Effect of Bicarbonate on Net Acid Excretion, Blood Pressure, and Metabolism in Patients With and Without CKD: The Acid Base Compensation in CKD Study.

RATIONALE & OBJECTIVE: Patients with CKD are at elevated risk of metabolic acidosis due to impaired net acid excretion (NAE). Identifying early markers of acidosis may guide prevention in chronic kidney disease (CKD). This study compared NAE in participants with and without CKD, as well as the NAE, blood pressure (BP), and metabolomic response to bicarbonate supplementation. STUDY DESIGN: Randomized order, cross-over study with controlled feeding. SETTING & PARTICIPANTS: Participants consisted of 8 patients with CKD (estimated glomerular filtration rate 30-59mL/min/1.73m2 or 60-70mL/min/1.73m2 with albuminuria) and 6 patients without CKD. All participants had baseline serum bicarbonate concentrations between 20 and 28 mEq/L; they did not have diabetes mellitus and did not use alkali supplements at baseline. INTERVENTION: Participants were fed a fixed-acid-load diet with bicarbonate supplementation (7 days) and with sodium chloride control (7 days) in a randomized order, cross-over fashion. OUTCOMES: Urine NAE, 24-hour ambulatory BP, and 24-hour urine and plasma metabolomic profiles were measured after each period. RESULTS: During the control period, mean NAE was 28.3±10.2 mEq/d overall without differences across groups (P=0.5). Urine pH, ammonium, and citrate were significantly lower in CKD than in non-CKD (P<0.05 for each). Bicarbonate supplementation reduced NAE and urine ammonium in the CKD group, increased urine pH in both groups (but more in patients with CKD than in those without), and increased; urine citrate in the CKD group (P< 0.2 for interaction for each). Metabolomic analysis revealed several urine organic anions were increased with bicarbonate in CKD, including 3-indoleacetate, citrate/isocitrate, and glutarate. BP was not significantly changed. LIMITATIONS: Small sample size and short feeding duration. CONCLUSIONS: Compared to patients without CKD, those with CKD had lower acid excretion in the form of ammonium but also lower base excretion such as citrate and other organic anions, a potential compensation to preserve acid-base homeostasis. In CKD, acid excretion decreased further, but base excretion (eg, citrate) increased in response to alkali. Urine citrate should be evaluated as an early and responsive marker of impaired acid-base homeostasis. FUNDING: National Institute of Diabetes and Digestive and Kidney Diseases and the Duke O'Brien Center for Kidney Research. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT02427594.

What Do Acute Kidney Injury Survivors Want to Know About Their Condition: A Qualitative Study.

Rationale & Objective: Acute kidney injury (AKI) in the hospital often occurs with other serious illnesses that take medical priority. Despite a persistent risk of adverse outcomes following hospital discharge, AKI survivors often receive inadequate education about how best to mitigate risks once home. We sought to identify AKI survivors' perceived barriers to shared and informed decision-making regarding their AKI diagnosis and self-management. Study Design: Semistructured phone interviews were used to assess patients' perceived barriers and facilitators to AKI self-management after a hospital-related AKI event. Setting & Participants: AKI survivors discharged from Duke University Hospital in Durham, NC, were recruited for interviews to discuss their AKI experiences. Those who received dialysis for AKI were excluded because their perceptions of AKI care were hypothesized to be much different from those of patients not requiring dialysis. Analytical Approach: Twenty-four interviews were conducted between May and August 2018. Interviews were recorded, transcribed, and analyzed by study team members to identify common themes and discrepancies and reach a final consensus. Results: Five consistent themes emerged after thematic saturation: (1) patients were unaware of their AKI diagnosis; (2) patients lacked information about AKI and how to manage it at home; (3) patients identified a lack of understanding about AKI; (4) patients were concerned about dialysis; and (5) patients wanted to know how to prevent AKI in the future. Limitations: Limitations include recruitment from a single center, all study participants receiving a nephrology consultation, and several patients being unable to participate because of persistent illness following hospitalization. Conclusions: AKI survivors are unaware of their diagnosis, receive suboptimal education while hospitalized, and are not equipped with tools to mitigate risks following discharge. Patient-centered interventions promoting AKI awareness and self-management may improve long-term outcomes for high-risk AKI survivors.

A Patient Safety Educational Tool for Patients With Chronic Kidney Disease: Development and Usability Study.

BACKGROUND: Chronic kidney disease (CKD) is a health condition that threatens patient safety; however, few interventions provide patient-centered education about kidney-specific safety hazards. OBJECTIVE: We sought to develop and test the usability of a mobile tablet-based educational tool designed to promote patient awareness of relevant safety topics in CKD. METHODS: We used plain language principles to develop content for the educational tool, targeting four patient-actionable safety objectives that are relevant for individuals with CKD. These four objectives included avoidance of nonsteroidal anti-inflammatory drugs (NSAIDs); hypoglycemia awareness (among individuals with diabetes); temporary cessation of certain medications during acute volume depletion to prevent acute kidney injury (ie, "sick day protocol"); and contrast dye risk awareness. Our teaching strategies optimized human-computer interaction and content retention using audio, animation, and clinical vignettes to reinforce themes. For example, using a vignette of a patient with CKD with pain and pictures of common NSAIDs, participants were asked "Which of the following pain medicines are safe for Mr. Smith to take for his belly pain?" Assessment methods consisted of preknowledge and postknowledge surveys, with provision of correct responses and explanations. Usability testing of the tablet-based tool was performed among 12 patients with any stage of CKD, and program tasks were rated upon completion as no error, noncritical error (self-corrected), or critical error (needing assistance). RESULTS: The 12 participants in this usability study were predominantly 65 years of age or older (n=7, 58%) and female (n=7, 58%); all participants owned a mobile device and used it daily. Among the 725 total tasks that the participants completed, there were 31 noncritical errors (4.3%) and 15 critical errors (2.1%); 1 participant accounted for 30 of the total errors. Of the 12 participants, 10 (83%) easily completed 90% or more of their tasks. Most participants rated the use of the tablet as very easy (n=7, 58%), the activity length as "just right" (rather than too long or too short) (n=10, 83%), and the use of clinical vignettes as helpful (n=10, 83%); all participants stated that they would recommend this activity to others. The median rating of the activity was 8 on a scale of 1 to 10 (where 10 is best). We incorporated all participant recommendations into the final version of the educational tool. CONCLUSIONS: A tablet-based patient safety educational tool is acceptable and usable by individuals with CKD. Future studies leveraging iterations of this educational tool will explore its impact on health outcomes in this high-risk population.