A multicentre, cross-sectional study on chronic haemodialysis patients at four adult dialysis units in the Western Cape will be conducted.IDH will be defined as a rise of ≥10mmHg in systolic blood pressure between pre- and post-dialysis in at least 4 out of six dialysis sessions. Patients screened as eligible for inclusion in the study will be identified from haemodialysis charts by the primary investigator (PI). They will then be approached by the PI, who will try to obtain informed consent. Once informed consent has been obtained and no exclusion criteria are present, the patient will be enrolled. A study ID number will be allocated.