Hypertension in pregnancy: a future risk for chronic kidney disease in South Africa

ABSTRACT

Background. Hypertension in pregnancy is a risk factor for end-stage chronic kidney disease (ESKD) and is particularly common in South Africa (SA). There are no data for the risk of developing chronic kidney disease (CKD).Objectives. To conduct a study of all female patients who presented to the renal replacement programme at Groote Schuur Hospital, Cape Town, SA.Methods. This was a retrospective study of female patients with ESKD who were presented to renal replacement meetings between 2007 and 2017. For each patient who was assessed, there was a comprehensive letter detailing patient demographics, as well as psychosocial and medical history, which served as the source data. Patients with a history of hypertension in pregnancy were identified as the case group and those without the condition were the control group. Patient demographics, causes of CKD, kidney function and outcome of the meeting were documented.Results. Of the 415 female patients with ESKD, 70 (16.9%) had a history of hypertension in pregnancy. The ethnic breakdown was as follows 132 (42.44%) black, 172 (55.3%) mixed ancestry and 7 (2.25%) white. Compared with the control group, the patients were younger, with a median age of 33 v. 41 years (p<0.001), higher serum creatinine 1 045 v. 751 µmol/L (p=0.017) and lower estimated glomerular filtration rate (eGFR) 4.0 v. 5.1 mL/min (p=0.029). Patients were more likely to abuse methamphetamine (5.7 v. 1.7%; p=0.049), and less likely to be diabetic (1.4 v. 20.9%; p<0.001) or HIV-positive (2.9 v. 12.5%; p=0.019). There were no ethnic differences between patients and controls. Underlying causes of renal disease showed significant differences, as patients were more likely to have hypertensive nephropathy (57.1 v. 22.9%; p<0.0001), and less likely to have diabetic kidney disease (1.4 v. 20.4%; p<0.001), HIV-associated nephropathy (HIVAN) (1.4 v. 6.4%) or polycystic kidney disease (1.4 v. 7.0%). There was no difference in acceptance to the dialysis and transplant programme (53 v. 47%).Conclusions. This study suggests an important link between hypertension in pregnancy and ESKD. The patients were significantly younger, presented later and were more likely to have hypertensive nephropathy. Methamphetamine abuse appears to be a risk factor. The study suggests that all women with hypertensive disorders during pregnancy need further evaluation and follow-up postpartum