[Hypophosphatemia in the hospitalized patient]

Phosphate is an obligatory component of cellular function. Serum, levels are maintained within narrow levels by regulatory mechanisms. The normal range of phosphate concentration is 2.5-4.5 mg/dL. In certain clinical situations these mechanisms are insufficient and hypophosphatemia ensues.

This study aimed to compare hospitalization course and clinical outcome of patients with moderate hypophosphatemia (1.0-2.0 mg/dl) with patients with extreme hypophosphatemia (< 1.0 mg/dL).

Patients who had at least one measurement of serum phosphate level of 1.0 mg/dL or less comprised the extreme hypophosphatemic group. Patients with at least one serum, phosphate level of between 1.0 and 2.0 mg./dL, but never had a phosphate level of less than 1.0 mg/dL comprised the moderate hypophosphatemic group. Files of 50 consecutive patients who had extreme hypophosphatemia and 100 consecutive patients with moderate hypophosphatemia were retrieved and analyzed.

The two groups of patients were similar with reference to age, gender ratio, background disease and indication for hospitalization. There was a higher proportion of obese patients in the moderate hypophosphatemia group. There was a higher proportion of patients who consumed alcohol on a regular basis before hospitalization in the extreme hypophosphatemic group. Patients suffering from extreme hypophosphatemia were more likely to be hospitalized in the intensive care unit and ventilated on hospitalization. Length of hospitalization was longer for the extreme hypophosphatemia group than for the moderate hypophosphatemia group. When comparing the group outcomes it was found that more patients with severe hypophosphatemia died.

Severe hypophosphatemia is a severe metabolic derangement. It appears in critically sick patients, who should be followed closely and treated properly. The clinical relevance of moderate hypophosphatemia was not checked in this study.