Maggie Han, MSc

Research Scientist 

Maggie Han

Maggie has a bachelor’s degree from New York University, where she studied economics and has a master’s degree in health sciences from Pontifícia Universidade Católica do Paraná. Her work is mainly focused on pervasive sensing techniques, wearables, and study of physical activity, sleep, and patient-reported outcomes in chronic kidney disease patients

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Recent Articles by Maggie Han, MSc

  • Frontiers in nephrology
    July 22, 2022
    SARS-CoV-2 neutralizing antibody response after three doses of mRNA1273 vaccine and COVID-19 in hemodialysis patients
    Xiaoling Wang, Maggie Han, Lemuel Rivera Fuentes, Ohnmar Thwin, Nadja Grobe, Kevin Wang, Yuedong Wang, Peter Kotanko
    RESULTSForty-two patients had three doses of mRNA1273. Compared to levels prior to the third dose, nAb-WT increased 18-fold (peak at day 23) and nAb-Omicron increased 23-fold (peak at day 24) after the third dose. Peak nAb-WT exceeded peak nAb-Omicron 27-fold. Twenty-one patients had COVID-19 between December 24, 2021, and February 2, 2022. Following COVID-19, nAb-WT and nAb-Omicron increased 12- and 40-fold, respectively. While levels of vaccinal and post-COVID nAb-WT were comparable, post-COVID nAb-Omicron levels were 3.2 higher than the respective peak vaccinal nAb-Omicron. Four immunocompromised patients having reasons other than end-stage kidney disease have very low to no nAb after the third dose or COVID-19.CONCLUSIONSOur results suggest that most hemodialysis patients have a strong humoral response to the third dose of vaccination and an even stronger post-COVID-19 humoral response. Nevertheless, nAb levels clearly decay over time. These findings may inform ongoing discussions regarding a fourth vaccination in hemodialysis patients.BACKGROUNDIn hemodialysis patients, a third vaccination is frequently administered to augment protection against coronavirus disease 2019 (COVID-19). However, the newly emerged B.1.1.159 (Omicron) variant may evade vaccinal protection more easily than previous strains. It is of clinical interest to better understand the neutralizing activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants after booster vaccine or COVID-19 infection in these mostly immunocompromised patients.METHODSHemodialysis patients from four dialysis centers were recruited between June 2021 and February 2022. Each patient provided a median of six serum samples. SARS-CoV-2 neutralizing antibodies (nAbs) against wild type (WT) or Omicron were measured using the GenScript SARS-CoV-2 Surrogate Virus Neutralization Test Kit.
  • Nephrology, dialysis, transplantation
    October 15, 2021
    Effect of hemodiafiltration on measured physical activity: primary results of the HDFIT randomized controlled trial
    Roberto Pecoits-Filho, John Larkin, Carlos Eduardo Poli-de-Figueiredo, Américo Lourenço Cuvello-Neto, Ana Beatriz Lesqueves Barra, Priscila Bezerra Gonçalves, Shimul Sheth, Murilo Guedes, Maggie Han, Viviane Calice-Silva, Manuel Carlos Martins de Castro, Peter Kotanko, Thyago Proenca de Moraes, Jochen G Raimann, Maria Eugenia F Canziani
    RESULTSWe randomized 195 patients (HDF 97; HD 98) between August 2016 and October 2017. Despite the achievement of a high convective volume in the majority of sessions and a positive impact on solute removal, the treatment effect HDF on the primary outcome was +538 [95% confidence interval (CI) -330 to 1407] steps/24 h after dialysis compared with HD, and was not statistically significant. Despite a lack of statistical significance, the observed size of the treatment effect was modest and driven by steps taken between 1.5 and 24.0 h after dialysis, in particular between 20 and 24 h (+197 steps; 95% CI -95 to 488).CONCLUSIONSHDF did not have a statistically significant treatment effect on PA 24 h following dialysis, albeit effect sizes may be clinically meaningful and deserve further investigation.BACKGROUNDDialysis patients are typically inactive and their physical activity (PA) decreases over time. Uremic toxicity has been suggested as a potential causal factor of low PA in dialysis patients. Post-dilution high-volume online hemodiafiltration (HDF) provides greater higher molecular weight removal and studies suggest better clinical/patient-reported outcomes compared with hemodialysis (HD).METHODSHDFIT was a randomized controlled trial at 13 clinics in Brazil that aimed to investigate the effects of HDF on measured PA (step counts) as a primary outcome. Stable HD patients (vintage 3-24 months) were randomized to receive HDF or high-flux HD. Treatment effect of HDF on the primary outcome from baseline to 3 and 6 months was estimated using a linear mixed-effects model.
  • Blood purification
    March 31, 2021
    Effect of Statewide Lockdown in Response to COVID-19 Pandemic on Physical Activity Levels of Hemodialysis Patients
    Maggie Han, Priscila Preciado, Ohnmar Thwin, Xia Tao, Leticia M Tapia-Silva, Lemuel Rivera Fuentes, Mohamad Hakim, Amrish Patel, Lela Tisdale, Hanjie Zhang, Peter Kotanko
    RESULTS42 patients were included. Their mean age was 55 years, 79% were males, and 69% were African Americans. Between January 1 and February 13, 2020, patients took on average 5,963 (95% CI 4,909-7,017) steps/day. In the week prior to the mandated lockdown, when a national emergency was declared, and in the week of the shutdown, the average number of daily steps had decreased by 868 steps/day (95% CI 213-1,722) and 1,222 steps/day (95% CI 668-2300), respectively. Six patients were diagnosed with COVID-19 during the study period. Five of them exhibited significantly higher PAL in the 2 weeks prior to showing COVID-19 symptoms compared to COVID-19 negative patients.BACKGROUND/OBJECTIVESOn March 22, 2020, a statewide stay-at-home order for nonessential tasks was implemented in New York State. We aimed to determine the impact of the lockdown on physical activity levels (PAL) in hemodialysis patients.CONCLUSIONLockdown measures were associated with a significant decrease in PAL in hemodialysis patients. Patients who contracted COVID-19 had higher PAL during the incubation period. Methods to increase PAL while allowing for social distancing should be explored and implemented.METHODSStarting in May 2018, we are conducting an observational study with a 1-year follow-up on PAL in patients from 4 hemodialysis clinics in New York City. Patients active in the study as of March 22, 2020, were included. PAL was defined by steps taken per day measured by a wrist-based monitoring device (Fitbit Charge 2). Average steps/day were calculated for January 1 to February 13, 2020, and then weekly from February 14 to June 30.
  • Blood purification
    January 28, 2021
    Hepatitis B Vaccination Response in Hemodialysis Patients: The Impact of Dialysis Shift
    Maggie Han, Xiaoling Ye, Sharon Rao, Schantel Williams, Stephan Thijssen, Jeffrey Hymes, Franklin W Maddux, Peter Kotanko
    RESULTSPatients were 65 years old, 57% male, and had a HD vintage of 10 months. Patients whose dialysis treatments started before 8:30 a.m. were more likely to be younger, male, and have a greater dialysis vintage. Patients receiving Engerix B® and starting dialysis before 8:30 a.m. had a significantly higher seroconversion rate compared to patients who started dialysis after 8:30 a.m. Early dialysis start was a significant predictor of seroconversion in univariate and multivariate regression including male gender, but not in multivariate regression including age, neutrophil-to-lymphocyte ratio, and vintage.CONCLUSIONWhile better sleep following vaccination is associated with seroconversion in the general population, this is not the case in hemodialysis patients after multivariate adjustment. In the context of end-stage kidney disease, early dialysis start is not a significant predictor of HB vaccination response. The association between objectively measured postvaccination sleep duration and seroconversion rate should be investigated.BACKGROUND/AIMSHepatitis B (HB) vaccination in hemodialysis patients is important as they are at a higher risk of contracting HB. However, hemodialysis patients have a lower HB seroconversion rate than their healthy counterparts. As better sleep has been associated with better seroconversion in healthy populations and early hemodialysis start has been linked to significant sleep-wake disturbances in hemodialysis patients, we examined if hemodialysis treatment start time is associated with HB vaccination response.METHODSDemographics, standard-of-care clinical, laboratory, and treatment parameters, dialysis shift data, HB antigen status, HB vaccination status, and HB titers were collected from hemodialysis patients in Fresenius clinics from January 2010 to December 2015. Patients in our analysis received 90% of dialysis treatments either before or after 8:30 a.m., were negative for HB antigen, and received a complete series of HB vaccination (Engerix B® or Recombivax HB™). Univariate and multivariate regression models examined whether dialysis start time is a predictor of HB vaccination response.
  • Kidney360
    December 1, 2020
    SARS-CoV-2 in Spent Dialysate from Chronic Peritoneal Dialysis Patients with COVID-19
    Xiaoling Wang, Amrish Patel, Lela Tisdale, Zahin Haq, Xiaoling Ye, Rachel Lasky, Priscila Preciado, Xia Tao, Gabriela Ferreira Dias, Joshua E Chao, Mohamad Hakim, Maggie Han, Ohnmar Thwin, Jochen Raimann, Dinesh Chatoth, Peter Kotanko, Nadja Grobe
    RESULTSA total of 26 spent PD dialysate samples were collected from 11 patients from ten dialysis centers. Spent PD dialysate samples were collected, on average, 25±13 days (median, 20; range, 10-45) after the onset of symptoms. The temporal distance of PD effluent collection relative to the closest positive nasal-swab RT-PCR result was 15±11 days (median, 14; range, 1-41). All 26 PD effluent samples tested negative at three SARS-CoV-2 genomic regions.CONCLUSIONSOur findings indicate the absence of SARS-CoV-2 in spent PD dialysate collected at ≥10 days after the onset of COVID-19 symptoms. We cannot rule out the presence of SARS-CoV-2 in spent PD dialysate in the early stage of COVID-19.BACKGROUNDTo date, it is unclear whether SARS-CoV-2 is present in spent dialysate from patients with COVID-19 on peritoneal dialysis (PD). Our aim was to assess the presence or absence of SARS-CoV-2 in spent dialysate from patients on chronic PD who had a confirmed diagnosis of COVID-19.METHODSSpent PD dialysate samples from patients on PD who were positive for COVID-19 were collected between March and August 2020. The multiplexed, real-time RT-PCR assay contained primer/probe sets specific to different SARS-CoV-2 genomic regions and to bacteriophage MS2 as an internal process control for nucleic acid extraction. Demographic and clinical data were obtained from patients' electronic health records.
  • Nephrology (Carlton, Vic.)
    August 11, 2020
    Patient perception of vitality and measured physical activity in patients receiving haemodialysis
    Juliana Leme, Murilo Guedes, John Larkin, Maggie Han, Ana Beatriz Lesqueves Barra, Maria Eugenia F Canziani, Américo Lourenço Cuvello Neto, Carlos Eduardo Poli-de-Figueiredo, Thyago Proenca de Moraes, Roberto Pecoits-Filho
    RESULTSAmong 176 patients, Vitality score was 63 ± 21 and the DRT was ≤30 minutes in 57% of patients. The mean number of steps was 5288 ± 3540 in 24 hours after HD and 953 ± 617 in the 2-hour post-HD period. The multivariable analysis confirmed Vitality scores were associated with physical activity in the 24-hour post-HD period. In contrast, DRT was not associated with physical activity captured by the accelerometer in the period immediately (2 hours) after the HD session.AIMFatigue in haemodialysis (HD) patients can be captured in quality of life questionnaires and by the dialysis recovery time (DRT) question. The associations between fatigue and measured physical activity has not been explored until the present. We tested our hypothesis that the patient perception of chronic and post dialysis fatigue would be associated with lower physical activity.CONCLUSIONChronic fatigue was negatively associated with step counts, while patient perception of post-dialysis fatigue was not associated with physical activity. These patterns indicate limitations in interpretation of DRT. Since physical activity is an important component of a healthy life, our results may partially explain the associations between fatigue and poor outcomes in HD patients.METHODSThis study was a cross sectional evaluation of baseline data from HD patients recruited in the HDFIT trial. Vitality scores from the Kidney Disease Quality of Life (KDQOL-36) and the dialysis recovery time (DRT) question were used as indicators of chronic and post dialysis fatigue, respectively. Granular physical activity was measured by accelerometers as part of the study protocol.
  • BMC nephrology
    May 25, 2020
    Impact of hemodialysis and post-dialysis period on granular activity levels
    John W Larkin, Maggie Han, Hao Han, Murilo H Guedes, Priscila Bezerra Gonçalves, Carlos Eduardo Poli-de-Figueiredo, Américo Lourenço Cuvello-Neto, Ana Beatriz L Barra, Thyago Proença de Moraes, Len A Usvyat, Peter Kotanko, Maria Eugenia F Canziani, Jochen G Raimann, Roberto Pecoits-Filho
    RESULTSAmong 195 patients (mean age 53 ± 15 years, 71% male), step counts per 24-h were 3919 ± 2899 on HD days, 5308 ± 3131 on first non-HD days (p < 0.001), and 4926 ± 3413 on second non-HD days (p = 0.032). During concurrent/parallel times to HD on first and second non-HD days, patients took 1308 and 1128 more steps (both p < 0.001). Patients took 276 more steps and had highest rates of steps/hour 2-h post-HD versus same times on first non-HD days (all p < 0.05). Consistent findings were observed on second non-HD days.CONCLUSIONSPA was higher within 2-h of HD versus same times on non-HD days. Lower PA on HD days was attributable to intradialytic inactivity. The established PA profiles are of importance to the design and development of exercise programs that aim to increase activity during and between HD treatments.TRIAL REGISTRATIONHDFIT was prospectively registered 20 April 2016 on (NCT02787161).BACKGROUNDPhysical activity (PA) is typically lower on hemodialysis (HD) days. Albeit intradialytic inactivity is expected, it is unknown whether recovery after HD contributes to low PA. We investigated the impact of HD and post-HD period on granular PA relative to HD timing.METHODSWe used baseline data from the HDFIT trial conducted from August 2016 to October 2017. Accelerometry measured PA over 1 week in patients who received thrice-weekly high-flux HD (vintage 3 to 24 months), were clinically stable, and had no ambulatory limitations. PA was assessed on HD days (0 to ≤24 h after start HD), first non-HD days (> 24 to ≤48 h after start HD) and second non-HD day (> 48 to ≤72 h after start HD). PA was recorded in blocks/slices: 4 h during HD, 0 to ≤2 h post-HD (30 min slices), and > 2 to ≤20 h post-HD (4.5 h slices). Blocks/slices of PA were captured at concurrent/parallel times on first/second non-HD days compared to HD days.

The culture at the Renal Research Institute promotes diversity, innovative thinking, and excellence.

Maggie Han, MSc
Research Scientist