Dataset From: Evaluation of potential kidney donors and outcomes post-donation at Charlotte Maxeke Johannesburg Academic Hospital (1983-2015)
Diana, Nina Elisabeth
Meyers, Anthony M.
Division of Nephrology, Charlotte Maxeke Johannesburg Academic Hospital
Data was collected from existing clinical records of the Living Donor Clinic held by the Division of Nephrology at Charlotte Maxeke Johannesburg Academic Hospital. This was performed by the primary investigator / first author in a pseudo-anonymized fashion and stored securely in an Excel database to which only the primary investigator had access along with the data key. Procedures pertaining to original data capturing to clinical records by the data manager (Sister Nancy Makoe), were in accordance with the standard operating procedure set out by the Transplant Unit at Charlotte Maxeke Johannesburg Academic Hospital. Objectives of research Primary Objective • To determine donor morbidity and mortality after donation. • Analysis of morbidity will focus on the development of - New onset hypertension following donation (BP ≥140/90) - Chronic kidney disease following donation, defined as the development of either of the following - New onset proteinuria (AER >300mg/day) - An eGFR <60 ml/min/1.73 m² (using the CKD-EPI formula) Secondary Objectives • To determine the reasons for exclusion of potential donors from living kidney donation • To determine the prevalence of ESKD following donation (eGFR <15 ml/min/1.73 m² using the CKD-EPI formula) • To determine potential risk factors associated with proteinuria and/or a reduced eGFR post kidney donation, by evaluating a. donor demographics b. the presence of isolated medical abnormalities prior to donation, defined by: - a borderline pre-donation 51Cr-EDTA GFR (<80 ml/min/1.73 m²) - pre-existing hypertension (well controlled on a single agent with no end-organ damage) - class I obesity (BMI 30-35 kg/m²) • To determine the proportion of patients lost to follow-up post donation 5.2 Study design A single centre retrospective observational study was conducted of all patients attending the Living Donor Clinic in the Renal Unit at CMJAH over a 32-year period between 01 January 1983 and 31 July 2015. The closing date for sampling reflects the period of protocol submission for this study. The cohort comprised of 1208 potential living donors, of which: • 910 are failed living donors, assessed between 01 January 1990 and 31 July 2015 • 298 are accepted living donors, assessed between 01 January 1983 and 31 July 2015 5.3 Data collection 5.2.1 Data collection for failed living donors Data collection for failed living donors comprised the following parameters: • Demographic data – age at assessment, gender and ethnicity • Family history of the donor • Relation to the intended recipient – whether related, unrelated or altruistic • The outcome of eligibility evaluation • If excluded from living donation, reasons for non-donation will be documented, which were categorised as: - donor-recipient related, - donor-related, - recipient-related, or - miscellaneous. • The indications and findings of any renal biopsy undertaken on a donor was recorded 5.2.2 Data collection for accepted living donors Data collection for accepted living donors comprised the following parameters: • Demographic information – gender, ethnicity, age at donation (as well as age at each follow-up point) • Family history of the accepted donor • Details pertaining to the donation, specifically: - relation to the recipient, as well as cause of renal failure in the recipient - the date of donation - the graft outcome (if known) • The last follow-up date at the Living Donor Clinic and the approximate number of post-donation follow-up visits • Domicile in relation to the Living Donor Clinic (in kilometres from transplant centre) • The reason for lost to follow-up (if known) • Baseline characteristics at donation, including: - Body mass index - Urine albumin: creatinine ratio - Systolic blood pressure - Diastolic blood pressure - Baseline serum creatinine - eGFR as defined by an isotope study, the chromium-51-ethylene-diamine-tetra-aceticacid scan (51Cr EDTA scan) as well as the CKD-EPI formula - Habits, including smoking status and history of alcohol consumption - History of pre-existing medical condition(s) • Characteristics at follow-up (correlated with time after donation), including: - Body mass index - Urine albumin: creatinine ratio - Systolic blood pressure - Diastolic blood pressure - Serum creatinine - eGFR as defined by the CKD-EPI formula - Habits, including smoking status and alcohol consumption - Development of co-morbid disease - History of nephrotoxic drug intake The above variables were retrospectively collected from data recorded at the patients’ first follow-up visit post-donation, one-year post-donation visit, and at the most recent follow-up visit. • Mortality data was collected in accepted living donors that demised during the study period, and will include: - age at death - the time from donation to mortality - cause of death, whether related to renal disease, a cardiovascular event or other cause 5.3 Definition of variables 5.3.1 Classification of donors • Potential living donors (PLDs) – refer to all donors assessed at the CMJAH Living Donor Clinic • Failed living donors (FLDs) – refer to the sub-group of PLDs excluded from living kidney donation • Accepted living donors (ALDs) – refer to the subgroup of PLDs that ultimately donated a kidney 5.3.2 Hypertension Defined as per the Eighth Joint National Committee (JNC8) guidelines for blood pressure targets: • For donors with a current age of more than sixty years: - a systolic blood pressure of more than 150mmHg, with - a diastolic blood pressure of more than 90mmHg • For donors with a current age of less than sixty years: - a systolic blood pressure of more than 140mmHg, with - a diastolic blood pressure of more than 90mmHg 5.3.2 Albuminuria Quantified as per the revised Kidney Disease Improving Global Outcomes (KDIGO) chronic kidney disease classification into three stages of albuminuria based on the albumin excretion rate (AER) in milligrams per day (mg/day): • A1: Normal or mildly increased (AER <30 mg/day) • A2: Moderately increased (AER between 30 - 300 mg/day) • A3: Severely increased (AER >300 mg/day, with nephrotic range proteinuria defined as >3500 mg/day) 5.3.3 Glomerular filtration rate • Pre-donation GFR will be defined: - as per isotope study: 51Cr EDTA scan - as calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula, expressed as: GFR = 141 × min (Scr /κ, 1) α × max (Scr /κ, 1)-1.209 × 0.993Age × 1.018 [if female] × 1.159 [if black] where: GFR = glomerular filtration rate in ml/min/1,73m2 Scr = serum creatinine in mg/dL κ = 0.7 for females and 0.9 for males α = -0.329 for females and -0.411 for males min indicates the minimum of Scr /κ or 1, and max indicates the maximum of Scr /κ or 1. • Post-donation GFR will be calculated by the CKD-EPI formula, as expressed above. 5.3.4 Chronic kidney disease Defined as per the revised Kidney Disease Outcomes Quality Initiative (KDOQI) as either kidney damage or GFR<60 ml/min/1.73 m² for ≥ 3 months. Kidney damage encompasses pathological abnormalities or markers of damage, including biochemical or radiological abnormalities. GFR is further classified into stages (table 1.1). Table 1.1 | Revised KDOQI classification for chronic kidney disease GFR Stages GFR (ml/min/1.73 m2) Classification 1 >90 Normal 2 60 – 89 Mildly decreased 3a 45 – 59 Mildly to moderately decreased 3b 30 – 44 Moderately to severely decreased 4 15 – 29 Severely decreased 5 <15 ESKD 5.3.5 Body mass index • BMI will be calculated as weight (in kilograms) divided by height (in meters) squared. • It will then be sub-classified as per the World Health Organisation (WHO) international BMI classification (table 1.2). Table 1.2 | WHO international classification of BMI Classification BMI (kg/m2) Underweight < 18.5 Normal Range 18.5 to 24.99 Overweight Pre-obese Obese - Obese Class I - Obese Class II - Obese Class III ≥ 25 25 to 29.99 ≥ 30 30 to 34.99 35 to 39.99 ≥ 40 5.3.6 Isolated medical abnormalities Refers to donors with any of the following characteristics prior to donation: • A borderline 51Cr-EDTA GFR <80 ml/min/1.73 m2 • Pre-existing hypertension well-controlled on a single agent with no end- organ damage • Class I obesity (BMI 30 - 35 kg/m2 )
Permission for this retrospective study was obtained from Prof. G. Paget (Head of Nephrology, Department of Internal Medicine, Charlotte Maxeke Johannesburg Academic Hospital), Ms. G. Bogoshi (Chief Executive Officer, Charlotte Maxeke Johannesburg Academic Hospital), and the Human Research Ethics Committee of the University of Witwatersrand (Clearance number M150923). Additional written consent to share the minimum data set was obtained from the Head of the Division of Nephrology at the institution the study was performed at as well as from the data manager of the Living Donor Clinic.