Hypophosphatemia and Outcomes in ICU: A Systematic Review and Meta-Analysis

Abstract

Purpose: Hypophosphatemia is reported in up to 5% of hospitalized patients and ranges from 20% to 80% in critically ill patients. The consequences of hypophosphatemia for critically ill patients remain controversial. We evaluated the effect of hypophosphatemia on mortality and length of stay in intensive care unit (ICU) patients. Methods: MEDLINE, EMBASE, Cochrane Library (Reviews and Trials), and PubMed were searched for articles in English. The primary outcome was mortality and secondary outcome was length of stay. The quality of evidence was graded using a modified Newcastle-Ottawa Scale. Results: Our search yielded 828 articles and ultimately included 12 studies with 7626 participants in the analysis. Hypophosphatemia was associated with increased hospital length of stay (2.19 days [95% CI, 1.74-2.64]) and ICU length of stay (2.22 days [95% CI, 1.00-3.44]) but not mortality (risk ratio: 1.13 [95% CI, 0.98-1.31]; P = .09). Conclusions: Hypophosphatemia in ICU was associated with increased hospital and ICU length of stay but not all-cause mortality. Hypophosphatemia appears to be a marker of disease severity. Limited number of available studies and varied study designs did not allow for the ascertainment of the effect of severe hypophosphatemia on patient mortality.

Hypophosphataemia is common in patients with aneurysmal subarachnoid haemorrhage

“…The present as well as previous studies in patients with acute brain injury or acute critical illness appear to question the value of routine phosphate measurements 8,9,21 . In most patients, hypophosphataemia may be a marker of disease severity more than an actual prognostic marker 8 .…”

“…Both the high prevalence of hypophosphataemia and the lack of association between phosphate levels and outcome have previously been observed in patients with non‐traumatic intracerebral haemorrhage 21 as well as general ICU patients 8 . Furthermore, a recent meta‐analysis has found no association between hypophosphataemia and in‐hospital or overall mortality 9 . As previously reported, the prognostic factors driving the association with poor outcome are disease severity, as measured by the WFNS and SOFA scores, and DCI 17 .…”

“…The normal plasma phosphate level ranges from 0.80 to 1.45 mmol/L. A reduction below the normal value, so‐called hypophosphataemia, has been reported in up to 2.2% of all admitted patients, 7 and in around 30% of patients admitted to ICUs, 6 but appears not to be related with mortality in patients admitted to intensive care units (ICUs) 8,9 . Phosphate depletion may affect several organ systems and lead to respiratory failure 6 .…”

Hypophosphataemia, fibroblast growth factor 23 and third-generation intravenous iron compounds: a narrative review

“…Diaphragmatic contractility is severely affected and so is the myocardium, with reports suggestive of hypophosphataemia-induced respiratory failure, cardiomyopathy, and arrhythmias. 114 – 119 It is hence not surprising that hypophosphataemia is a negative outcome predictor in patients admitted in intensive care units as it can lead to respiratory failure, necessary prolonged weaning time from ventilation, and increased length of stay. 116 , 119 Moreover, hypophosphataemia is linked with fatigue, tremors, malaise, generalized weakness, neuropathy, irritability, and convulsions, and these non-specific symptoms can be mistaken as being associated with those symptoms commonly experienced with IDA.…”

“… 114 – 119 It is hence not surprising that hypophosphataemia is a negative outcome predictor in patients admitted in intensive care units as it can lead to respiratory failure, necessary prolonged weaning time from ventilation, and increased length of stay. 116 , 119 Moreover, hypophosphataemia is linked with fatigue, tremors, malaise, generalized weakness, neuropathy, irritability, and convulsions, and these non-specific symptoms can be mistaken as being associated with those symptoms commonly experienced with IDA. 120 Rare cases of clinical presentations mimicking Guillain–Barre syndrome have also been reported to be associated with acute hypophosphataemia.…”