1.Predictors of moderate, severe, and critical COVID-19 infection in a largely vaccinated kidney transplant recipient cohort during the Omicron era: the importance of timely booster vaccinations and early presentation to care
Cherie Le Si GAN ; Shimin Jasmine CHUNG ; Quan Yao HO ; Thuan Tong TAN ; Ban Hock TAN ; Ian Tatt LIEW ; Carolyn Shan-Yeu TIEN ; Sobhana THANGARAJU ; Terence KEE
Clinical Transplantation and Research 2025;39(1):46-54
Background:
Kidney transplant recipients (KTRs) are at risk of coronavirus disease 2019 (COVID-19) complications and mortality. This study examined factors associated with moderate, severe, or critical COVID-19 infection among KTRs during the Omicron-predominant period.
Methods:
This single-center retrospective study included KTRs aged ≥18 years diag-nosed with COVID-19 between January 1, 2022, and December 31, 2023. Mild infection was defined as symptomatic illness without lower respiratory tract infection (LRTI);moderate infection as LRTI without hypoxia; severe infection as oxygen saturation <94% on room air; and critical infection as respiratory failure, septic shock, or multiple organ dysfunction. We compared the characteristics of KTRs with asymptomatic or mild COVID-19 versus those with moderate to critical disease. Logistic regression analysis was performed to identify factors associated with moderate to critical illness.
Results:
Most KTRs (94.4%) had received three or more vaccine doses. Of 603 episodes of COVID-19 infection during the study period, 554 (91.9%) were asymptomatic or mild, while 49 (8.1%) were moderate to critical. Multivariate analysis revealed that older age (adjusted odds ratio [aOR], 1.037; 95% confidence interval [CI], 1.006–1.069) and longer symptom duration before seeking care (aOR, 1.288; 95% CI, 1.155–1.436) were associated with higher odds of moderate to critical disease. Protective factors included receiving a vaccine booster within the past year (aOR, 0.414; 95% CI, 0.212–0.809) and higher glomerular filtration rate (aOR, 0.971; 95% CI, 0.956–0.986).
Conclusions
KTRs should seek care early if infected with COVID-19 and keep their COVID-19 vaccine boosters updated within 1 year of the last dose.
2.Predictors of moderate, severe, and critical COVID-19 infection in a largely vaccinated kidney transplant recipient cohort during the Omicron era: the importance of timely booster vaccinations and early presentation to care
Cherie Le Si GAN ; Shimin Jasmine CHUNG ; Quan Yao HO ; Thuan Tong TAN ; Ban Hock TAN ; Ian Tatt LIEW ; Carolyn Shan-Yeu TIEN ; Sobhana THANGARAJU ; Terence KEE
Clinical Transplantation and Research 2025;39(1):46-54
Background:
Kidney transplant recipients (KTRs) are at risk of coronavirus disease 2019 (COVID-19) complications and mortality. This study examined factors associated with moderate, severe, or critical COVID-19 infection among KTRs during the Omicron-predominant period.
Methods:
This single-center retrospective study included KTRs aged ≥18 years diag-nosed with COVID-19 between January 1, 2022, and December 31, 2023. Mild infection was defined as symptomatic illness without lower respiratory tract infection (LRTI);moderate infection as LRTI without hypoxia; severe infection as oxygen saturation <94% on room air; and critical infection as respiratory failure, septic shock, or multiple organ dysfunction. We compared the characteristics of KTRs with asymptomatic or mild COVID-19 versus those with moderate to critical disease. Logistic regression analysis was performed to identify factors associated with moderate to critical illness.
Results:
Most KTRs (94.4%) had received three or more vaccine doses. Of 603 episodes of COVID-19 infection during the study period, 554 (91.9%) were asymptomatic or mild, while 49 (8.1%) were moderate to critical. Multivariate analysis revealed that older age (adjusted odds ratio [aOR], 1.037; 95% confidence interval [CI], 1.006–1.069) and longer symptom duration before seeking care (aOR, 1.288; 95% CI, 1.155–1.436) were associated with higher odds of moderate to critical disease. Protective factors included receiving a vaccine booster within the past year (aOR, 0.414; 95% CI, 0.212–0.809) and higher glomerular filtration rate (aOR, 0.971; 95% CI, 0.956–0.986).
Conclusions
KTRs should seek care early if infected with COVID-19 and keep their COVID-19 vaccine boosters updated within 1 year of the last dose.
3.Predictors of moderate, severe, and critical COVID-19 infection in a largely vaccinated kidney transplant recipient cohort during the Omicron era: the importance of timely booster vaccinations and early presentation to care
Cherie Le Si GAN ; Shimin Jasmine CHUNG ; Quan Yao HO ; Thuan Tong TAN ; Ban Hock TAN ; Ian Tatt LIEW ; Carolyn Shan-Yeu TIEN ; Sobhana THANGARAJU ; Terence KEE
Clinical Transplantation and Research 2025;39(1):46-54
Background:
Kidney transplant recipients (KTRs) are at risk of coronavirus disease 2019 (COVID-19) complications and mortality. This study examined factors associated with moderate, severe, or critical COVID-19 infection among KTRs during the Omicron-predominant period.
Methods:
This single-center retrospective study included KTRs aged ≥18 years diag-nosed with COVID-19 between January 1, 2022, and December 31, 2023. Mild infection was defined as symptomatic illness without lower respiratory tract infection (LRTI);moderate infection as LRTI without hypoxia; severe infection as oxygen saturation <94% on room air; and critical infection as respiratory failure, septic shock, or multiple organ dysfunction. We compared the characteristics of KTRs with asymptomatic or mild COVID-19 versus those with moderate to critical disease. Logistic regression analysis was performed to identify factors associated with moderate to critical illness.
Results:
Most KTRs (94.4%) had received three or more vaccine doses. Of 603 episodes of COVID-19 infection during the study period, 554 (91.9%) were asymptomatic or mild, while 49 (8.1%) were moderate to critical. Multivariate analysis revealed that older age (adjusted odds ratio [aOR], 1.037; 95% confidence interval [CI], 1.006–1.069) and longer symptom duration before seeking care (aOR, 1.288; 95% CI, 1.155–1.436) were associated with higher odds of moderate to critical disease. Protective factors included receiving a vaccine booster within the past year (aOR, 0.414; 95% CI, 0.212–0.809) and higher glomerular filtration rate (aOR, 0.971; 95% CI, 0.956–0.986).
Conclusions
KTRs should seek care early if infected with COVID-19 and keep their COVID-19 vaccine boosters updated within 1 year of the last dose.
4.Predictors of moderate, severe, and critical COVID-19 infection in a largely vaccinated kidney transplant recipient cohort during the Omicron era: the importance of timely booster vaccinations and early presentation to care
Cherie Le Si GAN ; Shimin Jasmine CHUNG ; Quan Yao HO ; Thuan Tong TAN ; Ban Hock TAN ; Ian Tatt LIEW ; Carolyn Shan-Yeu TIEN ; Sobhana THANGARAJU ; Terence KEE
Clinical Transplantation and Research 2025;39(1):46-54
Background:
Kidney transplant recipients (KTRs) are at risk of coronavirus disease 2019 (COVID-19) complications and mortality. This study examined factors associated with moderate, severe, or critical COVID-19 infection among KTRs during the Omicron-predominant period.
Methods:
This single-center retrospective study included KTRs aged ≥18 years diag-nosed with COVID-19 between January 1, 2022, and December 31, 2023. Mild infection was defined as symptomatic illness without lower respiratory tract infection (LRTI);moderate infection as LRTI without hypoxia; severe infection as oxygen saturation <94% on room air; and critical infection as respiratory failure, septic shock, or multiple organ dysfunction. We compared the characteristics of KTRs with asymptomatic or mild COVID-19 versus those with moderate to critical disease. Logistic regression analysis was performed to identify factors associated with moderate to critical illness.
Results:
Most KTRs (94.4%) had received three or more vaccine doses. Of 603 episodes of COVID-19 infection during the study period, 554 (91.9%) were asymptomatic or mild, while 49 (8.1%) were moderate to critical. Multivariate analysis revealed that older age (adjusted odds ratio [aOR], 1.037; 95% confidence interval [CI], 1.006–1.069) and longer symptom duration before seeking care (aOR, 1.288; 95% CI, 1.155–1.436) were associated with higher odds of moderate to critical disease. Protective factors included receiving a vaccine booster within the past year (aOR, 0.414; 95% CI, 0.212–0.809) and higher glomerular filtration rate (aOR, 0.971; 95% CI, 0.956–0.986).
Conclusions
KTRs should seek care early if infected with COVID-19 and keep their COVID-19 vaccine boosters updated within 1 year of the last dose.
5.COVID-19 vaccine acceptance among kidney transplant recipients in Singapore.
Ian Tatt LIEW ; Hanis Abdul KADIR ; Sobhana THANGARAJU ; Quan Yao HO ; Eleanor NG ; Fiona FOO ; Terence KEE
Singapore medical journal 2025;66(2):73-80
INTRODUCTION:
A successful vaccination programme forms the cornerstone of controlling coronavirus disease 2019 (COVID-19). The unprecedented speed of COVID-19 vaccine development and lack of long-term data have raised fears regarding its safety and efficacy. Vaccine hesitancy can undermine the uptake, and hence success of the vaccination programme. Given the high complication rates of COVID-19 infections in kidney transplant recipients, it is particularly important to identify and address vaccine hesitancy in this population.
METHODS:
We conducted a cross-sectional survey among kidney transplant recipients attending transplant clinic between 5 April and 5 May 2021. The survey assessed attitudes towards COVID-19, willingness/hesitancy towards COVID-19 vaccination, vaccination concerns and prompts to vaccination. This was scored on a Likert scale with scores ranging from 'strongly disagree' - 1 point to 'strongly agree' - 5 points.
RESULTS:
One hundred and one completed responses were captured. Of these, 86% respondents reported to agree or strongly agree to vaccination. This was despite significant concerns of allograft rejection (mean score 4.12, standard deviation [SD] 0.97) and decreased immunosuppressant efficacy (mean score 4.14, SD 0.96) with vaccination. Multivariable model showed a positive association with transplant vintage of ≥ 5 years (median 2.41), lower educational levels of secondary school or less (median 5.82) and healthcare provider advocacy (median 1.88) in predicting vaccine acceptance.
CONCLUSIONS
Vaccine acceptance rate was high among kidney transplant recipients. Vaccine hesitancy remains a concern in those with a transplant vintage of less than 5 years and those with tertiary educational level. Healthcare provider advocacy is important in improving vaccine acceptance rates.
Humans
;
Kidney Transplantation
;
Singapore/epidemiology*
;
Male
;
Cross-Sectional Studies
;
Female
;
COVID-19 Vaccines
;
COVID-19/epidemiology*
;
Middle Aged
;
Adult
;
Transplant Recipients/psychology*
;
Patient Acceptance of Health Care/statistics & numerical data*
;
Vaccination Hesitancy/psychology*
;
Surveys and Questionnaires
;
Vaccination/psychology*
;
Aged
;
SARS-CoV-2
6.Knowledge of COVID-19 and associated factors among kidney transplant recipients and donors in Singapore.
Ian Tatt LIEW ; Yeli WANG ; Terence KEE ; Ping Sing TEE ; Rupesh Madhukar SHIRORE ; Sobhana THANGARAJU ; Quan Yao HO ; York Moi LU ; Jin Hua YONG ; Fiona FOO ; Eleanor NG ; Xia HE ; Constance LEE ; Shannon BAEY ; Marjorie FOO ; Tazeen Hasan JAFAR
Singapore medical journal 2025;66(2):81-90
BACKGROUND:
Effective interventions during the coronavirus disease 2019 (COVID-19) pandemic require an understanding of patients' knowledge and perceptions that influence their behaviour. Our study assessed knowledge of COVID-19 among kidney transplant recipients and donors, hitherto unevaluated.
METHODS:
We conducted a cross-sectional survey among 325 kidney transplant recipients and 172 donors between 1 May 2020 and 30 June 2020. The survey questionnaire assessed knowledge levels of COVID-19, sociodemographic data, health status, psychosocial impact of COVID-19 and precautionary behaviours during the pandemic.
RESULTS:
The mean COVID-19 knowledge score of the study population was 7.5 (standard deviation: 2.2) out of 10. The mean score was significantly higher among kidney recipients compared to kidney donors (7.9 [1.9] vs. 6.7 [2.6]; P <0.001). Younger age (21-49 vs. ≥50 years) and higher education (diploma and higher vs. secondary and lower) were associated with significantly higher knowledge scores in donors, but not among recipients ( P -interactions ≤0.01). In both kidney recipients and donors, financial concerns and/or social isolation were associated with lower knowledge levels.
CONCLUSIONS
Concerted efforts are needed to improve COVID-19 knowledge in kidney transplant recipients and donors, particularly older donors, donors with lower education and patients with financial concerns or feelings of social isolation. Intensive patient education may mitigate the impact of education levels on COVID-19 knowledge levels.
Humans
;
COVID-19/epidemiology*
;
Kidney Transplantation
;
Middle Aged
;
Singapore/epidemiology*
;
Male
;
Female
;
Adult
;
Cross-Sectional Studies
;
Health Knowledge, Attitudes, Practice
;
Transplant Recipients/psychology*
;
Surveys and Questionnaires
;
Tissue Donors/psychology*
;
SARS-CoV-2
;
Young Adult
;
Aged
;
Pandemics
7.Coronavirus disease 2019 in kidney transplant recipients: a systematic review and meta-analysis.
Quan Yao HO ; Rehena SULTANA ; Tung Lin LEE ; Sobhana THANGARAJU ; Terence KEE ; Htay HTAY
Singapore medical journal 2023;64(10):593-602
INTRODUCTION:
The clinical presentation and outcomes of coronavirus disease 2019 (COVID-19) in kidney transplant recipients (KTRs) have not been well studied.
METHODS:
We performed a meta-analysis to examine the presenting features, outcomes and the effect of treatment on outcomes of KTRs with COVID-19. Database search was performed up to 5 September 2020 through PubMed, Embase, Web of Science, Scopus and CENTRAL.
RESULTS:
Overall, 23 studies (1,373 patients) were included in the review and meta-analysis. The most common presenting symptoms included fever (74.0%, 95% confidence interval [CI] 65.3-81.1), cough (63.3%, 95% CI 56.5-69.6) and dyspnoea (47.5%, 95% CI 39.6-55.6). Pooled rates of mortality and critical illness were 21.1% (95% CI 15.3-28.4) and 27.7% (95% CI 21.5-34.8), respectively. Acute kidney injury occurred in 38.9% (95% CI 30.6-48.1) and dialysis was required in 12.4% (95% CI 8.3-18.0) of the cases.
CONCLUSION
Kidney transplant recipients with COVID-19 have a similar clinical presentation as the general population, but they have higher morbidity and mortality. It is uncertain whether high-dose corticosteroid or hydroxychloroquine reduces the risks of mortality in KTRs with COVID-19.
8.Impact of COVID-19 infections among kidney transplant recipients.
Shimin Jasmine CHUNG ; Quan Yao HO ; Ian Tatt LIEW ; Siew Yee THIEN ; Yvonne Fu Zi CHAN ; Benjamin Pei Zhi CHERNG ; Hei Man WONG ; Ying Ying CHUA ; Terence KEE ; Thuan Tong TAN
Annals of the Academy of Medicine, Singapore 2022;51(2):122-126
9.Incidence, risk factors and outcomes of malignancies after kidney transplantation in Singapore: a 12-year experience.
Su Hooi TEO ; Kian-Guan LEE ; Gek Hsiang LIM ; Si Xuan KOO ; Maria Erika RAMIREZ ; Khuan Yew CHOW ; Terence KEE
Singapore medical journal 2019;60(5):253-259
INTRODUCTION:
Data on malignancy after kidney transplantation (KTX) is limited in our region, leading to challenges in the care of renal allograft recipients. We aimed to examine the epidemiology, risk factors and outcomes of post-KTX patients.
METHODS:
A retrospective cohort study was conducted of 491 patients who underwent KTX from 1 January 2000 to 31 December 2011. Data linkage analysis was done between our centre and the National Registry of Diseases Office to determine the standardised incidence ratio (SIR), standardised mortality ratio (SMR) and risk factors for malignancy after KTX.
RESULTS:
31 patients (61.3% male) developed malignancy during this period, and their median age at diagnosis was 50 (range 18-65) years. Median time to malignancy diagnosis was 2.6 (range 0.3-7.9) years, with cumulative incidence of 1%, 4% and 10% at one, five and ten years, respectively. The commonest malignancy type was lymphoma, followed by kidney cancer, colorectal cancer and malignancy of the male genital organs. Multivariate analysis identified cyclosporine use as an independent risk factor for malignancy. Compared to the general population, KTX recipients had higher malignancy and mortality rates after malignancy diagnosis (SIR 3.36; SMR 9.45). Survival rates for KTX recipients with malignancy versus those without malignancy were 100%, 93% and 64% versus 97%, 93% and 83% at one, five and ten years, respectively.
CONCLUSION
KTX was associated with higher mortality and incidence of malignancy. Newer immunosuppressive agents and induction therapies were not found to be risk factors for malignancy, possibly due to our relatively small sample size.
10.Dermatological conditions seen in renal transplant recipients in a Singapore tertiary hospital.
Choon Chiat OH ; Haur Yueh LEE ; Bien Keem TAN ; Pryseley Nkouibert ASSAM ; Terence Yi Shern KEE ; Shiu Ming PANG
Singapore medical journal 2018;59(10):519-523
INTRODUCTIONLifelong immunosuppression after renal transplant exerts effects on the recipients' skin, including skin infections, skin cancers and drug-induced skin disorders. Our study aimed to determine the epidemiology of skin conditions among renal transplant recipients in the largest tertiary hospital in Singapore.
METHODSWe reviewed the medical records of kidney transplant recipients at Singapore General Hospital, Singapore, between 1 January 2003 and 31 December 2013. Among these patients, the clinical data of patients who sought skin consultations with either dermatologists or plastic surgeons within the hospital was captured.
RESULTSA total of 178 patients were included in our study. There were 88 (45.6%) skin infections, 23 (11.9%) drug-induced skin conditions, 9 (4.7%) skin cancers and 73 (37.8%) other skin conditions. Skin infection was the predominant reason for consultation, with viral warts (15%, n = 29) being the most common. Of the nine cases in our cohort with skin cancer, there were three cases of basal cell carcinoma, three cases of Bowen's disease, two cases of extramammary Paget's disease and one case of squamous cell carcinoma. Drug-induced skin conditions, mainly attributable to long-term steroids and cyclosporin use, were represented by acne (9.3%, n = 18) and sebaceous hyperplasia (2.6%, n = 5).
CONCLUSIONOur study demonstrated the spectrum of skin conditions that can be expected after renal transplantation. We wish to highlight the importance of careful dermatological screening and long-term follow-up for these patients, in order to reduce post-transplant skin complications.

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