Low serum albumin levels predict short- and long-term mortality risk in patients hospitalised to general surgery wards

Abstract

Background: Previous studies have reported conflicting results on the association between hypoalbuminaemia and morbidity and mortality in hospitalised patients.

Aims: To investigate the association of albumin levels on admission and change in levels during hospitalisation of patients in general surgery wards with hospitalisation outcomes.

Methods: Historical prospective data of patients hospitalised between January 2011 and December 2017. Albumin levels were classified as follows: marked hypoalbuminaemia (<2.5 mg/dL), mild hypoalbuminaemia (2.5-3.5 mg/dL), normal albumin (3.5-4.5 mg/dL) and hyperalbuminaemia (>4.5 mg/dL). Main outcomes were length of hospitalisation, 30-days and long-term mortality.

Results: The cohort included 17 930 patients (mean age 58 ± 20 years, 49% male). Most had normal albumin levels on admission (n = 11 087, 62%), 16% had mild hypoalbuminaemia (n = 2824) and 3% had marked hypoalbuminaemia (n = 529). Hyperalbuminaemia on admission was evident in 20% of the patients (n = 3490). Follow-up time was up to 7.2 years (median ± SD = 3 ± 2 years). Compared to 30-day mortality with normal albumin on admission (2%), mortality was higher with mild (9%) and marked hypoalbuminaemia (22%) and lower with hyperalbuminaemia (0.4%). The mortality rate at the end of follow up was 14% with normal albumin levels, and 35% and 58% with mild and marked hypoalbuminaemia respectively. Patients with hyperalbuminaemia on admission and before discharge had the best short- and long-term survival. This pattern was similar when analysed separately in different age groups. In patients with hypoalbuminaemia on admission, normalisation of albumin levels before discharge was associated with lower short- (12% vs 1%) and long-term mortality risk (42% vs 17%).

Conclusions: Low albumin levels on admission to general surgery wards are associated with increased short- and long-term mortality. Normalisation of albumin levels before discharge was associated with lower mortality, compared to hypoalbuminaemia before discharge.

Keywords: albumin; hospitalisation; mortality; surgery.