Introduction: It has long been recognised that thiazide therapy can raise serum cholesterol, specifically low density lipoprotein (LDL), in contradiction to their well evidenced benefit to cardiovascular outcomes1. This has also been recognised in those receiving loop diuretics, to a lesser extent2. The cause of this is unclear, although it has previously been attributed to serum volume contraction. The rare genetic salt-losing tubulopathies – Gitelman and Bartter syndromes – are equivalent to chronic thiazide and loop diuretic use, respectively3, but the lipid profiles of these patients have not been explored.
Aims/Objectives: We sought to describe lipid profiles in patients with genetically confirmed Gitelman and Bartter syndromes.
Method: Patients attending a specialist Renal Tubular Clinic were prospectively enrolled in the study over a six month period. ‘Control’ patients included those with nephrogenic diabetes insipidus, distal renal tubular acidosis, recurrent renal stones, and EAST syndrome. Data were compared using Mann Whitney U Tests.
Results: We recruited 54 patients with Gitelman syndrome, 36 with Bartter syndrome and 139 controls. The mean serum total cholesterol for Gitelman patients was 4.9mmol/L, HDL 1.41mmol/L, LDL 2.68mmol/L and triglycerides 1.94mmol/L. Whilst these are in the normal ranges, both total cholesterol and LDL are significantly higher than in control tubular patients (p=0.029 and p=0.031 respectively). In the case of Bartter syndrome (types 1 to 4 grouped), the mean total cholesterol was 5.38mmol/L, HDL 1.48mmol/L, LDL 3.08mmol/L and triglycerides 1.98mmol/L. Again, both total cholesterol and LDL were significantly higher than in the controls (p=0.00973 and 0.00858). There was no significant difference in weight or HbA1c between patients with Gitelman syndrome and the control group, or patients with Bartter syndrome and the control group.
Conclusions: Findings in patients with rare genetic salt-losing tubulopathies mirror those previously described in cohorts taking diuretic therapy, specifically thiazides and loop-diuretics. This is interesting, and further establishes their role in studying the physiology of the wider population, especially those with hypertensive disease. This study has not established why this should be the case, since we do not think patients with Gitelman or Bartter syndrome are chronically volume contracted. We therefore hope this small study acts as a catalyst for further enquiry.