Results

Behavioral theories guided the needs assessment and the design of the multi-level mHealth intervention. In designing the evaluation approach, we combined two implementation frameworks to best account for the contextual complexity at the organizational, provider, and patient levels: (1) the Consolidated Framework for Implementation Research (CFIR) that details barriers and facilitators to implementing the mHealth intervention at multiple levels (users, organization, intervention characteristics, broader community), and (2) the Technology Acceptance Model (TAM), a conceptual model specific for explaining the intent to use new information technology (including mHealth). The Reach Effectiveness Adoption Implementation and Maintenance (RE-AIM) framework was used to measure the outcomes.

Discussion

Our research project can serve as a case study of a potential approach to combining different models/frameworks to help organize and plan the evaluation of interventions to increase medication adherence. The description of our process may serve as a blueprint for future studies developing and testing new strategies to foster evidence-based treatments for individuals living with SCD.

Evaluation of SWI in children with sickle cell disease

BACKGROUND AND PURPOSE

SWI is a powerful tool for imaging of the cerebral venous system. The SWI venous contrast is affected by blood flow, which may be altered in sickle cell disease. In this study, we characterized SWI venous contrast in patients with sickle cell disease and healthy control participants and examined the relationships among SWI venous contrast, and hematologic variables in the group with sickle cell disease.

MATERIALS AND METHODS

A retrospective review of MR imaging and hematologic variables from 21 patients with sickle cell disease and age- and sex-matched healthy control participants was performed. A Frangi vesselness filter was used to quantify the attenuation of visible veins from the SWI. The normalized visible venous volume was calculated for quantitative analysis of venous vessel conspicuity.

RESULTS

The normalized visible venous volume was significantly lower in the group with sickle cell disease vs the control group (P < .001). Normalized visible venous volume was not associated with hemoglobin, percent hemoglobin F, percent hemoglobin S, absolute reticulocyte count, or white blood cell count. A hypointense arterial signal on SWI was observed in 18 of the 21 patients with sickle cell disease and none of the 21 healthy control participants.

CONCLUSIONS

This study demonstrates the variable and significantly lower normalized visible venous volume in patients with sickle cell disease compared with healthy control participants. Decreased venous contrast in sickle cell disease may reflect abnormal cerebral blood flow, volume, velocity, or oxygenation. Quantitative analysis of SWI contrast may be useful for investigation of cerebrovascular pathology in patients with sickle cell disease, and as a tool to monitor therapies. However, future studies are needed to elucidate physiologic mechanisms of decreased venous conspicuity in sickle cell disease.

Application of oligo-(14-amino-3,6,9,12-tetraoxatetradecanoic acid) lipid conjugates as steric barrier molecules in liposomal formulations

Lipid conjugates of oligo-(14-amino-3,6,9,12-tetraoxatetradecanoic acid) (ATTAn) were synthesized as monodisperse analogues of poly(ethylene glycol) (PEG) derivatives used in liposomal drug delivery systems. The new lipids were shown to be at least equivalent to MePEGA-2000-DSPE in assays designed to evaluate the effectiveness of polymers as steric barrier molecules in liposomes. Liposomes containing 1-5% of ATTA8-DSPE (octamer) showed comparable long circulation behavior relative to PEG-2000-DSPE analogues. Surprisingly, the shorter ATTA4-DSPE (tetramer) appeared to be quite effective in reducing clearance. Liver enzyme levels and systemic single dose tolerability of ATTA8-DSPE liposomes were comparable to controls, suggesting that the new materials are nontoxic. Prolonged exposure of ATTA8-DSPE liposomes to splenocytes in vitro showed no evidence of mitogenicity relative to controls or MePEGA-2000-DSPE liposomes. ATTA8-DSPE was as effective as MePEGC-2000-DSPE in preventing complement activation by cationic liposome systems. Repeat dosage in vivo regimes in ICR mice using DSPC/cholesterol liposomes, with and without 5% ATTA8-DSPE and MePEGC-2000-DSPE, showed no evidence of enhanced clearance on successive doses. Splenocytes recovered after repeat doses showed no significant evidence of mitogenicity on restimulation with liposomes. Cellular differentiation and activation marker levels in splenocytes recovered after the fourth in vivo administration were at normal levels. These results suggest that ATTAn oligomers do not induce an immune response in isolation. It was demonstrated that ATTA8-DSPE could be used to replace PEG-lipids in the formulation of doxorubicin, plasmid DNA and oligonucleotides using a variety of formulation techniques. The study demonstrates that ATTAn oligomers can be safely and effectively used in place of poly(ethylene glycol) as well-defined biomaterials in liposomal applications where reproducible behavior is critical.

Plasma vitamins E and C concentrations of adult patients during cardiopulmonary bypass

OBJECTIVE

This study was designed with two aims: 1) to determine if the coronary artery bypass graft (CABG) procedure alters plasma vitamin E and C concentrations of adult patients through repeated determinations of vitamin levels at time points before, during and following CABG, and 2) to assess whether plasma vitamin E concentrations reflect myocardial tissue content.

METHODS

A consecutive sample of 38 patients undergoing CABG surgery at a Midwest tertiary care hospital was enrolled. Patients receiving blood transfusions before or during surgery were excluded.

RESULTS

Plasma vitamin E/total lipid ratios rose with reperfusion, remained elevated immediately following bypass, and fell to preoperative concentrations by 24 hours. Plasma vitamin E/total cholesterol levels varied little throughout this time course. Both plasma uric acid and ascorbate concentrations (corrected for hemodilution) also rose by the preischemic interval, and remained elevated until a return to preoperative levels by 24 hours. Corrected malondialdehyde (MDA) concentrations rose by pre-ischemia but returned more quickly to preoperative levels. Atrial appendage tissue vitamin E concentrations bore a significant relationship to those of plasma prior to surgery (r=+0.49, p=0.004). Reported supplement use, plasma concentrations and body mass index contributed to the variability in atrial tissue concentrations of vitamin E.

CONCLUSIONS

In short, when not confounded by transfusions or hemodilution, several peripheral indices of antioxidants increase with the reperfusion segment of CABG procedure and return to baseline levels within 24 hours of surgery. Parallel changes in MDA were observed. The observed changes are consistent with the hypothesis that oxidative stress accompanies the ischemia-reperfusion components of the CABG procedure.