Hypomagnesemia in hemodialysis patients: role of proton pump inhibitors.

BACKGROUND: Recent observations have associated hypomagnesemia with increased risk of cardiovascular morbidity and mortality in hemodialysis patients. METHODS: We did a 3-month chart review of 62 chronic hemodialysis patients at a single US hospital. All were dialyzed using a dialysate [Mg] of 0.75-1.0 mEq/l. Patients were divided into two groups: hypomagnesemic (mean predialysis plasma [Mg] <1.5 mEq/l) and non-hypomagnesemic (mean predialysis plasma [Mg] ≥1.5 mEq/l). RESULTS: All patients were male; mean age was 64.3 ± 8.7 years and the majority (73%) diabetic. 24 patients (39%) had hypomagnesemia and 38 (61%) were not hypomagnesemic. There were no significant differences between the two groups in age, diabetes status, blood pressure, duration of dialysis, plasma calcium, phosphorus, albumin, intact parathyroid hormone (PTH), dialysis adequacy (Kt/V), or dietary protein intake (as estimated by normalized protein catabolic rate, nPCR). However, use of proton pump inhibitors (PPIs) was significantly associated with hypomagnesemia (plasma [Mg] 1.48 ± 0.16 mEq/l in the PPI group vs. 1.65 ± 0.26 mEq/l in the non-PPI group, p = 0.007). Adjustment for age, diabetes status, duration of dialysis, plasma albumin, Kt/V, nPCR, and diuretic use did not affect the association between PPI use and hypomagnesemia. CONCLUSIONS: Use of PPIs in patients dialyzed using a dialysate [Mg] of 0.75-1.0 mEq/l is associated with hypomagnesemia. We suggest monitoring plasma [Mg] in patients taking PPIs, with discontinuation of the medication if possible and/or adjustment of dialysate [Mg] to normalize plasma [Mg].

Left ventricular end-systolic stress in young adults: distribution, risk factors, and relation to cardiovascular disease events.

BACKGROUND: We examined the relationship of left ventricular (LV) end-systolic meridional wall stress (LVESS), a measure of LV afterload, with race, gender, other cardiovascular risk factors and LV mass in 3,994 young adults in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. METHODS: From transthoracic echocardiography, LVESS was derived from LV internal dimension and posterior wall thickness and systolic blood pressure (BP). RESULTS: Adjusted LVESS was significantly greater in black men versus women (59.0 vs. 54.8 dynes/cm, P < 0.01) and in white men versus women (59.0 vs. 55.4 dynes/cm(2), P < 0.01), but did not differ in comparing whites versus blacks either in men or women. In multiple regression analyses, age and LV mass were inversely (P < 0.01) and height was positively (P < 0.01) associated with LVESS. The overall variance of LVESS explained by the models in each race-sex subgroup was low (R(2) less than 0.03), suggesting that standard risk factors contribute little to determining LVESS in young adults. Over a 15-year follow-up period, LVESS, after the adjustment for covarieties, was not associated with the incidence of coronary heart disease (CHD) and cardiovascular disease (CVD) events. CONCLUSION: LVESS may not be a useful marker of cardiovascular risk in young adults; further study is needed to determine whether other echocardiographic measures may be more useful predictors.