Drinking recommended daily water significantly alters haemato-biochemical parameters in prospective blood donors; a one-center quasi-experimental study in a tropical setting.

BACKGROUND: In sub-Saharan Africa, the prevailing high ambient temperatures should warrant increased daily water intake (DWI) to prevent haemo-concentration and its potential to confound patients' laboratory data.

AIM: To assess the impact that the recommended DWI has on the haemato-biochemical variables in a tropical setting.

MATERIALS AND METHODS: This quasi-experimental study recruited 101 apparently healthy individuals (18-60 years) in the Bawku municipality. DWI, anthropometrics, and haemato-biochemical variables were assessed at baseline. Participants were encouraged to increase their DWI to ≥4 L over a 30-day period; haemato-biochemical variables were re-evaluated. Total body water (TBW) was anthropometrically estimated.

RESULTS: The median post-treatment DWI significantly increased; consequently, anaemia cases increased by >20-fold (2.0 % vs 47.5 % post-treatment). RBC count, platelet count, WBC count, and median haemoglobin significantly decreased compared to baseline (p < 0.0001). Biochemically, median plasma osmolality (p < 0.0001), serum sodium (p < 0.0001), serum potassium (p = 0.0012) and random blood sugar (p = 0.0403) significantly decreased. Compared to baseline, significantly higher proportion of participants classified as thrombocytopenic (8.9 % vs 3.0 %), hyponatraemia (10.9 % vs 2.0 %), or normal osmolarity (77.2 % vs 20.8 %). There were differential bivariate correlations between pre- and post-treatment haemato-biochemical variables.

CONCLUSION: Sub-optimal DWI is a likely confounder in haemato-biochemical data interpretation in the tropics.