Prevalence of hypomagnesemia (HM) in a geriatric long-term care (LTC) setting.

Electrolyte abnormalities are frequently observed in elderly long-term care (LTC) patients. Magnesium is a trace mineral, but is the second most abundant intracellular cation and the fourth most abundant cation in the body. This was a cross-sectional study to assess the prevalence of hypomagnesemia (HM) in non-selected elderly LTC patients. A total of 159 patients aged 65 years and older were included in the study. The attributes and variables related to the patients' hospital course were used to compare the two groups. We used univariate and multivariate analyses to correlate magnesium levels with demographic, clinical factors and laboratory data. HM was found in 36% of the patients, of whom 35% presented with moderate HM (0.8-0.9 microequiv./l) and 18% with severe HM (<or=0.7 microequiv./l). Patients with HM had a higher number of comorbid diseases per patient (p=0.038), low body mass index (BMI) (p=0.044) and more of them presented with laboratory markers of malnutrition, such as low total cholesterol (TC) and serum albumin (SA) levels. Coexistence with other electrolyte abnormalities was higher among patients with HM than without (p=0.006), predominantly hypocalcemia and hypokalemia (p=0.023 and 0.032, respectively). Using regression analysis, independent variables significantly associated with serum magnesium levels were serum albumin, calcium, potassium, urea levels, chronic renal failure (CRF), chronic heart failure (CHF), diabetes mellitus (DM) and diuretic drugs (R(2)=0.877). Both early (up to 30 days) and late rate of death were higher in patients with HM. The incidence of HM in LTC elderly patients is high and multifactorial. Understanding the causes of HM, correction of magnesium level, and definitive and effective treatment of the cause leading to HM is important to improve patient prognosis.