PowerPoint Slides for: Thiazide-Associated Hyponatremia, Report of the Hyponatremia Registry: An Observational Multicenter International Study

Background: Hyponatremia is a frequent and potentially
life-threatening adverse side effect of thiazide diuretics. This
sub-analysis of the Hyponatremia Registry database focuses on current
management practices of thiazide-associated hyponatremia (TAH) and
compares differences between TAH and syndrome of inappropriate
antidiuretic hormone secretion (SIADH). Methods: We analyzed 477 patients from 225 US and EU sites with euvolemic hyponatremia ([Na+] ≤130 mEq/L) who were receiving a thiazide diuretic. Of these, 118 met criteria for true thiazide-induced hyponatremia (TIH). Results:
Thiazide was withdrawn immediately after hyponatremia was diagnosed
only in 57% of TAH; in these patients, the median rate of [Na+] change (Δdaily[Na+])
was significantly higher than those with continued thiazide treatment
(3.8 [interquartile range: 4.0] vs. 1.7 [3.8] mEq/L/day). The most
frequently employed therapies were isotonic saline (29.6%), fluid
restriction (19.9%), the combination of these two (8.2%), and hypertonic
saline (5.2%). Hypertonic saline produced the greatest Δdaily[Na+]
(8.0[6.4] mEq/L/day) followed by a combination of fluid restriction and
normal saline (4.5 [3.8] mEq/L/day) and normal saline alone (3.6 [3.5]
mEq/L/day). Fluid restriction was markedly less effective (2.7 [2.7]
mEq/L/day). Overly rapid correction of hyponatremia occurred in 3.1%
overall, but in up to 21.4% given hypertonic saline. Although there are
highly significant differences in the biochemical profiles between TIH
and SIADH, no predictive diagnostic test could be derived. Conclusions:
Despite its high incidence and potential risks, the management of TAH
is often poor. Immediate withdrawal of the thiazide is crucial for
treatment success. Hypertonic saline is most effective in correcting
hyponatremia but associated with a high rate of overly rapid correction.
We could not establish a diagnostic laboratory-based test to
differentiate TIH from SIADH.