Are patients admitted to hospitals from care homes dehydrated? A retrospective analysis of hypernatraemia and in-hospital mortality

Abstract

Objectives: To compare risks of hypernatraemia on admission to hospital in persons who were with those who were not identified as care home residents and evaluate the association of hypernatraemia with in-hospital mortality. Design: Retrospective observational study. Setting: A National Health Service Trust in London. Participants: A total of 21,610 patients aged over 65 years whose first admission to the Trust was between 1 January 2011 and 31 December 2013. Main outcome measures: Hypernatraemia on admission (plasma Na > 145 mmol/L) and in-hospital death. Results: Patients admitted from care homes had 10-fold higher prevalence of hypernatraemia than those from their own homes (12.0% versus 1.3%, respectively; odds ratio [OR]: 10.5, 95% confidence interval [CI]: 8.43-13.0). Of those with hypernatraemia, nine in 10 cases were associated with nursing home ECOHOST residency (attributable fraction exposure: 90.5%), and the population attributable fraction of hypernatraemia on admission associated with care homes was 36.0%. After correcting for age, gender, mode of admission and dementia, care home residents were significantly more likely to be admitted with hypernatraemia than were own-home residents (adjusted odds ratio [AOR]: 5.32, 95% CI: 3.85-7.37). Compared with own-home residents, care home residents were also at about a two-fold higher risk of in-hospital mortality compared with non-care home residents (AOR: 1.97, 95% CI: 1.59-2.45). Consistent with evidence that hypernatraemia is implicated in higher mortality, the association of nursing homes with in-hospital mortality was attenuated after adjustment for it (AOR: 1.61, 95% CI: 1.26-2.06). Conclusions: Patients admitted to hospital from care homes are commonly dehydrated on admission and, as a result, appear to experience significantly greater risks of inhospital mortality.

‘Normal’ serum sodium concentration among inpatients over 65 admitted to hospital: an observational study

“…First, the mean values and distribution of serum sodium are much larger than previous studies which were used to set the commonly accepted reference range. Second, among older patients admitted to hospital, serum sodium is lower among those admitted as emergencies but substantially higher among those admitted from care homes, consistent with our previous study 8. Third, we find that mortality among inpatients begins to increase sharply at serum sodium levels >139 mmol/L, which is usually considered within the normal range.…”

“…However, none of the studies have considered the alternative approach of identifying the range beyond which morbidity or mortality increase. Our interest in the ‘normal’ range of serum sodium arose from an earlier study in which we found that a substantial proportion of patients admitted from care homes had high serum sodium on admission and this was associated with a disproportionately high inhospital mortality 8. However, within our data, there was a suggestion that mortality was rising even at levels within the ‘normal’ range.…”

Priorities for the professional development of registered nurses in nursing homes: a Delphi study

“…Recent research has found that patients from care homes (which includes nursing and residential homes) are commonly dehydrated on admission to hospital and are at greater risks of in-hospital mortality as a result [26]. Such reports may explain why training in personal care was the highest ranked priority for professional development.…”

Is the UK government right that seven day working in hospitals would save 6000 lives a year?

“…Factors such as the level of dehydration in patients, not picked up in routine data, can have a huge effect on subsequent mortality. 11 The observation that a change to seven day working in stroke services does not necessarily reduce mortality does not help to resolve the issue. 12 …”