Multidisciplinary Team versus a "Phosphate-Counting" App for Serum Phosphate Control: A Randomized Controlled Trial.

Background: Hyperphosphatemia is almost universal in well-nourished patients with ESKD treated with dialysis due to an imbalance between dietary intake and phosphate removal via residual kidney function and dialysis. Although food phosphate content can vary dramatically between meals, the current standard is to prescribe a fixed dose of phosphate binder that may not match meal phosphate intake. The primary objective of our study was to determine if the use of an app that matches phosphate binder dose with food phosphate content would be associated with an improvement in serum phosphate and a reduction in calcium carbonate intake compared with the multidisciplinary renal team. Methods: Eighty patients with ESKD treated with peritoneal dialysis at a tertiary care hospital in Canada were randomized to the standard of care for serum phosphate management (multidisciplinary renal team) versus the OkKidney app. Serum phosphate was measured at baseline and then monthly for 3 months with adjustments to phosphate management as deemed necessary by the multidisciplinary team (control) or the phosphate binder multiplier in the OkKidney app (intervention) on the basis of the laboratory values. The primary analysis was an unpaired t test of the serum phosphate at study completion. Results: The participants were 56 (±14) years old, and 54% were men; the most common cause of ESKD was diabetes mellitus. The serum phosphate values were 1.96 (0.41) and 1.85 (0.44) mmol/L in the control and intervention groups, respectively, at the end of 3 months (P=0.30). The median elemental daily dose of calcium carbonate did not differ between the groups at study completion (587 mg [309-928] versus 799 mg [567-1183], P=0.29). Conclusions: The OkKidney app was associated with similar but not superior serum phosphate control to the standard of care, which included renal dietician support. Clinical Trial registry name and registration number: US National Library Medicine ClinicalTrials.gov, NCT01643486.

In Search of a Simple and Reliable Method of Measuring Intra-abdominal Pressure in Peritoneal Dialysis Patients.

BACKGROUND: Patients treated with peritoneal dialysis (PD) are at increased risk of developing mechanical complications such as dialysate leaks and hernias thought to be partially related to an increase in intra-abdominal pressure (IAP) secondary to dialysate in the abdomen. However, measurement of IAP requires specialized equipment that is not readily available in the home dialysis unit. OBJECTIVES: To develop a reliable method of measuring IAP in PD patients that could be easily used in the home dialysis unit. We hypothesized that the handheld Stryker pressure monitor would be suitable for this purpose via connection to the PD catheter. DESIGN: Cross-sectional. SETTING: Tertiary Care Hospital, Ottawa, Ontario, Canada. PATIENTS: Patients who were having a PD catheter inserted via laparoscopic surgery at The Ottawa Hospital were recruited for the study. MEASUREMENTS: With the patients at end-expiration, the IAP measured with the Stryker monitor connected to the PD catheter was compared with the insufflator pressures of 15, 10, and 5 mm Hg. METHODS: Bland-Altman plots were constructed and intraclass correlation coefficients were calculated for each pressure. RESULTS: Twelve patients participated in the study: 9 men and 3 women. They were on average 53 ± 15 years old and 81 ± 13.4 kg. Two patients had to be excluded from the analysis due to difficulties zeroing the Stryker pressure monitor at the time of surgery. There were also rapid fluctuations in the insufflator pressure recording, creating additional challenges in comparing the 2 measurements at end-expiration. The 95% limits of agreement for the Bland-Altman plots ranged from 7.9 (@15 mm Hg) to 12.2 (@10 mm Hg). The intraclass correlation coefficients for reliability of the individual measurements ranged from 0.015 (10 mm Hg) to 0.634 (15 mm Hg). LIMITATIONS: Small sample size and lack of a gold standard comparator may have affected our results. CONCLUSIONS: In our study, we used the operating room insufflator as the gold standard for measuring IAP. By Bland-Altman plots and intraclass correlation coefficients, the pressure values obtained with the Stryker pressure monitor were not a reliable estimate of insufflator IAP especially at lower pressures. Further studies are needed to identify an ideal tool for measurement of IAP to guide PD management.

CONTEXTE: Les patients traités par dialyse péritonéale (DP) sont plus sujets aux complications mécaniques (hernies, fuites de dialysat) attribuées en partie à une augmentation de la pression intra-abdominale (PIA) due à l'accumulation de dialysat dans l'abdomen. La mesure de la PIA requiert toutefois de l'équipement spécialisé difficilement accessible en contexte de dialyse à domicile. OBJECTIF: Développer une méthode fiable, et facile à utiliser en contexte de dialyse à domicile, pour mesurer la PIA chez les patients traités par DP. Nous avons émis l'hypothèse qu'un tensiomètre portatif Stryker raccordé au cathéter de DP pourrait convenir à cet usage. TYPE D'ÉTUDE: Étude transversale. CADRE: Un centre de soins tertiaires d'Ottawa (Ontario) au Canada. SUJETS: Des patients de l'hôpital d'Ottawa à qui on avait inséré un cathéter de DP par chirurgie laparoscopique. MESURES: La pression intra-abdominale, mesurée en fin d'expiration à l'aide d'un tensiomètre Stryker raccordé au cathéter de DP, a été comparée aux pressions de 15, 10 et 5 mm Hg de l'insufflateur. MÉTHODOLOGIE: Des courbes de Bland-Altman ont été établies et des coefficients de corrélation intraclasse ont été calculés pour chaque mesure de pression. RÉSULTATS: Douze patients, soit neuf hommes et trois femmes, âgés de 53 ± 15 ans et pesant 81 ±13,4 kg en moyenne, ont participé à l'étude. Deux patients ont été exclus de l'analyse en raison de difficultés à remettre le tensiomètre Stryker à zéro au moment de l'intervention. On a observé de rapides fluctuations dans l'enregistrement de la pression avec l'insufflateur, ce qui a compliqué davantage la comparaison des deux mesures en fin d'expiration. Les limites de concordance à 95 % pour les courbes de Bland-Altman se situaient entre 7,9 (15 mm Hg) et 12,2 (10 mm Hg). Les coefficients de corrélation intraclasses pour la fiabilité des mesures individuelles s'échelonnaient entre 0,015 (10 mm Hg) et 0,634 (15 mm Hg). LIMITES: Les résultats sont limités par la faible taille de l'échantillon et l'absence d'étalon-or pour la comparaison. CONCLUSION: Pour cette étude, l'insufflateur de la salle d'opération a servi d'étalon-or pour la mesure de la PIA. Selon les courbes de Bland-Altman et les coefficients de corrélation intraclasses, les valeurs de pression obtenues avec le tensiomètre Stryker n'ont pas constitué une estimation fiable de la PIA de l'insufflateur, particulièrement pour les faibles valeurs de pression. Des études supplémentaires sont nécessaires pour proposer un outil de mesure fiable de la PIA afin de guider la gestion de la DP.

A Pilot Study of OkKidney, a Phosphate Counting Application in Patients on Peritoneal Dialysis.

BACKGROUND: Hyperphosphatemia is associated with adverse outcomes in patients treated with peritoneal dialysis (PD). We have shown that a fixed meal phosphate binder dosing schedule is not appropriate. The purpose of this study was to evaluate the beta version of OkKidney, a phosphate counting app that matches meal phosphate content with binder dose. METHODS: A convenience sample of adult patients treated with PD completed a pre-survey that included the technology readiness index (TRI 2.0). After a short information session, patients used OkKidney for 30 days. Pre- and post-intervention serum calcium, serum phosphate, and calcium carbonate binder intake were collected and compared using a paired t-test. A post-intervention survey using a 5-point Likert scale was used to gather patient feedback. RESULTS: Ten patients (5M, 5F) completed the study protocol. Participants were 55 ± 17 years old, predominately Caucasian, retired (60%), and owned a smartphone (70%). The median TRI score was 3.66 (max 5), indicating a moderate level of readiness. The post-survey results indicated a favorable rating for ease of use (µ = 4.4 ± 0.84) and usefulness (µ = 4.3 ± 0.68) of OkKidney. The average serum phosphate (p = 0.99) and calcium (p = 0.68) were not different pre-/post-intervention, but calcium carbonate intake tended to decrease (p = 0.12). CONCLUSION: Patients reported a positive experience with OkKidney. Further patient-specific adjustments of the binder dose to meal phosphate content may be required to demonstrate a statistically significant decrease in phosphate levels. We believe a larger trial is warranted to investigate the clinical implications of this app.