High prevalence of hypophosphataemia amongst patients with infectious diseases. A retrospective study

Objectives, To describe the prevalence of hypophosphataemia amongst all pat ients treated during 1993 for infectious diseases. The associations between serum C-reactive protein, serum albumin and white blood cells in blood wer e studied amongst hypophosphataemic patients. Comparisons were made accordi ng to the severity of infection. Design. A retrospective study of the prevalence of hypophosphataemia, and a case-control study amongst a subgroup of patients. Setting. The Department of Infectious Diseases, University Hospital, Umea, Sweden. Subjects. For the prevalence study all 967 patients (449 women and 518 men) treated during 1993 were included. In the case-control study, 108 cases, w ith serum phosphate less than or equal to 0.64 mmol L-1, 216 age-and sex-ma tched controls with serum phosphate > 0.82 nmol L-1 (men) and > 0.86 mmol L -l (women), respectively, were included. Results, In 402 of 967 patients (42%) at least one serum phosphate value wa s below the reference level, Hypophosphataemia was found in 573 of 1966 blo od samples (29%). Severe hypophosphataemia (< 0.30 mmol L-1) was seen in 1. 2% of the patients (0.9% of blood samples). The prevalence of hypophosphata emia was higher amongst women than amongst men. In the case-control study, the serum C-reactive protein and the number of white blood cells was higher amongst the cases compared with the controls (124 vs. 94 mg L-1 and 11.4 v s. 9.3 cells/L, x 10(9), respectively). The multiple logistic regression sh owed a 4-fold higher risk of having low serum phosphate in patients with se vere infection, compared with mild infections, None of the other variables (albumin, days of hospital stay or white blood cells in blood) increased th e risk for hypophosphataemia. Conclusions, The high prevalence of low serum phosphate levels and the incr eased risk of having low levels in severe infections shown in this study ne eds further attention.