Anion gap determination in preeclampsia

OBJECTIVE: To determine if the calculated anion gap differs according to presence or absence of hypertension in pregnant women. METHODS: Retrospective data were obtained for 1223 patients who delivered at a community hospital during a 6-month period. Fifty-six (4.6%) of these patients were considered to have proteinuric hypertension, 66 (5.4%) to have non-proteinuric hypertension, and 1101 (90%) to be normotensive. The Kruskal-Wallis and Mann-Whitney tests were used to compare these groups with respect to the anion gap and serum sodium, chloride, and bicarbonate. RESULTS: Compared with the other two groups, proteinuric hypertensive patients tended to have lower values for serum sodium (P < .005) and the anion gap (P < .005). There were no statistically significant differences between the groups with respect to serum chloride or bicarbonate. CONCLUSION: The anion gap appears to be smaller with proteinuric hypertension than it is without.