[The occurrence of hypophosphatemia and its prognostic value in intensive care unit patients].

To investigate the occurrence of hypophosphatemia in intensive care unit (ICU) patients, and to study the influence of different levels of phosphorus on the prognosis of patients.One hundred and forty-seven patients admitted to Shengjing Hospital during April to November in 2010 were enrolled. The serum phosphorous level was measured consecutively, and the incidence of hypophosphatemia was observed. Acute physiology and chronic health evaluation II (APACHE II ) score, length of ICU-stay, the main laboratory findings and mortality were compared among patients with different serum phosphate levels. Receiver operating characteristic curve (ROC curve) was plotted according to the serum phosphate level and the survivability of patients to study the prognostic value of serum phosphate level in the ICU patients.A large number of ICU patients (77.6%) had developed hypophosphatemia, mild in 21, midrange in 70, and marked in 23, amounting to 63.3% of patients suffering from medium and marked hypophosphatemia. The APACHE II score, duration of artificial ventilation (days), length of ICU-stay (days) as well as mortality rate were higher in hypophosphatemia patients compared with those of the normal group (APACHE II score: mild 18.2 ± 6.0, midrange 21.4 ± 7.6, marked 25.6 ± 8.8, normal 18.9 ± 8.8; length of artificial ventilation: mild 6.6 ± 5.1, midrange 11.3 ± 9.5, marked 15.7 ± 10.4, normal 6.7 ± 5.9; length of ICU-stay: mild 9.7 ± 6.4, medium 10.6 ± 8.2, marked 18.9 ± 13.1, normal 9.9 ± 7.1; mortality rate: mild 14.3%, medium 25.7%, marked 39.1%, normal 9.1%). The mortality of ICU patients (22.4%) was negatively correlated with the degree of hypophosphatemia (r = -0.225, P = 0.01). The serum phosphate level had a prognostic value when it was less than 0.40 mmol/L, with sensitivity of 78.6%, specificity of 51.5%.For most of ICU patients, the serum phosphorus is at a relatively low level. ICU patients have multiple risk factors to develop hypophosphatemia and severe hypophosphatemia is a predictor of a poor prognosis.