Prevalence of malnutrition among hospital admissions to English NHS hospitals over two economically constrained decades: evidence from routine health data.

Introduction: To examine the rates and distribution of hospital admissions for malnutrition in England between 2001 and 2021 using routine hospital admission data from Hospital Episode Statistics. Methods: A retrospective, longitudinal study using routinely collected data for the whole of England between 2001 and 2021 across private and National Health Service providers. We estimated age-standardised and age-specific rates of admission with diagnoses for protein-energy malnutrition or vitamin deficiencies among patients who did not suffer from a medical condition likely to cause malnutrition between 2001 and 2021. A geospatial analysis estimated the spatiotemporal distribution of age and income-adjusted risk. Results: Combining primary and secondary causes for admission, age-adjusted hospital admission rates doubled for protein-energy malnutrition (from 0.2/10 000 person years in 2001/2002 to 0.4/10 000 person years in 2020/2021). Vitamin deficiency admissions increased 5.4-fold from 0.5/10 000 person years in 2001/2002 to 2.6/10 000 person years in 2020/2021. However, these changes follow national recommendations to screen all inpatient admissions for malnutrition and a sharp increase in testing for vitamin deficiency. Changes in reporting are therefore likely to be largely (or completely) an artefact of awareness and testing. Furthermore, there was no increase in cases of protein-energy or vitamin deficiency when malnutrition was the primary cause of admission. Overall, poorer areas did have higher malnutrition admission rates than richer areas. Conclusions: There was a steep rise in admissions with a code for protein-energy malnutrition and for vitamin deficiency in any diagnosis position among adults. However, increased diagnosis could be explained by new guidelines and increased testing. Moreover, there was no increase in admission with either type of malnutrition when this was the primary cause of admission. The pattern was similar for all admissions and admissions excluding alcohol-related conditions.